Energy for the 21st Century r.....i COAL 93 4 COAL Coal suffers from an incredibly bad image. It has few advocates other than the hundreds of thousands whose livelihoods depend on mining and burning coal by the trainload for generating electricity. No one strikes it rich in coal; that metaphor is reserved for oil. For some, coal brings back an image of coal miners who go in hock to buy a set of tools when they are young and quit decades later with black lung, still in hock to the company store. That might be one of the better images. Another would be the mangled bodies of miners caught in mine mishaps or those trapped by cave-ins awaiting their fate in pitch blackness. Still another would be youngsters harnessed to sleds dragging coal up narrow underground passageways on their hands and knees like pack animals or straddling precariously above fast-moving conveyor belts of coal, picking out the rocks. For still others the image of coal is as a pollutant of the first order that has to be eliminated under any or all circumstances. Nothing short of unconditional surrender can appease these environmental militants. Yet, at the same time, this biomass fuel from ages past is irreplaceable and absolutely essential to ensure that the lights go on when we flick the switch. World coal consumption, essentially stagnant during the 1990s, surged by 47 percent between 2000 and 2008. Not only is (he world consuming more coal, but its share of the energy pie increased from 23.4 percent in 2000 to 29.2 percent in 2008. Coa! is becoming more important as a primary source of energy, not less as many people desire. Wishful thinking will not make coa! go away, but there are ways to alleviate the worst of its adverse environmental consequences. This chapter reviews the history of coal, its importance in today's economy, and what is being done to overcome its principal drawbacks. THE FIRST ENERGY CRISIS The first energy crisis was associated with living biomass (wood). It was an on-and-off-again crisis that extended over centuries. One of several reasons why the natural growth of forests could not keep up with the axe was glassmaking. Glassmaking has a long history, going back to about 3000-3500 BCE, as a glaze on ceramic objects and nontransparent glass beads. The first true glass vases were made about 1500 BCE in Egypt and Mesopotamia, where the art flourished and spread along the eastern Mediterranean. Glassmaking was a slow, costly process and glass objects were considered as valuable as jewels; Manhattan Island was purchased from the Indians for $24 worth of glass beads, and Cortez was able to exchange glass trinkets for gold! The blowpipe was invented in Syria around 30 BCE. Using a long thin metal tube to blow hollow glass shapes within a mold greatly increased the variety of glass items and considerably lowered their cost. This technique, still in practice today, spread throughout the Roman Empire and made glass available to the common people. Transparent glass was first made around J00 CE in Alexandria, which became a center of glassmaking expertise, along with the German Rhineland city of Köln (Cologne). During the first golden age of glass, glassmaking became quite sophisticated. For example, glassmakers learned to layer transparent glass of different colors and then cut designs in high relief. All these achievements in glassmaking were lost in the 400s with the fail of the Western Roman Empire. The so-called Dark Ages take on new meaning with the disappearance of glassmaking, but vestiges of glassmaking remained in Germany, where craftsmen invented the technique for making glass panes around 1000 CE. These were pieced together and joined by lead strips to create transparent or stained glass windows for palaces and churches. The second golden age of glass started in the 1200s when the Crusaders reimported glassmaking technology from the eastern Mediterranean. Centered in the Venetian island of Murano, glassblowers created Cristailo glass, which was nearly colorless, transparent, and blown to extreme thinness in nearly any shape. In the 1400s and 1500s, glassmaking spread to Germany and Bohemia (Czech Republic) and then to England, with each country producing variations in type and design of glass objects. The ubiquitous glass mirror was invented comparatively late, in 1688 in France.' Glass is made from melting a mixture of mostly sand (silicon dioxide) plus limestone (calcium carbonate) and soda ash (sodium carbonate) in a furnace, along with glass waste, at a temperature of around 2,600-2,900°F. Considering what has to be heated to such high temperatures, clearly glassmaking was an energy-intensive process that consumed a lot of wood. As forests were cleared, glassmaking furnaces were moved to keep close to the source of energy rather than moving the source of energy to the furnaces. The first energy crisis began when English manors for the rich and famous were built with wide expanses of glass panes that opened up their interiors to sunlight. Not only did this put a strain on wood resources for making the glass, but also on heating since interior heat passes more easily through a glass pane than a stone wall covered by a heavy wool tapestry. The growing popularity of glass was not the only villain responsible for deforestation. Part of the blame lies with the increased demand for charcoal used in smelting iron, lead, tin, and copper. Consumption of these metals increased from a growing population, greater economic activity, and an improving standard of living as humanity emerged from the deep sleep of the Dark Ages. Deforestation started around London in 1200 and spread throughout the kingdom. By the 1500s metal ores had to be shipped to Ireland, Scotland, and Wales for smelting, deforesting these regions in turn. One of the economic drivers for the founding of the Jamestown colony in Virginia in 1607 was to take advantage of the New World's ready supply of trees to make glass for export to England. The rapidly escalating price of firewood, the economic consequence of deforestation, provided the necessary incentive to search for an alternative source of energy. The final answer to the energy crisis was not deforesting the living biomass of the New World, but burning the long-dead biomass of the Old World. THE ORIGIN AND HISTORY OF COAL Switching from wood to coal had an environmental consequence. Living plants absorb carbon dioxide from the air, which is released when they decay. For sustainable biomass energy, carbon dioxide is simply recycled between living and dead plant matter and its content in the atmosphere remains unchanged. One way to decrease the amount of carbon dioxide in the atmosphere is to increase the biomass, such as planting trees on treeless land (afforestation), but this is neutralized when living and dead plant matter are once again in balance. The other way is to interrupt the decay process. And this is what happened eons ago when huge quantities of dead plants were 92 94 ENERGY FOR THE 21 ST CENTU RY COAL 95 quickly submerged in oxygen-starved waters. This delayed onslaught of decay interrupted the natural carbon dioxide cycle. The partially decayed plants submerged in swamps first became peat. Peat has a high moisture content that is squeezed out if buried by silt of sand, clay, and other minerals from flowing water. Continued burying, either by the land submerging or the ocean rising, added sufficient weight to transform the original deposits of sand and clay to sedimentary rocks and peat to coal. Three to seven feet of compacted plant matter is required to form one foot of coal. Some coal veins are 100 feet thick, which gives one pause to consider how much plant life is incorporated in coal. Most coal was formed 300-400 million years ago during the Devonian and Carboniferous geologic epochs when swamps covered much of the earth and plant life thrived in a higher atmospheric concentration of carbon dioxide. The interruption of plant decay by the formation of massive peat bogs removed huge amounts of carbon dioxide from the atmosphere, clearing the way for a more hospitable environment for animal life. However, some coal is of more recent vintage, laid down 15-100 million years ago, and the newest coal has an estimated age of only 1 million years. When coal is burned we are completing a recycling process interrupted eons ago, or much more recently for those who believe that coal stems from Noah's Flood. Peat bogs are found in Ireland, England, the Netherlands, Germany, Sweden, Finland, Poland, Russia, Indonesia, and in the United States (the Great Dismal Swamp in North Carolina and Virginia, the Okefenokee Swamp in Georgia, and the Florida Everglades). The high water content has to be removed before peat can be burned as a biomass fuel whose heat content is much lower than coal. Peat is burned in Ireland for heating homes and in Finland for heating homes and generating electricity as a substitute, along with wood waste, for imported fossil fuels. Peat is also mixed with soil to improve its water-holding properties and is a filter material for sewage plants. Once removed, fish can be raised in the resulting pond or, if the peat bog is drained, agricultural crops can be grown, or the peat bog can simply remain fallow. There is always the possibility that these peat bogs may one day become coal beds if buried by hundreds of feet of silt and water. As in many other areas, the Chinese beat out the Europeans in burning coal. Coal from the Fu-shun mine in northeastern China was consumed for smelting copper and casting coins around 1000 BCE. In 300 BCE the Greek philosopher Theophrastus described how blacksmiths burned a black substance that was quite different from charcoal. From evidence in the form of coal cinders found in archaeological excavations, it is known that Roman forces in England burned coal as a fuel before 400 CE. Although the Romans did not record burning coal, they did record a "pitch-black mineral" that could be carved into trinkets for adorning the human body. That pitch-black mineral was an especially dense type of coal. Like glassmaking, burning coal for heat and blaeksmithing and offerings to the gods, plus carving into trinkets for the fashionable of Rome, disappeared along with the Roman Empire. We presume that ever-expanding human knowledge being passed on to following generations has always been ongoing, is ongoing, and will always be ongoing. This, as history clearly shows, is an unwarranted presumption. The English rediscovered coal in the 1200s during an early episode of deforestation around London, about the same time that the Hopi and Pueblo Indians began burning coal to glaze their ceramic ware in what is now the U.S. Southwest. After the coal gatherers picked up the coal lying on the ground on the banks of the River Tyne near Newcastle, they began chipping away at the exposed seams of coal in the nearby hillsides. Coal mining started when holes became tunnels that bored deep into the thick underground seams of coal. A new profession and a new class of people emerged, ostracized by the rest of society by their origin (displaced peasants) and the widely perceived degrading nature of their work. Coal miners as individuals were at the mercy of the mine owners until they learned to band together for their mutual benefit and protection, giving birth to the modern labor movement. And there was plenty of incentive for miners to band together as the coal miners bored deeper into the earth. Mining is a very dangerous occupation. Cave-ins can trap the miners. If not immediately snuffed out by the falling rock, they remain trapped, awaiting rescue or dying from asphyxiation or starvation. To combat the peril of cave-ins, miners bonded with huge rats that lived in coal mines by sharing their meals with them. Miners remained alert to the comings and goings of the rats on the theory that rats could sense a cave-in before it occurred, not unlike rats deserting a sinking ship. Perhaps miners' casualty lists best document the perspicacity of rats to sense impending disaster. fn addition to cave-ins, coal miners had to contend with poisonous gases. Mining could release pockets of carbon dioxide or carbon monoxide, odorless and colorless gases of plant decay trapped within the coal seam that quickly killed their victims by asphyxiation. Canaries were the best defense since their chirping meant that they were alive. When they stopped chirping, they were already dead, a dubious warning system at best. A third colorless and odorless gas was methane, also released by mining operations when they exposed pockets of natural gas embedded in the coal seam. Unlike carbon dioxide and monoxide, methane is lighter than air and combustible. As methane accumulates along the ceiling of a mine, it eventually comes in contact with a lighted candle where it either burns or sets off a horrific explosion, depending on its concentration. A new professional, called, euphemistically, a fireman, would wrap his wretched body with wet rags and crawl along the bottom of the mine holding up a stick with a candle at the end, hoping he would discover methane before it was sufficiently concentrated to set off an explosion. Now all he had to do was hug the mine floor while the methane blazed above him. Coal found in the hills around the RiverTyne was moved down to the river and loaded on vessels for shipment to other parts of coastline England, notably London. Access to water provided cheap transportation on ships whereas the overland movement of coal on packhorses was prohibitively expensive. Roads hardly existed and, where they did, deep ruts made them impassable for heavily laden horse-drawn wagons. By 1325, coal became the first internationally traded energy commodity when exported from Newcastle to France and then elsewhere in northern Europe. Thus, coal saved not only the English but also the European forests from devastation. The saying "carrying coals to Newcastle" originally referred to something only a simpleton would do since Newcastle was the world's hist and largest and most famous coal-exporting port. Six and a half centuries later, coal was carried to Newcastle when Britain began importing coal. Burning coal made an immediate impression on the people. In 1306, the nobles of England left their country estates to travel to London to serve in Parliament, as was their custom. This time there was something new in the air besides the stench of animal dung, raw sewage, and rotting garbage. The nobles did not like the new pungent aroma spiced with brimstone (sulfur) and succeeded in inducing King Edward I to issue a ban on burning coal. It is one thing for a king to issue a ban, and quite another to enforce it, the classic limit of power faced by parents of teenagers. Regardless of the king's edict, the merchant class of newly emerging metallurgical enterprises had to burn coal because wood was not available in sufficient quantities around London, and what was available was too expensive. Simple economics overruled the king's ban. The fouling of the air of London and other English cities remained for centuries to come. It is hard to imagine that the charming English countryside we know, speckled with quaint towns, cottages, and farms was once, like the eastern United States, nearly one continuous forest. From the beginning, coal was a matter of dispute between the church, which happened to own the land where the coa! was found, the crown, which coveted this natural resource, and the 96 ENERGY FOR THE 21 ST CENTURY merchant class that Iransformed coal into a considerable amount of persona! wealth. As church, crown, and capital struggled over who would reap the financial benefits, merchant vessels were built to ship coal on the high seas. This, in turn, necessitated building naval vessels to protect (he merchant