Solar, Hydropower, Geothermal and Wind are renewable and cleaner sources of energy than fossil fuels. The more we use these clean sources of energy, the cleaner our environment will become and the healthier we will be. Some renewable energy systems, like solar, can be set up in remote areas bringing power, energy and light to people all over the world.
Solar power is the cleanest, most abundant renewable resource at humanity’s disposal. Solar energy, the radiant light and heat from the sun, is harnessed into usable energy in the form of solar power.
Hydropower uses moving water as the source of power. The ability it harness energy from the movement of water makes this form of energy reliant upon the water cycle. https://www.eia.gov/energyexplained/?page=geothermal_home
Geothermal energy comes from steam, hot water, hot rock, molten rock found in the earth. The heat energy is found on the surface of the earth and deep in the core. This energy is naturally produced making it a renewable resource.
Wind energy is harnessed by using the wind to move giant wind turbines that produce energy. This renewable energy is clean. A form of solar energy (Jane, link to What is solar page), wind currents are formed as the sun heats the earth unevenly because the Earth’s terrain of water and land is so varied. http://windeis.anl.gov/guide/basics/