Clean cookstoves (improved biomass, ethanol, biogas)

Buildings consume about 40% of global energy and produce roughly the same share of carbon emissions. Most of this energy gets wasted through poor insulation, inefficient heating and cooling systems, and outdated design practices.

The building sector moves slowly — most structures last decades, and retrofitting existing buildings is complex and expensive. Meanwhile, billions of people worldwide still rely on polluting fuels for basic needs like cooking and heating water, creating both climate and health problems.

Solving building energy waste requires both cutting-edge technology and practical approaches that work at massive scale. The opportunity is enormous: dramatically reducing emissions while making buildings more comfortable and affordable to operate.

About 3 billion people worldwide cook with wood, charcoal, kerosene, or other polluting fuels, often indoors without proper ventilation. This creates deadly indoor air pollution that kills millions annually, while also contributing to deforestation and climate change.

Providing clean cooking and water heating solutions for low-income households requires technologies that are affordable, culturally appropriate, and work reliably in challenging conditions.

Efficient stoves that burn traditional fuels much more cleanly than open fires or basic stoves. Improved biomass stoves use better combustion design to reduce smoke and fuel use. Ethanol and biogas stoves burn cleaner liquid and gaseous fuels. These stoves can reduce indoor air pollution by 80-90% while cutting fuel costs.