The model for the fusion power plant, the sun, is a source of practically unlimited energy, most of which is wasted but nevertheless provides us with millions of kilowatts of power, keeps us warm, and grows all our food. To top it off, solar energy is safe, pollution-free energy on and in which living things have thrived since they first appeared on earth.
Every day the sun showers Earth with several thousand times as much energy as we use. Even the small amount that strikes our roof is many times as much as all the energy that comes in through electric wires. With the sun straight overhead, a single acre of land receives some four thousand horsepower, about equivalent to a large railroad locomotive. In less than three days the solar energy reaching Earth more than matches the estimated total of all the fossil fuels on Earth!
The logical question at this point is, Why are we not making use of this incredible bonanza in the form of solar energy? The answer, of course, is that we are using it, and have been from the beginning. All our energy-except nuclear- comes originally from the sun. A solar-powered radio draws on the sun directly, but a gasoline fueled automobile also uses solar energy-stored solar energy, in which the sunshine of ages ago was trapped in the earth until reclaimed by oil drillers. The challenge is to make use of solar energy directly and in a non-polluting fashion.
The Russian philosopher, Kuzma Prutkov, decided that the moon is more useful than the sun, since it shines at night when light is needed; while the sun is of little use in the daytime since it is light anyway! In such a fashion we, too, have dismissed the importance and potential of the sun. It appears that the fruitful application of solar energy is destined to wait until the bottom of the energy stockpile the sun has willed us is depleted.
Now is the time to make realistic goals and strategies to harness the power of the sun.
The harnessing of solar energy is not new in fact, development of solar energy dates back more than 100 years, to the middle of the industrial revolution. Several pioneering solar power plants were constructed to produce steam from the heat of the sun, which was used to drive the machinery of the time. At the same time, Henri Becquerel discovered the photovoltaic effect; that is, the production of electricity directly from the sun. Becquerel’s research was investigated and extended by, among others, Werner Siemens. Photovoltaic power remained a curiosity for many years, since it was very inefficient at turning sunlight into electricity.
Another pioneer of solar systems was Philadelphia inventor, Frank Shuman. In 1912, Shuman built a series of parabolic solar collectors along the Nile River in a small farming community 15 miles south of Cairo, Egypt. Each collector was 204 feet in length, 13 feet in width and fitted with a mechanical tracker which automatically tilted it to appropriately absorb sunlight.
The heat produced by these collectors was used to produce steam to power a series of large water pumps. This system produces about 55 horsepower and enabled the pumps to move 6000 gallons of water per minute. This water was used to irrigate vast areas of arid desert land.
Shuman planned to build over 20,000 square miles of the solar collectors across the Sahara, but the idea died with the outbreak of World War I. After WWI, the world discovered the vast amounts of oil in the Middle East and Venezuela, which put an end to Shuman’s solar dreams.
Early photovoltaic applications were geared more towards sensing and measuring light (such as a camera’s light meter) than towards producing power. With the advent of the transistor and accompanying semiconductor technology, however, the efficiency of photovoltaic power increased dramatically. Photovoltaic power became more practical. Over the years, many companies, including Siemens Solar, have worked to increase the efficiency of photovoltaic power. Today, commonly available solar panels are 12% efficient, which is four times greater than only a few years ago. Today, solar power is still used in two primary forms: thermal solar, where the heat of the sun is used to heat water or another working fluid, which drives turbines or other machinery to create electricity; and photovoltaic, where electricity is produced directly from the sun with no moving parts. Siemens Solar manufactures photovoltaic panels which produce electricity directly from the sun.