Plug Into the Sun

The Sun is Earth's biggest power plant, sending more us more sunlight—solar power—than we could ever use. Fortunately, we have a variety of ways of using solar power. In one process, solar panels capture sunlight and convert it directly into electricity. In another, solar concentrators use mirrors to focus sunlight to heat fluid, which can then be used to boil water, turn a turbine, and generate electricity.

Solar power is...

• clean.
  Solar power produces no greenhouse gases and is pollution-free.
• unlimited.
  Every hour, the Sun provides Earth with as much energy as the world uses in an entire year.
• flexible.
  Solar panels are particularly useful for providing electricity to individual structures or isolated settlements. Solar concentrators work best as large power plants.
• getting cheaper.
  The price of electricity from large power plants using solar concentrators may soon approach that from coal-fired power plants. Solar panels are still expensive, but costs will drop if they become more efficient and widespread.
• here today.
  Solar technology works: large-scale solar power plants have been in operation in California since the 1970s. And the use of solar panels is expanding quickly, particularly in Japan and Germany.
• site-specific.
  Solar panels and concentrators work best in sunny spots—deserts, for instance—so solar power is not practical in some countries. High-voltage electrical lines could make solar power more practical by carrying electricity from remote solar farms to consumers.
• intermittent.
  Solar panels only provide power when the Sun is shining. Solar concentrators can store power for several hours, but long-term energy storage systems are still needed.

100% of global electricity needs could be met by solar power.

In principle, the Sun could eventually provide all the world's electricity. At present, solar power makes up only a miniscule portion of the global electricity supply, but it is growing rapidly.

Personal Power

Solar panels are extremely popular in Kenya, where they are mostly used to power TVs, charge cell phones and run other small appliances. More than 25,000 solar panels are sold every year in the country, and about 5 percent of rural households own solar power systems.

From Sun to Salt to You

The enormous mirror arrays seen in this photo concentrate sunlight onto pipes filled with liquid salts. The hot fluid—about 386°C (727°F)—is used to boil water, turn a turbine, and generate as much electricity as a small coal plant, without the emissions. The fluid can also be stored and its heat extracted for use at night.