This report was lightly updated in November 2022. The prior version of this report was published in October 2021. We may do a more detailed investigation of this area in the future.
Giving Green believes that donating to our top recommendations is likely to be the most impactful giving strategy for supporting climate action. However, we recognize that contributing to policy advocacy (as most of these recommendations do) may not be tenable for all donors, especially businesses. Taking this into consideration, we recommend BURN specifically for businesses given its focus on carbon removal and more direct alignment with corporate net-zero ambitions.We believe BURN to be a high-impact option, but we are unsure of the extent to which its cost-effectiveness approaches that of our top recommendations.
Overview of BURN stoves
BURN Manufacturing designs, manufactures, and distributes a line of fuel-efficient cookstoves in nine countries across Africa. With two solar-powered manufacturing facilities in Kenya, BURN describes itself as “the only vertically integrated modern cookstove company in Sub-Saharan Africa”. It has distributed over two million stoves through several channels. The models it primarily uses for carbon credit purposes are the charcoal-burning Jikokoa Classic and the wood-burning Kuniokoa stoves, which are directly distributed or delivered through partnerships.
Giving Green recommends BURN stoves on the weight of randomized controlled trial (RCT) evidence demonstrating high causality of emissions reductions. BURN stoves also have the co-benefit of reducing household spending on cooking fuel, improving health outcomes, and reducing time spent cooking.
Theory of Change
The following theory of change maps the link between BURN stoves and reduced GHG emissions. While BURN primarily sells its stoves in the market, its offsets fund projects that provide stoves to households at heavily reduced prices or for free. BURN stoves are designed to increase the fuel efficiency of households that use biomass as their primary cooking fuel source. Offsets contribute to all facets of these projects, including production, consumer engagement, and stove distribution. Increased stove usage over time leads to reduced GHGs over time as consumers switch from their traditional cookstoves to BURN’s fuel-efficient cookstoves.
We also lay out key parameters we use to model the cost-effectiveness of purchasing offsets from BURN:
Assumptions (relevant stage of theory of change as described above in parentheses):
Offsets increase stove production and distribution. (2)
There is marginal additionality in the number of BURN stoves being used due to offset money. (3)
Stoves are fuel efficient. (4)
Consumer behavior is modified. (4)
Money saved by consumers doesn't lead to GHG emitted elsewhere. (4)
How many offset dollars are needed for one additional stove? (3)
What is the reduction in fuel use over time? (4)
How is reduction in fuel converted to GHGs averted? (4)
What % of GHG reduction is maintained? (4)
The use of BURN’s cookstoves avoids emissions that would have been released by less fuel-efficient methods of cooking.
As mentioned in our overview of cookstove offsets, the academic literature on the link between efficient cookstoves and reduced emissions is mixed. The amount of credits a stove generates is highly variable, depending on the methodology, geography, profile of households receiving products, fuel usage (which is measured pre- and post-intervention), cooking practices, and product specs. For example, stoves in Somalia are credited more due to the less efficient standard baseline stoves, larger household size, higher rate of deforestation, and lower fuel-stacking.
Berkouwer and Dean (2022) conducted a rigorous RCT trial on the impact of BURN stoves and found that charcoal fuel usage, as measured by weighing of ashes and by self-reported use, declined by around 39%. This is close to BURN’s claims of a 50% reduction in fuel usage. Additionally, a smaller experiment involving 154 stove users confirmed that these reductions in fuel use persisted 18 months later. We would have liked to see long-term usage data from their larger RCT sample to verify the persistence of fuel use reduction, but we view these results as encouraging. The stove model studied in this RCT was the Jikokoa Classic, which is still primarily used for most credit-producing projects alongside the Kuniokoa model. Target markets remain similar to the context used within the study.
Overall, we view the evidence on the causality of BURN stoves in reducing GHG emissions to be quite strong. However, our assessment of the exact greenhouse gas reduction is less certain now that BURN has expanded to different geographies and stove types.
