According to David Claridge, vice chair of ASME’s Solar Energy Division, nearly 1 percent of homes in the United States today use solar energy to help heat water. In addition, photovoltaic systems have been installed in more than a quarter-million homes worldwide. And within a decade, wind and photovoltaic systems should account for more than 1 percent of world electric-generating capacity.

But the greatest challenge has been in forecasting the availability of solar energy, capturing the solar energy in the form of radiation and converting it into a form of useful energy, and storing the energy for later use.

Consider that the amount of energy falling on a flat, level surface 1 square meter over the course of one day is roughly 5 kilowatt-hours. This averages to about 0.2 kilowatt-hours per square meter in a 24-hour period. This is not very concentrated when compared with other modern energy sources. Clearly, capturing the sun’s energy remains a challenge. But while solar energy is hard-pressed to make significant inroads in the United States, it is booming in hard-to-wire areas, such as the jungles and deserts of developing countries from India to Mexico and Brazil.

The U.S. Department of Energy predicts that sales of solar equipment globally will jump by 70 percent in the next five years. And U.S. companies are capturing 30 percent of the worldwide market, which is estimated at $300 million per year.

The driving force behind this growth is the sheer size of the potential international market. About one-third of the world’s populationÑ2 billion peopleÑlive without electricity. For many countries, power from the sun is an appealing answer. One solar panel containing photovoltaic cellsÑmade from semiconductor materials that convert light to electricityÑinstalled on a house can power two light bulbs, a television, and a radio.

As the cost of manufacturing this equipment drops, some solar experts predict that the interest in this type of renewable energy could be rekindled here at home. While no one believes solar energy will fully replace any mainstream source of power in the United States, the sun’s rays still continue to play a role in this country. One recent example is the solar heating system designed for the newly built Aquatic Center on the Georgia Institute of Technology campus, which was home to the swimming and diving events at the 1996 Summer Games in Atlanta (see “Swimming with the Sun” in Input/Output).

Hundreds of other examples exists. In our feature focus section this month, beginning on page 54, you can read about three different projects that use renewable-energy sources. The first technology is an open-cycle desiccant system that dehumidifies and cools air directly; the second is a solar photocatalytic technology that breaks up toxic chemicals and disinfects water and air; and solar-water-heater technology is described in the third story.

With the increased international emphasis on using sustainable-energy sources, the next 20 years should prove to be an exciting time for advocates of solar energy, as they look to enhance techniques that retain the sun’s energy and deliver them to our homes.

Email your comments or questions to: falcionij@asme.org

home | features | weekly news | marketplace | departments | about ME | back issues | ASME | site search

© 1996 by The American Society of Mechanical Engineers