Can clean cooking developers convince credit buyers the carbon maths add up?

Carbon credit scandal reveals decade of flawed clean cookstove claims

Clean cookstove carbon offset projects have overstated their climate benefits by up to 1,000%, according to research from the University of California, Berkeley. For years, major polluters including Shell have purchased these credits to offset their emissions. However, new evidence shows most of these projects used flawed methods that multiplied small errors into massive over-crediting.

The problem stems from poor measurement practices and unrealistic assumptions about how households actually use cookstoves. Projects relied on surveys rather than direct monitoring. They also assumed abnormally high baseline fuel consumption that rarely matched reality. Consequently, credits sold to businesses represented far less carbon reduction than claimed.

A new methodology launched in July 2024 aims to restore credibility to this troubled market. The CLEAR standard mandates direct in-home fuel measurement and caps baseline assumptions. For UK businesses buying carbon credits, this represents a fundamental shift. Legacy credits purchased before 2024 may prove worthless, while new credits will cost more but carry genuine verification.

Berkeley study exposes systematic over-crediting across global projects

Research published in 2024 revealed that clean cookstove projects likely overestimate their emissions reductions by a factor of ten. This means projects claimed to save 10 tonnes of CO₂ when they actually saved just one tonne. The Berkeley team examined projects across multiple countries and found this pattern repeated consistently.

The Carbon Market Watch analysis of South Korea’s carbon market found even worse results. Korea operates the world’s second-largest carbon market. Their review showed cookstove projects overestimated reductions by an average factor of 18.3 times. One specific project claimed impacts 67.9 times higher than actual measurements demonstrated.

A Bangladesh clean cooking project for refugees illustrates how scrutiny forces corrections. Initially, the project claimed it would reduce emissions by 84%. After independent review challenged their baseline assumptions, developers cut the claim to 39%. This represents a reduction of more than half in claimed benefits.

The Integrity Council for the Voluntary Carbon Market recently rejected the two legacy methodologies these projects used. Their decision cited fundamental flaws in how the formulas work. Small errors in input data get multiplied through the calculation process, creating massive over-crediting at the output stage.

Benja Faecks, author of the Carbon Market Watch report, explained the multiplication problem clearly. Methods for tracking impact lack sufficient rigour in measuring fuel consumption and cookstove use. If one value is slightly wrong, that error alone can lead to double-time over-crediting. When multiple assumptions are wrong simultaneously, errors multiply exponentially.

Why measurement failures created a billion-pound credibility crisis

The core problem lies in how projects measured and verified actual cookstove usage. Legacy methodologies allowed developers to use household surveys as their primary data source. Families were simply asked how much fuel they used and how often they cooked with their new stove. This approach proved unreliable for several reasons.

Households often overestimate their use of new cookstoves when responding to surveys. They want to please the interviewer or justify the equipment they received. Additionally, survey timing matters significantly. A family might use their clean cookstove extensively during the first month, then gradually revert to traditional methods. A survey conducted early would capture peak usage, not long-term patterns.

Baseline assumptions compounded the survey data problems. Projects needed to establish how much wood or charcoal households would have burned without the intervention. Many used abnormally high baseline figures that didn’t reflect actual local practices. Some assumed deforestation rates two or three times higher than government forestry data showed.

The methodology then multiplied these questionable inputs together. Total claimed savings equalled baseline fuel consumption, multiplied by adoption rate, multiplied by usage frequency, multiplied by the carbon content of avoided fuel. Each multiplication step amplified any errors in the underlying data. A 10% error in baseline fuel estimates, combined with a 10% error in usage rates, could easily produce a 50% or 100% error in final credits issued.

Gill-Wiehl from Berkeley emphasized a fundamental point about cookstove projects. Assumed emission reductions don’t happen unless recipients actually use the stove. This differs from many other carbon projects where the intervention creates permanent change. A solar panel generates electricity regardless of human behaviour. A cookstove only saves emissions when someone chooses to use it instead of their traditional method.

