Can other energy sources meet the need?

Are there alternatives to conventional oil? Perhaps. Certainly the world contains vast fossil-fuel supplies in other forms, enough to last for centuries if they can be exploited in an economical and environmentally sound way. These supplies include tar sand, oil shale, natural gas, and coal.

All told, perhaps 1.5 trillion barrels of hydrocarbons are trapped in tar sands and 3 trillion barrels trapped in oil shale. In addition, there are coal deposits that could meet our energy needs for the next few centuries. But extracting tar sand, oil shale, and coal requires the construction of huge mines, which might scar the landscape. Natural gas and coal bed methane are probably our best alternatives in the near future, but they remain very expensive to transport.

Can nuclear power or hydroelectric power fill the need? Vast supplies of uranium, the fuel of traditional nuclear plants, remain untapped, and in addition, nuclear engineers have designed alternative plants, powered by “breeder reactors,” that essentially produce their own fuel. But many people view nuclear plants with suspicion, because of concerns about radiation, accidents, terrorism, and waste storage, and these concerns have stalled the industry. A substantial increase in hydroelectric power production is not likely, as most appropriate rivers have already been dammed, and industrialized countries have little appetite for taming any more. Similarly, the growth of geothermal-energy output seems limited.

Because of the problems that would result from relying more on coal, hydroelectric, and nuclear energy, researchers have been increasingly exploring “clean energy” options. One possibility is solar power. Unfortunately, affordable technologies for large-scale solar energy do not yet exist, and the idea of covering the landscape with solar cells is an unattractive one. Similarly, we can turn to wind power for small-scale energy production in areas where strong gusts blow, but covering the landscape with windmills is no more appealing. Fusion power may be possible, but physicists and engineers have not yet figured out a way to harness it. Despite their inherent problems, natural gas, coal, and nuclear power will probably step in for oil when the Oil Age comes to a close, but clearly society will be facing difficult choices in the not-so-distant future about where to obtain energy, and we will need to invest in the research needed to discover new alternatives.

Environmental issues

Environmental concerns about energy resources begin right at the source. Oil drilling requires substantial equipment, the use of which can damage the land. Oil spills from pipelines or trucks sink into the subsurface and contaminate groundwater, and oil spills from ships create slicks that spread over the sea surface and foul the shoreline. Coal and uranium mining also scar the land and can lead to the production of acid mine runoff, a dilute solution of sulfuric acid produced when sulfur-bearing minerals such as pyrite (FeS2) in mines react with rainwater. The runoff enters streams and kills fish and plants. Extensive coal mining may also cause the ground surface to subside. This happens when an underground mine collapses, so that the ground sinks. As a result, building foundations may crack. Coal-seam fires may also pose a problem. If ignited, a seam may smolder underground for years, releasing noxious gases that seep through cracks and pores to the ground surface, making the region above uninhabitable.

Numerous air-pollution issues also arise from the burning of fossil fuels, which sends soot, carbon monoxide, sulfur dioxide, nitrous oxide, and unburned hydrocarbons into the air, all pollutants that cause smog. Coal, for example, commonly contains sulfur, primarily in the form of pyrite, which enters the air as sulfur dioxide (SO2) when coal is burned. This gas combines with rainwater to form sulfuric acid (H2SO4), or acid rain. For this reason, many countries now regulate the amount of sulfur that coal can contain when it is burned. Because of these regulations, low-sulfur coal, such as the coal that occurs in Cretaceous seams of the western United States, commands a higher price per ton than the higher-sulfur coals of the Midwest.

But even if pollutants can be decreased, the burning of fossil fuels still releases carbon dioxide (CO2) into the atmosphere. CO2 is important because it traps heat in the Earth’s atmosphere much as the glass traps heat in a greenhouse— this is the “greenhouse effect.” Too much CO2 may lead to a global increase in atmospheric temperature (global warming), which in turn may alter the distribution of climatic belts.