Experiment turns slash piles into electricity

Tons of slash from a 250-acre logging site north of Loon Lake, Wash., could have gone up in smoke.

Instead, the woody debris will be chipped and hauled to Avista Corp.’s biomass facility in Kettle Falls, where it will produce enough electricity to meet the needs of 37,500 homes for about eight hours.

“There’s no real reason to burn that stuff on a slash pile when we can turn it into clean, green energy,” said Russ Vaagen, vice president of Vaagen Bros. Lumber Inc.

Slash could be the next cash item for loggers. Spindly branches, treetops and other wood waste are routinely burned at logging sites. Through a collaborative effort, Avista, Vaagen Bros. and the Washington Department of Natural Resources are exploring whether it’s cost effective to turn slash into fuel.

At the moment, slash is “the dirtiest and highest-cost fuel we have to deal with,” said Ron Gray, fuel manager at the Kettle Falls Generating Station. “Loggers aren’t used to seeing it as the next product. They’re used to seeing a forester … put a match to the pile.”

But Avista is looking for new fuel sources. A national slowdown in the housing market means fewer sawmills are operating. That’s reduced supplies of sawdust, chips and bark.

Avista burns bark at its Kettle Falls biomass facility, turning water into superheated steam of 950 degrees.

“We’re a giant firebox that heats water for steam, which turns turbines,” Gray said.

The plant, which has operated since 1983, puts out very few emissions, said Greg Wiggins, the control operator. And it’s part of Avista’s renewable energy portfolio.

About half of Avista’s bark came from Canadian sawmills, which have been particularly hard hit by market downturns. When Avista and Vaagen Bros. – already a supplier to the biomass facility – noticed the slash piles at a DNR timber sale, they proposed the pilot project.

The DNR sale about three miles north of Loon Lake was a thinning operation, designed to remove skinny lodgepole pines and improve the health of the remaining ponderosa stand. Each acre thinned produced tons of slash.

“We’re looking at alternatives to burning slash for smoke management,” said Bob McKellar, DNR’s Northeast Region management forester.

While turning waste into energy is an attractive option, “we also have to look at the costs versus the benefits,” he said

Most of DNR’s land is managed to provide income for Washington’s public schools, so the agency can’t lose money on projects, McKellar said.

Each entity is putting up about $5,000 for the test project. Avista’s contribution will include a sign along Highway 395 explaining the work. Vaagen Bros. is grinding the slash and hauling it to Kettle Falls.

When the numbers come in, Avista will determine whether it can produce electricity from the slash for less than the utility could buy the electricity for on the open market. In the Northwest, a kilowatt of electricity sells for 6 to 8 cents on the open market, said Hugh Imhof, Avista spokesman.

With some experimentation, Vaagen said he’s confident that slash piles can contribute to green energy.

“It’s an evolution of the use of material from the forest,” he said.