Solar Energy

Solar energy means energy, heat or electricity is produced directly using the energy radiated from the Sun (renewable energy) to Earth. At any time the Sun on the Earth sends 1367 watts per square meter.

Solar energy is the one normally used by autotrophic organisms, ie those that perform photosynthesis, also called “vegetable”. Other living organisms instead exploit the chemical energy derived from plants (or other bodies which in turn feed on plants), and also take advantage of solar power, albeit indirectly.

Taking into account the fact that the Earth is a sphere that rotates moreover, the average solar radiation, the European latitudes, about 200 watts per square meter. Multiplying this average power per square meter for the land surface of the hemisphere from moment to moment in the sun you get a power greater than 50 million GW (a GW – gigawatts – is about the average power of a large power plant).

The amount of solar energy that reaches the Earth’s soil is so huge, about ten thousand times greater than all the energy used by humanity as a whole, but not concentrated in the sense that it is necessary to collect energy from very large areas to have significant amounts , and quite difficult to convert into energy that is easily exploitable with acceptable efficiencies. Products needed for its operation generally high cost of making solar power much cheaper than other methods of generating energy. The development of technologies that can make economic use of solar energy is a very active area of research but, for now, did not have revolutionary results.

The solar panels convert sunlight directly into electricity. These panels take advantage of the photoelectric effect and have a conversion efficiency of up to 32.5% in cells lab. In practice, once the modules from the cells and the modules and panels when assembled on site, the average efficiency is about 12%. These panels, with no moving parts or other things, require very little maintenance: in essence only be cleaned periodically. The estimated lifetime of the solar panels is about 30 years. The main defects of these systems are the cost of the panels and the storage of energy.

Thanks to legislation that provides economic incentives for photovoltaics and the possibility of selling the energy produced in excess to the operator of the transmission system, Germany is in first place in Europe for the electric power produced by solar energy: the amount represents 1.0% of German energy and therefore is now totally inadequate to support the growing trend of energy demand (in Germany the primary source of electricity generation is coal, which accounts for about 43%, while the second place is the nuclear energy with almost 23%).