List and briefly define the five types of renewable energy. Also give one example of how that energy source is already being used today. Discuss some reasons why these renewable sources are not yet widely used today. Electricity - This is not discussed as an energy source in this unit. This unit deals with primary, or natural, energy sources.
Electricity is a secondary energy source.
It is derived from a primary source. 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.