Solar Photovoltaic and Photovoltic Systems

Well functioning photovoltaic facilities based on monocrystalline silicon can turn 15 % of the sunlight into electrical energy. At noon on a warm summer day, the incident solar energy output amounts to about 1100 watts of thermal energy per square meter. Thus this solar cell produces 165 watts of electrical output, enough to power three light bulbs. Over the course of a year, 1000 k Wh of thermal solar energy per square meter of horizontal surface can be generated, for an output of 150 k Wh. A household with a medium-level stock of equipment uses more than 4000 k Wh of electricity per year. To meet this need with a photovoltaic facility alone, 27 sq.m. of active photovoltaic surface would need to be installed – say 30 sq.m., including the area needed for the frames. However, that household could not cut itself off from from the power grid, for the production of photovoltaic power is dependent exclusively on solar irradiation and the consumption of electric power in the household is subject to a different set of factors. The surface area required for solar panels is not an important factor, since experience has shown that there is almost always enough space available to set up a photovoltaic system. Therefore, a photovoltaics facility which operates with a considerably lower degree of efficiency than the 15 % just described for a monocrystalline silicon panel can certainly be advantages; it ultimately depends on the cost-benefit ratio. Amorphous silicon can be produced more cheaply than monocrystalline silicon, but yields less electrical energy from the incident light; still, it can be a good alternative in cost-benefit terms.

The introduction of solar photovoltaic at a scale significant for the energy industry is not possible at the present cost level. One example will service to show the scope of financial support which that would require. Say we wanted to produce 10% of Germany’s electric power from photovoltaic. It would be necessary, given German irradiation conditions, to install a photovoltaic output capacity of all power stations existing in Germany in 2007. If that large number sounds surprising, remember that under German conditions, a photovoltaic facility with one kW of rated output can only produce a little less than 1000 k Wh of electricity a year – half what it could deliver in sunny areas elsewhere in the world. It could be assumed that, given this large number of systems, the investment costs would drop considerably- and the electricity-generation costs along with them. We have noted that photovoltaic power now costs 35 cents per kWh; let us assume that we could force that down to only 25 cents per kWh: we would then still have to bridge a gap of about 20 cents per k Wh compared with today’s production expenses in new power stations. Projected onto a 10% share of electric-power generation, that would represent a total of Pound billion per year in additional investment funding for photovoltaic that would have to be raised. One might correctly object at this point, that in terms of the kilowatt hour, that would only be a matter of a few cents. But the appropriate question in this situation is a different one: Could not the same desired environmental and resource –saving effect be achieved with less money – for instance, by investing it in energy-saving measures? That would permit environmental goals in the form of CO2 reductions to be achieved more cheaply than by such an expansion of photovoltaic.

The above examples and arguments apply to conditions in the first decade of the 21st century. They may no longer apply in twenty or thirty years. As the examples show, the key to the introduction of photovoltaic at a scale relevant to the energy economy is not a price increase for fossil fuels, since, while that might narrow the gap, it would not close it. The key is the reduction of the costs of photovoltaic production. There are a number of approaches which would make such a reduction realistic over the course of the next few decades.

You may also be interested to learn more on how to build a solar panel.

Useful information photovoltaic system:
http://ezinearticles.com/?What-Are-Photovoltaic-Systems?&id=1536758

Useful information solar photovoltaic:
http://ezinearticles.com/?Are-You-Familiar-With-Solar-Photovoltaic?&id=1537686

Useful information how to build a solar panel:
http://ezinearticles.com/?Learn-How-to-Build-a-Solar-Panel-to-Save-Electricity-in-Your-Home&id=2727558

How Solar Photovoltaic Systems Can Help You

Photovoltaic alone cannot guarantee the electric-power supply of a consumer; storage systems for the electricity or a secondary power-supply system must be available. Photovoltaic is excellently suited to operate one or two lamps in a house, or to power a telecommunications systems, a refrigerator or a TV set in developing countries. Remember that 1.6 billion people worldwide are still not connected to a power grid. For these purposes, batteries such as those we use in cars are possible storage systems for electrical energy.

