Wood chips help Falmouth save on school heating
FALMOUTH — When Topper West began his career at Falmouth Schools, coal was being phased out as a heating fuel in favor of cleaner, less expensive oil.
Forty-three years later, West, the district's director of transportation and maintenance, has embraced an even cleaner, less expensive fuel, which is also renewable and can be locally sourced: wood chips.
Over the past academic year, for the first time, all three of Falmouth's public schools were tied into the district's wood-chip boiler system. Between September and June, the district didn't burn a single drop of oil, and saved an estimated $400,000 in heating costs.
The use of wood as a fuel is nothing new in Maine. But wood chips and compressed wood pellets burn more cleanly, reliably and efficiently than any log fire.
Falmouth's campus-wide system uses two wood-chip boilers to heat water, which is then pumped through underground pipes into the three school buildings, West explained.
In the high school and middle school buildings, the system heats air that is blown into classrooms; in the elementary school, the hot water is pushed through smaller pipes to create radiant floor heating.
By the time the water returns to the boilers, its temperature has dropped 10 degrees or more, meaning that the system is highly efficient, West said.
Wood chips also have a minimal carbon footprint.
Most of the emissions from the smokestacks that loom above each boiler are water vapor, because the system literally "cooks” the wood, according to West. And a 35-ton truckload of wood chips, when burned, leaves only a small amount of fine ash – barely enough to fill a 30-gallon drum. The ash is used as fertilizer by local farmers, West said.
The entire system costs about $3.5 million.
The first boiler, located behind the high school, was installed in 2009 and began heating the new elementary school in 2010. The boiler's cost was paid as part of the state-funded elementary school construction project, in lieu of an oil system that would otherwise have been needed.
The second boiler, at the middle school, came online in January 2013. The $2 million cost was financed by a Maine Forest Service grant of $500,000, plus capital funds from the town and school. In May 2013, the middle school was added to the loop. All three schools were connected to the same campus-wide loop in the fall of 2013.
District Finance Manager Dan O'Shea said the system essentially eliminates oil consumption, but the schools keep a 10,000-gallon tank of heating oil as a backup.
Still, that's a drop in a bucket.
In previous years, the district burned about 150,000 gallons of oil annually. At current prices, that amount works out to a cost of roughly $552,000 per year, versus $140,400 for wood chips that produce an equivalent amount of heat, O'Shea said.
West said he was initially skeptical of the wood works, thinking it would take too much time to operate and maintain. But the largely automated system requires only 20 minutes per day to operate.
Trucks deliver the wood chips directly to a hopper. From there, a large automated auger pushes the chips onto a conveyor belt, which carries them to the burners. Each night, a worker scrapes ash and ember into a cooling tray. The next morning, the ashes are transferred into a 30-gallon barrel.
"I thought this was going to be a huge pain," West said. "But I would recommend this to any school district."
He and O'Shea also have no regrets about using wood chips as a fuel instead of the natural gas that is expected to become available in the area over the next five years. The district will use gas for cooking food in its kitchens, the two agreed, but for heating Falmouth classrooms, wood chips remain the least costly, most renewable option.
"It also provides the satisfaction that Falmouth is, in some small way, supporting Maine’s sustainable forests and wood harvest economy," O'Shea said.