You step off the bus or out of your car, immediately you are smacked by the raw winter air. Your eyes begin to water. Less than 25 feet from the door and you feel the inside of your nose freeze; you pick up your pace. By the time you reach the door your vision is blurry and fingers non-responsive. The door swings open and a warm breeze rolls over your frigid body. The further you move into the school the warmer it gets. “How?” you wonder, “How is the school kept so warm through these brutal winters?” The answer is the Harwood Woodchip Boiler.

What is a woodchip boiler?

Way back in the year 2006 Harwood decided that burning oil to heat the school cost too much and was too bad for the environment. Their solution? To install a woodchip boiler.

A WB works by loading woodchips into a furnace and burning them at extremely high temperatures. This heat in turn boils water in a boiler above the furnace. Temperatures in the boiler were at 181°F when I visited the boiler house. In fact they have to cool the water when it comes out of the tap in the school!

How Environmentally Friendly is it?

The woodchips themselves produce very little waste due to the high temperature in the furnace. The ash produced gets cleaned out daily and is then given to Mr. Macleod to fertilize his fields. The woodchips are also locally-sourced instead of imported like the oil was.

The smoke stack actually produces steam, not smoke.

How does it work?

The entire machine is basically a series of conveyors and augers (giant screws) transporting the woodchips from a storage pit to the furnace. The furnace then heats up water in the boiler which is then whisked away to the school, looping through and back to the boiler to be heated again.

A youtube video of the process in action:

https://www.youtube.com/watch?v=UdfiNmN1lPk&t=1s

Quick Facts:

• The system was installed winter 2006-07. (10 years ago)
• It cost 1.6 million dollars.
  • 90% was paid for by the federal and state government.
  • 10% Harwood investment was paid back in three years.
• Costs $50,000 to run yearly compared to the $130,000 it cost to operate the oil boiler.
• Approx. 900 tons of woodchips are burned every winter.
• The woodchips are locally sourced.
• The burner runs from mid-October to April break depending on weather.
• Only requires 15 minutes of maintenance daily.