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The greenest way of producing energy
Background information:
Photo (Greek.'phos') stands for 'light'. Voltaic derives from the name of an Italian pioneer who did successful research in electricity, called Alessandro Volta. So photovoltaics is the transformation of solar or radiant energies into electricity. This transformation was already discovered by Bequerel in 1839 and scientifically analysed by Albert Einstein, who got the Nobel Price for it. As the necessary semiconductor (a material which resistor qualities are less than those of an isolator, but more than those of a conductor, for example Silicium) was developed, the Americans Chapin, Fuller and Pearson used the transformation of sun rays into electricity in 1954 for the first time. On average a German person consumes 130 kWh of energy per day. To cover this need, more and more renewable sources of energy, like water and windpower, but mainly solar power, are going to be used. Solar power is mainly generated in the southern part of Germany with peak values from 1.120 kW/h to 1.160 kW/h. Altogether Germany possesses a surface of 1.60km² free photovoltaics facilities. However, economically there can be only considered 700 km². This acoords to an output of 90000 MW or 80 mio. MW/h. That is ca. 33% of the current consumption.
Conclusion:
The financial support that the government offers for the installation of renewable energies depends on the size of the facilities. For the construction in 2008 following prices applied.
| ≤ 3kWp | →54,53 ct |
| ≤ 30 kWp | →51,87 ct |
| ≤100 kWp | →51,30 ct |
The prices sink at a rate of a few cents per year. So it is recommended to install photovoltaics facilities as soon as possible. Cheap loans for the investment in photovoltaics facilities are shown in the diagram. The interest's average is ca 5% and there are two ways of amortisation. One is the immediate amortisation of the credit by the income. Thus, one can pay back the loan immediately to avoid the expensive interest and the compound interest. The other is to pay it back in rates by getting monthly profit from the construction. The amortisation(called Break-Even-Point) of the facility begins after about 15 years. So the five remaining years the construction mean profit. And with one kWh of photovolatics energy the current saving are about 98 kg of CO2, an installation of such a construction can help us to have a clear conscience about nature.
Technical information:
The incidence of solar radiation (photons) on superposed layers of semiconductors causes a disentanglement
of electrons. Following the loose positive and negative charge carriers are seperated of each other with an electrical field.
The complex technical implementation benefits from this electrophysical basic principle. In average one solar module generates a voltage of seventeen Volts.
In interconnexion with other modules, called "string", the voltage can reach nearly 600 Volts.
One can distinguish between three types of photovoltaic cells:
| amorphous cells: | polycrystalline cells: | monocrystalline cells: |
|---|---|---|
| incognizable crystalline structure | cognizable crystals | one crystal per cell |
| low costs | middle costs | highest costs |
| low efficiency factor | middle efficiency factor | highest efficiency factor |
| can be found in: mobile devices, e.g. solar calculators |
Solar power system at "Paul-Klee-Gymnasium":
First things first: The following calculation is just showcase because of several varying expense factors e.g. costs for solar panels, installation on different rooftypes or subsidization of the power input price. We made a calculation for the Paul-Klee-Gymnasium (PKG) in Gersthofen, running time twenty years that accords to the common guarantee period of solar panels. However, we tried to realize an approximation to the existing local conditions.
| location: | PKG gymnasium's rooftop |
| area: | 1,812 m2 |
| number of panels: | 1,275 |
| avg. costs/module (including installation, cables, power inverter): | 855.00 € |
| weight (one module): | 17 kg |
| weight (total): | 21,675 kg |
| estimated installation costs (total): | 1,091,056 € |
| power output (total): | 223.1 kW |
| costs/power: | 4,890 €/kW p |
| carbondioxyde economization: | 125,082.36 kg |
| performance rate: | 41.1 % |
| decrease in profits: | 0.5 %/year |
| power output per year: | 212,004 kWh/year |
All aspects considered, it can be concluded that the professional consultation of an expert is needed essentially.
Demonstration diagram / chartWikipedia
EnviComCenter
Stephan Lidel
translator: Valerie Hecht and Julian Schöler