Pellet experiment looking good
Wood pellets stored in a silo behind the Senior Center haven’t absorbed measurable amounts of moisture since being loaded there in November, according to a study conducted by Haines High School’s Power Systems Engineering class.
The question of absorbing moisture was one that was raised last fall when the Haines Borough was considering a pellet-heat system now being tested at the center.
Using a test method developed by the U.S. Forest Service, the class found the pellets had a moisture content of 5.4 percent on Nov. 20 and 5.32 percent March 5-6. The testing involves placing pellets in a microwave for intervals and weighing them after each heating.
“It clearly shows they’re not absorbing moisture,” said science teacher Mark Fontenot.
Fontenot said he wasn’t particularly surprised by the study’s results so far. The moisture tests will be repeated in about three months. “If you don’t have a temperature difference between the inside and outside or a heat source on the inside, you wouldn’t expect a big problem with moisture.”
Fontenot said the composition of the pellets – essentially sawdust compressed by a bonding agent – wouldn’t suggest they’d take up moisture quickly. “They end up hard, glossy and non-porous looking. They don’t behave like saw chips.”
Darsie Culbeck, the borough’s executive assistant, said the center has burned through about half of the 8.5 tons of pellets loaded into the silo in November, an apparent improvement over projections last fall that the supply would be depleted by April. The borough initially estimated the center might consume 12 to 14 tons per year.
“With four tons left, we could probably go until summer” before refilling the silo, he said.
The building’s pellet-burning boiler has required even less maintenance than anticipated, Culbeck said. Borough facilities manager Carlos Jimenez said last week that the system “runs flawlessly” and generates minimum ash.
Culbeck said the per-ton cost of pellets has gone up from an initial estimate of $362 per ton to $400 per ton. The cost difference over a year would be little more than $500, an amount he characterized as not appreciable.
Energy officials with the U.S. Coast Guard, U.S. Forest Service, National Renewable Energy Lab, as well as ones from the Chilkoot Indian Association, state Division of Forestry and Yukon-based Dimok Timber met with borough officials last Wednesday. One of the topics discussed was how to get pellets more cheaply.
“Once we get a regional or local supply (of pellets), that’s a big gain,” Culbeck said.
CIA is putting a system similar to the one in the Senior Center in its office building under construction on Third Avenue. “It’s about growing demand. That’s happening,” Culbeck said.
Mayor Stephanie Scott said she was encouraged by a pitch from Haines forester Greg Palmieri about the potential for using local wood chips in single-building boilers.