Most modern nations rely on natural gas, oil, and coal for most of their energy needs, but reliance on fossil fuels is a big dilemma. Fossil fuels are considered a finite resource, meaning the world can and will run out of fossil fuels. These fuels can also cause air, soil, and water pollution. However, people are turning to renewable energy sources.

These are the three main sources of renewable energy:

The first of the three main sources of renewable energy is solar energy and it is probably the most well-known method. The sun is our most powerful natural energy source. Solar energy, which is light from the sun, can be used for light, heat, home cooling, electricity, water heating, and many more industrial processes. Most forms of renewable energy are derived directly or indirectly from the sun. For example, the heat of the sun causes the wind to blow. This, in turn, contributes to the growth of plants and trees used for biomass energy. This plays an important role in the cycle of evaporation and precipitation that powers hydroelectric power.

The second of the top three renewable energy sources is wind power. Wind is the movement of air that occurs when warm air rises and cooler air moves in, replacing it. Wind power has been a centuries-old tool for sailing ships and for moving windmills to grind grain. Currently, wind energy is used to generate electricity through wind turbines.

The third most important renewable energy source is hydroelectric power. The force of the water flowing downstream is powerful. Water is a renewable resource in itself, being constantly recharged by the evaporation-precipitation cycle. The heat from the sun causes the water in the oceans and lakes to evaporate, thus forming clouds. The most familiar part, of course, is the water that falls back to earth as rain or snow, draining into streams and rivers that return to the ocean. The power of flowing water can be used to drive water wheels. The energy can be captured by generators and turbines and used to generate electricity.