Cookstoves Under Fire: Rubicon Carbon's Take

By Dr. Jennifer Jenkins, Dr. Brian Clough

This week, an article from Gill-Wiehl et al. in Nature Sustainability, accompanied by additional coverage in Financial Times and The Guardian, describes systematic over-crediting in cookstove carbon projects. This is yet another criticism of VCM 1.0, and let’s be honest: all of this headline-grabbing attention to well-known flaws in the outdated legacy methodologies in the VCM is getting old and even a little bit boring. Ho hum.

The article and related media coverage are sure to set off another round of “Is the voluntary carbon market effective?” discourse. But to us, this just highlights – once again – the importance of investing in the improvements inherent in the Voluntary Carbon Market (VCM) 2.0.

In the study, the authors analyzed cookstove projects from the most widely used (and oldest) methodologies. They reported over-crediting of about 9.2 times the reported number of credits across all projects, with a range of results depending on the methodology utilized.

(We should point out that a.) Rubicon Carbon does not own any credits from cookstove projects today, and b.) the paper's findings, published initially as an online preprint in February 2023, have been contested on technical grounds in an open letter published by a group of carbon market stakeholders.) 

What are cookstove projects?

Cookstove projects aim to reduce the degradation of forests and other ecosystems by providing fuel-efficient stoves. They work by giving people a less energy-intensive alternative that increases energy efficiency and/or reduces the use of ‘non-renewable’ biofuels - for example, encouraging agricultural residues instead of firewood for cooking. 

Ultimately, when people switch to cookstoves, they emit less carbon dioxide. In addition to the carbon benefit, switching to cleaner, more fuel-efficient stoves can have significant health benefits for households that use them. While the basic idea may seem simple, designing and executing a high-quality cookstove project is quite complex. 

Quality for cookstove projects

Because we at Rubicon Carbon have taken a cautious approach to evaluating cookstove projects, we do not currently (Jan/24) own any credits from cookstove projects. Our reasons align with many of the potential issues cited by Gill-Wiehl et al., including:

  • Baselines: Most widely used methodologies fail to use conservative values for critical parameters, such as the fraction of biomass harvested for cooking fires that is unlikely to regrow, resulting in project over-crediting. 
  • Monitoring: Cookstove projects are challenging to monitor, as they involve quantifying losses of carbon storage related to gradual forest degradation and ongoing usage rates in households that receive improved stoves.
  • Verification: The effectiveness of cookstove projects is sensitive to how quickly communities adopt the new stoves and the usage rate throughout the project period. Continued community engagement is necessary to ensure stoves are well maintained and to develop more informed surveys to inform more accurate baselines.

Despite these risks, cookstove projects have some appealing qualities for credit buyers:

  • Additionality: Cookstove projects would only happen with financing for the new stoves. Even if the risk of over-crediting is high, the chances of a project not being additional are low. 
  • Co-benefits: Cookstove projects support several UN Sustainable Development Goals (SDGs), including goals 3 (health), 5 (gender), and 7 (energy). More efficient cookstoves can reduce indoor air pollution, lower the burden of unpaid work that disproportionately falls on women, such as fuel collecting and cooking, and increase energy security, especially in rural communities.

We agree with the conclusions of several authors, most recently Gill-Wiehl et al., that the possibility of over-crediting using VCM 1.0 cookstove methodologies is high and that failing to perform robust due diligence on individual projects risks channeling investments to low-integrity credits. 

That said, given the positive opportunities they present, particularly the potential for strong social co-benefits, we believe there is substantial opportunity for improvement in this sector by following the blueprint of VCM 2.0.

Moving cookstoves to VCM 2.0

In a previous post, we highlighted “What’s Out and What’s In” as the Voluntary Carbon Market transitions to VCM 2.0. At a high level, it’s pretty straightforward: VCM includes fewer assumptions, more data and models, more robust community engagement, and leveraging financial management tools to de-risk climate investments and give buyers greater confidence. 

What might this look like for cookstove projects? Here are a few ideas:

  • More conservative assumptions: As the Nature Sustainability study highlights, simply adopting a more cautious baseline compared to what is recommended by most current methodologies would substantially reduce over-crediting risk. 

  • Robust monitoring approaches: Deploying innovative monitoring approaches, such as remote monitors that can provide more realistic data on usage, will reduce the need for basic assumptions about the degree to which new stoves will be adopted. 

In addition, project developers must use satellite analysis to assess changes in forest carbon stocks, which can help refine critical parameters, such as the fraction of non-renewable biomass harvested for fuel.  We also need robust survey methods to quantify uptake that can augment monitoring data. 

  • Better community engagement: Involving local communities in the early stages of project development is also critical, mainly using local knowledge to set projects up for success. Maintaining a continued, collaborative presence yields a more accurate baseline and promotes robust continued verification.

  • Risk management: Managing portfolio risk, for example by applying Rubicon’s risk adjustment approach, can address residual uncertainty and make buyers confident that the climate impact of a cookstove-based carbon credit is tangible and quantifiable. 

Getting things right in VCM 2.0

Objective, analytical criticism is vital for highlighting issues that may undermine the integrity of carbon projects. To that end, this week’s Nature Sustainability paper confirms the risk of over-crediting in cookstove projects reported by other analysts while highlighting several paths for improvement that align with the shift towards VCM 2.0. 

The findings of Gill-Wiehl et al. are valuable. However, we should be wary of analyses that use these methodological shortcomings to suggest that the voluntary carbon market as a whole cannot create climate impact. 

The fact that many VCM 1.0 project methodologies are insufficient isn’t news. But that doesn’t mean methodologies can’t improve. As we highlighted here for cookstove projects, there are often fairly obvious improvements, such as modern data and analytical approaches. And when we have done almost everything we can to improve project methodologies, we can utilize portfolio and risk management to account for the remaining uncertainties. Implementing these improvements is how we transition to VCM 2.0. 

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At Rubicon Carbon, we use our portfolio and capital investments to help catalyze this transition. To learn more, subscribe to our newsletter and follow our blog. 




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