Utility companies are racing to find alternative fuels to generate electricity, and one possible new source is also one of the oldest: burning wood.
The James River Power Station in Springfield, Mo., has been working with torrefied wood, which looks like dark sawdust. Torrefaction, also known as biochar, is a process of roasting wood chips in a large furnace, but not to the point of becoming charcoal.
Some consider burning torrefied wood a cleaner energy alternative to burning coal â€” which scientists say is responsible for more than one-third of the world's carbon dioxide emissions.
Coal and wood both give off carbon dioxide when burned, but the trees originally got their carbon from the atmosphere as they grew, so burning wood doesn't put new carbon dioxide into the air.
Torrefaction has been gaining momentum in Europe, and now American companies are experimenting with the process.
Kansas-based Earth Care Products creates torrefied wood and other biomass energy products. In Springfield, the company is testing whether local provider City Utilities can mix a 10 percent blend of the wood with 90 percent coal and still get good results.
"We have a lot of hardwoods. We have a lot of trees that need to be cleaned up, wood chips that need to be cleaned up initially," says Steve Myers, director of the James River facility.
While many environmentalists see some benefits to burning wood instead of coal, they also have reservations about where that wood might come from.
"Anytime you have a situation where you have trees being cut on a significant scale, directly for power plant use, for combustion in a power plant, you do run the risk of some ecological impacts in that forest," says Terrence Bensel, a professor of environmental science at Allegheny College in Meadville, Pa.
But Chris Hopkins, a researcher at North Carolina State University who produces torrefied wood on a small scale, says large coal-burning facilities are still reluctant to sign onto the idea without seeing solid results from much larger test burns.
"It's just unknown as to whether you can produce machinery at that scale for a reasonable amount," Hopkins said. "You don't know what the technical hurdles may be as you scale up."
Utility officials are still analyzing data from the Springfield tests. But they say they like the idea of burning larger quantities of torrefied wood, as well as other biomass products like switchgrass, to fuel the power station.
And they say that in doing so, they hope to take a small step toward weaning the hundreds of coal-burning power plants in America off of the one fuel they currently rely on.