Recommendations for California's wood stove replacement program

In the fall of 2022, the California Air Resources Board (CARB) published their draft guidelines for their annual wood smoke reduction program. The State legislature committed $5 million for the program that offers financial incentives for homeowners to replace older, high-polluting wood burning devices with newer, cleaner burning units.  The Alliance for Green Heat submitted the following comments, urging California to 1. focus first on households in more densely populated areas where the public health ramifications are the highest, 2. to consider the benefits of hybrid stoves over catalytic stoves and to expand the number of eligible non-cat stoves, 3. to make sure California fully integrates wood stoves into its energy audit and weatherization programs, which would lead to more voluntary stove removals and repairs, 4. and to study and better understand the actual carbon footprint of firewood based on estimates of how people source their wood.

Dec. 8, 2022 

Hon. Steven Cliff, 

Executive Officer

Channel Fletcher, 

Deputy Executive Officer, Environmental Justice

California Air Resources Board

1001 I St,

Sacramento, CA 95814

 

Dear Mr. Cliff and Ms. Fletcher,

Thank you for the opportunity to provide comments on your draft Program Guidelines to reduce wood smoke. Funds to replace older stoves with cleaner sources heat are funds well-spent, especially since many old stoves provide primary heat to homes of marginalized, lower-income households.  

1.      Focus on households in densely populated areas

Our biggest recommendation is to focus your resources on households in areas that are more densely populated and/or experience frequent weather inversions, where the public health ramifications of older wood stoves are the highest.  Stoves in very rural homes with few or no neighbors will have very few public health impacts. This is an area that more change-out programs should explore.  Hopefully, homes in these sensitive areas would opt for heat pumps or pellet stoves. For homes in densely populated areas, we would also encourage you to see if the home has a woodshed or a way to store their fuel.  

2.     Replacement devices

We fully support CARB’s decision to replace older wood stoves with low-carbon alternatives such as heat pumps and pellet stoves.  We would be wary to include electric resistance stove heaters because this may burden lower income homes with higher electric bills than they can afford, assuming electric rates rise in the future.  We are glad that CARB does not include gas stoves as that would have a counterproductive carbon impact and hinder electrification goals.

We do not have a high level of confidence in catalytic stoves as they often are not maintained or used properly as the years go by, especially in lower income homes who may not be able to pay to replace the catalyst when needed.  Hybrid stoves are a far better option, and we would urge CARB to focus on hybrid stoves because they still provide valuable PM reduction technology even if the cat is not engaged.  It is important to understand how stoves are likely to work in the real world, once they leave the lab, and cat stoves are a class of stoves that can work even worse than non-cats if they are not maintained or used properly, particularly after the home or stove is sold and the device is being operated by a new owner.  Some owners of older cat stove do not even know they have a cat stove.

We are extremely concerned that CARB is only making four models of non-cats eligible for change-outs. The four non-cats selected by CARB may operate better than some with greater testing flaws, but there is no proof that many non-cat stoves are just as good as the four you identify.  The process undertaken by the Alaska and NESCAUM was valuable in many ways, but it does not easily lend itself to being used to qualify stoves for change-out programs.  If CARB wants to identify non-cat stoves that would burn more cleanly, allowing more single burn rate stoves to qualify may be the best way.  However, most households do not want single-burn rate stoves, particularly if the stove is their primary heat source.  

A major dilemma for your program is that you are trying to serve many marginalized, lower income households and balance their legitimate energy needs with the impact their smoke will have on neighbors.  By choosing only 4 non-cats, you are sidelining the heating needs of these households in favor of a very questionable process to identify only 4 models, some of which are not likely to be available near these homes.

We support the effort undertaken by Alaska and NESCAUM but decisions like this, to select four stoves, takes their data beyond its usefulness. We think there is disconnect between limiting to 4 non-cats and serving low-income households.  Though we understand the desire to put Alaska’s work to use, it will likely be ineffectual in reducing PM in this change-out program. 