fleet from marauders and pirates. The English also imposed a tax on non-English vessels carrying coal exports, which greatly favored the building and manning of English ships. In this way, coal contributed to making England a sea power and is, therefore, partly responsible for the emergence of England as the world's greatest colonial power. Growth of sea power put more pressure on forests for lumber to build ships and, in particular, trees fit for masts, which eventually would be harvested in English colonies in the New World. The Black Death did not enhance coal's reputation as its victims turned black while smelling brimstone in the air from burning coal, widely interpreted as to where they might be heading. The Black Death wiped out about one-third of Europeans. The depopulation of London meant less coal had to be burned, improving the quality of its air, and forests regained a toehold in the countryside. The reign of Elizabeth I was marked by increases in population and economic recovery after the Black Death, spurring demand for firewood. She greatly expanded the English Navy to defend the kingdom against the Spanish Armada, increasing the demand for lumber and masts to build warships and charcoal for smelting iron for ship armament. This again put pressure on the kingdom's forests, resulting in widespread deforestation throughout England and another steep rise in the price of firewood. The adoption of the chimney in London homes in the 1500s allowed for the conversion from wood to coal for heating in the early 1600s, a conversion already completed by industry. While the ability of chimneys to keep the heat inside and channel smoke outside was an advantage for those who dwelt inside, the same could not be said for those who ventured outside. Appalling amounts of acrid smoke eroded and blackened stone in statues and buildings, stunted plant life, affected the health of the population, and made black and dark brown the colors of choice for furnishings and fashion. London was not the only city that suffered from severe air pollution. During the rapid advance of the Industrial Revolution in the nineteenth century, Manchester became the center of British textile manufacturing and Pittsburgh the center of American steclmaking. The former suffered mightily from coal burned in steam engines to run the textile machines and the latter from coal consumed in making steel. Not all cities suffered equally. Philadelphia and New York were spared at first because of rich anthracite coalfields in eastern Pennsylvania. Anthracite, a hard coal of nearly pure carbon, burns with little smoke. Unfortunately, anthracite reserves were in short supply when coal-burning electricity-generating plants were built at the end of the nineteenth and early twentieth centuries. These plants burned cheaper and more available bituminous coal. New Yorkers staged an early environmental protest against the fouled air that the utility managers could not ignore, so they switched to anthracite coal to appease people while they were awake, but switched back to bituminous while they slept. We tend to think of air pollution caused by burning coal as a nineteenth-century phenomenon affecting London, Manchester, and Pittsburgh. Yet, only a little over a halt-century ago, for four days in early December 1952, a temperature inversion settled over London, trapping a natural white fog so dense that traffic slowed to a crawl and the opera had to be cancelled when the performers could no longer see the conductor. Then coal smoke, also trapped in the temperature inversion, mixed with the fog to produce an unnatural black fog that hugged the ground and cut visibility to less than a foot. Perhaps unbelievably from our vantage point, 4,000 Londoners died from traffic accidents and inhaling sulfur dioxide fumes. Parliament subsequently banned the burning of soft coal in central London, bringing to an end a quaint 700-year-long tradition. In the twenty-first COAL 97 century, Beijing, Shanghai, and other cities in Asia have picked up where London left off. While the results of living in a cloud of polluted air are not as calamitous as in London, nevertheless dwellers in Asian cities suffer from various health impairments.2 Coal and the Industrial Revolution Coal played an important role in England's emergence as the world's greatest seafaring nation and, subsequently, as the world's leading trading nation and colonial power. It also played an important, if not a pivotal, role in bringing about the Industrial Revolution and England's subsequent emergence as the world's greatest industrial power. At first coal mines were above the River Tyne and narrow downward shafts dug from the mines to the outside world took care of removing water seepage from rain. As the coal seams bent downward, it was only a matter of time before mining took place under the River Tyne and the North Sea. This opened up a whole new peril for the miners: death by drowning. Even if mining did not breach the river or the sea, water was continually seeping in through the ground, threatening to flood the mines, though not necessarily the miners. For many years the chief way to prevent flooding was to have men haul up buckets of water to the mine surface. As mines went deeper into the earth, a vertical shaft was dug where a continuous chain loop with attached buckets brought water from the bottom of the mine to the surface. Water wheels and windmills powered a few of these continuous chain operations, but most were powered by horses. The capital cost in chain loops, along with their attached buckets and the operating cost of feeding and tending to the horses, encouraged the development of bigger mines employing larger numbers of miners in order to produce the greater quantities of coal needed to cover the higher capital and operating costs. Concentrating coal mining in a smaller number of larger operations meant even deeper mines, perversely exacerbating the problem of water removal. By the 1690s, Britain's principal industry of providing 80 percent of the world's coal was threatened with a watery extinction. The nation's intellectual resources were focused on solving what seemed to be an overwhelming challenge: how to prevent water from flooding the ever-deeper mines. Denis Papin proposed the idea of having a piston inside a cylinder where water at the bottom of the cylinder would be heated to generate steam under the piston that would drive the piston up. Then the heat would be removed, creating a pressure differential between the top and bottom of the piston as the steam condensed to form a vacuum. Atmospheric pressure on top of the piston would drive the piston down and then the water in the bottom of the cylinder would be reheated to generate steam to drive the piston back up. The up-and-down motion of the piston could power a water pump. Thomas Newcomen, who may or may not have heard of Papin's idea, worked, ten years to develop a working engine that did just that. The Newcomen engine was a piston within a cylinder. Steam from burning coal was fed into the cylinder space below the piston, forcing it up. Then a cold-water spray entered the cylinder space and condensed the steam to create a vacuum and a pressure differential between the top and the bottom of the cylinder. Atmospheric pressure on top of the piston would drive the piston down. Simultaneously, an exhaust gate would open, allowing the water from the spray and condensed steam to drain from the cylinder space. Then the exhaust gate would close and steam would reenter the cylinder space. This continual cycle of feeding steam followed by a spray of water into the bottom of the cylinder kept the piston moving up and down. A crossbeam connected the moving piston to a water pump. Mines could now be emptied of water without horses and chain loops with attached buckets, which by this time had reached their limits of effectiveness. By 1725 Newcomen engines were everywhere and had grown to prodigious size, but the alternate heating and cool- 98 ENERGY FOR THE 21ST CENTURY COAL 99 ing of the, lower cylinder waifs during each cycle of the piston movement made them extremely energy-inefficient. With coal cheap and plentiful, the Newcomen engine had no technological rival for sixty years. As energy-inefficient as Newcomen engines were, they nevertheless saved the English coal mining industry from a watery grave and enabled England to maintain its preeminence in coal mining for another century. Thus, coal or, to be more exact, the threat of coal mines filling with water, brought into existence the first industrial fossil-fueled machine that delivered much more power with far greater dependability than wind or water. The fickleness of the wind makes wind power vulnerable and water power is constrained by the capacity of a water wheel to translate falling or moving water into useful power and by the occurrence of droughts. The Newcomen engine had no such limitations. The building of Newcomen engines required iron and smelting iron consumed charcoal, anT other contributor to the deforestation of England. The pressure on forests was lifted in 1709 when Abraham Darby, who also advanced the technology of casting pistons and cylinders for Newcomen engines, discovered that coke from coal could substitute for charcoal from wood in smelting iron, ft is a bit ironic that coke itself had been discovered some sixty years earlier, in 1642, for brewing beer. London brewers needed a great deal of wood to dry malt. As wood supplies dwindled, they first experimented with coal, but quickly found out that sulfur in coal tainted the malt and, thus, the flavor of the beer. The brewers discovered coke by copying the process of making charcoal from wood, which is essentially baking coal in the absence of oxygen to drive out volatile elements and impurities. Coke is harder than coal, almost pure carbon, and burns at a high temperature without smoke. Malt dried with coke produced a pure, sweet beer. In 1757 James Watt, an instrument maker for the University of Glasgow, was given an assignment to repair the University's model of the Newcomen engine, which spurred his lifelong interest in steam engines. Watt soon realized that the shortcoming of the Newcomen engine was the energy consumed in reheating the cylinder wall after each injection of cold-water spray. His idea was not to cool the steam in the hot cylinder, but to redirect the steam to another cylinder, or condenser, surrounded by water, where the steam could be condensed without cooling the cylinder wall. Rather than a valve opening to allow a cold spray to condense the steam, a valve opened to allow the expended steam to escape from the cylinder to the condenser. The condensed steam created a vacuum in the bottom of the cylinder, which allowed atmospheric pressure on top of the cylinder to push the piston down. In this way the power cylinder wall would remain hot throughout the operation of the engine, improving its thermal efficiency. James Watt was assisted by the moral and financial support of Matthew Boulton, a well-known Birmingham manufacturer. After obtaining a patent, the first two steam engines were built in 1776. One pumped water from a coal mine and the other drove air bellows at an iron foundry. The foundry owner, John Wilkenson, invented a new type of lathe to bore cylinders with greater precision, a device that would prove useful for manufacturing steam engines. The final version of the Watt engine came in 1782, when Watt developed the double-acting engine where steam powered the piston in both directions. Steam entering one end of the cylinder drove the piston in one direction, while a valve opening on the other end of the cylinder allowed the spent steam from the previous stroke to exhaust into a condenser. This operation was reversed to drive the piston in the opposite direction. Valves for allowing live steam to enter the cylinder space or spent steam to enter the condenser were opened and shut by the movement of the piston. To further enhance energy efficiency, steam was admitted inside the cylinder only during the first part of the piston stroke, allowing the expansion of the steam to complete the stroke. To further cut heat losses a warm steam jacket surrounded the cylinder and a governor controlled the engine speed. With these enhancements, the Watt steam engine could operate with one-quarter to one-third the energy necessary to operate an equivalent Newcomen engine. Both the Newcomen and Watt engines spurred technological advances in metallurgy to improve metal performance and in manufacturing technology to make cylinders and pistons, lessons not lost on the military for building bigger and better cannons. Watt's intention was to improve the energy efficiency of the Newcomen engine for pumping water out of mines. Boulton saw Watt's invention as something greater than a more efficient Newcomen engine or a more reliable means of powering his factories than water wheels. Boulton was a visionary who saw the steam engine as a means to harness power for the good of humanity. In Boulton's vision, steam engines would not only drain mines of water but power factories that could be built at any location where coal was nearby. Goods made by machines powered by steam engines would free humans from the curse of drudgery and poverty that had plagued them throughout history. The world's first industrialized urban center was Manchester, England. The city became the textile center of the world, processing cotton from slave plantations in the United States. Coal was consumed in making iron that went into constructing factory buildings, steam engines, and textile-making machines. Coal also fueled the steam engines that powered the machines and gas given off by heating coal was piped into the factory buildings and burned in lamps to allow round-the-clock operations. All this coal burning smothered Manchester in a thick black blanket of smoke that rivaled pollution in London and, later, Pittsburgh. The demand for coal from mines near Manchester was so great that narrow shaft seams, which only children could fit into, were brought into use. They had to crawl on their feet and hands dragging heavy sleds of coal behind them like pack animals. Many of these children lived like animals in abandoned portions of mine shafts, separated from their families and daylight. For workers in the Manchester factories, the long hours, the harsh working conditions, the poor pay, the putrid stench of the atmosphere, their appallingly poor health and high death rates, and the breakdown of the family had to be an Orwellian nightmare at its worst, not Boulton's vision at its best. What Freidrich Engels saw in Manchester was recorded in his work The Condition of the Working Class in England (1844), which in turn helped Karl Marx shape The Communist Manifesto (1848). Coal and Railroads The amount of coal a horse can carry on its back is limited, but its carrying capacity can be improved by having it pull a wagon. The dirt roads of the day, with their deep muddy ruts, were impassable for horses hauling heavy wagonloads of coal. A horse's capacity to move cargo jumps by several orders of magnitude when, instead, it pulls a barge on still water. Canals, not roads, could move large volumes of coal to inland destinations. One of the first canals in Britain moved coal to Manchester from nearby coalfields where horses pulled barges from towpaths alongside the canal. This began the canal-building boom in England where, by the early 1800s, canals were used not only to move coal, but all sorts of raw materials and finished goods to and from cities. Since the nature of the terrain and the availability of water restricted canal construction, wagon ways, where horses were harnessed to cargo-laden carriages riding on wooden rails, complemented