Fuel types refer to the various materials used to produce energy, primarily for transportation, heating, and electricity generation. Common fuel types include gasoline, diesel, natural gas, coal, and renewable sources like solar and wind. Each fuel type has different properties, costs, and environmental impacts, influencing their use in different applications. Fossil fuels, such as coal, oil, and natural gas, are derived from ancient organic matter and are the most widely used energy sources. In contrast, renewable fuels, like biofuels and hydropower, are derived from natural processes and are considered more sustainable. The choice of fuel type affects energy efficiency, emissions, and overall environmental health.