Liquid fuels are substances that can be burned to produce energy, typically in the form of heat or power. Common examples include gasoline, diesel, and kerosene. These fuels are derived from fossil sources, such as crude oil, and are widely used in transportation, heating, and electricity generation. Liquid fuels are stored in tanks and transported via pipelines, trucks, or ships. They are favored for their high energy density, meaning they can store a large amount of energy in a small volume. However, their combustion releases greenhouse gases, contributing to environmental concerns and climate change.