3.     Inspection, repair and safety

One of the best ways to start to identify, repair and/or remove old stoves is to ensure that local energy audits and weatherization programs have integrated wood stoves into their work.  Most energy auditors still do not have the training or the software to do undertake stove inspections, even though DOE and state regulations claim to require that all heaters are inspected.  If they did, they would find many self-installed stoves that are dangerous, higher polluting and in need of replacement or removal.  LIHEAP funding and low-income weatherization programs will cover these costs where the stove is the primary heat source.  If the stove is a secondary heater, these programs could cover repairs.  Few states have demanded that the US Department of Energy develop standards for inspecting wood stoves, like there are for boilers and furnaces, and the DOE is still hesitant to take this on, even though it would have a major impact for lower-income households across the country.  We urge CARB to review how wood stoves are inspected during energy audits and weatherization programs in California and see whether they are being repaired, replaced or removed.

4.     GHG reductions 

We are pleased that CARB is no longer using carbon to justify switching from a wood stove to a gas stove.  In its 2016-2017 Woodsmoke Reduction Program Guidelines, CARB stated, ”Switching from an uncertified wood stove to a natural gas or electric heating device reduces GHG emissions.”  We find this statement to be without scientific basis.  We understand that the GHG calculations are not central to how CARB runs this change-out program, but we want to open a conversation about it.  

In the current Program Guidelines, CARB seems to assert that 100% of carbon released from wood and pellets should be attributed to this form of heating.  The Guidelines say that “biogenic CO2 is included in the calculation of GHG benefits for these devices.”  We agree that some biogenic carbon should be included, as some carbon can be attributed to all energy sources.

To make scientific estimates of carbon released from firewood that would not have been released anyway, there is a lot of data that can be considered.  For CARB to start to gain a basic understanding of the carbon cycles from firewood, you could also ask on your change-out application, “where do you get your wood?”.  A researcher can also get data from a sampling of California firewood dealers and households who use firewood. 

By not engaging in basic research, CARB is putting the burden on low-income households who heat with wood and is inferring their carbon impact of their heating is far higher than it is. This flies in the face of current thinking about energy justice that seeks to remediate social, economic, and health burdens on those disproportionately harmed by the energy system. 

Estimating carbon from gas, oil and electricity involves a complex set of assumptions and calculations and there is no reason that similar effort could be made to assess the carbon cycle from firewood.

In California, as in the rest of the country, it is likely that a substantial number of homes who heat with wood acquire their firewood in a very responsible way by using dead and downed wood, as lower-income households do around the rest of the country.  A lot of firewood used for home heating could otherwise end up in the landfill where it would produce worse GHG emissions.  

The Minnesota Residential Wood Combustion Survey Results, (May 2019) done by the Minnesota Department of Natural Resources is one of the most definitive studies on firewood procurement and use.  The report says, “Most of the wood cut (84%) by residential households comes from dead or downed trees, land clearing, and logging residues (Table 15). Approximately 9.3% comes from live standing trees in the forest.”  This is a crucial statistic for understanding carbon impacts of firewood.  If 84% of wood cut by households comes from dead of downed trees, it means that carbon was already in the process of being released unlike when a live tree is cut.  

Household income generally correlates to how firewood is procured and how much firewood is used.  The lower the income of a household, the more wood they use and the more likely they gather their own wood, assuming wood is being used for heating, and not for recreation.  More urban and higher income families are more likely to purchase wood. The chart below is based on EIA data.

The Minnesota Residential Wood Combustion Survey Results, found that 60% of firewood is cut by households and 40% is purchased.

 

Table 15, below, provides further detail of where firewood comes from in Minnesota, and these trends are likely to exist in other states. 

Table 17 shows a breakdown of firewood from both household and loggers.  Even where firewood is provided by commercial loggers, most of it is still from trees that are dead, down or from the residues of a commercial harvest, which usually is for sawlogs (lumber).

In conclusion, we believe that whether firewood comes from a “locally or nationally approved” forestry plan is not as relevant as existing data about where firewood comes, how sustainable it is and how to understand carbon implications. From a carbon perspective, we believe a rigorous look at the carbon footprint across the value chain of gas production and usage will always be higher than the footprint of firewood, across its value chain. The Achilles heel of firewood is the excessive PM that comes from most wood stoves, and it is that PM which fully justifies change out programs like this one.

