Solar photovoltaic (PV) technology refers to harvesting direct sun light and converting it into electricity using solar cells. They are considered to be a very clean energy, safe and robust technology – PV don’t produce any noise, radiation or pollution. The PV are made from silicon, which is the most common material on earth. In fact, PV are the ideal energy technology, if their high cost is not taken into consideration.
Scientists estimate that the sun’s energy can produce about 5000 times the energy the world needs in a year. Over the last decade, design strategies and many governments considerations have welcomed the production and usage of solar photovoltaic panels. Photovoltaics, or solar cells, technology is one of the solar strategies. Some other solar strategies include passive solar, active solar, daylighting and shading.
The first observation of the PV effect is attributed to Alexander-Edmund Becquerel in 1839. However, it was not until 1972 that PVs were considered by scientists and academics for terrestrial purposes. In 1981, the very first solar powered lighthouse in the world, False Duck, Ontario, was commissioned.
In order to yield high voltage, the individual solar cells are combined into solar modules, which in turn can be combined into solar generators of any size. There are two main kinds of PV, or solar photovoltaic cells:
Monocrystalline solar cells are used most in the production of high-efficiency commercial solar products. They have a very uniform structure of the silicon, resembling that of a diamond, but with silicon instead of carbon. Melted purified silicon are fused into a highly structured mold. Wafers are then cut from the silicon, chemically treated, and printed with electrical contacts to make a solar cell. The drawback is that Monocrystalline PV cells are more complicated to manufacture, and thus more expensive.
Polycrystalline solar cells are about 15 percent less efficient, but less expensive than monocrystalline cells. Melted silicon are fused into a simple mold. Wafers are cut from the solidified rectangular polycrystalline block, treated, and printed with electrical contacts onto the surface.
1 Amorphous silicon. A very thin layer of silicon and other elements is deposited in gaseous form onto a glass or a thin metal, and then etched into individual cells.
2 Copper indium gallium diselenide (CIGS) are an emerging technology. They use several semiconducting layers deposited onto a substrate to create a low-cost PV module.
3 Cadmium telluride (CdTe). Thin layers of cadmium sulfide and zinc telluride create a light-absorbing layer.
Although the usage of PV is still not wide-spread due to their cost, the good news, over the last 30 years there has been a decrease in PV price. PV is already associated with a fast growing industry with a growth rate of about 40% per year. For now, the best solution for us is to design cities and buildings that will accept them easily as soon as they become more affordable.