Myren Consulting and AGH apply for Department of Energy R&D Grant

Down drafting stove would be open-source

Myren Consulting and the Alliance for Great Heat, along with Stonybrook University and German experts from DBFZ (Deutsches Biomasseforschungszentrum) are seeking to build an open-source wood stove that can help any manufacturer adopt the innovative approaches used by this stove. The goal is to make an ultra-clean wood stove that will consistently burn around 1 gram an hour without a catalyst and 0.5 grams with a catalyst, regardless of who loads and starts the stove.

The stove will use a downdraft airflow that brings the flames through the coal bed, and it will have a fan that induces the draft until the flue gases are hot enough to shut it off. The team will employ Computational Fluid Dynamics (CFD) to optimize the design and the air flow. The stove will also have a robust, multi-purpose data logger that can engage the operator via lights on the stove or through a sophisticated smart phone app. The app will feature content from our partner groups and walk consumers through all stages of the purchase, installation, operation, troubleshooting and maintenance. The consumer can choose if they will be the only one with access to the data, or whether they are willing to share it with the manufacturer, the retailer and/or a chimney sweep, for example.

Throughout the entire project, if funded, the team will share R&D decisions, designs, and data with the stove industry, regulators, and the public. The team will also seek to “crowd-source” solutions to problems and issues that may emerge by regularly seeking input from a range of stakeholders, from industry players to public health and low-income advocates. The stove will undergo a series of rigorous tests in Ben Myren’s lab over a 3-year period because a novel, top-notch stove needs that amount of time to get the design, airflow and other features just right. The stove will be tested to the traditional EPA reference Method 28, and the more recently approved ASTM 303-5 and IDC protocols. The stove will also undergo in situ real world testing, round-robin lab testing and be tested to the rigorous Blue Angel standard in Germany (not with DOE funds) to understand how it can handle a variety of loading and testing methods. 

Current certified stove design configurations have been developed since the mid 1980’s and are all based upon the draft generated by an EPA freely communicated lab chimney that is 15 ±1 ft. These designs have been developed somewhat over the years using a vast number of prototypes that have had many design changes made to them during this multi-year, multi-prototype R&D process. However, R&D in the stove community has not been robust and most manufacturers simply follow a well-known design pattern that has proved to be successful enough. We are attempting to disrupt that design pattern by maximizing secondary combustion in the upper part of the firebox but then drawing the gases down through the coal bed for an even more efficient secondary (or tertiary) emission reduction process.

With the change in draft proposed in this proposal, that entire body of knowledge becomes questionable.  And the project’s timeframe doesn’t provide for the typical long, slow development of a stove that will meet the current emissions standards. Thus, we propose to build upon a technique that we have been successfully using where some stove components are bolted together, rather than being welded together. This technique will allow us to rapidly make design changes which will hasten the entire R&D process. It will also enable us to fine-tune the combustion system in the stove by changing known critical components, e.g., the internal cross-sectional area of secondary air side manifolds, to facilitate the reduction of particulate matter (PM) emissions. The following table contains a (partial) list of critical components known to affect emissions.  Almost all of these features will still be relevant for a downdraft stove, but their size, shape and placement may change based on the downdraft design and the results of computational fluid dynamics (CFD) analysis.

  

• LPAO: Lower primary air orifice
• Horizontal throat gap: shortest distance between the front edge of the baffle and the backside of the air wash
• Vertical throat gap: shortest distance between the top of the baffle and the bottom of the top

All equipment used in the revised dilution tunnel system will be maintained and calibrated using current EPA criteria. Our stove will first assess how consistently we can operate under 1 gram an hour without a catalyst, but we plan on designing a model with a catalyst as well. Wood stoves are often not sufficiently optimized in terms of low-emission combustion, so that the catalyst is subjected to excessive overloading.

The initial group of expert advisors who wrote letters of commitment include the Tribal Healthy Home Network, the German Biomass Research Centre, the Danish Technological Institute, the Hearth, Patio & Barbecue Association (HPBA), the National Fireplace Institute, Industrial Chimney Company-Renewable Solid Fuel (ICC-RSF), Masonry Heater Association, Sunstein Intellectual Property Law Firm, and 509 Fabrications.

The $2 million price tag would include $1.3 million expenses at Myren lab, $300,000 at AGH, $215,00 at Stony Brook University, $125,000 by the German team working at Myren labs (no DOE funds will be spent abroad) and about $70,000 for other vendors and subcontractors.  We are requesting $1.6 from the DOE’s Bioenergy Technology Office.

