What is solar power?

Every hour, the sun beams down enough solar energy to power the entire globe for one year. Simply put, solar power is the process of harnessing that energy. The most common manifestation of solar power is photovoltaics (PV), the science of converting sunlight directly into electricity.

At the heart of photovoltaics is the solar PV panel. Solar panels contain solar cells, the building blocks of solar power, or to carry on that cardiology metaphor, the veins that pump solar energy throughout the body. Special semiconductors within solar cells capture photons of light, which excite electrons with the semiconductor, creating electric current. That current is channeled through the solar panel (made up of several individual solar cells) and then wired to the home or electric grid.

Complementary to solar PV is solar thermal power. Solar thermal captures solar radiation to provide heat to the domestic water supply or living space. Solar thermal panels contain a fluid - typically water or a glycol (antifreeze) solution that runs through copper pipes attached or adjacent to a metal plate. The panel, or collector, is like a door inviting solar radiation inside. The transfer fluid coursing through it is heated by that radiation and carried into the home to the hot water tank. If the fluid is water, it can be sent directly into the tank and water outlets. If the fluid is a glycol solution, then it passes through a heat exchanger, where its heat is transferred to the water without direct contact. For solar thermal heating systems, air or liquid can be sent through collectors. Air is blown directly into the living space, and liquid enters a heat exchanger.

Solar power provides both heat and electricity, but hot water and photovoltaics are not the limit of solar's potential. Solar is also used for heated swimming pools, wireless outdoor lighting, air conditioning, ventilation, charging electronic devices and cooking. Solar power may be passive or active. Passive systems use no mechanical devices to function. These include daylighting, thermal mass walls, sunrooms and passive hot water heaters. Active systems use pumps, fans, blowers or other mechanical devices to distribute the collected solar power.

Most of all, however, solar power is green energy that is helping to clean our skies, provide energy independence, curb climate change and create quality jobs. Solar power is reliable, predictable, scalable and renewable.