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IMPROVED BIOMASS COOKSTOVES Improved biomass cookstoves use improved design to burn biomass more clean- ly and efficiently, resulting in lower smoke and particulate emissions and reduced overall fuel consumption. While not a fully clean solution, it is considered a transi- tional step towards cleaner cooking in low-income settings. It accounts for around 30 percent of those who gained access to clean cooking over the last decade. 85 Improved cookstoves use a range of biomass fuels, including firewood, charcoal, agricultural and forestry residues and processed fuels such as pellets and bri- quettes (see Box 6). The case for improved cookstoves (see Box 7) lies in their low cost and suitability for rapid deployment in rural or remote areas. 86 While the basic models are readily affordable, the price rises considerably with the more sophisticated designs associ- ated with higher fuel efficiency and emissions standards. 87 Nonetheless, the options continue to evolve rapidly, with international initiatives such as CCA, the Climate and Clean Air Coalition (CCAC) as well as private enterprises investing significant
People who gained access to clean cooking over the last
decade: 30 %
BOX 6: VARIETIES OF IMPROVED BIOMASS COOKSTOVES
The International Organization for Standardization (ISO), an independent, non-governmental body founded in 1947 and based in Switzerland, provides a set of testing and reporting standards for the emissions, efficiency, safety and durability of cook- stoves. Tests are done in a lab setting and cookstoves are rated from Tier 0 (lowest) to Tier 5 (highest). Tier 0 aligns with the performance of open fires. Basic portable cookstoves. These artisan-pro- duced ceramic or clay models offer moderate ef- ficiency improvements in the burning of wood and charcoal. In the past they were often distributed as part of national and donor clean cooking programs and are therefore often called “legacy” models. Un- der the ISO ratings for emissions they reach only Tier 1, indicating only modest improvement on tra- ditional stoves.
significant improvements in fuel efficiency, but with limited health and environmental benefits com- pared to cooking with modern fuels. They may be portable (e.g., the Envirofit charcoal and wood cookstoves), semi-portable (e.g., Ethiopia MIRT cookstoves) or built-in (e.g., Uganda Rocket Lore- na cookstove) and may be either unvented or com- bined with chimneys. They are rated Tier 2 for emis- sions and are considered a stepping stone towards cleaner solutions. Advanced biomass cookstoves. These more sophis- ticated designs use fans or natural draft to convert solid fuel into combustible gases (“gasification”), thereby achieving significant particulate emission reductions – although still not at the level of mod- ern fuel cookstoves. At peak performance and un- der lab conditions some gasifier stoves can now ex- ceed ISO Tier 3 emissions performance, particularly when combined with chimneys, making them signif- icantly safer to use. 88
Intermediate cookstoves. There is a wide range of intermediate-level solid fuel cookstoves that offer
AN OPEC FUND KNOWLEDGE SERIES REPORT 2024
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