Project-level additionality seeks to answer the following question: would BURN exist and sell stoves in the absence of offsets? The majority of BURN’s revenues are from stove sales. Offsets are just a small part of its income, estimated at roughly 2-3% of total revenues. Representatives from BURN claim that offsets are an unreliable source of income, and therefore they cannot rely on income from offsets to fund their core business.
However, offset money is generally tied to specific projects that distribute stoves among populations that normally would not have access to them. Carbon credit revenue allows Jikokoa and Kuniokoa stoves to be sold at a subsidized, more affordable price; we believe these projects would likely not exist without donor money.
Overall, we assess that BURN offsets have a medium level of project-level additionality, as it’s difficult to verify whether offset money is directly going to projects that distribute stoves for free or reduced prices. However, from 2022, BURN has lowered prices for all stoves in all markets, meaning that every stove sold is now subsidized by carbon offsetting. BURN claims that as a consequence, the vast majority of BURN's distribution would now not be feasible without the sale of credits.
To achieve marginal additionality, each offset purchased must lead directly to additional emission reductions. For BURN, there is certainly potential for each additional offset sold to lead to more stoves being sold or used. While offsets are generated from previous projects, showing a market for offsets allows BURN to continue developing and marketing new projects with subsidized stoves.
However, money is fungible. BURN could book money from offset sales as profits or raise salaries. It could also invest in marketing strategies that do not work. BURN, however, is a social enterprise with multiple impact investors on its board. BURN’s mission is “saving lives and forests.” It also claims that all of its offset projects are “break-even” and do not contribute to other parts of BURN’s business. While we cannot verify its claim of using offset revenues to increase stove distribution, we find the claim consistent with BURN’s expansion strategy and believe that the additional income earned will help put more stoves in the hands of families.
Overall, it is not possible to verify with certainty that an additional offset purchased leads directly to the purchase of additional stoves and, therefore, to the reduction of GHGs in the atmosphere. However, BURN is a social enterprise, and we believe that it is likely that with more revenue, it will increase stove distribution.
Fuel use reduction from clean cookstoves represents permanent decreases in emissions.
Beyond reducing GHG emissions, Berkouwer and Dean (2022) also found clear economic benefits for households using BURN stoves. Berkouwer and Dean (2022) estimate that for the study population, purchasing a BURN stove resulted in fuel savings of $119/year, roughly equivalent to one month of income. They conclude that relative to a $40 unit price, the internal rate of return for one household is 295% per year, and “larger than most relevant alternative investments likely available to households.” BURN stoves can make a real difference in a family’s spending power.
In addition, BURN stoves reduce the time spent cooking – a burden predominantly borne by women. Berkouwer and Dean (2022) find an average reduction of 54 minutes per day, for households using the BURN stoves.
Using improved cookstoves also improves health, as better indoor air quality could decrease the incidence and severity of respiratory diseases. Berkouwer and Dean (2022) find that BURN stove users self-report better respiratory health than those who did not use BURN stoves. BURN research finds that the Jikokoa reduces indoor air pollution (PM2.5 and CO) by 65%, and that the Kuniokoa reduces smoke by 82%.
Giving Green conducted a cost-effectiveness analysis to estimate the cost per ton of CO2 removed from using BURN’s fuel-efficient cookstoves. Our goal is to validate our recommendation of BURN as a highly effective agent in reducing GHG emissions. The data we use comes primarily from project-level data from BURN alongside impact estimates from Berkouwer and Dean (2022). View our model here.
The RCT conducted by Berkouwer and Dean (2022) concluded that study households annually spent 39% less on charcoal, which translated to a reduction of 331 kg in charcoal per household per year, given local charcoal prices at the time of the study. The Food and Agriculture Organization of the United Nations (2017) estimates that kg of charcoal emits 7.2–9.0 kg of CO2e from the production process alone; combustion adds 2.36 kg of CO2e. Taking the midpoint of the former range, we estimate that each stove avoids 3.46 metric tons of CO2e per household annually.