canals. Rails made horses more effective in moving coal than pulling loaded wagons on muddy, rutted, dirt roads. Rails also improved coal-mine productivity. It turned out that getting coal out of the mine was as labor-intensive as mining coal. Often human pack animals were responsible for hauling coal on its journey to the mine surface. One human pack animal would pick up a small wagonload from another human pack animal, tow it a bit, and pass it on to still another human pack animal, 100 ENERGY FOR THE 21 ST CENTURY COAL 101 then walk back to get the next. Lifetimes were spent hauling coal out of mines and, sometimes, living in mines. Mine operators did what they could to make hauling coal easier, but not strictly for altruistic reasons. Installing rails reduced operating costs by having the same work done by fewer human pack animals, thus improving productivity and, incidentally, profitability. Most rails were made of wood, but a few were made of iron. Because the use of rails had solved the problem of how to move heavy loads, the concept of the railroad was in place when George Stephenson, the father of railways, put together the elements of iron track with a high-pressure Watt's steam engine on a locomotive platform with flanged iron wheels that pulled flanged iron wheeled carriages. Fittingly, the world's first railroad connected a coal town with a river port twenty-six miles away. The Age of the Railroad began in earnest a few years later, in 1830, when a train on its inaugural run between Liverpool and Manchester hit a top speed of an unbelievable thirty-five miles per hour. By 1845 Britain had 2,200 miles of track, a figure that tripled over the next seven years. While the building of railroads meant relatively cheap and fast transportation between any two points in England, the iron for the rails was not cheap. Coal and Steel The Iron Age began sometime around 2000 BCE, perhaps in the Caucasus region, where iron first replaced bronze. Iron is harder, more durable, and holds a sharper edge longer than bronze. Tron is also the fourth most abundant element, making up 5 percent of the earth's crust. Iron ore is made up of iron oxides plus varying amounts of silicon, sulfur, manganese, and phosphorus. From its start, smelting iron consisted of heating iron ore mixed with charcoal until the iron oxides began reacting with the carbon in the charcoal to release its oxygen content as carbon monoxide or dioxide. Adding crushed seashells or limestone, called flux, removed impurities in the form of slag, which was separated from the heavier molten iron. This left relatively pure iron, intermixed with bits of charcoal and slag that could then be hammered on an anvil by a blacksmith to remove the remaining cinders, slag, and other impurities. The result of the hammering produced wrought (or "worked") iron with a carbon content between 0.02-0.08 percent. This small amount of carbon, absorbed from the charcoal, made the metal both tough and malleable. Wrought iron was the most commonly produced metal throughout the Iron Age. By the late Middle Ages, European iron makers had developed the blast furnace, a tall chimneylike structure in which combustion was intensified by a blast of air pumped through alternating layers of charcoal, flux, and iron ore. The medieval ironworkers harnessed water wheels to power bellows to force air through the blast furnaces. Centuries later, this would be one of the first tasks for James Walt's steam engines, in addition to pumping water out of coal mines. The blast of air increased the temperature, which allowed the iron to begin absorbing carbon, thereby lowering its melting point. The product of this high-temperature process was cast iron, with between 3-4.5 percent carbon. Cast iron is hard and brittle, liable to shatter under a heavy blow, and cannot be forged (that is, heated and shaped by hammer blows). The molten cast iron was fed through a system of sand troughs, formed into ingots, which reminded people of a sow suckling a litter of piglets, and became known as pig iron. Pig iron was either cast immediately or allowed to cool and shipped to a foundry as ingots, where it was remeited and poured directly into molds to cast stoves, pots, pans, cannons, cannonballs, and church bells. These early blast furnaces produced cast iron with great efficiency and less cost than wrought iron. However, the process of transforming cast iron to more useful wrought iron by oxidizing excess carbon out of the pig iron was inefficient and costly. More importantly, what was desired was not wrought iron from cast iron, but steel. Steel is iron with carbon content between 0.2-1.5 percent, higher than wrought iron but lower than cast iron. Crucible steel, named after its manufacturing process, was not only very expensive, but the extent of the oxidation of carbon, and therefore the carbon content, could not be controlled. Regardless of its cost, steel was preferred over wrought iron because it was harder and kept a sharp edge longer (the best swords were made of steel) and was preferred over cast iron because it was more malleable and resistant to shock. Early rails made from wrought iron were soft and had to be replaced every six to eight weeks along busy stretches of track. Steel, in contrast, is perfect for rails because it is harder than wrought iron and more malleable than cast iron. Steel rails, however, were prohibitively expensive. The man of the hour was Henry Bessemer, who was not responding to the needs of the railroad industry, but the military. Bessemer had invented a new artillery shell that had been used in the Crimean War (1853-1856). The army generals complained that the cast iron cannons of the day could not handle Bessemer's more powerful artillery shell. In response Bessemer developed an improved iron-smelting process that involved blasting compressed air through molten pig iron to allow the oxygen in the air to unite with the excess carbon and form carbon dioxide. Ironically, Bessemer's invention, patented in 1855, was similar to the method of refining steel used by the Chinese in the second century BCE. In 1856 the first Bessemer converter, large and pear-shaped with holes at the bottom for injecting compressed air, was completed. Other individuals contributed to improving the Bessemer converter by adding manganese to get rid of excess oxygen left in the metal by the compressed air and limestone to get rid of any phosphorus in the iron ore, which made steel excessively brittle. Limestone becomes slag after absorbing phosphorus and other impurities and floats at the top of the converter where it is skimmed off before the steel is poured out. Bessemer converters were batch operations to which iron ore, coke, and limestone were added; within a short period of time, molten steel was on the bottom and slag was floating on the top. After removing the slag, the converter was then emptied of its molten steel and then reloaded to make another batch. The economies of large-scale production utilizing the B essemer converter transformed undesired wrought-iron rail at $83 per ton in 1867 to desired steel rail at $32 per ton by 1884. It was not long before the Bessemer process had a technological rival: the open-hearth furnace. The open-hearth furnace, while it took longer, could make larger quantities of steel because raw materials were continuously added and slag and steel continually removed. Moreover, steel could be made with more precise technical specifications and scrap steel could be consumed as feedstock along with iron ore, coal, and limestone. Improvements in the chemical composition of steel had increased the life of steel rails and their weight-carrying capacity several fold by 1900, when the open-hearth furnace had largely replaced the Bessemer converter. Another man of the hour, Andrew Carnegie, organizationally shaped the steel industry and, in so doing, reduced the price of steel rail to $14 per ton by the end on the nineteenth century. Carnegie also introduced the I-shaped steel girder for building skyscrapers, a major addition to steel demand once the Otis elevator was perfected. By 1960, the basic oxygen furnace had, in its turn, replaced the open-hearth furnace. The basic oxygen furnace is essentially a modification of the original Bessemer converter. The first step is feeding iron ore, coke, and limestone into a furnace with air blasted through the mixture to produce molten iron, which is periodically tapped from the bottom of the furnace while the molten slag is periodically removed from the top. The molten iron then goes into the basic oxygen furnace where steel scrap and more limestone are added, along with a blast of oxygen to produce almost pure liquid steel. In making steel, coking coal supplies carbon to remove the oxygen in the iron ore and heat to melt the iron. Coking, or metallurgical coal, must support the weight of the heavy contents in a furnace yet be sufficiently permeable for gases to rise to the top and molten steel to sink to the 102 ENERGY FOR THE 21ST CENTURY COAL 103 bottom of the furnace. Thus, coals are divided into two types: thermal coal fit only for burning and coking coal fit for steeimaking. The liquid and gaseous byproducts in producing coke from metallurgical or coking coal find their way into a host of products such as synthetic rubber, ink, perfume, food and wood preservatives, plastics, varnish, stains, paints, and tars.3 The world's largest steel producers are China (501 million tons, over triple its 2001 production, Japan (119 million tons), the United States (91 million tons), Russia (69 million tons), India (55 million tons), South Korea (54 million tons), Germany (46 million tons), Ukraine (37mi!lion tons), Brazil (34 million tons), and Italy (31 million tons). The basic oxygen furnace produces 66 percent of the world's crude steel production—about 1,327 million tons in 2008—incidentally consuming 600 million tons of coal. Most of the remaining steel production is made from a more recent innovation, the electric arc furnace.4 The raw material for electric arc furnaces is scrap. Incidentally, steel is the most recycled commodity on Earth: fourteen million cars in the United States alone are recycled annually. Whereas 1 ton of steel made from raw materials requires, in round terms, 2 tons of iron ore, 1 ton of coal, and a half ton of limestone; 1 ton of recycled steel needs a bit more than 1 ton of scrap. While coal is absent as a raw material in making steel with the electric arc furnace, an electric arc furnace uses a lot of electricity, as one can imagine, which is mainly generated by burning coal augmented by capturing the waste heat of steeimaking. Thus, coal is consumed directly in making steel with the basic oxygen furnace and indirectly in making steel with the electric arc furnace. Coal played a vital role in shaping the world as we know it today. Coal was needed as a substitute for wood for producing glass and smelting metals after the forests were cut down. Coal became a major export item for England, spurring the development of the English navy. The challenge posed by flooding coal mines frantically called for a solution—the Newcomen engine—the first industrial power-generating machine not dependent on wind or water. The Newcomen engine spurred further advances in metal and toolmaking and led directly to Watt's steam engine. Watt's steam engine powered the Industrial Revolution with coal, steel, and railroads. Coal, then, is at least partly responsible for England becoming a world sea power, a colonial power, and, after the birth of the Industrial Revolution, the world's first and mightiest industrial power. This lasted for over half a century before being challenged by the emergence of rival centers of industrial power in the United States, Germany, and Japan. Rise and Fall of King Coal Though early steam locomotives were fueled by wood, it was not long before they switched to coal. One reason was deforestation; the other was the availability of coal as the most commonly carried commodity. Coal became the sole source of energy for fueling locomotives, which for decades before the automobile age was the sole source of transportation on land other than horses. Robert Fulton invented the first steam-driven riverboat, the Clermont, which propelled itself from New York to Albany in 1807. While wood could be burned on riverboats, ocean-going vessels burned coal, a more concentrated form of energy that took up a lot less volume. The famed clipper ships of the waning decades of the nineteenth century marked the final transition from a source of power that was undependable, renewable, and pollution- and cost-free to one that was dependable, nonrenewable, polluting, and not cost-free. Now coal had it all on land and sea. Thomas Edison's first electricity-generating plants were fueled by coal, although hydropower was soon harnessed at Niagara Falls. Coat and hydropower were the principal sources of energy for generating electricity during the first half of the twentieth century. Coal's share of the energy pie peaked at 60 percent in 1910. Oil, natural gas, and hydropower contributed another 10 percent, and biomass 30 percent. After 1910, things began to change for King Coal. Coal maintained its pre-eminence in passenger transportation until Henry Ford put America, and the world, on gasoline-driven wheels. In 1912, the Titanic had 162 coal-fired furnaces fed continuously by 160 stokers working shifts 24/7 shoveling as much as 600 tons of coal per day. This might work well for passenger vessels, but coal-burning warships were constrained in fulfilling their primary mission by the large portion of the crew dedicated to shoveling coal, rather than manning guns, and the amount of space dedicated to holding coal rather than carrying ammunition. Moreover, warships with a heavy cargo of coal moved slowly and their pillars of smoke signaled the enemy as to their whereabouts. Admiral Sir John Fisher, head of the British Navy, spearheaded the transformation from marine boilers powered by coal to oil in the years prior to the First World War. Naysayers scoffed at the idea, but as soon as the obvious advantages of oil over coal were demonstrated in higher speed, greater firepower, and less emissions to betray a vessel's presence, it became a race to dump coal in favor of oil. As ships made the transition from coal to oil, the worldwide network of coal-bunkering stations supplied by coal colliers was converted in tandem to handle oil supplied by tankers (ship's fuel is still referred to as bunkers). Coal and wood remained the chief sources of energy for cooking until the advent of the electric stove in the 1920s, along with stoves that burned natural gas and liquid propane. About this time, homes began a slow conversion from coal to heating oil and natural gas. Automobiles were taking passengers away from electric trolleys, whose electricity was generated from coal, for inner-city transportation. Intercity railroad passenger train traffic, powered by coal-fueled locomotives, declined as a network of roads sprang into existence. When the fall of King Coal from pre-eminence sped up during and after the Second World War, one individual stood out: John L. Lewis, a former coal miner and president of the United Mine Workers. A contentious personality who had the audacity to defy President Franklin Delano Roosevelt by leading a coal miners' strike during the war, Lewis was instrumental in raising the pay and improving the health and retirement benefits and working conditions for coal miners. As laudable as these well-deserved benefits were, they also increased the price of coal and, in so doing, hastened its demise. Perhaps no better proof of this was Perez Alfonso, a Venezuelan oil minister, who wanted to erect a statue to honor Lewis for boosting