As we initially stated, we fully support this program and see it is improving over the years, and we hope that our comments help improve it in future years.  Thank you for undertaking the program and accepting comments from the public. 

Sincerely, 

John Ackerly

President

Further reading: State Parks give downed trees to public for firewood (March 2023)

Thermal certificates can fuel commercial wood heating

Renewable Energy Certificates (RECs) are the market instruments used by state governments to identify who produced renewable energy.  When states require utilities to meet a certain percent of their energy from renewables, they can either produce it themselves or buy RECs.  RECs have been the core mechanism for solar to grow in the United States, but rarely were they used for renewable heat.  Currently a number of states provide RECs for renewable heat, which could come from biomass, solar thermal or geothermal.   A handful of states, including New Hampshire and Massachusetts now include thermal biomass and Maine, Maryland and others are exploring it.

The Governor of Maryland proposed adding thermal RECs to Maryland's renewable portfolio standard (RPS) as part of its legislative package this year.  The Alliance for Green Heat was invited to testify to the Senate Finance Committee on February 23 and we reproduce our testimony below.  During the hearing on the House side, several witnesses opposed the legislation based on particulate matter emissions and carbon, so AGH focused comments on those areas.  

Chair Kelly and Vice-Chair Feldman and Members of the Senate Finance Committee:

Thank you for the opportunity to testify before this committee.  My name is John Ackerly and I am the President and Founder of the Alliance for Green Heat, a non-profit group based in Takoma Park Maryland that promotes renewable heating options.  As you may know, Takoma Park has a corn heating co-op, started by Mike Tidwell, before he founded the Chesapeake Climate Action Network.  What we are debating here is even better than heating with corn, because corn involved forest land conversion into agricultural fields.

We worked particularly closely with the Maryland Energy Administration and Delegate Heather Mizeur back in 2012 to set up their popular Wood Stove Grant Program, where about 85% of grants go to very clean burning pellet stoves.

We enthusiastically support the passage of Senate Bill 549 and the companion House Bill 682 because of the significant benefits to displacing fossil fuel.  We also support the amendments that would end Tier 1 RECs for black liquor since RECs should incentivize more renewable energy capacity, not subsidize existing renewable energy.  Thermal RECs have fallen prey to black liquor politics for too long.  It is time for a vote on their own merits.  

Particulate matter

Larger biomass systems are able to drastically reduce particulate matter (PM2.5) through electrostatic precipitators and other PM reduction technologies.  In terms of pollution, the most important thing to recognize with biomass heating is that residential wood stoves and boilers – whether EPA certified or not – are the biggest threat to local air quality.  A study done for the State of Minnesota shows the advantages of automated biomass boilers compared to traditional wood stoves. It shows that per unit of heat, wood stoves emit 12 to 25 times more PM10 than modern boilers.  

If Maryland wants to tackle wood smoke, the best solution would be to reduce the number of traditional wood stoves, particularly in more populated areas.  Pellet stove are an excellent residential heat option, and together with solar panels, can reduce a home’s fossil fuel usage by 50 – 90%.  

The benefit of passing this legislation in Maryland, is that the Maryland Department of the Environment has strict air quality regulations and staff that understand pollution control technologies.  The commercial systems that this legislation would enable will have to have technologies like electrostatic precipitators (ESPs) or similar technologies.  Most if not all Northeastern states have similar air quality protections but in some parts of the United States, ESPs would not be required and biomass heating plants could pose local air quality problems. 

Carbon

 From a carbon perspective, wood pellet heating emits less than half the carbon of propane and is even more favorable compared to heating oil or gas.  My organization has reviewed scores of Life Cycle Analyses (LCAs) and has not found any that show wood or pellets is worse than fossil heating fuels.  It’s important for this committee not to confuse the Life Cycle Analysis of industrial scale wood or pellets used make electricity, which is a far different equation.  When biomass is used for electricity, it is combusted at about 30% efficiency, but when it is combusted for heat it is up to 80% efficiency.  In addition, the harvesting methods for industrial scale pellets, for example, that are shipped to Europe, involve using more whole trees, not residuals as they do in Maryland.  

