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Solar 101 – How It Works

Energy from the sun can be used for many purposes, like generating electricity, powering mechanical devices, providing natural light, supplying heating, or even cooling.

The most commonly-used solar technologies for homes and businesses are Solar Photovoltaic (PV), Solar Thermal, Solar Lighting, Passive Solar, and Solar Appliances.

Solar Photovoltaic (PV): Solar cells, also called photovoltaic (PV) cells, convert solar energy into electricity. When the sun’s rays hit the solar cells inside a solar panel, the light energy excites the electrons of a material (usually silicon) inside the cell. The cell has an electrical field that collects these electrons and forces them through a conduit to become usable electricity. Solar cells were first used to power space satellites and smaller items such as calculators and watches. Today, thousands of people power their homes and businesses with solar PV systems in the form of rooftop solar panels or community solar arrays, and utility companies use large-scale PV technology to generate renewable power.

Solar Thermal: Solar thermal technologies convert solar energy into heat. Solar thermal collectors (which look like solar PV panels) positioned on the roof gather heat from the sun and distribute throughout the building through a heat exchanger or water pipes. That heat can then be used to heat water or air, or – less commonly - be converted into electricity. Solar thermal technologies are most often used to provide hot water in businesses and homes, but can also be used to heat swimming pools or as space heaters in homes.

Solar Lighting / Daylighting: Solar lighting, also called daylighting, is a design practice to allow natural sunlight to provide indoor lighting. Daylighting technologies such as windows, skylights, and solar tubes channel sunlight from the outdoors to indoors, even to rooms that have no windows. For example: a solar tube is made up of a clear dome placed on the outside of a building that collects sunlight and channels it into a tube, where it reflects off mirrors and enters the building.

Passive Solar Design: Passive solar is a design practice that uses a building’s site and construction to maximize use of sunlight for heating and lighting. Have you ever entered a room with lots of south-facing windows and noticed that it’s warmer than the rest of the building? If so, you’ve experienced passive solar heating. When that window-filled room is also brighter than the rest of the house, you experience passive solar lighting. In both cases, sunlight is being used as energy to improve the home environment without electric technologies like solar PV or solar thermal. Strategically placing windows, using certain building materials, and planting deciduous trees are all examples of passive solar design that will help keep your building cool in summer and warm in winter.

Solar Appliances: This technology is a type of solar PV that brings the convenience of electricity to places where electricity is unreliable or very expensive, such as developing nations, areas with severe weather, and more. Solar appliances such as solar ovens allow people to cook food without access to fire or electricity.

Learn more about solar power at