the market for Venezuelan oil exports. The rise in the price of coal from John L. Lewis's success was an added inducement for homeowners to switch from coal, which had to be shoveled into a furnace (from which ashes had to be removed and disposed of) to the much greater convenience of heating oil, propane, and natural gas, which did not require the effort associated with coal. In cooking, the switch was already far advanced from coal to electricity and natural gas and propane.5 While oil-driven automobiles, buses, and airplanes were diverting people from coal-burning passenger trains, and trucks had taken over local distribution of freight, railroad freight trains still carried the bulk of the nation's intercity freight. Trucks were unable to cut deeply into intercity freight traffic because the road network was relatively undeveloped and better fit for automobiles than trucks. All this changed with the launching of the interstate highway system by President Dwight D. Eisenhower. A large steam locomotive pulling a loaded freight train burned 1 ton of coal per mile, which required a fulltime fireman to continually shovel coal. Railroads were enormous consumers of coal and railroad executives displayed equally enormous reluctance to abandon steam locomotives when the diesel engine first appeared in the late 1930s. Steam locomotives had become an intimate part of railroading folklore. Distinct in design and operating nuances, they had to be maintained by a dedicated crew that became inseparable from the locomotive, which required a lot of downtime for maintenance and repair. Railroaders were unwilling to switch from steam to diesel, even though diesel locomotives had 104 ENERGY FOR THE 21 ST CENTURY COAL 105 inherent advantages. Diesel engines were fuei-efficient because they burned gallons of diesel fuel per mile, not a ton of coal per mile. The diesel engine avoided the inherent energy inefficiency of a steam engine from which the latent heat of vaporization was passed to the atmosphere. In a diesel engine, fuel sprayed into the cylinder space above a piston is ignited by heated compressed air. The expansion of the gases of combustion powers the first downward stroke. After the power stroke, the piston is forced up to expel the exhaust gases, then down to draw in fresh air, then up to compress the air. The heated compressed air ignites another spray of fuel whose expanding gases of combustion powers another downward stroke. Thus, every other downward stroke is a power stroke that, through a crankshaft connected to the other pistons, drives an electricity generator that powers electric motors attached to the engine wheels. Diesel engines have other advantages as well. They are more reliable because they require less maintenance and repair, both in downtime and cost; less manpower, because no coal has to be shoveled; and less frequent refueling. Steam locomotives of various horsepower have to be built to handle freight trains of different sizes, whereas a number of standard-sized diesel engines can be hooked together to obtain the requisite horsepower. Tn short, the only reason to keep steam locomotives once diesel engines made their appearance was management's reluctance to change. The advantages of the diesel engine couid no longer be ignored when John L. Lewis's success in improving the lot of coal miners increased the price of coal. The first diese! engines were restricted to moving freight cars around freight yards and were excluded from long intercity runs, the exclusive domain of the steam locomotive. Steam locomotives could persevere as long as all railroad managers agreed to use steam locomotives on intercity freight trains, ensuring equal inefficiency in operations for all. But this holding action couid not ignore the competitive threat of a growing volume of trucks gaining access to intercity traffic made possible by the interstate highway system, ff any railroad bolted to diesel for hauling intercity freight, then the inherent efficiencies and advantages of diesel locomotion would give that railroad a competitive edge over the others. And that is what happened: one railroad bolted. As soon as one made the switch to diese! for intercity freight trains, it was a race to convert locomotives from coal to oil similar to the race to convert ships from coal to oil. Despite efforts by steam locomotive aficionados and railroad executives to hold the fort, the steam whistle and the chugging locomotive spewing steam, smoke, and at times blazing ashes disappeared within a decade. Adding to King Coal's woes, electricity-generating plants built after the Second World War were designed to run on oil, natural gas, and nuclear power in addition to coal and hydro. King Coal was no longer king in transportation, electricity generation, heating houses and commercial buildings, and home cooking. By 1965, its share of the energy pie was down to a still respectable 39 percent and declined to 30 percent in 1970 and remained around 25-29 percent until recent years when its share expanded to 30 percent. TYPES OF COAL Aside from peat, a precursor to coal, there are four types of coal. The lowest quality of coal and the largest portion of the world's coal reserves is lignite, a geologically young, soft, brownish-black coal, some of which retains the texture of the original wood. Of all coals, it has the lowest carbon content, 25-35 percent, and the lowest heat content, 4,000-8,300 British thermal units (Btus) per pound. The next step up is sub-bituminous coal, a dull black coal with a carbon content of 35^f5 percent and heat content 8,300-13,000 Btus per pound. Both lignite and sub-bituminous coals, known as soft coals, are primarily thermal coals for generating electricity. Some sub-bituminous coals have lower sulfur content than bituminous coal, an environmental advantage. Next are the hard coals, bituminous and anthracite. Bituminous is superior to soft coal in terms of carbon content, 45-86 percent, and energy content, 10,500-15,500 Btus per pound. Bituminous coal is the most plentiful form of coal in the United States and is used both to generate electricity (thermal coai) and, if it has the right properties, as coking or metallurgical coke for steel production. Anthracite coal has the highest carbon content, 86-98 percent, and a heat content of nearly 15,000 Btus per pound. Anthracite coal was closely associated with home heating because it burned nearly smokeless. As desirable as anthracite is, it is also scarce. In the United States, anthracite is found in only eleven counties in northeastern Pennsylvania and is a largely exhausted resource. COAL MINING Coal mines have historically been subterranean regions where accidents and black lung have taken their toll. Mining coal in the twenty-first century is an activity carried out differently than it was in the past. In developed nations, no gangs of men swing pickaxes to remove the over- and underburden of rock to gain access to the coal, then again to chip out the coal No gangs of men shovel the rock or coal into small wagons or carts for the trip to the surface. Now the most popular way of removing coal is continuous mining machines with large, rotating, drum-shaped cutting heads studded with carbide-tipped teeth that rip into a seam of coal. Large gathering arms scoop the coal directly into a built-in conveyor for loading into shuttle cars or a conveyor for the trip to the surface. Continuous cutters ripping and grinding their way through coal seams can do in minutes what gangs of miners with pickaxes and shovels took days to accomplish. The next most popular method for removing is a machine resembling an oversized chain saw that cuts out a section of coal in preparation for blasting to allow for expansion. Holes are then drilled for explosives that blast large chunks of coal loose from the seam. Loaders scoop up the coal into conveyors that fill shuttle cars to haul the coal out through the shaft. For both methods of mining, long rods or roof bolts are driven into the roof of the mine to bind layers of weak strata into a single layer strong enough to support its own weight. If necessary, braces arc used for additional support. Wood is favored because it makes a sharp cracking sound if the roof begins to weaken. An increasingly popular and efficient means of mining introduced into the United States from Europe in the 1950s is longwall mining where a rotating shear moves back and forth in a continuous, smooth motion for several hundred feet across the face or wall of a block of coal. The cut coal drops into a conveyor and is removed from the mine. Some of the rock on top of the coal also collapses, which is then removed to the surface or piled in areas where the coal has been removed. The main supports for the rooms created by longwall mining are pillars of solid coal, which are the last to be mined before a mine is abandoned. Regardless of the type of mining technology employed, mine shafts for transporting miners and coal either slope down to coal beds that are not too deeply located in the earth or are vertical to reach beds of coal more than 2,000 feet beneath the surface. Huge ventilation fans on the surface pump air through the mineshafts to reduce the amount of coal dust in the air, prevent the accumulation of dangerous gases, and ensure a supply of fresh air for the miners. In recent decades, surface mining has gained prominence over subterranean mining. In the western part of the United States, 75 percent of the coal produced is obtained from surface mines with coal deposits up to 100 hundred feet thick. Surface mining also occurs in Appalachia. Surface mines produce 60 percent of the coal mined in the United States, while the remaining 40 percent comes from underground coal mines located primarily in Appalachia. Although there are large 106 ENERGY FOR THE 21 ST CENTURY COAL 107 open-pit mines in other parts of the world, such as Australia and Indonesia, globally speaking about two-thirds of coal comes from underground mines. A few utility plants are located at the mouths of mines, but most coal is loaded on barges and railroad cars for transport to electricity-generating plants or export ports. In the United States, about 60 percent of the coal mined is moved by railroad to the consumer, often in unit trains of a hundred automatically unloading coal cars, each holding 100 tons of coal, or 10,000 tons of coal in a single trainload. Coal is unloaded by hoppers in the bottom of coal cars that open to drop the coal onto a conveyor belt located below the rails or by a rotating mechanism that empties 100 tons of coal by turning the coal cars upside down as though they were toys. Coal is still a major revenue generator for railroads around the world. Coal in the United States not moved by rail is primarily moved by barge on 25,000 miles of inland waterways. One unconventional way to move coal is to pipeline pulverized coal mixed with water from a coal inine to a power station, where the water is decanted and the pulverized coal is fed directly into a boiler. After inining, coal is processed to ensure a uniform size and washed to reduce its ash and sulfur content. Washing consists of floating the coal across a tank of water containing magnetite for the correct specific gravity. Heavier rock and other impurities sink to the bottom and are removed as waste. Washing reduces the ash and pyretic sulfur-iron compounds clinging to the surface of the coal, but not the sulfur chemically bonded within the coal. Washing can also reduce carbon dioxide emissions by 5 percent. Magnetite clinging to the coal after washing is separated with a spray of water and recycled. Coal is then shipped by rail or barge to power plants. Some power plants run off a single source of coal while others buy various grades of coal that are mixed together before burning in order to obtain optimal results in heat generation, pollution emissions, and cost control. Coal-inining operations are highly regulated in the developed world. In the United States, a company must comply with hundreds of laws and thousands of regulations, many of which have to do with the safely and health of the miners and the impact of coal mining on the environment. Legal hurdles may require ten years before a new mine can be developed. Amining company must provide detailed information about how the coal will be mined, the precautions taken to protect the health and safely of the miners, and the mine's impact on the environment. For surface mining, the existing condition of the land must be carefully documented to make sure that reclamation requirements have been successfully fulfilled. Other legal requirements cover archaeological and historical preservation, protection and conservation of endangered species, special provisions to protect fish and wildlife, forest and rangeland, wild and scenic river views, water purity, and noise abatement. In surface or strip mining, specially designed draglines, wheel excavators, and large shovels strip the overburden to expose the coal seam, which can cover the entire top of an Appalachian mountain. Coal is loaded into huge specially designed trucks by large mechanical shovels for shipment to a coal-burning utility or to awaiting railroad cars or barges. Surface mining has lower operating and capital costs and provides a safer and healthier environment for the workers than underground mining. After the coal is removed, the overburden is replaced and replanted with plant life to restore the land as closely as possible to its original state. Reclaimed land can also be transformed into farmland, recreational areas, or residential or commercial development, as permitted by the regulators. Critics of surface mining point out the damage done to the landscape when the overburden removed from the top of a mountain or hill is dumped into nearby valleys, called "valley fill." In addition to the destruction of the landscape and vegetation, valley fills become dams creating contaminated ponds of acid runoff from sulfur-bearing rocks and heavy metals such as copper, Table 4.1 Employment, Productivity, and Safety Employment (2000) Miners per Million Tons Output Deaths Deaths per Million , Tons Output Australia 18 76 4 0.02 United States 77 96 38 0.05 United Kingdom 8 241 4 0.05 South Africa 54 298 30 0.17 Poland 158 1,561 28 0.28 India 456 2,171 100 0.48 Russia 197 1,195 137 0.83 China 5,000 5,501 5,786 6.36 lead, mercury, and arsenic exposed by coal mining. They also object to the dust and noise of strip-mining operations and "fly-rocks" raining down on those unfortunately residing nearby. The scars of surface mining are clear from the air. Residents in West Virginia are split between those who support the economic benefits of surface coal mining and those who want to transform West Virginia into a recreational destination for tourists.6 Another problem is abandoned underground mines, which eventually fill with water. The water can range from being nearly fit for drinking to containing dangerously high concentrations of acids and metallic compounds that may end up contaminating ground and drinking water. Of course, the record also shows that there are large established companies mindful of their legal obligations to restore the landscape and protect the environment. There are instances of reclamation carried out so effectively that, with the passage of time, there is no apparent evidence that strip-mining had ever taken place. Aside from corporate ethics, there are sound business reasons for being a responsible corporate citizen such as the desire to remain in business for decades to come. For these companies, the extra costs in protecting the health and safety of the miners and safeguarding the environment generate huge payoffs by allowing them to remain in business over the long haul. Private ownership