Sun Energy - Photovoltaic Systems

Photovoltaic systems convert light energy into electricity.

The use of Photovoltaic energy or solar power (a clean, and virtually unlimited energy source) has been growing at a rate of about 48% since 2002, making it the worlds fastest growing energy source. Australia, Israel, Japan, Germany, and the United states have led the way worldwide in the expansion of solar power. But just what does the term “photovoltaics” mean, and how was it discovered & commercialized to rise to its present levels of worldwide usage?

Where does the term Photovoltaics Stem from?

Photo stems from the Greek work “Phos” which means “light”. “Volt” refers to Alessandro Volta (mid 1700s to early 1800s), who made key discoveries in electricity. Together the whole word Photovoltaics means “light energy” or “light electricity”. And solar panels do just this; these devices convert radiant sunlight into electrical energy.

Pictured below: In 1839, A. E. Becquerel, a French physicist who studied the solar spectrum, discovered the Photovoltaic effect.


“Sol” or “Solar” refers to sunlight which these panels use to convert into electrical energy. The gamma rays from sunlight strike the atoms in the solar panel, freeing up electrons to move, creating an electrical flow between both positively and negatively charged internal panels, especially designed to efficiently absorb sunlight and convert it to electrical power. The generated energy is stored in batteries when it can then be used on-demand.

Below: President Jimmy Carter, a renewable energy advocate, installed solar power on the white house grounds in 1979. In 1977 Jimmy Carter had form the Solar Energy Research Institute (SERI) to help avoid a future energy crisis (this demonstrated great foresight!) and create incentives to help expand and create renewable energy sources, such as solar power. Later Ronald Reagan later removed the panels-presumably because they were no longer completely functional.

History of Photovoltaics: Laying the Groundwork

It the late 1800s Edmond Becquerel, a French physicist, investigated the photochemical and spectroscopic characteristics of electrical light and solar radiation as well as the phenomena of phosphorescence. This led to Becquerel’s discovery of the phosphoroscope, a device engineered to accurately measure the effects of light exposure. With this device, Becquerel found that certain materials would produce small amounts of electric current when exposed to light. Although the photovoltaic phenomena was discovered during the mid 1800s, no practical applications (solar power) would be discovered for the greater part of the next century.

Below: California Governor Arnold Schwarzenegger walks on a commercial building with a large solar power array. His 2004 California statewide Million Solar Roof Plan incentive will help build many more such structures.


Heinrich Hertz further laid the groundwork for solar technology when he discovered selenium photovoltaic cells and successfully converted light to solar power at about 1.5% efficiency. His discoveries led to the use of selenium in photography and in light-measuring devices. The practical use of PV cells in commercial solar power would however not be made possible until the 1900s.

History of Photovoltaics: Commercialization

The Polish scientist Jan Czochralski provided the final piece of the puzzle needed to make the use of photovoltaic cells practical. In 1916, while Czochralski was studying the crystallization rates of metals, he discovered a way to obtain single crystals of semiconductors, metals, salts and synthetic gemstones. The “Czochralski process”, named after Jan Czochralski, made possible the development of a crystalline photovoltaic cell. This new improved photovoltaic cell operated at an efficiency level of 6% (3 to 6 times more effective than the original selenium photovoltaic cells).

Below: This array in Dimbach Germany, based on thin film solar power modules, supplies 1.45 megawatts of power.

Photovoltaics: Present Day

The use of photovoltaic (PV) cells or “solar cells” has grown dramatically during the past few decades in both residential and commercial applications. Photovoltaic cells represent the worlds fastest growing energy source, with cumulative installed global megawatts reaching 15,200 in 2008. Solar powered watches, calculators, and external home lighting are now commonplace in our day and age. Both government supports and the rising costs of traditional energy, and the increasing scarcity of fossil fuels have all contributed to the advancement of photovoltaics. Solar power is an energy source of the future, and one of the few great energy sources which will not be consumed or diminished over time (in contrast to fossil fuels, like oil, coal, and natural gas, of which there is a limited supply).

Find a local Solar Power contractor.

Photovoltaic solar systems use solar panels made of silicon to convert sunlight into electricity. It is a simple means of harnessing the sun’s power and putting it to work for you. After all, solar energy is an unending and renewable resource that is 100% pollution free. Where on this earth is solar energy not found? Could you ever imagine the sun planet charging you fees to make use of its plentiful energy? There it is, up in the sky, just waiting for us to use it for our heating, lighting, mechanical and electrical needs.

With a photovoltaic solar system you can convert sunlight into electricity using photovoltaic or solar cells. PV cells are semiconductor devices, usually made of silicon, that contain no liquids, corrosive chemicals, or moving parts. As long as sunlight shines upon them – they will produce electricity. They require minimal maintenance, do not pollute, and operate silently. A photovoltaic solar system is without a doubt the cleanest and safest method of power generation available to the world today.

Below: A commercial solar power plant converts sunlight into electrical energy through the use of photovoltaic cells.


Learn more about Solar Power here.

Although I agree with what you wrote, it seems you went a bit off-topic, since the subject of this post is the history of photovoltaics.

Thanks for posting the history of solar power--I had no idea that 'arnie' or the gubernator was such a big advocate of solar power and renewable energy!