BSL Physics Glossary - renewable energy - definition
Translation: We can make renewable energy from the sun. The heat energy comes down from the sun and hits a solar panel where it is changed into electrical energy. The sun rises and sets, but it is always there as a source of power. It doesn't reduce over time. And we can make renewable energy from the waves. The waves go up and down, and this makes a float move up and down. The movement energy is changed to electrical energy. Waves always go up and down in the sea. We can also make renewable energy from wind power. The wind blows and a windmill turns. The movement energy is changed by a turbine to electrical energy. The wind blows all the time, so it's renewable energy.
There is another sort of energy which is not renewable. For example, energy from coal that we dig up out of the ground and use in a fire. When the coal is burnt, we have to dig more from the ground, until it's all used up. Coal takes millions and millions of years to be made - we can't wait so long for more to be made. So coal is not renewable energy. Solar power from the sun, wave power, wind power are all renewable energy.