On pellet stoves

On pellet stoves

05 Feb 2007

Got questions about the environment? Ask Umbra.

Dear Umbra,

I am a policy analyst with Californians Against Waste, a recycling advocacy group. Just wondering why pellet stoves were not considered in your wood stove analysis. I have one and feel that overall they rate well compared to other heating options.

Thanks,
Scott Smithline
Sacramento, Calif.

Ask Umbra continues below

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Dearest Scott,

Omitting pellet stoves from my analysis was just a plain old oversight. Only honesty between us, my friends. Let's talk about pellet stoves this week to make up for lost time, because they are dandy.

Waste not, shiver not.

Pellet stoves are similar to modern wood stoves in aspect: they are metal boxes with a window showing the toasty fire inside. Reminiscent of a giant welding helmet. But they have three main differences: their toastiness is regulated by an electronic gizmo, they burn pellets instead of logs, and they burn more cleanly and efficiently than most modern wood stoves. Any pellet-stove proponent will point out that the EPA doesn't even bother to certify pellet stoves, since they burn very little waste ash and release relatively few particulate emissions.

How do they work? A hopper at the back of the stove holds the eponymous pellets and regularly feeds them through a little auger chute into the burn chamber, where a blower blows the perfect amount of air across the pellets, the pellets burn very hot and clean, another blower blows the heat out to the room, and the exhaust vents out a small pipe to the outdoors. The vent doesn't require a chimney, and the stove is not hot to the touch.

The pellets themselves are small pieces of compressed biomass, usually wood but sometimes crop or paper waste, which are described as looking "like rabbit food." They come in 40-pound bags, like rabbit food, and are easily, tidily stored until the moment when one tips them into the hopper. One reason these stoves burn so cleanly is because the fuel has low moisture content: 5 to 10 percent, compared to firewood's 20 percent. Remember we talked about moisture during our wood fuel discussion, and the less the better.

The hopper needs to be filled daily when the stove is used regularly; the stoves generally use one to three tons of pellets a year. You'd have to check with your supplier about the provenance of their pellets, but in theory you could get a clean burn and divert solid waste in one fell swoop. The Royal We previously noted that wood burned from sustainably harvested sources is carbon-neutral, and this would apply to pellets as well.

The stoves do have a few drawbacks, such as requiring regular maintenance and a dependable pellet supplier. Also, as mentioned, they rely on electricity so they may be an ineffective way to take your heating needs off the grid unless you have an off-the-grid power source such as solar, wind, etc. Normal usage will see your stove consuming 100 kilowatt-hours per month.

Pellet stoves are more expensive than traditional wood stoves, but they are easier to install and may be cheaper to operate, depending on your fuel source. But remember, these factors are all in comparison to traditional wood stoves, to which their resemblance is mostly visual. All heat sources have their drawbacks and advantages, and pellet stoves will be perfect for some applications.

Correctively,
Umbra

Yours is to wonder why, hers is to answer (or try). Please send Umbra any nagging question pertaining to the environment -- but first check out her FAQs!

The claims made in this column may not reflect the views of this magazine. Neither the magazine nor the author guarantees that any advice contained in this column is wise or safe. Please use this column at your own risk.

Umbra Fisk is Grist Research Associate II, Hardcover and Periodicals Unit, floors 2B-4B.

Comments: (6 comments)

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On Pellet Supply

Many readers who investigate pellet stoves further will soon find out that the supply concern you mentioned is quite a big deal in some areas. This recent article, "Pellet Stove Prospects: Will Supply Meet Demand?" offers additional clarification, and may be helpful in determining if a pellet stove is the best option for a particular situation.

Thanks for the opportunity to comment!
-----------------
Tabitha Alterman
Associate Editor, Mother Earth News

by talterman at 11:02 AM on 05 Feb 2007

Pellet Stoves

I just purchased a wood pellet stove and love it. I have found a good source here in the Charlotte NC area but that may be because it doesn't get as cold here. When I travel and pass a Tractor Supply Store, I buy two or three bags just in case.
Tony Esposito

by espo53 at 12:59 PM on 05 Feb 2007

Self-powered pellet stove

There is no need for alternative power sources, such as solar, wind, etc., as Umbra proposes. (Solar or wind might not be available anyhow to run that stove in the still of a dark winter's night.)

Five or so years ago, where I previously worked, I did a proposal for a project for what was called the Western Regional Biomass Energy Program. We won a contract for designing and building a self-powered pellet stove. This was not just a thermoelectric fan to go on the stovetop, but a fully autonomous unit. We partnered with a stove manufacturer. It seemed like a winning idea for locations off the electric grid or strung out on an unreliable line. Here is a reference, and you will note that the prototype won a prize at the 2002 Hearth Products Association trade show:

http://www.hi-z.com/websit11.htm

I guess there was not sufficient capital or market incentive to go ahead, but I still like the idea.

by danallen at 1:31 PM on 05 Feb 2007

Pellet Stoves

I'm on my third pellet stove over a 15 year period and I think that the pellet stove could play a large part of the overall energy solution.
I call it a bio-fuel stove to try to accelerate the meme.
It is much cheaper and a more pleasing heat than forced air electric.

by baiss at 3:14 PM on 05 Feb 2007

The Hypocracy In Action

Ok, here it is in all its glory. Gristers who daily bemoan the "big industrialists" who pollute -- meanwhile these bearded hippies are choking us to death with wood stoves.

Really. Read all about it in Seattle -- during a recent cold snap the air was UNBREATHABLE in a swath across half the Olympic peninsula, all of Puget Sound and some eastward. I live in Kent East Hill and I was feeling asphyxiated.

by jabailo at 9:36 AM on 06 Feb 2007

Corn Stoves - one step up from wood pellets

Unfortunately, in illuminating about WOOD pellet stoves, Umbra neglected (probably by no fault of her own) CORN burning stoves. This fuel burns cleaner than wood with less smoke, ash and particulate; is renewable each year by growing about 1/3 acre per household; and if grown sustainably results in carbon neutral emissions.

I am one of almost 60 households in the DC area (and one of thousands of others mostly from Mid-Western states) who have corn burning pellet stoves to get even more eco- (and financial) efficiency from buying a home-grown fuel, than from using fossil fuels, and also better than wood.

And for those who believe corn is a hugely unsustainable crop... I do too, if it is CONVENTIONAL corn. But we source our sustainable corn from a small family farm in MD, using organic, local fertilizer, low/no-till agriculture practices and non-GMO corn seeds.

For more visit our website at: www.SaveOurSky.com

Warmly,
Sat Jiwan Ikle-Khalsa
president, Save Our Sky Home Heating Cooperative

by satjiwan at 2:16 PM on 06 Feb 2007

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Re: Heat