Most of the energy on Earth comes from the sun either directly or indirectly. The sun provides energy for organisms whose death and decomposition eventually create fossil fuels, and it produces wind and wave energy as it warms the atmosphere. Technological inventions such as solar panels have made it possible to convert energy from the sun into electricity as an alternative to fossil fuels.
Fossil fuels are sources of energy formed from decomposing dead organisms deep within the earth. Fossil fuels are the most commonly exploited sources of energy, and include oil, coal and natural gases. People use fossil fuels to power vehicles and other machinery, and for lighting, heating and cooking. Fossil fuels are non-renewable, meaning they will run out if continually exploited.
Alternative sources of energy include wind and water, which turn turbines to produce electrical energy using the force they exert as they flow. Large wind turbines and hydroelectric power equipment are used to harvest these energy sources. Both wind and water are renewable and clean energy sources that do not harm the environment.
Nuclear energy derives power from nuclear fission, which involves the splitting of atoms. This process yields an enormous amount of radioactive heat energy. In a nuclear power plant, the heat then turns water into steam to drive electricity-generating turbines. Nuclear power is an alternative energy source on which many countries around the world have become increasingly reliant.