Craig plans to use Tongass waste wood to heat buildings

Posted: Monday, February 11, 2008

ANCHORAGE - The small community of Craig is proud of its big swimming pool.

City Of Craig Via The Associated Press
City Of Craig Via The Associated Press

But what city administrator Jon Bolling discovered while reviewing the budget was that the cost of heating the competition-size pool was a big drain on the Southeast Alaska town and its 1,100 residents, siphoning off about $80,000 last year.

"It is expensive to operate," he said, of the Craig Aquatic Center.

Bolling next looked at how much it cost the school district to heat the school buildings with diesel heat - $45,000 a year.

The city first considered converting the pool from propane to diesel. But then a woman Bolling describes as a "progressive thinker" approached with an idea.

Bolling didn't warm to it right away.

What about using all the waste wood from the local sawmills to heat the pool and school buildings with wood?

"I thought she was nuts to be honest with you," he said.

Later this month, Craig will become the first town in Alaska to use waste wood - mostly leftover bark, branches and wood stripped from trees at the sawmill - to heat buildings. The wood-fired boiler is expected to burn about 2 tons of waste wood a day, saving the sawmill companies the cost of carting the stuff away. The town will get the wood for free as long as it pays for delivery.

Craig and the school district combined expect to save $85,000 a year with the wood-fired boiler. The city will save about $50,000 - not an insignificant amount given the town's $2 million operating budget, Bolling said.

Karen Petersen said Bolling wasn't the only one who thought her idea was crazy. Four years ago diesel was only 80 cents a gallon. A barrel of North Slope crude was $17.

But Petersen had a feeling that fuel prices were going up and staying up. During the six months discussing whether to convert to diesel or a wood-fired boiler, crude prices nearly doubled.

"They thought it was a temporary spike. I said 'You know guys I think it will keep going up. It is the right thing to do. We're getting off the diesel,"' she said.

Now, diesel costs nearly $4 a gallon and propane is $2.61 a gallon.

The wood Craig gets for its boiler comes from the Tongass National Forest, at nearly 17 million acres the largest national forest in the United States. Craig is situated within the forest.

Petersen, who works for the University of Alaska cooperative extension service, said she was hired five years ago to improve the economy on Prince of Wales Island, where many residents found themselves out of work when two Southeast pulp mills closed several years ago.

Her job was to find new markets for value-added wood products.

"I looked at all the wood waste that is generated at the sawmill operations and thought there ought to be something we can do with it," she said.

Craig estimates that if none of the wood mills on the island shipped out their wood waste or burned it for one year, they could supply a furnace three times the size of Craig's for 20 years.

"It is really an unlimited supply," said Greg Killinger, Craig district ranger for the U.S. Forest Service, of the wood and wood waste available from the Tongass.

While reducing greenhouse gasses was not a hot topic four years ago, Petersen said she was aware even then of the harm that fossil fuels were doing to the environment. Wood-fired boilers have the added bonus of being carbon neutral, she said. That's because living trees take up carbon dioxide. As long as trees are grown to replace the wood that is burned in the boiler, burning it does not increase carbon dioxide in the atmosphere, she said.

The wood-fired boiler also helps improve air quality because it reduces the need for burning forest slash in open piles - a practice, along with wildfires, that cloaks some areas of Alaska in a perpetual blue haze during the summer.

While the conversion to wood heat sounded increasingly good to Craig, it took a trip to Darby, Mont., to convince city officials. A wood heating system there replaced three oil burners to heat three school buildings, reducing Darby's heating costs from $120,000 to $40,000 a year.

Darby's boiler is being fed with wood shavings from a post and pole plant.

"It is working wonderfully," said Darby school superintendent Bruce Wallace. "He helps us use his waste product and he makes a little, and we get fairly cheap fuel."

Craig found various funding sources for its $1.5 million project, including federal, state and local money. Craig provided a half-million dollars by getting a low-interest loan.

"That is a lot for this little town," Bolling said.

The town had to spend $100,000 for a system to dry the mostly hemlock waste wood so that it can be used efficiently in the boiler.

"We have a lot of rain in the Tongass National Forest," Bolling said. "Hemlock is a very wet wood. It soaks up water like crazy."

The system uses the heat from the boiler to heat air to 185 degrees. The air is then sent through ducts in the floor of the wood waste storage area. An electric motor moves the air through the pile of wood waste to dry it.

The goal is to reduce the water content of the wood to 35 percent or less. Above 50 percent and it won't burn well, emitting smoke and odor from the smokestack, Bolling said.

However, at the proper moisture content to the wood, people in the town won't even know the boiler is operating, he said. The exhaust stack on the boiler will not emit smoke, just a moist, steamy gas at times.

Wallace said when the Darby boiler is working at peak efficiency all that can be seen is heat waves coming from the chimney.

While wood-fired boilers emit a variety of pollutants, including particulate matter, nitrogen oxides and carbon monoxide, the levels are below where a state permit is required, Bolling said. Craig's boiler is equipped with a cyclone separator that removes most of the particulate matter.

Michael Matson, owner of Alternative Building Services in Trinidad, Ca., said high-efficiency wood boilers are a good alternative to fossil fuels. However, an anti-forestry attitude is keeping more people and businesses from making the switch, he said.

"It is a resource. It can be grown back again and again like corn. As long as we do that, we have a perpetually renewable product," Matson said.

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