Solar Electricity Basics

SEPA (2005)

SEPA focuses exclusively on solar electric technologies, of which there are two basic types - photovoltaics and solar-thermal electric.

1. Photovoltaics

Photovoltaic (PV) is the technical word for solar panels that create electricity. Photovoltaic material, most commonly utilizing highly-purified silicon, converts sunlight directly into electricity. When sunlight strikes the material, electrons are dislodged, creating an electrical current which can be captured and harnessed. The photovoltaic materials can be several individual solar cells or a single thin layer, which make up a larger solar panel.


Photovoltaic cells power many of the small calculators and wrist watches in use every day. More complex systems provide electricity to pump water, power communications equipment or highway construction signs, and a myriad of other small, off-grid uses, which almost always provide electricity for small and/or intermittent electricity needs that are cleaner and cheaper to operate than extending a power line or using liquid fuels. Rural solar electrification in the developing world, away from the electric grid, can also provide much needed electricity to replace or reduce the use of kerosene lamps, diesel generators, and wood fires for lighting, refrigeration, communication, etc.


Photovoltaics are also making inroads as supplementary power for utility customers already served by the electric grid. In the last two years, grid-connected solar systems are now a larger market than off-grid applications. Currently, compared to most conventional fuel options, photovoltaics are still a very small part of the energy make-up of any country. However, more and more individuals, companies, and communities are choosing PV for a variety of environmental, economic development, emergency back-up, fuel and risk diversification, and now, economic reasons. The economics of a photovoltaic system for your home or business is not just the solar resource (see map below), but rather a combination of the solar resource, electricity prices, and local/national incentives.