How Wood Chips Can Keep You Warm — and Green

By Pat Dawson / Moscow, Idaho Saturday, Oct. 24, 2009
A mountains of cedar chips
Tracy Ferrero / Alamy

The tall smokestack and the industrial clanking of conveyors in Moscow, Idaho, may look ominously anti-ecological but, the visitors senses are quickly jolted by a fresh aroma reminiscent of a walk-in cedar closet. It is indeed red cedar: tons of chips discarded by a timber mill and trucked in to fuel the University of Idaho's steam plant in the town of Moscow (population roughly 23,000). Thermal biomass provides over 80% of heat and hot water to the campus of nearly 11,000 students. Wood-fueled steam also powers five of the eight chiller units that cool the campus buildings during warm weather. Plant Manager Mike Lyngholm says the process significantly reduces the school's net carbon emissions and saves $2 million a year over natural gas.

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"It's pretty much a no-brainer," explains Lyngholm during a tour of the facility. He is an academically trained forester who worked for many years running Northwest lumber mills but now enjoys being perceived as "one of the good guys" for running such a green operation. Idaho's system was a pioneer, coming on-line in 1986, and has been evolving since 2002 under Lyngholm, whose innovations include erecting a large building for stockpiling wood chips for times of supply shortages. The plant also burns campus landscape trimmings and discarded wooden cargo pallets.
(See new ways to boost energy efficiency.)

Idaho's central boiler is heated by burning wood to temperatures approaching 2,000 degrees Fahrenheit, performing on a par with what is called Advanced Wood Combustion (AWC) technology developed in Europe. "AWC is so clean and safe that AWC systems are commonly deployed in the midst of picture-perfect European towns and villages," says Daniel Richter, Professor of Soils and Forest Ecology at Duke University. They are different from ordinary plants that generate electricity by burning wood. In a piece in the journal Science last March, Richter wrote that 90% of the solar energy stored in wood is transformed into heat and power by AWC technology compared to 20% to 40% by simply firing wood. Furthermore, AWC burns so efficiently that it is considered to be virtually carbon neutral.
(See an interactive graphic of a green home.)

One-third of U.S. energy supplies goes towards heating, making useof electricity, natural gas, oil, coal, propane and some wood. Advocates of technology like AWC argue that one third of that could be provided by modern wood combustion which would eliminate significant outlays for imported oil and cut net contributions of carbon emissions.

Even though such power plants have very little political backing, they have been popping up from New England to the Pacific Northwest. The new technology does have support — for now. Fuels For Schools is a a six-state program funded by federal and state money that helps to retrofit school boilers, switching them from burning oil and gas to wood. Starting in Vermont, it spread westward, giving budget-strapped local districts huge savings, and a way to cut into buildups of forest deadfall that might otherwise fuel wildfires. However, it is now almost out of federal money. Even after the program helped retrofit heating systems in 10 Montana schools, the last state Legislature refused to renew appropriations.

The grade school in Deer Lodge, Montana, recently converted to burning sawmill wastes, allowing its heating gas bill to immediately drop from $6,600 a month to $1,100. Townsend, Montana, schools converted their boilers from propane and oil to wood pellets. The new system is expected to pay for itself in fuel savings, plus selling CO2 emission offsets through The Climate Trust. Meanwhile, Vermont's Middlebury College is completing a central thermal biomass system that will provide heating and cooling, saving $2 million a year on fuel-oil bills, plus generating one-fifth of campus electrical-power needs. Middlebury is planting fast-growing willow shrubs on ten acres hoping it will provide as much as half the woody fuels needed by the new system. Says Duke's Richter: "It's a technology whose time has come."

Comment

Burning wood doesnt sound all that Green, but I guess if its waste wood chips its okay. I thought that a lot of timber mills were using the sawdust to make this plastic wood. Maybe not. There is a cost to ship it in tho.