Solar Energy

1. Solar Energy

1.1 What Is Solar Power?

The sun is expected to emit radiant energy for another four billion years, the only perpetually renewable energy source for our planet. Obviously, it is time to learn how to use the massive amounts of energy the sun gives us each day. Three processes by which the sun’s radiation can be used are heliochemical (photosynthesis, photography), helioelectrical (manmade devices that convert solar radiation into electricity), and heliothermal (devices that absorb solar radiation on blackened surfaces and convert it to heat).

All energy on earth originally came from the sun. All of our hydrocarbon fuels such as coal, oil, and natural gas were originally produced by the action of sunlight on vegetation.

Light is a form of electromagnetic energy. Energy is the capacity to do work, and power is the rate at which energy is generated or used (measured in watts or kilowatts). The amount of power we can get from any solar device depends on the amount of sunlight it intercepts and on the efficiency of the energy conversion device. Solar energy intercepted by an area the size of a small tennis court would supply the energy needs of an average household. The radiant energy in sunlight must be converted into some form of energy that is easier to use, such as electricity—the solar cell is just such a device.

The photovoltaic effect, where electricity is produced when certain materials are illuminated, was first noted in 1839, and the photovoltaic effect, where electricity is produced when certain materials are illuminated, was first noted in 1839, and the photovoltaic cell is probably the first solid-state electronic device ever invented. Its use has been slow because of the abundance of hydrocarbon fuels like coal, oil, and natural gas. Photovoltaics were first used in selenium cells to measure light levels (as with the light meter used in photography). The space program uses photovoltaic cells because conventional batteries will run down, but solar cells will continue to deliver electric power as long as sunlight is available.

1.2 Advantages of Using Solar Power

The basic reason for using solar energy is that it is a renewable, limitless energy source that promises freedom from dependency on nonrenewable energy sources, thus freeing humankind from the threat of war over dwindling natural resources.

Solar power is clean, nonpolluting, and safe. Once the basic systems are installed, the sun is free; and since power is produced locally, on the spot where it is to be used, transportation of fuels and distribution of power aren’t necessary. Solar electricity can be brought to remote locations that are too far away for bringing power lines, for example. Solar research can be carried out in small laboratories with inexpensive equipment.

Solar energy usage will create jobs—about four times as many as nuclear power. It is labor-intensive, that is, about half the money that goes to building a solar space or water-heating system goes to paying the wages of the people building or installing it. A solar-based economy would put more people to work than a fossil/nuclear one. (It also employ’s people from a wider range of abilities, whereas nuclear power plants, aside from preliminary construction workers, use mostly professionals. Most jobs at nuclear plants will be for security personnel.) Solar power  is community-based, but nuclear power is centralized and monopolized by certain monied interests. Tax credits can be received for certain home-improvement and energy conservation installations.

1.3 History of Solar Power

The concepts behind solar energy use are not new, by any means. Legend has it that in 212 B.C. Archimedes set fire to an attacking Roman fleet by turning a “burning glass” composed of small, hinged square mirrors so as to reflect concentrated sunlight onto the ships. For years scientists argued about whether this was myth or fact, but in 1747 a Frenchman proved that it could have been done by burning wood from a distance of 200 feet with an array of 168 small flat mirrors, and then melted lead at 130 feet and silver at 60 feet. In the same century, an optician in France built polished iron solar furnaces that could smelt iron, copper, and other metals. Another investor used two lens to achieve a temperature close to 1750° Fahrenheit—far beyond any temperature attained by man up to this time.

In the 1800s came many models of solar-powered engines and solar steam engines. In 1871, a solar still in Chile provided 6,000 gallons of pure water a day for forty years. In 1880, a solar engine was built in France that ran a printing press.

Of course, foods have been sun-dried for ages, using solar power without the need for technology. In the early 1900s, solar ovens appeared.

Solar water heaters were known in southern California and other states in the 1920s and 30s. After World War II, solar sciences flourished in Europe and a boom in solar water heaters began in Japan and Israel. Heaters were installed by the 100,000’s in Japan.

Here in America, the military picked up interest in solar power. The navy wanted solar battery power supplies for buoys and other installations. The Air Force had small solar-powered radio transceivers for aviators’ survival kits. The Army used solar panels to transmit radio signals and put smaller units in helmet radios for soldiers.

These are but a few of the many experiments in solar power undertaken through the centuries, and one would need to read a whole book to go into greater depth. The point is, that many inventors have long trusted in the power of the sun, and their greatest obstacle has probably always been the apathetic lack of interest by their fellow men in using the sun’s power. In fact, there is an interesting analogy that serves as a parallel to the solar/nuclear industry. When Thomas Edison was first working on his experimental light bulb, the gas company did all it could to discredit this inventor calling his work foolishness. They wanted, of course, to preserve their energy monopoly as gas suppliers to all those gas lamps! When Edison finally perfected his light bulb, not only did he change the future of the human race, but he also showed the gas company who was foolish. It is certain that the nuclear power industry would rather have people remain ignorant of solar power and its grand potential for as long as possible. They would rather have people perceive it as “futuristic,” when the truth is that much can be done now in solar energy, and its use and history are as old as the sun itself.