Solid fuels are materials that can be burned to produce energy in the form of heat. Common examples include coal, wood, and biomass. These fuels are often used in homes for heating and cooking, as well as in industries for generating power. When burned, solid fuels release energy, but they can also produce smoke and other emissions. The use of solid fuels has been a traditional method of energy production for centuries. While they are generally more affordable than some other energy sources, their environmental impact is a concern. Efforts are being made to develop cleaner burning technologies and alternative fuels to reduce pollution associated with solid fuel use.