Even as public debate rages over the question of whether coal should continue to provide the majority of U.S. electric power needs, the U.S.

With the recent dwindling of traditional petroleum supplies, some energy corporations have shifted their attention to oil sands, a mixture of sand, water, and a viscous form of petroleum called bitumen. Despite economic uncertainties in the oil sands market, many in the United States see the resource as a stable, secure alternative to overseas oil, with primary deposits found in Canada.

As more and more multibillion-dollar projects for sequestering carbon dioxide (CO2) deep within the Earth seek financial support, human-formed fertile black soils in the Amazon basin suggest a cheaper, lower-tech route toward the same destination.

Biofuels are being promoted as energy sources that could reduce both dependence on imported oil and fossil fuel emissions. Currently, a large percentage of biofuels are produced from food crops, a situation that some experts say is leading to food insecurity around the world.