You might find it hard to believe that people have been converting the power of the Sun to electricity for 180 years. In 1839 Alexandre Edmon Becquerellar demonstrated the photovoltaic effect, the ability to convert sunlight into electricity. It was about four decades later, in 1883, that Charles Fritts installed the world’s first rooftop solar array in New York. This was a year after Thomas Edison opened the world’s first commercial coal power plant, and four years before the first wind power plant was installed in Scotland in 1887.
Fritts used glass panels coated with selenium to produce a very weak electric current, but he did not really understand why it worked. It was not until 1905 that Albert Einstein published a paper explaining the photoelectric effect. Between Becquerellar and Einstein, the basis of all solar technology development was formed.
|Photo by Scott Hamilton, A local 6000-watt solar array
designed to power an off-grid home.
The photovoltaic effect is caused when a material, such as selenium, absorbs light, and as a result, the atoms in the substance get excited, causing them to shed an electron. This electron gets passed to a neighboring atom create a voltage difference between the two atoms. This is known as the photovoltaic effect. There is a second effect at work in solar panels as well that is created by the heat from the absorption of the light. As the panel absorbs light, it heats up, creating a temperature difference between the top and bottom of the panel. The mixture of chemicals in the panel along with the temperature difference creates a voltage by the Seebeck effect.
The Seebeck effect occurs when two different metals, or semiconductor materials touch and a temperature difference is created between them. This causes electrons to move from the hot side of the contact point to the cold side, creating a voltage difference between the hot and cold side. This effect is used in modern thermostats to measure and control the temperature in most buildings today.
Bell Labs developed the modern photovoltaic cell in 1954 and the technology was quickly adopted by the U.S. Navel Research Laboratory for use on the first space craft to utilize solar panels. The Vanguard I was launched in 1958, and by 1964 NASA has launched Nimbus I, the first satellite equipped with panels that automatically tracked the Sun. It was not until the Emergency Petroleum Allocation Act of 1973, which brought about an energy crisis, that the public release and availability of solar power occurred.
The “Solar Heating and Cooling Demonstration Act of 1974” turned several federal buildings into billboards for solar energy. Around the same time additional legislation mobilized federal agencies to research how to make solar technology more affordable. The goal of the coordinated federal effort was to make solar viable and affordable to the public. There have been several waves of federal moneys turned into incentives for solar energy, and yet today it is only holding about 1% of the total electric generation market.
Solar panels are not the only method of extracting energy from the sun, and they are also not the most efficient use of solar power. If you have ever opened your car door on a sunny afternoon to find the temperature inside well over 2000 degrees, you have experienced the most efficient use of solar energy. There are experiments all over the internet that allow you to observe the extreme heating power of the sun. One is called, “Burning Stuff with 2000-degree solar power” by The King of Random, where he melts concrete, pennies, glass, and steel with a four foot magnifying lens he took from a rear projection TV.