In 2015, all United Nations Member States adopted 17 Sustainable Development Goals (SDGs), which are an urgent call for action by all countries – developed and developing – in a global partnership. The SDGs recognize that ending poverty and other deprivations must go together with strategies that improve health and education, reduce inequality, and spur economic growth – all while tackling climate change and working to preserve our oceans and forests.1
SDG 7 aims to “ensure access to affordable, reliable, sustainable, and modern energy for all.” SDG7 addresses a glaring deprivation and inequity: about 2.3 billion people lack access to clean cooking facilities, relying instead on the traditional use of solid fuels (wood, animal dung, charcoal, crop wastes, and coal) or kerosene as their primary cooking fuel. Household air pollution, mostly from cooking smoke, causes about 3.7 million premature deaths a year.2 Women and children, typically responsible for household chores such as cooking and collecting firewood, bear the greatest health burden from using polluting fuels and technologies in homes.3
What exactly makes a cooking experience “clean?” The World Health Organization (WHO) assesses fuel and technology combinations based on their emission of two harmful air pollutants: fine particulate matter (PM2.5) and carbon monoxide (CO).4 One expert panel on cookstove technology set the “clean” benchmark at a minimum of 90% emissions reductions and 50% fuel savings over a baseline technology (a traditional open, three-stone fire).5
Two energy-related factors come into play: the type of fuel used and the conversion device (fireplace, stove) that converts the energy into heat. In general, kerosene and solid fuels such as coal and wood have higher emissions compared to gaseous fuels, electricity, and solar cookers. But cookstove technology is also important. Open fires and other simple solid fuel cookstove technologies are less than 10% efficient. New cookstoves can exceed 50% efficiency which dramatically reduces fuel use and toxic emissions while also improving safety, reducing costs, and reducing time invested in fuel collection and cooking.6
Based on this, the WHO classifies solar, electric, biogas, natural gas, liquefied petroleum gas (LPG), and alcohol fuels including ethanol as clean. The WHO recommends against the use of unprocessed coal and discourages the use of kerosene due to their emissions of PM2.5 and CO.4 The classification of other fuels and technologies including biomass depends on the specific fuel, type of cookstove, and other factors.4
Natural gas and LPG are not clean from a climate perspective because their supply chains and combustion release greenhouse gases such as methane and carbon dioxide. However, they meet the narrower criteria for clean cooking and may be an affordable and readily deployed strategy in some low- and middle-income countries that yield significant health and social benefits.
1 United Nations Department of Economic and Social Affairs, “The 17 Goals,” accessed December 28, 2023, https://sdgs.un.org/goals
2 International Energy Agency, “Access to clean cooking,” accessed December 28, 2023, https://www.iea.org/reports/sdg7-data-and-projections/access-to-clean-cooking
3 World Health Organization, “Household air pollution,” accessed December 28, 2023, Link
4 World Health Organization, “WHO guidelines for indoor air quality: household fuel combustion, 2014, https://iris.who.int/handle/10665/141496
5 U.S. Department of Energy, “Biomass Cookstoves Technical Meeting: Summary Report, Alexandra, VA, January 11-12, 2011, Link
6 Sutar, Kailasnath B. “Energy Efficiency, Emissions and Adoption of Biomass Cookstoves.” In Alternative Energies and Efficiency Evaluation. IntechOpen, 2022. https://doi.org/10.5772/intechopen.101886.