is a right granted by governments on the basis that the conduct of business is better handled by businesspeople than government bureaucrats. If in reality, or if in the perception of the electorate, the supposed benefits of private ownership are not being achieved, then private ownership itself is threatened. There has been environmental degradation, but much of this lies with fly-by-night companies that fold without meeting their Hght-of-day responsibilities. While critics of coal extraction in developed nations abound, the developing nations, most notably China and India, seem to exist on another planet. Coal mining, particularly in the tens of thousands of small mines, violates elemental concerns over health and safety of the workers and the environment. No one in those countries seems to care about spontaneous combustion of coal-mining residues that burn on forever or drinking water and agricultural lands permanently contaminated with poisonous metal compounds. Employment of coal miners has changed drastically in recent decades as machines have replaced labor. Although there are 7 million coal miners in the world, 5 million are in China and another half million are in India, where the use of picks and shovels is the dominant coalmining technique. Table 4.1 shows employment, productivity, and safety in terms of the number of miners per million tons of output, the number of miners' deaths, and deaths in terms of a million tons of output for 2000.7 The table shows the enormous disparity in worker productivity 108 ENERGY FOR THE 21ST CENTURY and mortality rates between the developed and developing worlds. More recent data suggest that official coal mining deaths in China may be closer to 4,000, but there is also an element of underreporting from remote areas that suggest that the death rate may be higher than what the statistics show. Note that coal mining in the United Kingdom, where it all began, is now a faint vestige of its former vigor. Needless to say, the lowest fatality rates occur in nations where there is the strongest commitment to health and safety standards for miners and for workers in general. China has the most abysmal safety record, and that may be a gross understatement. Most casualties are associated with small mines employing women and children, not the large state-owned mines. Methane explosions from lack of proper ventilation and gas monitoring are responsible for half of the deaths. These figures reflect mine mishaps, not deaths from health impairment from mining. A nonfatal occupational risk for miners and for many other industrial workers is loss of hearing. For coal miners, loss of hearing, caused by explosives used to dislodge coal and machinery noise in close quarters, occurs slowly and often without the miner's awareness. With regard to fatal occupational risks, the most common disease is pneumoconiosis, commonly known as black lung disease. Black lung disease has dropped precipitously for mines with ample ventilation to reduce coal dust, but still remains a problem in China and India and other nations where relatively little is invested in protecting the workers' health. China's terrible record in protecting miners extends to the end users. Drying chilies with coal contaminated with arsenic was responsible for thousands of cases of arsenic poisoning. Drying corn with coal contaminated with fluorine caused millions to suffer from dental and skeletal fluorosis. COAL IN THE TWENTY-FIRST CENTURY Coal's retreat in relative standing among other energy sources ended in 2000. Coal is here to stay and is gaining ground in absolute and relative terms. Despite criticisms leveled against coal, it does have virtues that cannot be ignored such as being: « abundant, frequently reserves are measured in hundreds of years; • secure, in that coal is available in sufficient quantities without the need for large-scale imports for most coaLconsuming nations; • safe (does not explode like natural gas, but of course mine safety is an issue); • nonpolluting of water resources as oil spills are (although there are other adverse environmental consequences of mining and burning coal); • cost-effective, by far the cheapest source of energy. As seen in Figure 4.1, the volume of coal production leveled out in the 1990s but is heading upward again. The top line is coal mined in physical tons and the bottom line is coal production expressed in terms of the equivalent amount of oil that would have to be burned to match the energy released by burning coal. As the figure shows, close to 2 short tons of coal have to be burned to obtain the same energy release as burning 1 metric ton of oil.8 Figure 4.1 also shows the relative contribution that coal makes in satisfying world energy demand for commercial sources, excluding biomass. Since 1981, the percentage of coal's share in satisfying energy needs had been slowly eroding until 2001 when there was a resurgence in coal consumption and in its share of the energy pie. This trend is expected to continue from coal-fired electricity generation capacity being added ail over the world but particularly in the United States, COAL 109 Figure 4.1 Global Coal Production and Percent Contribution to Global Energy 7,000 n.....--------------................................-----------.........-...............................-—.........----------.........................................................................-.......----------r 70% 6,000 5,000 4,000 ■MM Tons Mined "MM Tons Oil Equivalent ' % Share Global Energy 0 -1-r—i-1—i-1—i-r~~i—-r—i—i—i.......i-i---1—r—r—~i-1—i-1—r—i-1—r~ ŕ 9? ^ 9^ 9? (ŕ Q?> dí1 í (?> ňN (í1 CS^ Nc?> NdJ» NoJ> N<£> ^> Nc£> ^ N# ^ j? j§> 60% 50% 40% - 30% - 20% 10% 0% China, and India. However, there has been a sharp decline in ordering new coal-fired electricity-generating capacity in the United States because of the risk of a cap and trade program being imposed by the Obama administration. The global economic recession starting in 2008 also affects utility plans to add capacity. Regardless of the situation in the United States, China and India will remain principal drivers of the world coal business. Figure 4.2 shows the world's largest consumers and producers of coal in 2008 in terms of millions of tons oil equivalent. China is the world's largest consumer and producer of coal and both exports and imports coal. China suffers from a poorly developed internal logistics system. Movement from inland distributions to coastline population centers relies heavily on China's river systems. Movement of goods and commodities along China's long coastline, where a number of its principal population centers are located, is by water rather than by land. As a substitute for moving commodities along its coastline, China selectively exports and imports. China imports thermal coal to utilities located on its coast from Australia and Indonesia and exports thermal coal to neighboring countries such as North and South Korea and Japan. By becoming a major world steel producer, China has becoine a major importer of metallurgical or coking coal. The steam locomotive has not entirely gone the way of dinosaurs. China, India, and South Africa still rely on steam locomotives to move coal. The relative importance of the United States, along with Canada and China, as consumers and producers of coal can be seen by the huge step down to the third largest consumer and producer, India. Thermal and metallurgical or coking coal are two distinct markets. It is possible for a large bulk carrier to move thermal coal from Australia to Europe and return with a cargo of metallurgical coal from the United States or South Africa to Japan. The largest steam and coking coal exporters in 2008 were Australia (252 million tons), Indonesia (203 million tons), Russia (101 million i 10 ENERGY FOR THE 21 ST CENTURY Figure 4.2 World's Leading Producers and Consumers of Coal (MM Tons Oil Equivalent) in 2008 China U.S./Canada India Russia/Ukraine Japan S. Africa Germany S.Korea Poland Australia Taiwan United Kingdom K Indonesia Colombia ■ Production D Consumption 200 400 600 800 1,000 1,200 1,400 1,600 tons), Colombia (74 million tons), United States (74 million tons), South Africa (62 million tons), and China (47 million tons). The largest importers were Japan (186 million tons), South Korea (100 million tons), Taiwan (66 million tons), India (60 million tons), Germany (46 million tons), China (46 million tons), and United Kingdom (44 million tons). Japan, South Korea, and Taiwan view coal as a means of reducing their reliance on Middle East oil. The United Kingdom, once the world's largest exporter of coal, now imports a large share of its coal needs. Both the United Kingdom and Germany have been phasing out the large subsidies paid to keep its domestic coal-producing industry alive in favor of far cheaper imports. South Africa has abundant coal resources and limited oil resources, and oil-exporting nations were reluctant to trade because of its past apartheid policies. As a consequence, South Africa became a world leader in producing petroleum products (synthetic fuels) and chemicals from coal. The Fischer-Tropsch process, dating back to the 1920s, transforms low-quality coal to high-grade petroleum fuels plus other products.8 The Germans relied on this technology to make gasoline from its plenteous supplies of coal during the Second World War to compensate for not having indigenous oil resources to run its war machine. These plants were the highest priority targets during Allied bombing of Nazi Germany. The South African plants have been producing 130,000 barrels per day of a mix of 20-30 percent naphtha and 70-80 percent diesel, kerosene, and fuel oil since 1955. About 0.4 tons of coal are consumed for every barrel of oil produced with an overall energy efficiency of 40 percent (60 percent of the energy content of the coal is consumed in transforming coal to liquids). Coal is first gasified to yield a mixture of hydrogen and carbon monoxide, which, after passing through iron or cobalt catalysts, is transformed into methane, synthetic gasoline or diesel fuel, waxes, and alcohols, with water and carbon dioxide as byproducts. Synthetic fuels from coal are higher in quality than those made from oil. For instance, diesel fuel made by the Fischer-Tropsch process has reduced COAL Figure 4.3 Known Coal Reserves (Billion Tons) and R/P Ratio (Years) 250 200 M M M 150 T o 100 n s 50 ♦ i=i Soft Coa! esi Hard Coal -#_ R/p Ratj0 500 400 Y 300 e a 200 r s h 100 NT / 4? ^ J* nitrous oxides, hydrocarbons, and carbon monoxide emissions with little or no particulate emissions compared to oii-based diesel fuels.9 China is building a coal-to-liquids plant in Inner Mongolia that will produce 20,000 barrels per day of motor vehicle fuel plus other oil products with a planned expansion to 100,000 bpd. The process is a direct liquefaction process transforming coal to a solvent at a high temperature and pressure and then followed by a more complex chemistry to produce 20-30 percent naphtha and 70-80 percent diesel fuel and liquefied petroleum gas. The process is more efficient and uses 0.3-0.4 tons of coa! per barrel of oil produced. If successful, other coal-to-liquid plants will be built. One adverse environmental aspect of coal-to-liquid technology is a large emission of carbon dioxide during the production process amounting to about 0.6 tons of carbon dioxide for every barrel of oil.10 Unlike oil, where the world's total proven reserves divided by current consumption equal only forty years, over a century (120 years) would be required for current consumption to eat away at proven coa! reserves. The reserve to production (R/P) ratio has to be handled gingerly as we have a knack for discovering new reserves. (Theodore Roosevelt estimated that oil reserves would be exhausted in twenty years, given consumption and known reserves in the 1910s.) Moreover, reserves are made up of known reserves plus estimates of probable reserves, and as such are subject to error. Some criticize R/P ratios because they are based on current, not future, consumption and to that extent overestimate the life of existing reserves. On the other hand, they do not take into account future discoveries and so underestimate the life of existing reserves. Unlike oil, there is no active ongoing search for new coal reserves, which means that coal reserves could be substantially upgraded. Figure 4.3 shows the world's largest known coal reserves in terms of size, ranked by how long they will last at the present rate of consumption. The United States has the world's largest reserves of coal of 238 billion tons with a R/P ratio of 234 years, whereas Russia has 157 billion tons with a R/P of 481 years. The world's largest 112 ENERGY FOR THE 21ST CENTURY Figure 4.4 U.S. $/Ton Oil, Natural Gas, and Coal Prices (Constant 2008 $) $800 ■ - - * Natura! 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The space program normally uses more expensive PV cells made of gallium arsenide, whose efficiency in transforming solar energy to electricity can exceed 30 percent.24 Multicrystalline PV cells depend on a less-expensive melting and solidification process, but have a marginally lower commercial efficiency of 14 percent. An even lower-cost solar cell is a film of extremely thin layers of PV semiconductor materials such as amorphous silicon, copper-indium-gallium-diselenidc, or cadmium telluride, deposited on a backing of glass, stainless steel, or plastic. While cheaper to make, thin-filmPV arrays have a lower efficiency that ranges between 7-13 percent, so they have to cover more area to produce the same output than conventional solar panels. The advantage of thin films is avoiding the glass covering and mechanical frames of conventional solar panels. Thin films on a plastic covering can be made to look like roofing material and designed to fulfill the twin roles of protecting the roof from weather plus generating electricity from the sun. The savings in not having to install roofing reduces the cost of the solar power system. There is also research on employing nanotechnology to produce organic solar cells of molecular polymers and other esoteric materials. Progress in thin films technology has spurred their growth from 6 percent of PV capacity in 2005 to 13 percent in 2007; the remaining is primarily wafer design. A PV, or solar, cell is the basic building block, small in size, and capable of producing 1 or 2 watts of power. These are combined into larger units, called modules or panels, which produce 50-300 watts of power, which are then joined together to form solar arrays sized to meet the desired power output. Solar arrays are particularly useful for serving isolated buildings in sunny climates such as lodges in national parks, lighthouses, and other buildings and facilities far from an electricity grid. Smaller solar modules can light signs, streets, gardens, pools, and provide power for remote telephones or automatic teller machines, or any need with similar power requirements. These applications normally have an associated battery that is charged by day in order to supply power at night or during times of inclement weather. Solar arrays are given serious consideration by government bodies to help launch economic development in areas too remote and/or sparsely populated to justify building an electricity grid. An independent solar-power system, with a battery to store electricity for times of cloud cover or at night, in isolated locations obviates the need for building a generation, transmission, and distribution system. A good example of this is a $48 million solar-power project on the island of Mindanao in the Philippines. The project, funded by the Spanish government and built by BP Solar, will supply electricity to 400,000 people in 150 villages plus