Energy - Energy is something that causes a change in matter. The forms of energy are light, heat, motion, sound, electricity, chemical energy, and nuclear energy. Energy cannot be created or destroyed but it can be changed from one form to another. It took millions of years for these fuels to form. Solar energy is produced when light energy is absorbed and is changed into heat and used for power.
Wind energy is produced when wind turns turbines that are used to generate electricity.
Hydropower is energy produced from falling water. Today this is usually harnessed by building dams on rivers. Geothermal energy comes from heat trapped under the earth's surface. Most renewable energy sources cost more than fossil fuels to produce. More research needed.