Seattle Steam Co., a major supplier of heat to downtown Seattle buildings, is going to begin turning waste into a source of energy. The company began construction yesterday on a hybrid heating plant, with a boiler that is able to burn waste wood as well as Seattle Steam's current primary energy source, natural gas. According to this article by Seattle Times reporter Will Mari, Seattle Steam plans that about 60 percent of the new boiler's energy will come from waste wood collected from urban construction sites, sawmills, factory crates and pallets, and other products.
Combusting waste wood closes the "carbon loop," said Patrick Mazza, research director for Climate Solutions, a Seattle-based research and advocacy group.
"You're contrasting a fuel source that has been notably volatile in terms of price with a local, renewable fuel source," he said. "It's one of those things that we know to do well, but that we've kind of forgot during the age of cheap energy."
But what of the greenhouse gases released by burning wood? Coverage by Bill Virgin at the P-I addressed this issue in a question to Seattle Steam President Stan Gent:
Burning wood actually will release more of those gases than burning natural gas, Gent says. But advocates of such a switch argue that over the full life cycle of the tree, the net release is zero, since the tree is absorbing and storing carbon dioxide while growing.
The ash produced from burning the wood will be collected and sold to concrete companies, which can use the waste as an industrial nutrient.
As Mike Mann of the Office of Sustainability and the Environment told the Times, the $25 million plant will prevent 50,000 metric tons of carbon from being released each year, by replacing the use of a fossil fuel with the use of waste wood. The facility is expected to open in July 2009.
You can read previous waste-to-energy articles in the Worldchanging archives, including our piece on Denmark's iconic Kalundborg industrial park, or Alex's posts on the neobiological industry and Svend Auken's energy plan.
Image courtesy of Seattle Steam Co.