Solar Energy
Solar energy is the energy derived from the sun. The two main types of solar energy are thermal, photovoltaic. Neither of which give off any harmful by-products. To learn more continue reading below.
Thermal Energy
If you've ever gotten out of a pool and just "air-dried," you were actually using solar thermal energy. Almost everyone has either directly indirectly used solar thermal energy. Solar thermal energy is just the old fashioned use of the suns heat. Uses of this form of energy include heating things, drying things, and distilling water. This is a great form of energy because the sun is constantly providing and its free. The harnessing of this energy can range anywhere from hanging a wet shirt on a wire, to high-tech trough systems.
Photovoltaic Cells
The other type of solar energy is the use of photovoltaic cells (PV) to convert sunlight into the much more useful form of energy, electricity. PVs are little sections of semiconducting materials that have the property of the photovoltaic effect. Or in other words, when these materials come in contact with light, they produce electricity. These PVs are arranged together in a solar panel. Solar panels can go anywhere from a a calculator to a house roof. If the sun is providing free energy, we might as well use it.