In the spirit of this open source project and collaboration with other teams, the following materials can be downloaded:

The full technical volume 

Letters of commitment

Summary slide

Resumes

Diversity, Equity and Inclusion Plan

Pellet Stoves are hot commodity in Maryland rebate program

Alliance for Green Heat - A Maryland program that provides rebates for select pellet stoves and EPA certified wood stoves has been an overwhelming success for pellet stoves.  Of the 773 rebates given since the program started in September 2012, 646 or 83% of them have been for pellet stoves.

To date, the Maryland program has provided nearly $400,000 in rebate grants for pellet stoves and $67,000 for wood stoves.  The program is only open to families who heat with oil, propane or electricity in order to target those who have highest heating costs and the most carbon intensive fuels.

 The wood and pellet stove grant program is quickly catching up with the Maryland solar and geothermal grant programs, with 28% of all grants going to wood and pellet stoves and nearly 15% of total funding. The rebates range from $500 for wood stoves and solar hot water to $3,000 for geothermal.  All of the programs are designed and managed by the Maryland Energy Administration (MEA) with input from stakeholders and funded from Strategic Energy Investment Fund (SEIF), part of the Regional Greenhouse Gas Initiative (RGGI).

“These results show that rebates for pellet stoves can help a state meet residential carbon and electricity reduction goals,” said John Ackerly, the President of the Alliance for Green Heat and one of the advocates for this program.  “Per dollar of state funds invested, this has enabled Maryland to help many more families reduce energy costs and drastically reduce their fossil fuel use,” Ackerly added.

The greater interest in pellet stoves is result of a combination of factors, including people using the rebate to upgrade from an old, uncertified wood stove to a pellet stove, a higher rebate amount for pellet stoves and not as many wood stoves qualifying for the program’s 3-gram per hour emission requirement.  Pellet stoves are held to 2-gram an hour emission limit.

Another factor is that pellet stoves are simply becoming more popular in Maryland as they are nationally. The state has one of the premier pellet stove dealers in the nation and a full 58% of the 79 wood and pellet stove grants listed one month were being handled by that dealer, Courtland Hearth & Hardware, that has 3 stores in northeast Maryland.

On a per capita basis, the rebate program has been most popular in Harford County and Maryland’s rural eastern shore, a peninsula between the Chesapeake Bay and the Atlantic that has very little natural gas penetration.  On a numerical basis, the most rebates are in Harford, Anne Arundel and Baltimore County, more heavily populated counties that also have higher median household incomes and can better afford the up front costs of purchasing and installing a stove.  Garrett County, one of Maryland’s counties with the lowest average household income and the highest rate of wood heating, had very few participants in the rebate program and they were only one of two counties that favored wood over pellet stoves.

In Maryland, the western counties and the Eastern shore have the lowest average household incomes and the center, which is part of the Washington, Baltimore,  Philadelphia corridor are the wealthiest, with the exception of inner city Baltimore. This corridor also has very high rates of national gas penetration. 

Unlike many programs in other states and areas, where wood smoke is a worse problem, the Maryland program does not require the homeowner to turn in an old uncertified stove to qualify for a rebate.  Nevertheless, according to several stove retailers, between 50% and 75% of old uncertified stoves are removed and recycled anyway. Recyclers usually pay $25 - $40 for old wood stoves.  This indicates that a rebate program that requires professional installation can be an inexpensive way to remove old wood stoves from the airshed compared to many change out programs, which tend to be more expensive.

The $500 - $700 rebate from the state helps Maryland achieve several objectives.  Other than helping people replace or significantly reduce fossil heating fuel, it also steers people to pellet stoves instead of wood ones and leads consumers to buy a cleaner stove and ensures that it is professionally installed and/or inspected, depending on permit and inspection requirements of the county.  Without the rebate, it is more likely that more consumers may buy off the second hand market, or buy higher emitting wood or pellet stove, or hang on to an older stove for longer.

From a carbon perspective, incenting the purchase of wood and pellet stoves can be a very good investment as a wood or pellet stove is often about 10% of the cost of solar or geothermal and can displace about the same amount of fossil fuel as the typical solar or geothermal installation.  Pellet stovesGenerally, pellet stoves are more likely to be a primary or sole heat source for a home because they can be easily run 24/7.  