Bangladesh research revealed what actually drives cookstove adoption decisions. Households prioritize fuel usage, smoke emissions, and maintenance frequency over cost alone. Families are willing to pay approximately £5.50 for a 25% reduction in smoke and fuel consumption. However, adoption rates remain low despite this willingness to pay. Installation costs and lack of awareness create barriers that surveyed intentions don’t capture.

The scale of investment makes these accuracy problems particularly significant. Bangladesh alone needs more than £1.6 billion over ten years to achieve universal clean cooking access. Projects there have already distributed roughly 1.7 million stoves. If each stove generates overestimated credits, the cumulative impact on carbon market integrity becomes enormous.

Shell and other major buyers funded decade of questionable offsets

Major corporations purchased millions of these cookstove credits to claim carbon neutrality. Shell notably bought substantial volumes as part of their offset strategy. Companies used these credits to balance emissions from their core operations, telling customers and investors they had achieved net zero targets. The Berkeley findings suggest much of this claimed neutrality was built on overestimated reductions.

This creates both reputational and compliance risks for UK businesses. Companies that purchased legacy cookstove credits may face challenges when stakeholders scrutinize their carbon claims. Supply chain partners and tender evaluators increasingly verify the quality of carbon credits companies use. Credits later proven to be overestimated can undermine years of reported progress.

The financial exposure extends beyond reputational damage. Some UK regulations and procurement frameworks now require carbon credits to meet specific quality standards. The Integrity Council for the Voluntary Carbon Market has established criteria that legacy cookstove credits cannot meet. Therefore, businesses holding these credits may find them unacceptable for regulatory compliance or tender requirements.

Furthermore, this situation affects how businesses should approach future credit purchases. Prices for genuinely verified credits will inevitably increase as standards tighten. The cost difference between verified and unverified credits may widen significantly. Companies that continue buying cheap legacy-methodology credits face growing risks that buyers and regulators will reject them.

New CLEAR methodology mandates direct measurement and stricter baselines

The Clean Cooking Alliance launched the CLEAR methodology in July 2024 specifically to address these credibility problems. This represents the first comprehensive standard covering all common cooking transition scenarios. The methodology fundamentally changes how projects must verify their climate impact.

CLEAR mandates direct in-home measurement of fuel consumption rather than relying on surveys. Projects must install monitoring devices that track actual stove usage over time. These devices record when the stove is used, for how long, and at what temperature. This creates an objective data trail that eliminates self-reported usage claims.

The methodology also caps baseline assumptions at realistic levels. For example, baseline wood consumption cannot exceed 2.0 tonnes per person per year without extraordinary justification. This prevents projects from claiming savings against inflated hypothetical scenarios. Caps are based on verified local data from government sources and independent surveys.

Projects must now demonstrate additionality more rigorously. They cannot simply distribute stoves and assume usage. Instead, they must prove that recipients would not have acquired similar cookstoves without the carbon finance. This might involve showing price barriers, lack of supply chains, or absence of government programs that would have provided stoves anyway.

The verification requirements under CLEAR occur much more frequently. Legacy methods often verified projects once every few years. The new standard requires annual verification with statistical sampling of actual household usage. Verifiers must physically visit homes, check monitoring devices, and interview families independently.

These changes mean credits from CLEAR-aligned projects will cost considerably more than legacy credits. Direct measurement equipment, frequent verification visits, and more conservative baseline assumptions all increase project costs. However, buyers gain genuine confidence that credits represent real, additional emissions reductions.