A peer reviewed University of New Hampshire study in 2017 found that heating with pellets reduces greenhouse gas emissions by 54 percent vs. home heating oil, and 59 percent vs. natural gas. This chart summarizes their results.

Other factors

When comparing modern biomass heating systems to fossil heating fuels, there is more to look at than just PM and carbon.  There are toxicity implications for soil, water and humans.  The chart below compares softwood (pine) pellets with other fuels.  (Brassica pellets are not used in America and refer to pellets made from agricultural crops, or possibly hay.). This is important because the Chesapeake Bay watershed is a sensitive one, and we are confident that these modern biomass heating plants compare relatively well in almost all respects to other fuels.

This committee is considering other bills to expand Maryland’s renewable energy portfolio and one that specifically seeks to expand geothermal energy in Maryland.  We also urge you to support the geothermal bill and urge you to consider the cost/benefit analysis of geothermal and look at other socio-economic factors.  We need to be mindful that investments in various renewable energy pathways benefit different communities and different workforces in Maryland.  Biomass heating – both at the residential and commercial scale – has far more benefits for rural Marylanders, whose homes and businesses do not have access to natural gas lines.  In this age where we all know that environmental justice is important and jobs for lower income Marylanders is important. We urge you to vote favorably on SB 549.

Sincerely,

John Ackerly,

President

A reader responds to the wood vs. coal debate

In our October newsletter, we reprinted a column by Cory Hatch from the Jackson Hole News & Guide.  We found it to be a thoughtful piece by a person grappling with energy choices and trying to fairly weigh their costs and benefits.  We got a lot of positive feedback about the article but one reader, a former professor of thermodynamics thought it was important enough to clarify something the author said.

The column made many good points, and concluded:

"After you factor in the energy and associated emissions it takes to extract, refine and transport fossil fuels, wood starts to look pretty good again. If you harvest trees close to home, firewood is fairly efficient and renewable, even if storing that carbon again takes some time. Unfortunately, woodstoves have local impacts, too. Chimney smoke contains particulates, nitrogen oxides and other gasses that can degrade air quality and cause health problems, especially for people with respiratory or cardiovascular disease."

The author also noted: "according to the Sierra Club, burning coal for electricity is only about 35 percent efficient, whereas a modern wood stove is about 75 percent."

Professor Gael Ulrich took issue with that:

" It is true that wood is superior in that it is renewable and not a fossil fuel, and it does not contain sulfur or other elements that can be problems in coal stack emissions.  But his statement, attributed to the Sierra Club, implying that wood combustion is twice as efficient as coal combustion is incorrect.  The distinction is subtle and not appreciated by someone without a background in thermodynamics, but I will try to make the reason clear.  

Converting fuel energy to heat and then to electricity can never be done with 100% efficiency.  Even the most modern efficient power plants seldom succeed 40%.  Historically, that principle was elucidated by Carnot, and the theoretical maximum possible is known as the Carnot efficiency.  In short, electricity or "stored work” is a higher form of energy than heat.  Converting “heat" to “work” always represents an energy loss manifest as “waste heat.” 

Coal power plants probably don’t do much better that 35% as suggested, but wood-fired electricgenerators are even less efficient (for reasons that would require more explanation).  Converting the energy content of coal to heat can, on the other hand, be done with high efficiency, matching or exceeding that of biomass combustors.  

Thus, the statement as worded in Hatch’s column is misleading.  His arguments regarding global warming, etc. are ok.  

I thought you might be interested in the error in case someone else has not already called it to your attention."

Periodically we publish substantive comments such as this one on our blog. Scores of shorter comments are left on our Facebook site.  If you have a longer substantive comment, we can't promise to publish it but please don't hesitate to send to info@forgreenheat.org.