From an emissions perspective, pellet stoves are clearly better than wood because the fuel size is small, it has consistent low moisture content and is fed into a more controlled combustion chamber. By limiting the rebate to homes that heat with electricity, oil or propane, the program effectively limits the vast majority of participants to rural areas, where stove emissions are not as problematic. 

Nationally, wood stoves have always outsold pellet stoves, but pellet stoves have twice come close to selling more than wood stoves annually.  Over the five years preceding 2013, manufacturers shipped an average of 90,000 pellet stoves per year versus 137,000 wood stoves, according to data from the industry association, the Hearth, Patio and Barbecue Association (HPBA).

Sampling of data from applications:

The MEA provided the Alliance for Green Heat with a sampling of data from 110 applications.  This data helps the MEA and other stakeholders understand which fossil fuels are being offset, what applicants do with old wood stoves and other metrics that can help assess the strengths and weaknesses of the program.  It appears that the fossil fuel most commonly displaced was electricity, which was twice as common as oil and propane.  It is unclear if electric heating means electric resistance heat or a heat pump and that has a large bearing on the amount of electricity reduced.  Many Marylanders have older, inefficient heat pumps that work poorly in very cold temperatures. 

The application does not ask if the person intended the new stove to be a primary or secondary heat source or whether an old wood or pellet stove being replaced was a primary or secondary heat source.  That will be one of the recommendations the Alliance makes to the MEA about future data collection to provide better metrics for the program.

Of the 110 applications, 33 of the households already had an older stove.  What is surprising is that   Pellet stoves have many moving parts and are not as durable as wood stoves and often need to be replaced every 10 – 15 years.  Of the 33 households with existing stoves, nearly 60% had their old one recycled or otherwise disposed of.  Six of them, or 18%, sold them on the second hand market, including a few old pellet stoves.  And 3 people kept their old wood stove installed as an emergency back-up heat for their new pellet stove.  Nearly half of these households already had a pellet stove and wanted to upgrade to a newer pellet stove.

This analysis is based on much more data but continues the trends that were noted in a similar analysis in February of 2013 after the pilot phase of the program.  During the pilot phase, rebates were $400 for wood stoves and $600 for pellet stoves.  

More info:
Maryland wood and pellet stove program details and application
Other Maryland renewable energy programs
Background on how the program began
Common questions and answers about the program

HB 829, Summary of Renewable Energy for All Act

Purpose: to establish a renewable energy grant program in Maryland for residential wood and pellet heating units. Unlike the current renewable energy grant programs for solar, wind and geothermal, this program is designed mainly for low and middle-income families. Unlike those programs, which can provide very large grants mainly to wealthy families, this would provide a maximum grant of $1,500 so that available funds can benefit many families. The program would establish the strictest emission limits on wood and pellet stoves in the United States.

Benefits:
• Displaces expensive and carbon intensive heating fuels: oil, electricity and propane.
• Keeps heating dollars in the U.S. and often in Maryland.
• Provides jobs in rural communities.
• Provides energy independence and security.
• Provides more economic security for low-income families who would otherwise have to pay high-cost fossil fuel utility bills.
• Drives customers to the cleanest stoves and thus avoids the installation of hundreds of dirtier models.
Grant amount: 30 – 40% of purchase and installation price up to a maximum of $1,500 per family. Installation by a certified installer required.
• 30% Household income > $75,000
• 40% Household income < $75,000
• Extra $250 for the trade in of a non-certified EPA stove. The installer and/or stove retailer is responsible for handling trade-ins.

Rationale: This provides 1. larger grants for low-income families who most need it, 2. An incentive to choose the cleanest stoves on the market today, and 3. an additional incentive to get older, polluting stoves out of circulation instead of being sold on second hand market.

Equipment eligibility: Pellet stoves that emit less than 1.5 grams per hour and wood stoves that emit under 3.0 grams per hour.
Rationale: EPA currently allows up to 7.5 gr/hr for wood stoves and no upper limit for pellet stoves. The only other statewide limits are in Washington that allows up to 4.5 gr/hr and Oregon that allows up to 2.5 gr/hr for their tax incentive program. This would establish Maryland as a leader in promoting the cleanest stoves on the market today.

Household eligibility: For woodstoves, families whose primary heat is electricity, oil or propane; for pellet stoves, any household in the state.
Rationale: This would target 1. Families who have the most expensive heating systems, and 2. Rural families who do not live in densely inhabited areas and 3. Rural families who do not live in the air quality non-attainment zone that extends up and down the DC – Baltimore corridor .