This past week, a Senate subcommittee passed a bill that would be a major step toward controlling greenhouse gases. The legislation would target places like Maryland's Brandon Shores, a large coal-fired power plant that emits 10 million tons of carbon dioxide a year.
Coal-fired power plants like Brandon Shores, located outside Baltimore, are the United States' biggest contributors to global warming. But they also supply about half of the country's electricity.
On a recent tour of the plant, Paul Allen, senior vice president of Constellation Energy — which owns Brandon Shores — discussed the plant's future.
"This power plant serves the electrical needs of perhaps a million customers. It's a very significant portion of the generation supply for the Baltimore metropolitan area," Allen said. Asked how long he expects the plant to operate, his response is optimistic. "Oh decades," he said.
That could mean Brandon Shores will also be pumping out carbon dioxide for decades. Right now, that doesn't cost the company anything. But that will change if one of the bills making their way through Congress becomes law.
The two measures would cover power plants, refineries and factories in a cap and trade system, in which they would need allowances for every ton of carbon dioxide they emit.
At first, the government would probably give Brandon Shores and other polluters some of those allowances. But over time, the company will have to buy them.
The price will be dynamic," Allen said. It could go up it could go down. But if we are serious about meeting the kind of targets that climatologists tell us need to be met, it's possible to think the price of carbon control could be pretty high."
Allen says Constellation will have no choice but to buy the allowances from other companies or the government.
"We recognize that ultimately this is going to be an additional cost of doing business."
Over time, as the cap gets tighter, that could lead to customers paying more expensive electricity bills.
Allen says Constellation can't just install a pollution control device for carbon dioxide, the way it's doing to strip out other pollutants like the ones that create smog and acid rain. The difference is that carbon dioxide is an unavoidable byproduct of burning coal.
Some engineers are working on ways to capture carbon dioxide from coal-fired power plants and then inject it underground. But Allen doesn't expect those technologies to be available any time soon.
Allen says the prospect of carbon dioxide regulation is already having a huge impact on his business. For instance, Constellation is planning to build new nuclear plants, mostly because they don't emit carbon dioxide.
"If you believe as we do, that carbon policy is both good and inevitable, and that it's going to have to be pretty significant to make a difference ecologically speaking," Allen said, "then you begin to believe that it has to be at the center of all your business planning — and for us, it is."
Economist Billy Pizer, from the Washington think tank Resources for the Future, says that Allen's statement reflects exactly the kind of thinking supporters of climate change policies are hoping to inspire by making it expensive to emit greenhouse gases.
"Suddenly this activity that had no consequence before has a consequence, a financial consequence," Pizer said.
"So, it's going to change the way people think. It's going to change the way they use the fuels they currently have and it's going to change the way people invest in research and development to try to find cleaner technologies."
Pizer says the hope is that over the long run, the changes will be enough to stabilize concentrations of greenhouse gases in the atmosphere at a level that will protect the environment.
But in the mean time, measures like the one passed this week by a Senate subcommittee will have to work their way through the political process. The bill, America's Climate Security Act, was sponsored by Sens. Joe Lieberman (I-CT) and John Warner (R-VA).
After being approved, 4-3, the bill moves on to the Environment and Public Works Committee, which is headed by Sen. Barbara Boxer (D-CA).