Solar energy is the most accessible energy source on Earth — and it’s currently the cheapest. It's a form of renewable energy, meaning it doesn’t use up finite resources; instead, it comes from natural sources that are naturally replenished. Compared with fossil fuels, solar power reduces the amount of carbon and other contaminants emitted into the environment, which ultimately creates less pollution and leads to cleaner air and water. When it comes to harnessing sunlight into usable energy, there are two main types of solar energy technologies: photovoltaic cell (PV) and concentrating solar power (CSP). Both convert sun energy into electrical power. Photovoltaic technology: Most common for home use, photovoltaic panels are made of many solar cells with semiconductor materials. When the sunlight hits those solar cells, electrons are knocked loose, which creates an electric current. Concentrating solar power: Concentrating solar power, or CSP, is used mostly in large power plants and is not typically recommended for residential use. CSP technology concentrates sunlight using mirrors and reflectors to collect solar energy and turn it into thermal energy.