What UK businesses need to know about cookstove carbon credits

• Clean cookstove carbon projects using legacy methodologies likely overestimated climate benefits by between 10 and 67 times actual reductions, according to peer-reviewed research from Berkeley and analysis of the Korean carbon market.
• The Integrity Council for the Voluntary Carbon Market formally rejected the two main legacy methodologies in 2024 because their formulas multiply errors, meaning slight inaccuracies in input data create massive over-crediting in final calculations.
• A new CLEAR methodology launched in July 2024 mandates direct in-home fuel measurement, annual verification visits, and caps baseline assumptions at 2.0 tonnes of wood per person per year to prevent inflated claims.
• Major corporations including Shell purchased substantial volumes of these questionable credits to claim carbon neutrality, creating potential reputational and compliance risks as the scale of over-crediting becomes widely known.
• UK businesses holding legacy cookstove credits may find them unacceptable for regulatory compliance, tender requirements, or supply chain standards as procurement frameworks increasingly require credits to meet current quality criteria.
• Credits from projects using the new CLEAR standard will cost more due to monitoring equipment, frequent verification, and conservative assumptions, but provide genuine assurance of real emissions reductions.

Commercial implications for UK procurement and compliance strategies

Businesses using carbon credits for PPN 06/21 compliance should review their existing portfolios immediately. Procurement Policy Note 06/21 requires suppliers bidding for major government contracts to demonstrate carbon reduction plans. Many suppliers use purchased credits as part of their strategy. However, credits that don’t meet current quality standards may not satisfy evaluators during tender assessment.

The risk extends to private sector supply chains as well. Large retailers and manufacturers increasingly require suppliers to demonstrate credible carbon reductions. Supply chain standards often reference the Integrity Council criteria or similar frameworks. Credits from rejected methodologies create gaps in supplier sustainability documentation that buyers will identify during audits.

Financial directors should consider the balance sheet implications. Carbon credits are often carried as assets representing future compliance value. If legacy cookstove credits lose acceptance in key markets or regulatory frameworks, their value may need to be written down. This particularly affects businesses that purchased large volumes at low prices expecting to use them over several years.

Conversely, this situation creates procurement opportunities. Some credit sellers may offer legacy cookstove credits at steep discounts as acceptance declines. While these look attractive, buyers should assess whether any realistic use case remains. Credits that cannot be used for compliance, tender requirements, or credible sustainability reporting have little practical value regardless of price.

Businesses developing their own carbon reduction strategies should focus resources on direct emission cuts rather than relying heavily on offsets. The cookstove scandal demonstrates that credit quality varies enormously. Even well-intentioned projects using approved methodologies at the time of purchase can later prove problematic. Therefore, reductions from operational changes, energy efficiency, and renewable power provide more secure foundations for carbon claims.

For companies that do purchase credits, due diligence requirements have intensified significantly. Buyers should verify which methodology projects use and check whether it meets current Integrity Council standards. They should request evidence of direct measurement rather than survey data. Finally, they should confirm that verification occurs annually with physical site visits rather than desktop reviews.

The transition to CLEAR-standard credits will take time. Many existing projects cannot retrofit direct measurement systems into homes where stoves were distributed years ago. Consequently, the market will experience a shortage of high-quality cookstove credits during the transition period. Prices for verified credits will likely rise substantially as demand exceeds supply of genuinely credible options.

Where to find authoritative guidance and current standards

The Clean Cooking Alliance published detailed documentation about the CLEAR methodology on their website. This includes the full technical specifications for monitoring, baseline calculations, and verification requirements. Businesses evaluating cookstove credits should review these standards to understand what current best practice requires.

The Integrity Council for the Voluntary Carbon Market maintains a public list of approved methodologies and their assessment status. Their website explains why specific methodologies were rejected and what criteria projects must meet for approval. This provides essential context for assessing credits in existing portfolios.

UK businesses requiring support with carbon reporting compliance and credit evaluation can access specialist guidance on methodology quality and regulatory requirements. Understanding which credits satisfy different compliance frameworks helps businesses make informed purchasing decisions and avoid stranded assets.

The Carbon Market Watch published their detailed analysis of cookstove project over-crediting in the Korean market. Their report includes specific case studies and methodology critiques that illustrate how over-estimation occurs. This serves as essential reading for anyone involved in carbon credit procurement or sustainability reporting.

For businesses working toward net zero commitments, the structured approach to carbon reduction and reporting offered through formal programs provides greater certainty than relying solely on purchased offsets. Current market conditions demonstrate the risks of offset-dependent strategies when underlying project quality comes under scrutiny.