What is PV ?
PV is an acronym which stands for 'photovoltaics', a way of directly producing electricity from light. More properly, the photovoltaic effect is an aspect of the photoelectric effect, and may be defined as the conversion of electromagnetic radiation to electrical energy by a material.
How do PV modules generate electricity ?
For solar electricity you need a solar module that consists of one or more solar cells. When sunlight falls onto a solar cell, the solar cell material absorbs some of the light particles (so called photons). Each photon contains a small amount of energy. When a photon is absorbed it starts a process of freeing an electron in the material of the solar cell. Because both sides of a solar cell are electrically connected with a wire, a current will flow when the photon is absorbed. The solar cell now produces electricity, which can be used instantly or stored in for example a battery.
How do I figure out what size of system I need for my home ?
To accurately size a system to meet your needs, you need to know how much energy you use per day. If your home is connected to the utility grid, simply look at your monthly electricity bill. Using this information, your PV dealer can design a system to meet your needs.
What components do I need for a grid-connected system ?
There are many components that make up a complete solar system, but the 4 main items are: solar modules, charge controller(s), batteries and/or inverter(s).
Can I use PV modules to heat water ?
Yes, but this is not advisable. Photovoltaics convert solar energy into DC electricity at a relatively low efficiency level (14-16%), so trying to operate a high power electric heating element from PV would be very inefficient and expensive. Solar thermal is the direct heating of air or water from the heat of the sun and is much more efficient for (but only for) heating applications than photovoltaics.
Who first used PV in space ?
NASA on the Vanguard I satellite launched March 17th, 1958
What is the history of PV ?
- In 1839, Edmund Becquerel of the famous French physicist family, discovered the photovoltaic effect. The material used was copper oxide in an electrolyte.
- In the 1860's, Willoughby Smith discovered the photoconductive properties of selenium.
In the 1870's, W.G. Adams and R.E. Day investigated the photovoltaic properties of selenium.
- In 1874, Charles Fritts made the first solar cell from selenium and gold. The efficiency was less than 1%.
- In 1887, H. Hertz discovered the photoelectric effect in metals.
- In 1904, Albert Einstein published his monograph on the photoelectric effect. His theory utilized Max Planck's idea of quanta. Notice that for almost a hundred years, from 1839 until the development of quantum theory in the 1920's and 1930's, there was no satisfactory scientific theory of solid state physics to explain the photovoltaic effect. It was an anomalous phenomenon, which some scientists considered a hoax.
- In 1954, Gordon Pearson discovered the photovoltaic properties of silicon. Later Pearson with Charles Fuller and Darryl Chapin work to improve the efficiency of the silicon solar cell. The efficiency was 4% to 6%.
- In the late 1950's, NASA determined that solar cells were an ideal energy source in space and serious funding of PV research began.
- In the late 1970's, the OPEC inspired oil embargo startled the first world nations into funding many forms of alternative energy research, including PV.
- In the late 1990's, with rising worries about the future energy supply and environment care, interest in photovoltaics again began to rise.
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