provide electricity for irrigation and drinking water systems and for schools and medical clinics.25 Solar power can bring electricity to a remote area at less cost than building a conventional generation, transmission, and distribution system, including the purchase of normally imported fuel. Solar and wind power, either singly or together, with a diesel backup, are viable means of supplying electricity on a local or distributive basis to the 2 billion people who live in isolated communities far from electricity grids or in areas of low population density. One of the chief benefits of introducing hybrid renewable electricity to remote locations is improving the health of the people. Females in some parts of the world spend nearly every waking hour collecting and transporting dung and wood on their heads or backs for cooking and heating. Some have to walk twenty miles a day, rising early in the morning and going to bed late at night, ruining their health in the process. Moreover, cooking with biomass in closed environments is a major health hazard that shortens life expectancy. Electricity from renewable sources eliminates these time-consuming and onerous tasks and their adverse health consequences. Electricity allows women to sleep longer, improving their health; and, when they are awake, have the energy to improve their lifestyle. If an electricity grid is available, solar arrays can be connected into the grid for a power sup- 330 ENERGY FOR THE 21 ST CENTURY Figure 9.4 Growth in Solar Photovoltaic Power (GW) 8 Others ply by night or on cloudy days, eliminating the need for a battery. Arrangements can be made for excess production of a solar array to be fed into the grid, the revenue of which can be part of the economic decision to install a solar power system. In addition to the solar panels, the capital investment also includes the cost of a mounting structure and the installation of the array, an inverter to convert the direct current output to alternating current, a storage battery for off-grid solar systems, along with a charge controller for battery operation or modifications to an existing electricity grid to allow the sale or purchase of electricity.26 As Figure 9.4 shows, growth in solar power is exponential, similar to wind, but in comparing Figure 9.4 with Figure 9.1, solar provides less than 10 percent of wind power's contribution. Three-quarters of the 50 percent growth in solar PV power in 2007 took place in Germany and Spain, and the figure is 90 percent by adding in Japan and the United States. The two major subdivisions of solar power are off-grid and grid-connected. Off-grid installations are at remote locations where homes and buildings are not connected to an electricity grid. Off-grid installations serve remote telecommunications stations, navigational aids, and other needed functions. Solar-powered emergency phones can be found along major highways. Grid-connected installations also serve homes and buildings, but are also connected to an electricity grid for service when the sun is not available and for sale of unneeded electricity back into the grid. In 1992, about 75 percent of installations were off-grid and 25 percent were grid-connected. In 2007, the ratio was 5 percent off-grid and 95 percent grid-connected. Table 9.2 shows the thirteen largest PV projects. The United States plays a less dominant role in PV projects than thermal projects listed in Table 9.1. The development of solar power, as with wind, started in the United Stales (California, to be precise) as a result of PURPAlegislation. Since the mid-1990s, Japan and Germany have become centers of solar energy development. The largest suppliers of PV cell production are located in Japan with a 38 percent share, Germany 35 percent, United States 11 percent, Norway 6 percent, and Spain 5 percent. The largest corporate suppliers of PV cell production are Q-Cells (Germany) with a 16 percent share, Sharp (Japan) 15 percent, Kyocera (Japan) 9 percent, Sanyo (Japan) 7 percent, Deutsche/SolarWorld (Germany/U.S.) 6 percent, Scancell (Norway) 6 percent, Mitsubi- SUSTAINABLE ENERGY 331 Table 9.2 World's Thirteen Largest Solar Photovoltaic Power Projects Location Size Solar Co. Utility Start New Mexico, US 300 MW New Solar Ventures and Solar Torx on 3,200 acres 2011 Arizona, US 280 MW Abengoa on 1,900 acres Arizona Public Service Not yet finally approved Victoria, Australia 270 MW Solar Systems (company intends to build 270,000 MW to fulfill Australia 20% goal for renewable by 2020) TRUenergy 2013 California, US 80 MW Cleantech and California Construction Authority on 640 acres 2011; California also has legislation calling for solar panels to be installed on 1 million roofs by 2018 Leipzig, Germany 40 MW Juwi Solar 2009 Murcia, Spain 20 MW 120,000 PV panels on 247 acres Atersa Operating since 2008 Alicante, Spain 20 MW 100,000 PV panels City Solar Operating since 2007 Slnan, Korea 20 MW 109,000 PV panels SunTechnics Operating since 2008 Nevada, US 14.2 MW 90,000 PV panels on 140 acres Sunpower Operating since 2008 Salamanca, Spain 13.8 MW 70,000 PV panels Kyocera Operating since 2007 Murcia, Spain 12.7 MW 80,000 PV panels Ecostream In operation Bavaria, Germany 12 MW 1,400 sun-tracking PV panels Solon AG Operating since 2006 Alentejo, Portugal 11 MW 52,000 PV panels on 150 acres Operating since 2007 shi (Japan) 5 percent, First Solar (U.S./Germany) 5 percent, and Isofoton (Spain) 4 percent. The largest suppliers dominating the solar photovoltaic grade silicon market are Wacker (Germany), REC Solar Grade Silicon and Hemlock Semiconductor (U.S.), andTokuyama (Japan). The U.S. is a major provider of PV grade silicon in the PV supply chain. A large number of companies are involved with other aspects of solar power including supplying semiconductor materials, producing PV modules, and installing solar panel arrays. In addition, there is a great deal of entrepreneurial effort by companies trying to establish a niche in this emerging business. Significant government monies are being invested in the development of solar power. In 2007, the four nations that spent the most for solar energy research and development were the United States ($138 million), Germany ($61 million), Japan ($39 million), and South Korea ($18 million). Japan, Germany, United States, and other nations offer incentives for individuals and businesses to install solar energy. Like those provided for converting to wind and other alternative sources of energy, these come in various forms such as a direct grant or rebate paid to the individual or 332 ENERGY FOR THE 21 ST CENTURY SUSTAINABLE ENERGY 333 business for installing solar panels, various tax benefits, soft loans at below market interest rates and long payout periods, the right to sell excess production back to the utility at above-market rates (feed-in tariffs), and sustainable building standards that require installing PV panels. In the United States, most states have some sort of program to encourage the development of solar energy, ranging from personal, corporate, sales, and property tax exemptions plus loan and grant programs as a means of inducing homeowners to install solar power. Significant rebates of the order of 50 and 60 percent are offered by various states such as New York and New Jersey. In addition, the government has a production tax credit that can be applied against corporate taxes for companies that install solar power and other forms of renewable energy plus, as with wind, direct grants provided by the 2009 American Recovery and Reinvestment Act. Economics of Solar Power The economics of solar power depend on many variables. For example, an energy-efficient 2,000-square-foot home needs about 2 kilowatts of output from a solar array mounted on the roof. If the cost of installation is $ 16,000 and if there is a rebate available for $8,000, the net cost to the consumer is $8,000. The amount of electricity that the solar array can produce is 100,000 kilowatt hours over its twenty-five-year life, assuming that the sun is shining an average of 5.5 hours per day (2 kilowatts per hour x 5.5 hours per day x 365 days per year x 25 years). The 5.5 hours per day takes into consideration reduced output when the sun is near the horizon and during times of cloud cover. At higher latitudes, three hours per day might be a closer approximation for the equivalent of sunlight directly overhead with no cloud cover. If the average cost of electricity over the next twenty-five years were ten cents per kilowatt hour, then the avoidance of the need to purchase 100,000 kilowatts from a utility would equal the net investment of $10,000, including accrued interest. Without the rebate, there is no economic justification for installing solar power. Solar power works better if electricity rates are based on time-of-day metering when rates track actual demand. This would improve the economics of solar power immensely since the day rate for electricity is much higher than the night rate, reflecting marginal rates charged by base-load electricity providers. If electricity rates during daylight hours were sixteen cents per kilowatt hour, then the investment of $8,000 (after the rebate) will generate savings of $16,000 in avoided electricity purchases over a twenty-five-year period, providing a 2.8 percent return on the investment. If there were no rebate, the savings would only compensate for the investment, assuming the money has no time value. If it is profitable to install solar power, then one can consider oversizing the array and selling the excess power back to the utility. Regardless of the economic analysis, one may still choose solar power just for the satisfaction of having a home that does not require burning a fossil fuel or relying on nuclear power. Installing a 454-kilowatt solar array for Monmouth University in New Jersey had a capital cost, including installation, of $2,860,000. A substantial rebate was available from the state of New Jersey in the amount of $1,715,000 (60 percent of capital cost). This reduced the capital investment to $1,145,000. Table 9.3 shows the economic analysis of the installation assuming a cost of purchase often cents per kilowatt-hour, with 3 percent escalation over the twenty-five-year life of the solar panel. The net capital investment of $ 1.1 million earns a healthy return, primarily in the form of avoided electricity purchases. Any hike in electricity rates above ten cents per kilowatt-hour, which occurred as a consequence of much higher natural gas prices for the utility, increases the rate of return on the investment. As the analysis plainly shows, the internal rate of return is positive only because of the significant commitment on the part of the government to support the development of solar Table 9.3 Economic Analysis of Actual Solar Energy System Aggregate Savings (Costs) over 25-Year Life of Project Avoided Electricity Purchases $2,415,000 Avoided Transformer Losses $50,000 Estimate of Sales of Excess Electricity Back to Utility First 4 Years Only $315'000 Maintenance of Solar Energy System and Roof ($110,000) Aggregate Savings $2,670,000 Cost of System net of Rebate $1,145,000 Interna! Rate of Return over 25 Year Period _8-3%_ power. A review of the project in 2009 showed that its profitability was greater than originally anticipated because of subsequent hikes in electricity rates. The solar installation provided a fixed electricity rate that lowered the overall cost of electricity. Anew building on campus was not fitted with solar panels pending a study on the feasibility and economics of a thin-film solar installation that would be applied directly to the building without the need for frames to hold solar panels. One of the over 300 utilities that offer electricity from renewable energy to consumers is Arizona Power Service. Located in the Southwest, where the company can take advantage of the 300 days of sun, and with plenty of available desert land for installing solar arrays, the utility has become a leader in promoting solar power to its customers. The company intends to build two thermal solar systems totalling 0.6 GW and offers homeowners a free installation of rooftop solar panels that fixes the cost of their electricity for the next twenty years. The company's objective is to make Arizona the "Solar Capital of the World."27 Further government support for solar power occurred at the end of2005 when the Califomi a Public Utilities Commission unveiled a plan to install 3 gigawatts (3,000 megawatts) of capacity over the next eleven years. This plan would double the existing global solar power capacity and would supply 6 percent of California's peak electricity demand. The California Solar Initiative provides $3.2 billion in rebates over the next eleven years with the objective of installing solar panels on 1 million homes and public buildings. Funding would also be eligible for solar water heating along with other solar power technologies. The new initiative is actually an expansion of an existing program that adds a surcharge to consumer utility bills with the proceeds dedicated to rebates for solar power installations. In 2009, Public Service Electric & Gas of New Jersey announced a $0.5 billion plan to place small solar panels costing $ 1,000 each on telephone poles and rooftops in equal numbers to feed directly into the grid. The plan will add about 80 megawatts of power by 2013, making New Jersey second to California in solar-power generation. The U.S. Bureau of Land Management is examining 1,000 square miles of land on twenty-four tracts of public land in the Southwest to identify a potential site of three square miles for the generation of 100 GW of solar power (present U.S. output is less than 1 GW!). Four solar power plants (I solar array and 3 thermal) are under review for construction in Nevada and California totalling 2.4 GW. Progress in obtaining regulatory approval is impeded over species protection, availability of water for thermal solar projects, and the greatest barrier of them all, a maze of multiple government agencies' regulations with overlapping jurisdictions. Things are not much better on the state level—regulatory requirements are as much an impediment for adding renewable energy capacity as they are for fossil fuels. 