The people of Samsø have seen the future, and it is a wood-burning stove. Six years ago, the 4,400 residents of this diminutive Danish island made an ambitious pledge that they would learn to give up fossil fuels by 2008. Now they have largely closed in on the goal, primarily by embracing smart updates of traditional ways to tap renewable energy sources—sun, wind, biological gases, and wood.
The stove in question is actually a huge, state-of-the-art furnace that pipes hot water to about 180 nearby houses in the coastal village of Nordby. Above it, a giant scoop hangs motionless over an empty chute, its opposing claws clenched shut, a bundle of wood chips in their grasp. On a silent cue from the machinery’s digital brain, the claws release, and the chips tumble down to sustain a fire burning at 1,600 degrees Fahrenheit. The fire heats water; the water heats the houses.
After emptying, the scoop slides along a track on the ceiling, stops above an open container, reaches down to grab more wood, then whirs back to its ready position. On a cold winter’s day, the stove might consume seven tons of chips harvested from a forest on the other end of the island. Now, however, it is spring and merely brisk, so the fire’s daily appetite has dropped to something more like a steady nibble.
Some of the heat dissipates in transmission, but the design is 80 to 90 percent efficient, says Lasse Lillevang, a consultant and the former planner for Samsø Energiselskab, a company that organizes and provides consulting for renewable energy projects on the island. “When you cool down the smoke, you have condensation containing a lot of energy. So the plant is actually 105 percent efficient,” he says. Outside, Lillevang points to the cloud billowing from the smokestack. “It is only steam; you can see how white the smoke is,” he says. “That’s because the burning process is so clean.”
Next to the smokestack are 20 rows of solar panels, 10 panels to a row—all told, 27,000 square feet of them planted in a muddy field. In summertime the panels will supplant wood chips as Nordby’s sole energy source for heating water.
