NUI Galway and World Bank research finds time-savings key to household stacking of cookstoves in developing countries

Liquefied petroleum gas charcoal stove. Photo: Ryan Institute, NUI Galway
Nov 13 2020 Posted: 08:50 GMT

Energy poverty, where the poorest households in developing countries lack access to modern energy sources and services is prevalent worldwide, with almost 800 million people lacking access to electricity. Around three billion people globally are cooking everyday using polluting open fires or simple stoves fuelled by kerosene, biomass (wood, animal dung and crop waste) and coal.

A recent collaborative study in Kenya led by Dr Caroline Ochieng and Professor Charles Spillane from the Ryan Institute at NUI Galway, in collaboration with the World Bank ESMAP program, confirms that cookstove and fuel stacking is the norm; with just 17% of 71 respondents reporting exclusive use of one stove type or fuel.

Dr Caroline Ochieng from NUI Galway’s Ryan Institute, said: “We find that the main driver of stacking is the need to save time by preparing multiple dishes simultaneously, as opposed to cultural attachment to traditional cookstoves or food taste preferences that are generally seen as the major behavioral obstacles to cookstove adoption. Just like I have several cooking and heating devices in my own household that allow me to finalise these chores within a very short time, it is the same requirement these households have. Having the new stoves allows them to now have two as opposed to just one cooking and heating device that performs everything.”

Funded by the Irish Research Council and EU MSCA program, the study, published in the journal Energy for Sustainable Development observed that an overwhelming number of cookstove programs promote single burner designs, which implies a lack of understanding and appreciation of end-user needs. Based on this finding, the researchers are recommending standardization of a number of burners of cookstoves to more than one, as well as a marketing strategy that capitalizes on such benefits (demonstrating parallel dishes being prepared on a stove) to increase uptake of clean cookstoves.

Professor Charles Spillane, Director of the Ryan Institute at NUI Galway, highlights: “Each year, close to four million people die prematurely from illness attributable to household air pollution from inefficient cooking practices using polluting stoves paired with solid fuels and kerosene. If the massive investments in clean cookstove interventions globally are to improve household health outcomes, the reality of stove stacking has to be factored into the design of interventions. This is critical if cleaner cooking interventions are to reduce the burden of disease associated with polluting stoves.”

Amongst the 17 Sustainable Development Goals, SDG7 is focused on ensuring access to affordable, reliable and modern energy for all by 2030. Stove stacking, the practice of using multiple cookstoves and fuels at the same time, has important implications for programs and policies that are trying to transition poorer households away from traditional fuels and stoves and thereby achieve SDG7 targets regarding access to modern energy services.

The predominant reliance on biomass for cooking is a major environment and health risk concentrated in low and middle income countries where clean fuel alternatives such as electricity, liquefied petroleum gas (LPG), and cleaner burning woodstoves are either unavailable, or are not affordable to the majority of households.

What is now widely observed is that while cookstove users adopt the new cookstoves and fuels, they still retain the traditional ones. From a public health perspective, this is problematic. The health risks associated with burning of biomass fuels do not reduce at the same rate as reduction of emissions. As a result, where polluting cookstoves continue to be used even for secondary functions, the health risks within unventilated households still remain. It is therefore of policy interest to understand why cookstoves are stacked by households, and how policy measures can be redesigned to better respond to this practice.

Dr Yabei Zhang who is a co-author of the study and leads the World Bank’s Clean Cooking Fund, said: “For any user-centered clean cooking interventions, stacking has to be incorporated in the design. This study’s findings support ESMAP’s move toward national surveys that take into account multi-dimensionality of energy access, such as the Multi-Tier Framework surveys that collect information on cookstove and fuel stacking. This is also why we have used ‘two-burner’ as a cooking solution requirement when modeling a transition pathway toward universal access to modern energy cooking services in the recently published report the State of Modern Energy Cooking Services.”

The authors call for more research on stacking, that to date is often dealt with in post-hoc analyses while the primary focus remains on stove performance in reduction of household air pollution and health improvements. They highlight in the article the enormous benefits of stacking for households, where stacking needs to be viewed as part of the cookstove transition process.

“By stacking different stoves, women were able to save time and cook their meals on time, with important implications for the overall welfare of the family including children's education.” This is based on constant narrative from study participants that children would go to bed hungry and be late for school if meals took too long to cook, a common experience for those who had one cooking device/burner.

While this may not be a popular recommendation for programs targeting health benefits, the authors recommend that in the long term, trialing of different cookstoves and fuels within a stacking regime could provide the necessary learning and experience that could more effectively facilitate a switch away from traditional cookstoves.

To read the full study in Energy for Sustainable Development, visit:

For more information about the study contact:  and 


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