By David L. Brown
First, here’s the bad news: The world’s supply of available petroleum is about to peak just as demand is reaching record and growing levels due in part to the addition of the vast nations of China and India to the list of major oil importers. Natural gas supplies are also being drawn down at unsustainable rates. Soon, alternative energy sources will need to be found.
But there’s even worse news (you didn’t expect good news in relation to the challenge of energy use and climate change, did you?) In the near term at least, coal will be the alternate fuel of choice for energy production, through burning in power plants, gasification, and even liquification programs. There is enough coal to last for centuries at present rates and coincidentally much of the world’s coal reserves are found in places that will have the most demand, with 75% of the stuff being found in China, India, Russia, the United States and Australia.
Some see this as good news after all, but now for the even worst news: Coal produces more carbon dioxide than any other fossil fuel, twice as much as natural gas. At present coal burning is responsible for about 40 percent of CO2 emissions, and projections of energy use indicate that unless steps are taken, by the end of the century it will be cranking out fully 80 percent of the carbon entering the atmosphere.
Clearly, something must be done to rein in this runaway horse before the nightmare scenarios of worst-case climate change predictions become reality.
The best alternative, at least from the point of view of the environment, would be to replace fossil fuels with “clean and green” energy sources that do not release carbon into the air. These include solar, nuclear, wind, hydro, and thermal.
Unfortunately the economics strongly favor continued reliance on fossil fuels, at least for the next few critical decades, and the focus is turning more and more toward coal. In China a coal-fired power plant is coming online on the average of once each week. In the United States there are 150 planned coal-fired plants on the drawing boards or in the approval stage. Clearly the Age of Oil is morphing into a new Age of Coal. What to do?
There may be an answer, but it is not one that is particularly appealing to those who build and operate coal-fired plants. That is to capture the CO2 they produce and sink it into the ground. This is called sequestration, and it has the theoretical ability to hide the greenhouse gas for centuries. The gas could be stored in underground saline aquifers (reserves of water too salty to be used for agriculture or drinking); pumped into depleted oil and gas fields; injected into deep layers of sedimentary rock; or even buried beneath the sea bed.
This would be an expensive proposition, which explains why exploiters of coal are not eager to embrace the idea of sequestering their greenhouse gas. They are like dog owners on the sidewalks of Paris or New York, chafing at the idea of having to clean up after their pets. And yet, eventually it will become necessary to stop the pollution and enforce a greener model for power production. Only in that way can we both continue to provide power for our economies while preventing runaway global warming.
But are we ready?
At present, the technology to make sequestration work is available mostly in theory. There are some small pilot projects underway, but far too little is known about how to capture the CO2, transport it to appropriate places, and put it into the ground. Questions abound concerning the safety and practicality of sequestration, questions such as whether we can be certain the gas will stay in the ground or whether our economy can sustain the added expense.