Author Topic: Climate impact of heating with wood  (Read 372 times)

ergophobe

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Climate impact of heating with wood
« on: November 26, 2019, 09:07:33 PM »
I have sometimes idly wondered, given all the wood that comes down around here, whether it would reduce my footprint to heat with wood. I've never looked into it, but just stumbled across this:

https://features.weather.com/collateral/vermont-ramps-wood-burning-cut-fossil-fuel-use-climate-health/

TL;DR
 - It it renewable: obviously yes, but only over relatively long time spans (more time than we have)

 - Carbon-neutral: sort of. If all you measure is carbon and your time span is long enough, then yes, but the problem is all the other by-products, many of which are worse than CO2.

 - better than fossil fuels: only in the case where you burn pellets that are made from sawmill and paper mill by-product. If you are cutting down standing trees, much worse than just burning propane.


buckworks

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Re: Climate impact of heating with wood
« Reply #1 on: November 27, 2019, 11:58:02 PM »
I read the article and the line of thought it raised for me was this:

Fire is a natural part of the ecology in many regions. A tree in the wilderness will eventually either rot or burn.
So we not only have to compare wood heat vs fossil fuel heat, we have to compare wood heat with what happens in the forest's natural cycles.

So ... how would the greenhouse effects of burning wood to heat dwellings compare with the greenhouse effects when the same amount of wood burns in a naturally occurring forest fire?

ergophobe

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Re: Climate impact of heating with wood
« Reply #2 on: November 28, 2019, 07:48:24 AM »
That's true, but it's complex. I've seen articles saying old growth sequesters carbon much better than new growth. So when you have a tree farm, rather than a forest, and you keep harvesting and planting, harvesting and planting, you don't get nearly the carbon capture you do in an old forest that is adding mass (or something like that).

But your question is essentially the same as mine - the trees in my area are coming down regardless. Our option is to chip them, landfill them, or burn them. That's probably somewhat closer to the calculation they do for pellets, but we had a pellet stove and it is way, way cleaner burning than most woodstoves (running all out, you often see nothing coming out of the chimney).

So I'm still not sure in that case.

Brad

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Re: Climate impact of heating with wood
« Reply #3 on: November 28, 2019, 11:39:14 AM »
If I ever need to get a stove it will be a pellet stove.  It's a great way to use the sawmill waste.  A friend had a corn stove, burning shelled corn, which seemed clean, but I don't like the idea of stockpiling so much varmint bait in the house for fuel.  Wood pellets make more sense.

buckworks

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Re: Climate impact of heating with wood
« Reply #4 on: November 28, 2019, 08:57:14 PM »
>> varmint bait

Good point.

>> cleaner burning than most woodstoves

What species of wood are the woodstoves burning? And what's its moisture content?

Some woods burn cleaner than others, birch vs poplar for instance, and any wood will burn cleaner if it's well dried.

ergophobe

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Re: Climate impact of heating with wood
« Reply #5 on: November 29, 2019, 12:18:43 AM »
True, the species matter. Since the study is in Vermont, probably mostly oak.

What matters perhaps even more is the age of the woodstove. Modern stoves circulate the smoke back through the heat for secondary combustion, which cuts down on emissions a lot. A 1970s woodstove will pollute a lot more than a recent one.

But as the article notes, there's a lot of room for "user error."

I wonder about those Scandinavian stoves. They are built out of stone and heat follows a complex channel through the stones. Wood is stacked on end in a bundle so it burns super hot. You load it, burn it super hot for  40 minutes, heat up the stones and it heats for about 8 hours. Neighbors up the street have one