The Latest on Solar Energy

Updated: Feb. 19, 2009

By KATE GALBRAITH

From magnifying glasses to steam engines, scientists through the centuries have found innovative ways to harness the power of the sun. Converting more solar power into electricity is high on the political agenda in many countries, amid the push to find domestic energy sources that are less polluting than fossil fuels.

TABLE OF CONTENTS

• Distribution
• How it Works
• Drawbacks and Incentives

Distribution

Despite rapid growth in recent years, solar power accounts for less than 1 percent of United States electricity use. Solar power is more entrenched in European countries such as Spain and Germany, which have promoted its development with strong incentives called feed-in tariffs,which require electric utilities to buy solar power at a high, fixed price. In the United States, California is by far the leading solar state.

How it Works

There are several ways to use the sun’s power to generate electricity. One of the most promising is called concentrating solar power. This involves using mirrors to reflect and focus the sun’s rays, providing heat, which in turn helps power a generator. Another is photovoltaic panels, such as the displays on the rooftops of homes and office buildings (some of these displays, especially in California, have recently experienced problems with theft).

Drawbacks and Incentives

The drawback to solar power is that it is expensive to produce: generating power from photovoltaic panels costs more than four times as much as coal, and more than twice what wind power costs. In the United States, the federal government and states have offered a variety of incentives to encourage homeowners and businesses to put panels on their roofs, and for utilities to buy power from large displays. Solar panels produce no energy at night, but that is not a significant problem because the electricity is often most needed in the daytime, when consumers turn on lights and televisions and air-conditioning.

Solar energy is also used to heat water and pools — and of course a properly designed house will optimize the light and heat qualities of as it floods through the windows.