Guide Note

Solar power is usable energy derived directly from the Sun.

Fast Facts

1. The amount of solar-derived electricity has increased steadily since the 1970s
2. In 2004, solar cells produced 0.04 of world energy
3. An experimental solar aircraft, Helios, generates power from its photovoltaic wings

A Sustainable Resource

All usable energy on the earth is ultimately solar: Combustible fuels, for instance, are produced through chains of events beginning with plant photosynthesis, while geothermal, wind, and tidal energies are consequences of solar-derived heat. However, the term solar power generally refers to the direct conversion of solar radiation into electricity.

Backstory

The amount of usable solar energy that reaches the earth is vast, and is estimated to exceed current human consumption by a factor of roughly 6,000. While solar energy has been exploited in various ways throughout history (agriculture is one ancient method), technologies to convert this free energy to electricity were first developed in the 1950s, and have been widely available since the 1970s, when widespread interest in solar power briefly swept America and Europe.

Current and Future Use

Large-scale development of solar technology has, however, been slow, and funding has largely remained at a low priority. This is in part due to the high cost of producing solar energy plants, and the relatively slow rate of return on the investment. On the other hand, the amount of resources spent, worldwide, on the diminishing prize of fossil fuels, coupled with the environmental consequences of hydrocarbon use, may soon make solar power seem more attractive by comparison.

Basic Technology

Solar power is typically collected by heat-absorbing assemblies or solar cells, then converted to electricity. Other methods, such as concentrating solar heat via mirrors, are also widely in use.

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