Photovoltaic power generation is very expensive in comparison with the power we get “from the wall.” Large photovoltaic facilities in the megawatt range, in which the economies of scale are already exhausted, still produce power at a cost of 35 ct per k Wh, while the electric power from our outlets costs us just over 18 ct per k Wh. The calculation is different, however, for the areas of application in developing countries mentioned above. Here, the power which solar panels replace may come from a diesel-driven generator. Including the cost of transportation, the price for a liter of diesel would be about Pound 1.50, and it could generate 3 to 4 kWh of electricity; hence, the cost would be within the same range as that of photovoltaic power, or even higher. Under such conditions, photovoltaic makes economic sense. Since the utility of photovoltaic often depends on the storage question, it is primarily suitable for systems for which small outputs are needed, such as for powering television sets, refrigerators or lamps.

Government financial support measures for the development of solar photovoltaic in various countries have caused the installation of photovoltaic panels worldwide to rise continuously, In 2007, it amounted to 3.8 gigawatts (GW) of electrical output, a figure that is difficult to conceptualize, so that we might better view it in a comparison: A nuclear power plant has an electrical output of 1.3 GW; on the coldest day of the year, Germany maintains 80 GW of power-station output to assure its power supply; and total worldwide installed power station output amounts to about 3600 GW. Let us not forget, however, that the conditions which would provide such maximum photovoltaic output occur at the latitude of Germany only for a few hours a year. Despite all the successes of recent years, photovoltaic is therefore still far from being a “major player” in economic terms in the electric-power generation picture. The shore of the power generation of photovoltaic systems installed in Germany is about one percent. The keys to opening the photovoltaic option as a major energy-supply factor is in the industrialized countries, where the expense of producing facilities has to be brought down through further technological advances.

The peripheral parts of the system largely involve known technology, so that the cost reduction potential is in the photovoltaic component itself. Government support for photovoltaic makes sense in terms of acceleration of technological developments and opening up its potential, as well as in order to guarantee sufficient markets to maintain a critical industrial capacity. The photovoltaic industry could then earn its money in the niche markets in which it is already competitive today. You may also be interested to look into home solar power systems.

Useful information solar photovoltaic:
http://www.greenearth4energy.com/solar_photovoltaic.html

Useful information photovoltaic systems:
http://ezinearticles.com/?What-Are-Photovoltaic-Systems?&id=1536758

Useful information home solar power systems:
http://ezinearticles.com/?Home-Solar-Power-Systems-Uses&id=3547988

Solar Photovaltaic

The photovoltaic effect is the creation of an electric current in a solid as a result of the absorption of light – it was discovered almost 170 years ago. Solar photovoltaic cells consist of two extremely thin semiconductor layers of no more than 0.3 mm thickness altogether (Figure15). These are differently “contaminated” with atoms of various other elements: in one layer, the so-called p-type layer, this causes a linkage to be free which can be occupied by the electron; in the other layer, the n-type layer, there is an extra electron which is not used for the linkage between the silicon atoms. It can be released with little additional energy, and then moves freely. As a result, an electrical field builds up in the semiconductor at the interface between the two layers, which ensures that the electrons which have been rendered energetically freely mobile by the incident sunlight now move outward through the electrical circuit. That makes it possible to produce electrical energy with the help of the energy of incident light. The fascinating thing about photovoltaics facilities is that they have no moving parts, make no noise, and are actually not subject to any wear at all.

The preferred material is silicon in various forms: as high-quality monocrystalline silicon, as multicrystalline silicon, or as amorphous silicon. Other semiconductor compounds are possible, in addition to silicon, including gallium arsenide (Gas), copper indium diselenite (CIS), and some others; some have already secured their share of the market.

However, these solar photovoltaic modules are a little thicker and heavier than one would expect considering the thickness of the silicon layers of only 0.3 mm. They have to be held in a fixed shape, the electrical energy is tapped by means of contact plates and fingers, and ultimately, the whole thing must be protected by being embedded mechanically between glass plates. Another product is photovoltaic mats, also based on amorphous silicon, which have a somewhat thicker synthetic material on the back and are protected mechanically on the front by a thin permeable plastic layer. The technological development is very far advanced, and is in effect a mature system, but it is far from its goal as yet. Find out more photovoltaic systems.
Useful information Solar photovoltaic cells:
http://ezinearticles.com/?How-Crystalline-Solar-Photovoltaic-Cells-Work&id=2768475

Useful information solar photovoltaic:
http://www.greenearth4energy.com/solar_photovoltaic.html

Useful information photovoltaic systems:
http://www.greenearth4energy.com/photovoltaic_systems.html