334 ENERGY FOR THE 21 ST CENTURY One idea on the table is to convert 30,000 square miles of public lands into thin-film module arrays for the generation of 2,940 GW. This would require an increase in thin-film module conversion rale of solar energy to electricity from the present 10 percent to 14 percent and another 16,000 square miles for thermal solar systems with an increased conversion rate from the present 13 percent to 17 percent to generate 558 GW, plus the building of 100,000-500,000 miles of new high-voltage DC transmission lines to connect the Southwest with the nation's electricity grid. The cost of electricity will be near current rates if the indicated conversion-rate improvements can be achieved. Such a system could provide nearly 70 percent of the nation's electricity by 2050 and could be further expanded to provide 100 percent by 2100.2K GEOTHERMAL ENERGY Geothermal energy, from the Greek words geo (earth) and therme (heat), takes advantage of hot water or steam escaping from hot spots in the earth. Geothermal sources are located where magma is relatively close to the surface of the earth and where the rock above the magma is porous and filled with subsurface water with access to the surface. Geothermal sources are found near tectonic plate boundaries that are separating (the rift valley in east Africa and in Iceland) or colliding creating subduction zones (Japan) or sliding by one another (California). Geothermal energy sources are also found near volcanoes (Mount Vesuvius in Italy, the island of Hawaii, and the caldera at Yellowstone), where magma protrusions lie relatively close to the earth's surface. The Maoris in New Zealand and Native Americans used water from hot springs for cooking and medicinal purposes for thousands of years. Ancient Greeks and Romans had geothermal heated spas. The people of Pompeii, living too close to Mount Vesuvius, tapped hot water from the earth to heat their buildings. Romans used geothermal waters for treating eye and skin disease. The Japanese have enjoyed geothermal spas for centuries. The earth's crust insulates us from the hot interior of the mantle. The normal temperature gradient is about 50°F-87°F per mile or 17°C-30°C per kilometer of depth and higher where the crust is relatively thin or near plate boundaries and volcanoes. Magma trapped beneath the crust heats up the lower rock layers. If the hot rock is porous and filled with continually replenished subsurface water with access to the surface, then the result is fumaroles of escaping steam and hot gases, geysers of hot water, or pools of boiling mud. As a geothermal source, the earth becomes a boiler and escaping hot water and steam, called hydrothermal fluids, are tapped for hot spring baths, heating greenhouses (agriculture), heating water for marine life (aquaculture), space heating for homes, schools, and commercial establishments, heating streets and sidewalks to prevent ice formation, and as a source of hot water for industrial use or steam for generating electricity. Some cities have district heating using geothermal hot water to heat an entire area, best exemplified in Reykjavik, Iceland, where 95 percent of the city receives hot water from geothennal sources. There are three types of geothermal power plants for generating electricity. The first is a dry-steam geothermal reservoir in which emitted steam directly spins a turbine. These are relatively rare and were the first dedicated to generating electricity. One in Tuscany has been in operation since 1904 and The Geysers, 90 miles north of San Francisco, has been in operation since 1960. The Geysers represents the largest single source of tapped geothermal energy in the world and generates enough electricity to supply a city the size of San Francisco. A falloff in steam pressure in the 1990s was successfully countered by water injection to replenish the geothennal reservoir. Injected water was waste treatment water from neighboring communities, an innovative and environmentally safe method of disposal. Some thought has been given to tapping the world's most productive source of geothennal energy, Yellowstone, the caldera of a supervolcano that SUSTAINABLE ENERGY 335 last erupted 600,000 years ago. (Another eruption of that magnitude would wipe out half of the United States and emit an ash cloud large enough to send the planet into a "volcanic" winter.) But Yellowstone, as a national park, cannot be commercially developed. The second and most common form of geothermal power plant is driven by geothennal reservoirs that emit hot, pressurized water between 300°F-700°F. The drop in pressure inside a separator allows the liquid to flash to steam, which is then directed into a turbine. Any gases in the geothermal water such as carbon dioxide, hydrogen sulfide, and nitrous oxides pass to the atmosphere, but these are a tiny fraction of the emissions from a coal-burning plant with an equivalent power output. Water and steam remaining after flashing and passing through a turbine are usually reinjected to replenish the water in order to maintain the reservoir's pressure. If reservoir pressure can be maintained, then geothermal becomes a sustainable source of nearly nonpolluting clean energy. Shallower sources of geothermal energy in which the water temperature is between 250°F-350°F require a binary power plant where a heat exchanger transfers the heat of the geothermal water to a second or binary fluid such as isopentane or isobutane. The binary fluid boils at a lower temperature than water and its vapors pass through a turbine and are then condensed to a liquid for recycling. Binary plants are closed systems in which the hydrothermal fluid, along with any entrapped gases, is reinjected into the reservoir. A binary system may be necessary for water with a high mineral content to prevent forming a harmful scale on the turbine blades. Hybrid plants, part flash and part binary, are also available such as the one that supplies 25 percent of the electricity for the island of Hawaii. As of 2005, there were 490 geothermal power plants with 9 gigawatts (GW) of installed capacity, equivalent to the production of nine large-sized nuclear or coal-fired plants, enough to supply the electricity needs of 9 million people.29 The United States leads with 2.9 GW, mostly in California and Nevada, whose 209 operating plants supply 0.5 percent of the nation's energy needs. The second largest producer is the Philippines with 57 operating plants of 1.9 GW of capacity sufficient to meet 19 percent of the nation's electricity demand. The third largest is Mexico with 36 operating units of 0.95 GW, representing 3 percent of the nation's electricity. The fourth largest is Indonesia with 15 operating plants of 0.8 GW sufficient to satisfy nearly 7 percent of the nations' electricity needs. Italy is the fifth largest producer with 32 plants of nearly 0.8 GW of electricity or 2 percent of the nation's electricity needs (one center of activity is near Mount Vesuvius on the outskirts of Naples). Other nations have smaller outputs, but their generating capacities make a meaningful contribution in satisfying the nation's electricity needs such as El Salvador (22 percent of electricity is geothermal), Kenya (19 percent), Iceland (17 percent), Costa Rica (15 percent), and Nicaragua (10 percent). It is interesting to note that Central America is largely dependent on renewable sources, hydro and geothermal for electricity generation. Thermal uses, distinct from generation of electricity, total another 16 thermal GW for hot springs, agriculture and aquaculture, and district heating.30 Geothermal heat pumps use the constant underground temperature either for cooling or heating residences. Heat pumps are effective over a limited range of temperatures and require supplemental cooling and heating to handle more extreme variations in temperature. Geothermal sources are limited primarily to porous hot rock permeated with subsurface water that can escape to the surface. If water is trapped by a cover of impermeable caprock, then the geothermal reservoir must first be discovered before it can be exploited. The same technology for discovering oil fields and drilling wells to tap oil and natural gas reservoirs can be applied for discovering and developing geothermal reservoirs. The future of geothermal energy is limited in so far as current efforts are, for the most part, restricted to developing known sources of geothermal energy, not in discovering new ones. Hot rock underlies the entire crust. Its usefulness is a matter of depth and whether it is porous rock filled with subsurface water. But the presence of subsurface water and porous rock is no 336 ENERGY FOR THE 21 ST CENTURY SUSTAINABLE ENERGY 337 longer necessary. The feasibility of drilling two wells deep into the earth's crust to reach hot rock, and then fracturing the rock separating the two employing methods practiced by the oil industry, has been demonstrated. Water is then pumped down one well under pressure and forced through the fractured hot rock, where it is heated and rises to the surface via the other well as pressurized hydrothermal fluid. This can be flashed to produce steam and drive electricity generators or heat another liquid medium in a hybrid plant. Hot rock from a magma protrusion of up to 570°F was discovered two and three-quarter miles below the surface in southern Australia. Geodynamics, a start-up company that raised $150 million in capital, has drilled two wells 14,000 feet down to the hot granite. These wells, when fractured to allow the flow of water from one well to the other, will be able to generate geothermal energy. A small generator is scheduled for completion in 2009 followed by a larger one. It is hoped that these generators will establish the feasibility of generating geotherma! electricity on a commercial basis. If successful, large-sized electricity generators will be installed with the possibility of supplying a potential of 10 GW of electricity. A transmission system would have to be built to connect the geothermal-generating plant to the nation's electricity grid. It is possible that this hot rock formation may one day supply most of Australia's electricity needs.31 Another geothermal project had a far different outcome. The Swiss Deep Heat Mining Project near Basel, Switzerland, was to pump water down three-mile deep boreholes to hot rocks of 200 degrees Centigrade. The returning superheated steam would be sufficient to supply electrical power to 10,000 homes and hot water heat to another 2,700 homes. The project, partly backed with financial support by the Swiss government, was considered a safe and sustainable alternative to a nuclear power-plant project opposed by the Swiss people. Basel is prone to earthquakes, with one in 1356 strong enough (6.5 on the Richter scale) to raze the city. Pumping water down the boreholes was held responsible for setting off tremors measuring 3.3 on the Richter scale up to ten miles away from the site. The project was suspended. State prosecutors began looking into the possibility of criminal negligence on the part of the promoters despite support from the Swiss government.32 Nevertheless, there are a number of geothermal projects in various stages of development in India, Nevada, and California. A more esoteric idea is to mine heat from magma as a geothermal ore in places where it is accessible by current drilling technology. For this, a hole is drilled through the crust and a sealed pipe with a concentric inner pipe is thrust into the magma. Water is pumped down the inner pipe and is transformed into high-pressure hydrothermal fluid by the magma surrounding the bottom of the sealed pipe. From there, the hydrothermal fluid flows up the outer pipe to the surface to be flashed to steam to power electricity generators. A major obstacle to overcome is drilling all the way through the crust. The deepest bore hole ever drilled was in Russia 7.5 miles into crust 30 miles thick. Even if a bore hole were drilled into magma, precautions would have to be taken to prevent creating a mini-volcano if magma escapes to the surface. Another major obstacle is finding materials that can withstand the extreme high temperatures, pressures, and corrosive properties of being thrust into magma.33 But if the inner heat of the planet could be tapped, geothermal energy could conceivably satisfy the world's electricity demand. OCEAN ENERGY The oceans cover over 70 percent of the earth's surface and represent an immense reservoir of energy in the form of tides, currents, waves, and temperature differentials. Tides result from the gravitational interaction of the earth and the moon, with about two high and two low tides each day. The time between high tides is twelve hours and twenty-five minutes. The shift in maximum power output on a daily basis, while predictable, may not correspond to the timing of peak demand for electricity. Tides are also affected by the relative placement of the sun and moon with respect to the earth, which causes spring (maximum) and neap (minimum) tides. The elliptical path the earth traces around the sun, plus weather and other influences, affect tides, as does the topography of the shoreline. Unfortunately, coastal estuaries that can create tidal rises of up to fifty feet are located at high latitudes, far from population centers. Tidal power output must be viewed as a supplemental power source available only about eight to ten hours a day. The concept of tidal power is fairly old; waterwheels powered by tidal currents ground grain in eleventh-century England. Tidal power is tapped by building a dam with sluice gates across an estuary at a narrow opening to reduce construction costs. The sluice gates are opened to allow an incoming tide to increase the height of the water. When the tide turns, the sluice gates are closed, entrapping the water. As the tide goes out, the water level differential on either side of the dam widens until there is a sufficient head for water to pass through specially designed turbines to generate electricity. A tidal dam must be located where there is a marked difference between high and low tides. One favored area proposed for building a tidal dam is the Bay of Fundy in eastern Canada, where the difference in water level between tides is over fifty feet, the highest in the world. Other areas with pronounced tides in the northern hemisphere are Cook Inlet in Alaska, the White Sea in Russia, and the coastline along eastern Russia, northern China, and Korea. In the southern hemisphere, potential sites are in Argentina, Chile, and western Australia. With electricity production limited to between eight and ten hours a day, a tidal dam has an effective output of only 35 percent or so of rated capacity and the timing of its maximum output may not correspond to the timing of peak demand. Moreover, a substantial investment is necessary to transmit the generated electricity from remote sites conducive to tidal dams to population centers. The only major source of tidal energy in the world is the tidal dam at La Ranee estuary in France, built in the 1960s, capable of producing 240 megawatts of electricity. It has a maximum tidal range of twenty-six feet, operates at 26 percent of rated capacity on average, requires low maintenance, and is in service 97 percent of the time. Three other such dams are far smaller; an 18-megawatt tidal dam at Annapolis Royal, Canada (Bay of Fundy), which serves the local area, a 3.2-megawatt dam in eastern China at Jiangxia, and a 0.4-megawatt dam in the White Sea at Kislaya, Russia. One proposal under consideration since the 1980s is to build a sixteen-kilometer (ten-mile) dam across the Severn estuary in the United Kingdom. It would have a maximum output of 8.6 gigawatts, employing 214 electricity-generating turbines, and would be capable of supplying about 5-6 percent of the United Kingdom's electricity demand.34 Another under consideration since 1990 is a 48-megawatt tidal dam near Derby in northwestern Australia, but little progress has been made to date. South Korea is nearing the completion of what will be the world's largest tidal dam. An existing seawall between Sihung City and Daeboo Island created saltwater Lake Sihwa. Without an outlet, Lake Sihwa was becoming polluted. Constructing an outlet through the sea wall to flush the lake also allowed for the installation of turbines to take advantage of tidal flows. When in operation, the output of 254 MW will make it larger than the tidal dam at La Ranee, France. South Korea has also embarked on another tidal dam at Inchon, near Seoul. The project, to be completed in 2014, will consist of a 4,8 mile barrier connecting four islands and containing turbines capable of generating 812 MW when the tide is flowing.35 A more effective way to harness tidal power is channeling tidal flow through a restricted waterway so that the tidal current powers turbines during incoming and outgoing tides. This "double flow" system provides electricity generation whenever the tides are running but not during a change in tides when the tidal current reverses. Though the double flow system has a higher effective 338 ENERGY FOR THE 21 ST CENTURY SUSTAINABLE ENERGY 339 output than the tidal dam, electricity generation is still not continuous and may not be timed to accommodate demand. One proposal, now