News Section
Stories from Climate Central's Science Journalists and Content Partners

Wood Burning for Home Heating Trendy in Northeast

In New England, what’s old is new again, especially when it comes to the kind of fuel people use to heat their homes.

As prices of propane and heating oil have risen in recent years, residents in all Northeastern states are increasingly turning to wood as their primary source of home heating fuel, according to a U.S. Energy Information Administration (EIA) report released this week.

Existing regulations for wood heaters apply to older kinds of wood stoves that lack new emissions-reduction technology. New rules would require that new technology.
Credit: James Halliday/Flickr

There’s a problem with that, though: Black carbon, or emissions of soot from burning wood, is a major heat-trapping pollutant contributing to global warming. But the actual effect of more people burning wood for heating is very complicated. 

People are seeking cheaper alternatives to expensive fossil fuels to heat their homes, and they’re mostly turning to wood logs, though researchers are seeing an uptick in the use of wood pellets, too, said Chip Berry, EIA manager of the agency’s Residential Energy Consumption Survey, from which the wood burning data was gathered.

Heating oil prices have risen slightly over the past year, but residential propane prices have been volatile this winter. Heating oil, which is most commonly used in the Northeast and is second only to natural gas as a heating fuel in the region, cost just more than 1 cent higher than it was a year ago as of March 12, running about $4.20 per gallon, EIA data show.

Prices for propane, which is less commonly used in the Northeast than heating oil, are dramatically higher. A year ago, propane cost about $2.35 per gallon. Last week, it was nearly a dollar more at $3.17 per gallon, that after peaking at $4 in January, EIA data show.

All of the nine New England and Mid-Atlantic states together saw at least a 50 percent increase in the number of homes that use wood as their primary heating fuel between 2005 and 2012, EIA data show.

Rhode Island, Delaware and Alaska have seen the greatest increase in homes using wood as their main heating source, followed by New Hampshire, Massachusetts, Connecticut, Maine and Vermont.

About 2.5 million homes across the U.S. use wood as their primary home heating fuel, a 2.1 percent increase since 2005. About 9 million homes use wood as a secondary heating fuel.

Most of the wood used for heating is burned in wood stoves, and fireplaces are commonly used as a secondary heating source, according to the EIA, but Berry said there is no data on the source of the wood used.

Credit: U.S. Energy Information Administration

Who is most likely to burn wood as a primary heating fuel? Those with a household income of more than $100,000, according to EIA data. Though the affluent are more likely to use wood for heating, low income homes burning wood are likely to use more wood on average than more affluent households.

The effect more people burning wood for heating will have on the climate is extremely complex, said Drew Shindell, a National Aeronautics and Space Administration climate researcher who co-authored 2012 study on how short-lived climate pollutants, including soot and methane, can be reduced globally. 

"If you have emissions from wood (burning) in the Northeast, it's pretty easy for the pollution to get carried farther up to the north, all the way up into the Arctic and into Greenland," Shindell said. "When the black carbon comes down on the snow and ice, it really darkens it."

Heating oil and propane burn more cleanly than wood. Soot from wood stoves blowing into the Arctic can lead to more warming there in the short term as the darkened ice absorbs more heat. 

But over the long term, the effect of more wood smoke emissions is more complicated because the wood is replacing the use of propane, heating oil and other fossil fuels, Shindell said.

"There's a tradeoff to be made," he said. "It really depends on how clean the wood-burning stoves are and what source of power they're replacing.

"From an air pollution point of view, this (switching from heating oil or propane to wood for heating fuel) is probably not such a good thing, and near-term climate in the Arctic, not such a good thing," Shindell said. "For long-term climate and CO2, it probably is a good thing. It is a complicated tradeoff."

Because of wood burning's intricate effects on the climate and the fine-particle air pollution it creates contains black carbon, volatile organic compounds, carbon monoxide and other toxins, the U.S. Environmental Protection Agency proposed new emissions rules for newly manufactured wood heaters in January.

The EPA already has regulations for wood heaters, but they apply to older kinds of wood stoves that lack new emissions-reduction technology. The new rules would require improved low-emissions technology for many new woodstoves. No decision has been made on the proposed new regulations.

You May Also Like
CO2 on Path to Cross 400 ppm Threshold for a Month
New Greenland Ice Melt Fuels Sea Level Rise Concerns
What Winds From 20 Massive Winter Storms Look Like
East Greets Winter’s End; West Braces for Drought, Fire
Social Cost of Carbon Greatly Underestimated: Report

Comments

By Dr Dorothy L Robinson (NSW, Australia)
on March 19th, 2014

There’s an even greater problem with burning wood in enclosed heaters, like the one illustrated. Tests of real-life operation show that about 15% of fuel carbon is emitted as CO[1], and a substantial quantity of methane (CH4) is produced – about 30 grams per kg of softwood burned (or 19 grams per kg hardwood)[2].

