Capture and sequestration will help ensure the future of coal-fired power plants. Demonstration projects are allowing utilities to kick the tires on the latest technologies, and to learn how CCS...
Carbon Sequestration: Robin Hoods of the Forest?
Appearing as tree huggers, utilities draw skeptical reaction from environmentalists.
At first glance, it looks like the same old story: Environmentalists versus utilities. But this time, the utilities are the ones fighting for the forests (em with a twist.
Utilities, major producers of carbon dioxide, believe they've found a cost-effective way to offset emissions through carbon sequestration, or sinks, which means converting pastures to forests or maintaining old-growth groves.
But environmentalists call it an easy way out. They say forest sinks only avoid the real issue (em installing control technologies at power plant sites to reduce emissions. Besides other faults, they say it's difficult to predict how much C02 can be stored in a forest sink and nearly impossible to prove. Carbon dioxide generally is accepted as the primary source of global warming.
"This is a red herring ... it isn't really a solution to the problem," says Steve Pedery of the Sierra Club. "In general, it's just an incredibly hard thing to enforce and police."
Proponents admit that there are flaws to the idea, yet maintain that utilities are exploring every option to mitigate the harmful effects of carbon dioxide. "There's no way that utilities are going to make this their sole way of dealing with CO2," says John Kinsman, manager, atmospheric science at the Edison Electric Institute. The EEI helped form and now manages UtiliTree Carbon Co., a nonprofit organization of 40 electric companies. "It's a small piece of the pie. ... No one is going to take this practice and ignore emissions."
Measurement and benefit issues, however, will be debated until December when in Kyoto, Japan, State Department negotiators include mandatory sequestration proposals in the U.S. protocol. Global treaties now include sequestration as a voluntary measure.
Studies can show how fast trees grow on different soils. As a rule of thumb, for every cubic foot of wood that grows, 35 pounds of carbon are stored, which translates into one to two tons of carbon per forested acre per year, according to Neil Sampson of The Sampson Group Inc., a consulting firm which has helped utilities set up sinks.
According to the Energy Information Administration, a single coal plant in the U.S. released an average of 4.3 million tons of CO2 in 1995, assuming 100-percent combustion. About 1.8 billion tons of CO2 were released that year.
Sampson admits the link between atmospheric carbon dioxide and climate has not clearly been established. "But, we know pretty well how to measure the flows of carbon from the atmosphere into trees. Can we show them how to offset CO2? The answer is yes ... we can build the numbers for these. Can we build them with 100 percent certainty? No."
Carbon sinks can be modeled within a 10-percent error margin, he says. Although he does admit they make a small contribution to the international emissions picture. But there are only two choices, he says: either spend billions on huge projects (em which typically fail because they are too far-reaching (em or make a million small contributions that require modest investments.