defunct, was to build a tidal fence two and a half miles long (four kilometers) in the San Bernardino Strait in the Philippines between the islands of Samar and Daiupiri. The tidal fence would contain 274 turbines capable of generating 2,200 megawatts (2.2 gigawatts) at peak tidal flow. The Race Rocks Ecological Reserve off the coast of Vancouver Island has built a small power plant powered by tidal current in addition to a solar panel to supply most of its electricity demand by renewable sources. A larger installation has been built in Strangford Narrows, Northern Ireland, by Marine Current Turbines. When the tide is running, the tidal stream turbine powers a ! .2 megawatt generator sufficient to power 1,000 homes. Means to supply power when the tide is turning can be a battery charged when the tidal current is running. Another interesting solution is to use some of the generated electricity to compress air in a sealed cavern. During times when the tide is turning, or when the wind isn't blowing for wind turbines, the compressed air hecomes a motive force to generate electricity. The "double basin" method of tidal power provides a continuous supply of electricity because the water flows continually from a higher basin to a lower basin. Water in the upper basin is replenished during high tide and water accumulating in the lower basin is drained during low tide. Continuous power is possible by installing a turbine in a river as proposed for the Mississippi and the Niagara where power generation would not be interrupted by changing tides. Tidal or river currents with an optimal speed is 4.5 to 6.7 miles per hour (2 to 3 meters per second) turn a propeller that drives a generator whose output is transmitted to shore via underwater cables. In principle, this is similar to a wind turbine. The major difference is that water is 850 times denser than air, which allows a smaller propeller to generate electricity at a lower rate of rotation. (Fish learn to live with the rotating propellers whose speed is slow enough for them to escape contact.) A tidal turbine with thirly-four-foot-long blades has been built in Hammerfest, Norway, capable of generating 300 kilowatts of electricity when the tide is running to supply the local community of 35 homes. The European Marine Energy Centre describes tidal devices being built or proposed to capture tidal energy such as the horizontal axis turbine (one is installed in the East River of New York City), the vertical axis turbine, the oscillating hydrofoil, and other designs along with a list of over fifty companies in various stages of developing tidal power.36 The largest water current electricity-generating scheme ever devised is the proposal to dam the Mediterranean at Gibraltar where the waterway is about ten miles wide. There are two currents at Gibraltar; a surface current of outgoing water and a deeper current of incoming water (submarines during (he Second World War would "sneak" into the Mediterranean by drifting in this lower current)." The net flow of water is incoming as the Mediterranean and Black Seas evaporate more water than is entering via the Nile, Danube, Dnieper, and other rivers. Obviously gates would be necessary for the passage of ships. Enormous turbines would be installed in the dam powered by the incoming water current. The electricity-generating potential is enormous, but cost and obvious concerns over its environmental impact have stymied the project. Waves are caused by wind and their enormous energy potential can be tapped by using hydraulic or mechanical means to translate the up-and-down motion to rotate a generator. Calm weather and severe storms affect the operation of these devices, but when in operation, electricity can be delivered to shore via underwater cables. While one may feel that this energy source is futuristic, tens of thousands of navigational buoys have long relied on wave motion to power their lights. The height of a column of water in a cylinder within the buoy changes with the up-and-down motion of the buoy, creating an air-pressure differential that drives a piston powering a generator to supply power for the lights, sound signals, and other navigational aids of the buoy. A battery is kept charged by the wave motion in case of calm weather. One wave-power system has been in operation since 1989, producing 75 kilowatts for a remote community at Islay in Scotland. Pelamis Wave Power builds sausage looking semi submerged, articulated cylindrically shaped wave generators where internal hydraulic rams, driven by wave motion, pump high pressure oil through hydraulic motors to drive generators. Electricity is collected in a single underwater cable for transmission on shore. Load control maximizes output in quiet seas and limits output in dangerous weather. Precautions have to be taken to keep ships away from wave generators. Ocean Power Technologies produces a conventional looking buoy capable of converting wave energy to a mechanical stroking action that drives an electricity generator for servicing a shore community. Small generating buoys are deployed off the coast of New Jersey and Hawaii. A 1.4 megawatt installation is being built offshore northern Spain with a planned project for a 5 megawatt installation offshore U.K.38 An entrepreneurial professor of electrical engineering has invented a simple "wave-energy converter" with only one moving part. The buoy consists of an outer cylinder with copper wires wound on its inside tethered to the bottom so that it remains stationary. Inside the cylinder is a float free to move with the wave motion. The magnet in the float generates a current as it moves up and down within the cylinder, and the generated electricity is transmitted to shore by an underwater power cable.39 The last method of extracting energy from the ocean is to take advantage of temperature differentials. The warm temperature of ocean surface water can be used to vaporize a working fluid, such as ammonia, which boils at a low temperature, to drive a turbine to generate electricity. The working fluid is cooled and condensed for recycling by deeper cold water. The warmed cold water must be pumped back into the ocean's depths to prevent cooling the surface. Ocean thermal systems are located in the tropics, where warm surface waters lie over deep cold waters. This provides the greatest temperature differential for operating a turbine; even so, the efficiency of heat transfer at these relatively small temperature differentials is only 5 percent, a technical challenge that requires building and operating a heat exchanger large enough to produce a significant amount of electricity. Demonstration plants have been built, including one in Hawaii that produced up to 250 kilowatts of electricity for a number of years. However, technical problems associated with ocean thermal energy still pose a significant barrier to developing this source of energy on a commercial scale. One idea is to have "grazing plants" located far from shore where temperature differentials are the greatest. This precludes having an underwater cable connecting the grazing plant to the shore. The generated electricity would produce hydrogen by electrolyzing water. Hydrogen then becomes a stored form of electricity that can be shipped from the grazing plants in specially designed vessels to shore-based terminals for further distribution as an energy source for fuel cells in automobiles and homes. NOTES 1. Environment and Development (also known as the Bmndtland Commission), 1987. 2. "Energy Use in Cities" Chapter 8, Global Energy Outlook published by the 1EA, Paris, 2008; and "Emission Control Measures in Shanghai, China" published by Institute for Global Environmental Strategies Web site www.iges.or.jp/APEIS/RISPO/inventory/db/pdf/0031 .pdf. 3. "Energy Use in Cities" Chapter 8, Global Energy Outlook published by the IEA, Paris, 2008; and "Emission Control Measures in Shanghai, China" published by Institute for Global Environmental Strategies Web site www.iges.or.jp/APEIS/RISPO/inventory/db/pdf/003 i .pdf. 4. Anup Shah, "Sustainable Development Introduction" Web site www.globatissues.org/article/408/ sustainable-development-introduction 2005. 5. India Climate Solutions Web site www.indiaclimatesolutions.com/pump-sets-inigation-and-human-power. 6. Dairell M. Dodge, Illustrated History of Wind Power Development, Web site www.telosnet.com/ wind/index.html. Unless otherwise indicated, this is the chief source of information on the development of windmills and wind turbines. 7. Vaclav Smil, Energy in World History (Boulder, CO: Westview Press, 1994). 340 ENERGY FOR THE 21 ST CENTURY 8. As a child I lived on an estate dairy farm on Long Island that had a large wooden windmill, perched on top of a tall stucco and brick tower, that was used for pumping and storing water; but by then, the windmill was no longer operable and the tower had been converted to a silo for corn. 9. Web site energy.soui'ceguides.coni/businesses/byP/wRP/lwindturbine/byB/mfg/byN/byName.shtml contains a full listing of wind turbine manufacturers. 10. Figures 9.1, 9.2, and 9.3 data are from Global Wind Energy Council's Web site www.gwec.net, along with the American and the European Wind Energy Associations Web sites www.awca.org and www.ewea. org, respectively. 11, Keith Bradsher, "Drawing Critics, China Seeks to Dominate in Renewable Energy," New York Times (July 14,2009) p. BI. !2. General Electric Web site www.gepowcr.com/prod_serv/products/wind_turbines/en/15mw/ index.htm. 13. Terra Moya Aqua (TMA) Web site www.tmawind.com. 14. Outlook 2005for Wind Power, American Wind Energy Association Web site www.awea.org. 15. For example, the Australian joint venture utility company ActewAGL offers theGreenChoice Program, Web site www.aclewagl.com.au/environment/default.aspx. 16. Solar Energy Technologies Program of the U.S. Department of Energy, Energy Efficiency and Renewable Energy Web site www.eere.energy.gov/solar/solar_time_7bc-l200ad.html. 17. Solar Energy History Web site www.facts-about-solai'-energy.com/solar-energy-history.html; and Solar Panels Plus Web site www.solarpanclsplus.com/solar-energy-history; and Solar Energy History Web site www.solarevents.com/articies/solar-energy/solai'-energy-history; and Ausra "A History of Solar Power" Web site www.ausra.com/history/index.html. ! 8. United Nations Development Program (UNDP), "World Energy Assessment: Overview 2004 Update," New York, 2004. 19. National Renewable Energy Laboratory's Web site www.nrel.gov, 20. Energy Efficiency and Renewable Energy Solar Technologies Program Web site www.ecre.energy. gov/solar/csp.htmi. 21. EnviromissionCompanyWebsitewww.enviromission.com.au. 22. Data for Tables 9.1 and 9.2 obtained from ECO Worldly Web site ecoworldly.com. 23. Solar Energy Technologies Program oT the U.S. Department of Energy Efficiency and Renewable Energy Web site www.eere.energy.gov/solar/pv_cell_light.html. 24. PV Power Resource Web site www.pvpower.com. 25. For more information on BP Solar installations in remote locations, sec Web site www.bp.com/ge-nericartic!e.do?categorytd=3050422&contentld=7028813. 26. Internationa) Energy Agency Photovoltaic Power Systems Program 2007 Report, Web site www. iea-pvps.org. 27. Arizona Power Service solar program is described on Web site www.aps.com/main/green/choice/ choice_82.html, 28. "Solar Grand Plan," Scientific American (January 2008), p. 65-73; also available at Web site www. scientificamerican.com/articlc.cfm?id=a-solar-grand-plan. 29. Geothermal Education Office Web site geothermal.marin.org. 30. Geothermal Resources Council Web site geothermal.org. 31. GeodynamicsLtd.Websitewww.geodynamics.com.au. 32. "Swiss Geothermal Project Causes Earthquakes" published online by Scitizen (September 12, 2007), Web site http://www.scitizen.com/. 33. Wendell A. Duf field and John H. Sass, Geothermal Energy-Clean Power from the Earth's Heal, Circular 1249 (Washington, DC: U.S. Geological Survey, U.S. Department of the Interior, 2003). 34. For the current status of this project, see Web site www.reuk.co.uk/Sevei'n-Bari'age-Tidal-Power.htm. 35. Environmental & Energy Research at the Washington University in St. Louis, Web site www.eer. wustl.edu/McDonneIlMayWorkshop/Pre sentation_files/Saturday/Saturday/Park.pdf. 36. European Marine Energy Centre (EMEC) Web site www.emec.org.uk. 37. The 1981 movie Das Boot shows a submarine taking advantage of this current. 38. Patamis Wave Power Web site www.pelamiswave.com; Ocean Power Technologies Web site www. oceanpowertechnologies.com. See also European Marine Energy Centre for description of wave generating devices and companies involved with this technology Web site www.emec.ort.uk. 39. "Catching a Wave" by Elizabeth Rusch, Smithsonian (July 2009), vol. 40, no 4, p. 66. 10 LOOKING TOWARD THE FUTURE This chapter deals with the hydrogen economy, climate change, the impact of fossil fuels on the environment, legislative acts to deal with air pollution, and energy efficiency and conservation. THE HYDROGEN ECONOMY Hydrogen is the most abundant element in the universe, making up 75 percent of its mass and 90 percent of its molecules. Hydrogen, when burned as a fuel, emits only water and heat, the cleanest source of energy by far. Though plentiful in the universe, there is no free hydrogen here on Earth. While a portion is locked away in hydrocarbons and other chemicals, most of what there is has already been burned and its product of combustion is all around and in us: water. Curiously, human progress in energy has been marked with decarbonizing fuel sources. For most of history, humans burned wood, which has the highest ratio of carbon to hydrogen atoms, about ten carbon atoms per hydrogen atom, in comparison to fossil fuels. This means that burning wood emits more carbon dioxide than burning fossil fuels for an equivalent release of energy. Coal, the fossil fuel that sparked the Industrial Revolution, has about one or two carbon atoms per hydrogen atom, which means it emits less carbon dioxide than wood. Next is oil, with one half of a carbon atom per hydrogen atom (or one carbon atom for every two hydrogen atoms), and natural gas is last, with one-quarter of a carbon atom per hydrogen atom (or one carbon atom for every four hydrogen atoms). Thus, as people have learned to use new fuels, each one was a step down in carbon dioxide emissions for an equivalent release of energy. The ultimate step is hydrogen, which has no carbon atoms and, therefore, no carbon dioxide emissions, no emissions of carbon monoxide, sulfur, nitrous oxides and other progenitor chemicals that create smog, and no metallic emissions (mercury, arsenic); hydrogen produces only plain water and heat. Henry Cavendish discovered "inflammable air" in 1766 and Antoine Lavoisier renamed it hydrogen. Hydrogen is colorless, odorless, has no taste, and burns with a pale blue flame virtually invisible in daylight. In the 1870s, Jules Verne thought that water would be the fuel of the future. In 1923, John Haldane predicted that future energy would be in the form of liquid hydrogen: Rows of windmills would generate electricity to produce hydrogen by the electrolysis of water. Hydrogen gas would then be liquefied and stored in vacuum-jacketed underground reservoirs until needed to generate electricity when recombined with oxygen. Although his idea was ridiculed at the time, Haldane's prediction is essentially where we are headed today.1 The fuel for the engines on German-made Zeppelin dirigibles that carried passengers between European cities and across the Atlantic Ocean to the United States varied from diesel fuel to a mixture of benzene and gasoline, augmented by excess hydrogen blow-off as a booster fuel. The crash of the Hindenburg in 1937 ended the days of dirigibles filled with hydrogen, which was replaced with 341