The latest IPCC report (AR5) shows that (including climate-carbon feedbacks and oxidation to CO2) 1 kg of CH4 causes 88 times as much global warming as 1 kg of CO2, in the first 20 years after emission, but (because CH4 does not stay in the atmosphere as long as CO2), the overall effect over 100 years is only 35 times as much[3]. 

So, on top of the 2 tonnes of CO2 emitted directly into the atmosphere, the methane emissions from burning a tonne of wood will cause as much global warming over the next 100 years as emitting 35*19 = 0.66 tonnes of C02 (hardwood) or 1.05 tonnes of CO2 (softwood)

In many locations (e.g. Australia), methane emissions from domestic log-burning heaters cause 2 or 3 times as much global warming (over 100 years) as less polluting forms of heating[2].  Adding in the black carbon, plus increased global warming from CO2 emissions if (as is often the case) the firewood is not from a sustainable source, the additional global warming from domestic wood heating could last hundreds of years.

It would be prudent to stick to the Copenhagen agreement of limiting the global temperature rise to 2 degrees C (on track to be exceeded by 2050 under a business-as-usual scenario).  Unlike the complex calculations for the effect of black carbon emitted by wood heaters, estimating the effect of methane emissions is simple.  Given current technology and the much higher level of emissions in real-life than for perfectly-operated heaters in laboratory tests, any increase in the use enclosed log-burning heaters will set back our efforts to achieve this important 2 degree target.

See also:  http://environmentprogress.com/key-research-articles/australian-wood-heaters-currently-increase-global-warming-and-health-costs/

1. Meyer, C.P., et al., Measurement of real-world PM10 emission factors and emission profiles from woodheaters by in situ source monitoring and atmospheric verification methods, 2008, CSIRO Marine and Atmospheric Research (CMAR), (available at: http://www.environment.gov.au/atmosphere/airquality/publications/emission-factor.html ).
2. Robinson, D.L., Australian wood heaters currently increase global warming and health costs. Atmospheric Pollution Research, 2011. 2(3): p. 267-274.
3. Myhre, G., et al., Anthropogenic and Natural Radiative Forcing in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change T.F. [Stocker, D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley Editor 2013, Cambridge University Press: Cambridge, United Kingdom and New York, NY, USA.

Reply to this comment

By John Ackerly (Takoma Park, MD, 20912)
on March 20th, 2014

I think this article overstates the black carbon impacts.  Black carbon from wood is emitted mainly from open fires and unregulated cooking and heating appliances - which exist all over the world.  A study by the EPA found that modern heating appliances, that burn at high temperatures such as pellet stoves and most new wood stoves, emit extremely little black carbon.  Unfortunately, many new, unregulated heating appliances are still allowed to be manufactured and installed in the US. 

Dorothy Robinson commented on the article saying its methane, not black carbon which is easier to measure and has a greater greenhouse effect.  My question to her: how are you calculating the avoided methane emissions of that wood rotting in the forest.  A very large part of the firewood supply in the United States is from trees already taken down by tree services and storms.  That carbon and methane is beginning to be released regardless.  In advanced combustion, you have less methane release than if the wood rots or is burned at lower temperatures. 

Thanks for any insights either the author or the Ms. Robinson has on these points.

John Ackerly
Alliance for Green Heat

Reply to this comment

By Dr Dorothy L Robinson (NSW, Australia)
on March 22nd, 2014

According to Glen Ayers, author of ‘The Methane Myth’ “Forest debris left in the woods will produce very minor amounts of methane, if any, unless it is squashed into a swamp or buried in a stump dump. In fact, un-chipped slash is very slow to decompose, taking many years, and is unlikely to produce any measurable methane” http://www.greenfieldbiomass.info/uploads/The_methane_myth.pdf

Solar and wind technology are developing rapidly.  In the next 20 years, wind, solar (PV and solar thermal with molten salt or other storage), fuel cells and perhaps hydrogen obtained by electrolysis will provide cheaper, cleaner alternative to digging fossil fuels out of the ground.

A significant threat is the global warming that will occur in the next 20 years, while we develop cost-effective alternatives.  This near-term warming will determine whether the Copenhagen target is exceeded.  Over this period, every kg of methane emitted from a domestic log-burning heater will cause 88 times as much global warming as 1 kg of CO2.  This surely makes domestic log-burning heaters one of the dirtiest forms of heating, that will damage the climate more than heating up to a dozen similar homes with less polluting alternatives.

