Solar is the Latin word for Sun—a powerful source of energy that can be used to heat, cool, and light our homes and businesses. Various technologies convert sunlight to usable energy for buildings. The most commonly used solar technologies for homes and businesses are solar water heating, passive solar design for space heating and cooling, and solar photovoltaics for electricity.

Solar photovoltaic and concentrating solar power technologies are also being used by developers and utilities to produce electricity on a massive scale to power cities and small towns.