Australia Firewood Association Scores Win for Wood Heating

A green building standard in Australia has assigned very low carbon values for wood and pellet heating, which will encourage builders and architects to specify wood heating, because it is now a cost effective means of achieving points toward the green building. The standard, called BASIX stands for the Building Sustainability Index (BASIX) and aims to deliver equitable, effective water and greenhouse gas reductions across the state. BASIX is one of the strongest sustainable planning measures to be undertaken in Australia.  The US equivalent is LEED, Leadership in Energy and Environmental Design, and overseen by the US Green Building Council, which is also grappling with how to assign points to wood and pellet heating systems in LEED certified homes and buildings.

From the Firewood Association of Australia – This relates to New South Wales (NSW) building regulations, but the science behind it applies everywhere, wherever there are restrictions on using wood fires, or campaigns against the environmental credentials of firewood.

NSW BASIX, the Building and Sustainability Index, is an integral part of the planning system in NSW. All new dwellings and alterations/additions over $50,000 in NSW must have a BASIX certificate before they can be approved by the council. It has taken seven years but we have finally achieved a major change in the BASIX rules, which, instead of discriminating against wood fires, now gives them a significant advantage.

Here is how it all happened, and what it means.  In August 2007 we sent a letter to the NSW Department of Planning that set out our case for a decrease in the “greenhouse factor” that is used for wood heaters within the on-line rating tool used to generate BASIX certificates. We felt that wood heaters were unfairly prejudiced in the rating system by being given the same “greenhouse” emissions rating as a 4 Star gas heater, when it had been confirmed by the 2003 CSIRO Life Cycle Analysis that firewood was (practically) a greenhouse neutral heating fuel. The department’s response to our letter was that they could not accept firewood as being greenhouse neutral because the 2003 CSIRO study did not include an assessment of non-CO2 greenhouse gases like methane and carbon monoxide.

The FAA subsequently contacted the CSIRO research team that had carried out the 2003 analysis. They eventually agreed to revise and extend their initial study to include carbon monoxide and methane. The results were formally published by CSIRO in April 2012 in a scientific journal (see the article on the front page of the FAA web site). The revised life cycle analysis showed that the greenhouse effect of non-CO2 gas emissions from firewood is minimal.
Following the, we approached the Department of Planning again to request that they re-consider a revision of the BASIX rating for wood heaters. This time we received a more positive response and the team from the Department’s Sustainability Unit agreed to consider our detailed submission.

Finally on the 10^th of June 2014, after almost 18 months of negotiation with the DPI Sustainability Unit, the BASIX on-line rating tool was updated to reflect a very much reduced emission factor for wood heaters. As noted in previous issues of the FAA e-news, the proposed change was strenuously opposed by the NSW EPA because they are funding a local government campaign to reduce the number of wood heaters in the State.

Because of the complexity of the BASIX system the impact of this change on any individual rating assessment is a little difficult to quantify precisely, but it will have the effect of making wood heaters much better than a 5 Star gas heater or a 6 Star reverse cycle air conditioner and in fact better than every other type of domestic heating including ground source heat pumps.

One of the likely outcomes of this change is that builders and architects will be encouraged to specify wood heating, simply because it is now the most cost effective means of achieving the required BASIX target.

Obviously manufacturers and retailers of wood heaters will be the big winners from this change. However, from a firewood industry perspective there will undoubtedly be an increased demand for wood, even if some of the new wood heaters are only used occasionally. The other main benefit for both sectors of the wood heating industry is that we have finally got formal government acknowledgement of the greenhouse benefits of firewood, which is something that the entire industry can use to its advantage.

The next thing to do is to make sure that we effectively communicate and promote what is truly a landmark win for wood heating. To get the ball rolling the FAA is obtaining quotes from commercial marketing organisations in NSW for the preparation and delivery of an integrated and targeted marketing strategy. When we are in possession of these quotes the FAA will invite all parties with a vested interest in the NSW wood industry to attend a meeting where the detailed ramifications of the rating change can be explained and a marketing strategy can be agreed.

We would like to express our thanks to the team from the DPI Sustainability Unit for their cooperation in what has been a long and challenging process. Our thanks also go to Joel Belnick of Jetmaster Fireplaces (Aust) Pty Ltd for his encouragement and assistance.