Some forest debris is needed to maintain soil fertility and provide homes (e.g. hollow logs) for wildlife.  Although some people argue that producing electricity from biomass is also harmful to the climate, using any spare biomass (that might otherwise rot and produce methane) as a partial replacement for coal in existing power stations is much less of a threat to our health and the climate than using it in domestic log-burning heaters.

Manufacture of high-specification wood pellets for use in properly-designed heaters equipped with emissions control technology is another way to make use of our limited supplies of sustainably-produced biomass.  Just as improved specifications for diesels enabled new vehicles to achieve the Euro 5 limits of 0.005 grams/km (0.1 kg for a vehicle travelling 20,000 km), it may be possible to add filters to pellet heaters to satisfy a satisfactory health-based standard.

There is no chance of achieving a similar result for current log-burning heaters, which emit more PM2.5 pollution in a few hours than the average passenger car does in an entire year.  When operated in real homes by real people, measurements show that log-burning heaters are the worst possible choice for families who care about their health, or the health of the planet. 

Anyone with a log-burning heater who cares about the planet and wants to use green heat should switch to a less damaging alternative.

Reply to this comment

By Robert Wright (NJ 07436)
on September 27th, 2014

Dr. Robinson,

  While I agree that older wood fire stoves are very inefficient, and should be replaced for the reasons you mention, pellet stoves are not the answer. Most pellet stove fuel is made from nonrenewable deforestation, which for obvious reasons is not helping to get us to a sustainable future. I agree that the best option is solar / wind energy, and while they have come down greatly in cost, it’s still beyond the reach of many people. You didn’t mention however the other type of wood burning heater, the Kachelofen or Masonry heater. These heaters burn at much higher temperatures than common wood stoves and release very little black carbon or methane. What are your thoughts about Masonry heaters, as long as the wood is sustainably harvested on the same property as the home it heats?
(Reference:“Masonry Heaters” by Ken Matesz ISBN: 978-1-60358-213-1)

Reply to this comment

By Dr Dorothy L Robinson (NSW, Australia)
on March 24th, 2014

According to Glen Ayers, author of ‘The Methane Myth’ “Forest debris left in the woods will produce very minor amounts of methane, if any, unless it is squashed into a swamp or buried in a stump dump. In fact, un-chipped slash is very slow to decompose, taking many years, and is unlikely to produce any measurable methane” http://www.greenfieldbiomass.info/uploads/The_methane_myth.pdf

The rate of methane emission is perhaps the most important factor.  Solar and wind technology are developing rapidly.  In the next 20 years, wind, solar (PV and solar thermal with molten salt or other storage), fuel cells and perhaps hydrogen obtained by electrolysis have the potential to provide cheaper, cleaner alternative to digging fossil fuels out of the ground.

So the most significant threat to our planet could be the global warming that will occur in the next 20 years, while we develop cost-effective alternatives.  Short-term (also called near-term) warming will determine whether the Copenhagen target is exceeded.  In the first 20 years, every kg of methane emitted from a domestic log-burning heater will cause 88 times as much global warming as 1 kg of CO2.  This would appear to make domestic log-burning heaters one of the dirtiest forms of heating, that will damage the climate more than heating up to a dozen similar homes with less polluting alternatives.

Some forest debris is needed to maintain soil fertility and provide homes (e.g. hollow logs) for wildlife.  Although some people argue that producing electricity from biomass is also harmful to the climate, using any spare biomass (that might otherwise rot and produce methane) as a partial replacement for coal in existing power stations much, much less of a threat to our health and the climate than using domestic log-burning heaters.

Manufacture of high-specification wood pellets for use in properly-designed heaters equipped with emissions control technology is another way to make use of our limited supplies of sustainably-produced biomass.  Just as improved specifications for diesels enabled new vehicles to achieve the Euro 5 limits of 0.005 grams/km (0.1 kg for a vehicle travelling 20,000 km), it may be possible to add filters to pellet heaters to satisfy a satisfactory health-based standard.

There is no chance of achieving a similar result for current log-burning heaters, which emit more PM2.5 pollution in a few hours than the average passenger car does in an entire year.  When operated in real homes by real people, measurements show that log-burning heaters are the worst possible choice for families who care about their health, or the health of the planet. 

The evidence suggests that anyone with a log-burning heater who cares about the planet and wants to use green heat should switch to a less damaging alternative.

Reply to this comment

Name (required):
Email (required):
City/State/Zip:
Enter the word "climate" in the box below:

[+] View our comment guidelines.

Please note: Comment moderation is enabled. Your comment will not appear until reviewed by Climate Central staff. Thank you for your patience.