BURN lifetime analyses based on testing data and field data suggest that the lifetime of stoves subsidized by carbon credits may be around 5-7 years. BURN told us that field survey data have an approximate 6% annual attrition rate (i.e., BURN is no longer able to reach around 25% of initially-surveyed cookstove owners by the fifth year of surveys). If unreachable households are more likely to no longer use BURN stoves, relative to households that BURN is able to reach for surveys in subsequent years, it’s possible that we have overestimated the cookstove lifetime. As a rough adjustment for this, we use BURN’s lower-bound estimate of a five-year stove lifetime. Adding a 3% future carbon discount, our final estimate of GHGs avoided per household is 17.31 tCO2e over the lifetime of the stove. To then obtain the offset dollars required per tCO2e avoided, we incorporate BURN’s production-to-delivery cost of $76.28 USD, which is its estimate for certain offset-funded projects. Dividing this quantity by 17.31 tCO2e, we estimate that $4.81 in offsets avoids 1 ton of CO2e.
This number is less than the price at which BURN sells an offset for a ton of CO2 on its website—which varies over time but is $30/ton as of November 2022—and suggests that offsets from BURN are highly cost-effective. There are multiple reasons why our final estimate is not equal to the costs stated on BURN’s website.
First, despite the stove’s estimated lifetime of 5-7 years, the crediting period for BURN is shorter because not all stoves will last this long. As a result, it does not make financial sense to conduct the validation exercises needed to issue credits once a non-negligible proportion of stoves have failed. Next, there may be differences in which parts of the charcoal life cycle are accounted for in the estimation of GHG averted — combustion, or combustion plus production. According to BURN, it was conservative in its submissions to offset certifiers, and once these parameters have been submitted to a crediting body, they are difficult to change.
It is important to realize that supply and demand determine the price of offsets on the market rather than the program cost. BURN sells its carbon credits to different buyers at different prices, providing lower prices to corporate purchasers who buy in bulk. As the sale of one credit or 1,000 credits requires the same amount of administration, the recently increased prices on its website ensure the total cost of offset projects is covered, reflecting that most website sales are for one credit only. However, in this case, the marketed price of the credit is not meaningful: what matters is the total amount of money spent. Buyers who spend $100 on low-priced credits contribute the same amount to a project as those who spend $100 on high-priced credits.
As a result, our calculations show a discrepancy between BURN’s sale price and the actual cost per CO2e averted, meaning that per Giving Green’s analysis, each offset sold by BURN avoids more than 1 ton of CO2e.
We believe that BURN stoves are strongly linked to reduced GHG emissions and improve the well-being of their owners. As with almost all offsets, we do not think offset purchases viably translate to a specific amount of CO2 removed. However, we believe that purchasing offsets enables BURN to distribute more stoves and directionally leads to fewer emissions.
We thank Peter Scott, CEO/Founder, Chris McKinney, Chief Commerce Officer, Andrew Weiner, Strategic Associate, and Molly Brown, Strategic Associate to Carbon at BURN Manufacturing for a series of conversations that informed this document.
 “The vast majority of the crediting is using flagship products, the Jikokoa Classic and the Kuniokoa.” “Distribution itself is done through a mix of direct and via partnerships.” BURN email correspondence, 2022-10-04
 “Carbon revenue is used to subsidize the cost of our stoves to a price that is affordable for the majority of families. We are targeting prices of $15-25 for Jikokoas and $0-10 for Kuniokoas.” BURN email correspondence, 2022-10-04
 “In Somalia for instance, we credit more per stove due to the less efficient baseline stoves, larger household size, higher rate of deforestation, and lower fuel-stacking.” BURN email correspondence, 2022-10-04
 “The vast majority of the crediting is using flagship products, the Jikokoa Classic and the Kuniokoa.” BURN email correspondence, 2022-10-04
 "Yes, in general our target markets remain the same across geographies” BURN email correspondence, 2022-10-04
 BURN correspondence, 2022-11-15
 BURN correspondence, 2022-11-15
 In 2021 we used $50.85, which reflected the average cost in urban Kenya. BURN has begun expanding its operations to other countries and contexts and has noted that while it does not yet have an updated estimate for average cost, distribution in rural areas is significantly more expensive. To account for this, we have increased the cost by 50%, but we will revise this number when BURN generates an updated estimate.