Editor’s Note: This is the second part of a three-part story looking at Vermont’s ambitious wood energy goals and how heating with wood has evolved over time.
The first part of this series looked at Vermont’s goal of doubling the amount of people who heat with some form of wood by 2035 to decrease the state’s reliance on heating with fossil fuels. It also covered some of the reasons why cutting wood and proper forestry management can help sequester carbon and reduce climate change.
The Mad River Valley Planning District partnered with the Central Vermont Regional Planning Commission to host a digital meeting on December 9 with Emma Hanson, Fayston, who is the wood energy coordinator for the Vermont Department of Forests, Parks and Recreation.
This second story covers types of wood heat and the vehicles for burning it and how cleanly they heat.
“Vermont is 76% forested and 80% of that forest is privately owned. Vermont is currently harvesting less than half of the net new growth in its forests,” she said.
Hanson told participants there were main wood fuel types, starting with cordwood which is a 4-foot-by-4-foot-by-8-foot stacked pile of split wood.
“It’s DIY-able and affordable. But there is lots of room for error if you burn it before it’s dry or if the stove lets it smolder. Make sure to retire those older stoves,” she said urging people to replace older stoves with those that are EPA certified or with indoor wood boilers.
“A quick note on the fireplace. It is not a heating appliance. It sucks warm air out of a house and produces 30 times more pollution than woodstove emissions. Woodstoves provide three times the heat with one-third the wood. And, yes to a fireplace insert, either a cordwood or pellet insert,” she suggested.
Wood pellets, Hanson explained, are made of 100% compressed sawdust, burn very cleanly and are appropriate for residential and commercial buildings. Burning pellets can be fully automated and can function like liquid fuel, driven by a thermostat. They can be burned in stoves that look and function like a woodstove.
“They’re a great option for those who want to get away from heating with fossil fuels but not ready to switch to something more significant, “she said.
The other pellet option is a pellet boiler or furnace which is exactly like heating with propane or fuel oil. A truck delivers the fuel and people program their thermostat and the fuel is called to the boiler. Hanson said there are many work arounds for people who don’t have a pellet storage room.
She noted that the town of Fayston switched from fuel oil to a pellet system in 2009 which saves the town $3,590 annually and offsets 1,600-2,000 gallons of Number 2 heating oil each year.
Woodchips are the third way to heat with wood and are not advisable for residential use. They are the simplest wood fuel; a tree is fed into a chipper and the product taken to the final destination. Woodchips are very affordable, Hanson said, and appropriate for large buildings, district heating systems for schools and colleges.
“They do not scale down well,” she said.
She urged those present to think about the particulate matter (PM) that is emitted from each type of wood-heating system.
“An older pre-1990 outdoor wood boiler, not EPA certified, emits 4.6 pounds of PM per MMBTU,” she said. MMBTU, or MBTU, stands for one million British Thermal Units (BTU). A BTU is a measure of the energy content in fuel,
By contrast, a modern woodstove emits 1.4 pounds of PM per MMBTU, a modern pellet stove emits 0.49 pounds of PM per MMBTU.
A modern pellet boiler emits 0.0032 pounds of PM per MMBTU, new oil boilers emit 0.013 pounds of PM per MMBTU and new propane boilers emit 0.0083 pounds of PM per MMBTU.
“Residential users of wood heat created 95% of 2018 PM emissions, but 52% of those people were burning wet wood, had old appliances or were not using the appliance properly,” Hanson explained.
“If you see smoke coming out of someone’s chimney, that is unburnt fuel. That’s fuel going up into the air in the form of pollution. One nonEPA certified woodstove equals 200 pellet boilers,” she added.
Part 3 of this series on cleaner wood heating options will appear in the January 7 issue of The Valley Reporter. That story will report on the role of trees to function as carbon batteries and the costs of various types of wood heating vehicles as well as current financial incentives.
For those who can’t wait to learn more, here is the link to the Zoom meeting: https://transcripts.gotomeeting.com/#/s/77fc5cc25c892a92c9c50b1bb40a073b34580d4535735264eb10a868f72e5dc6.
