Photo: Rob Bailis / SEI

Rural Vietnamese households can significantly reduce their wood consumption and emissions by adding rock-beds or grates to their open cooking fires, according to a new, open-access study in Energy for Sustainable Development.

SEI teamed up with the non-governmental organization Sun24 and SNV Netherlands Development Organisation to test the effectiveness of these simple low-cost approaches. The team found that rock-beds and ceramic or metal grates could reduce wood consumption by 31–58% and emissions by 51–84%.

“Our findings indicate that easy, inexpensive modifications to existing cooking methods can make a real difference, by cutting down on unsustainable fuelwood harvesting, reducing climate impacts, and improving air quality,” said SEI Senior Scientist Rob Bailis, an author of the study. “Making these changes could also ease the burden of collecting wood, a task that often falls to women.”

Many current programs focus on the cleanest cooking options – such as stoves that use electricity, liquid petroleum gas (LPG), or ethanol – because they have very low emissions and are more likely to reduce health risks from indoor cooking.

But these ideal options are not available everywhere: the majority of rural households in sub-Saharan Africa have minimal access. In South Asia, access to clean fuels has increased, but consumption remains low. Where clean cooking options are available, many people use them alongside traditional fuels and cookstoves, a practice known as fuel or stove “stacking”.

The modifications in the study are unlikely to reduce health impacts. But they are attractive transitional solutions because they are inexpensive, simple to maintain, easy to replace, and require no change in cooking practices.

Cooking options tested in this study (clockwise from upper left): iron bar baseline stove; rock-bed; ceramic grate; and metal grate with rocks. Photo: SEI, SNV and Sun24.

For the study, researchers tested these modifications against a baseline iron bar stove, using both lab and field tests. The results were consistent and robust across all tests: the modifications reduced wood consumption and emissions.

A survey of users also revealed a high degree of satisfaction, indicating that they would likely use these modifications for most or all of their cooking.

“Rock beds are free and require little behavior modification. They also reduce the drudgery of collecting firewood – a task that often falls to women — and so are readily adopted. This makes training simple and inexpensive. We estimate that millions of households are using rock beds as a result of our training in a dozen African countries in partnership with the Catholic and Anglican Churches,” said Kevin McLean, president of Sun24. “In addition to the time saved collecting firewood, the cumulative reductions in forest destruction, indoor and ambient air pollution and climate damage are enormous.”

Sun24 promotes these low-cost approaches in rural communities throughout the Global South, with current activity focused in sub-Saharan Africa. The recent study was part of a partnership with SNV and SEI to better understand the impacts of these efforts.

Bastiaan Teune, Global Cookstoves Coordinator for SNV explained, “At the request of Sun 24, SNV tested this cooking concept in a laboratory in Hanoi that was set up with support from EnDev. As we have an experienced team that has conducted many household energy surveys, we were poised to bust the rock bed myth. To our astonishment, the lab and the field tests only confirmed the positive impact of rocks and grates as predicted by Sun 24. We see great potential for our energy projects in remote and refugee settings”.

A woman sitting in a kitchen with an open cookstove

This program seeks to better understand the implications of energy use in the developing world and explore more sustainable pathways with reduced impacts.