A Place Where Wood Heat Is a Lesson in Itself
Wolf Ridge Environmental Education Center
Finland, Minnesota, United States
Cordwood Heating System
Heating Capacity (output): 900 kW (3 MMBtu/hr)
Annual Cordwood Use: 175-200 cords
Year Installed: 1988
Thermal Output: Hot water
Wolf Ridge Environmental Learning Center PDF
To a great many of the 17,000 people who visit the Wolf Ridge Environmental Learning Center in upper Minnesota each year, a biomass-fired campus heating system is part of the learning process.
Since 1988, Wolf Ridge has used four GARN cordwood boilers to generate heat and hot water for its campus in Finland, northeastern Minnesota, about six miles from Lake Superior’s north shore. The system heats five buildings, in three loops, totaling 81,000 square feet—and although the big wood “stoves” (they are actually boilers) are low-tech and more than 30 years old, learning how well they work is still an education for many visitors.
“We probably get more enthused attitudes from the adults who come here for coursework than the kids,” says Peter Smerud, executive director at Wolf Ridge. “The kids think it’s cool. But the adults are really interested.”
About 70 miles northeast of Duluth, Wolf Ridge operates year-round with a staff of 60 and 380 beds for overnight programs. Elementary, middle, and sometimes high schoolers are the primary audience for its hikes, canoe and kayak trips, wilderness adventures, and onsite programs in environmental science and sustainability. The center also runs teacher workshops, family programs, and a grandparent-grandchild residency that it created within Elderhostel.
“You could say the education at Wolf Ridge is taking place on two levels,” explains Smerud. “One is the fourth through eighth graders who come here, but then we’re also teaching the teachers.
“When we were building a new facility in the mid-80s, we said, ‘What kind of technology should we be looking at?’ We’re in a forested environment, and it made sense to heat with wood,” Smerud says. The system, he adds, “helps bring jobs to an area that could use it.”
"That Birch Came off Our Property"
Each boiler heats 3,200 gallons of water, which circulates around the campus in a closed-loop system. The simple system is robust: It has kept Wolf Ridge warm through winter nights that have reached 58 below zero.
“It’s cost effective, but you’ve got to rely on people. We need to fill those stoves every three to four hours, because there’s a lot of buildings to heat.”
In the heating season, Wolf Ridge’s maintenance supervisor Gary Olson oversees the stoking of the system on each of its day, evening, and night shifts. At each stoking, wood is loaded from a pile just outside the building into a wheel barrel and moved over to the boilers to be unloaded. It takes 15-20 minutes for one person to stoke all four.
On average over the past decade, Wolf Ridge has burned 175-200 cords of wood per year, almost all paper birch. “We own 2,000 acres; last year and this, all of that birch came off our property,” Smerud says. “We’re trying to make commitments of certain parts of our property to look at sustainable fuel sources.
“The cost to run our system for a year, including all the wood, labor, maintenance, electricity for pumping water, etc., equals $47,000 in a very cold climate. We’re still throwing wood through most days in May!”
"They'll End with, 'Thank You'"
When they bring students and others to see the Energy Center that houses the biomass system, Wolf Ridge educators show how the system works. The fire in the stoves is burning very hot, above 1,600 degrees; a fire this hot creates a very clean burn.
The educators take students to the wood pile, and add logs to the fire. Then, to bring the fuel-supply side into focus, they talk about trees.
“We say it takes about four to five trees per cord,” Smerud said. For a year’s fuel supply, “we’re talking at least 800 trees. We can go right outside the building, outside our energy center. We can look at the woods and say, ‘Those trees right there.’
“Our goal is really to connect kids and adults to an energy need and to the resource. For most of us, there’s very little connection: When I get cold, I turn up the thermostat and it gets warmer. Here, it’s pretty easy to make the connection.
“We can also connect this to choices. I can choose to insulate more; I can choose how to design my house. What are actions we can take, besides just turning up or down my thermostat?
“We’ll get emails from parents periodically, saying ‘My kid came home as the new conservation police of the house! I can’t leave a light on; the thermostat is turned down when we leave for the day,’” Smerud says. “They’ll end with, ‘Thank you. My child is driving change within the household, because of the motivation they got at Wolf Ridge.’”
These days, Wolf Ridge is improving its system’s efficiency and considering new biomass options. In the summer of 2009, the center is replacing its aged, fiberglass heat distribution pipes. Unable to bury its pipeline very deep—because bedrock lies quite close to the ground surface—Wolf Ridge has been losing about 47 percent of its heat to the ground. Newer, insulated polyethelyne piping added with a new building in 1996 loses only about 12 percent, according to Smerud.
The fuel and labor savings that will result from replacing the older piping “could be really exciting for us,” Smerud says.
“Now we’re looking at replacing those GARN stoves. We’re committed to wood, and to staying with the centralized plant; but now we can look at going to woodchips, to automated systems where we don’t have to have someone there on Christmas night.
“But even in this heavily forested area of the state, there isn’t really the chip supply yet,” Smerud concludes. “There certainly is the potential for it—so we’re looking at that. It certainly seems logical that this is a great resource that will be there.”