Disponible uniquement sur Etudier
  • Pages : 5 (1010 mots )
  • Téléchargement(s) : 0
  • Publié le : 7 juin 2010
Lire le document complet
Aperçu du document
Solar power :


Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies.
Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of theavailable solar energy is used.
Solar powered electrical generation relies on heat engines and photovoltaics.


Solar power is the conversion of sunlight to electricity.
Sunlight can be converted directly into electricity using photovoltaics (PV), or indirectly with concentrating solar power (CSP), which normally focuses the sun's energy to boil water which isthen used to provide power, and technologies such as the Stirling engine dishes which use a Stirling cycle engine to power a generator.
Photovoltaics were initially used to power small and medium-sized applications, from the calculator powered by a single solar cell to off-grid homes powered by a photovoltaic array.
Solar power plants can face high installation costs, although this has beendecreasing due to the learning curve. Developing countries have started to build solar power plants, replacing other sources of energy generation.
Solar power has great potential, but in 2008 supplied only 0.02% of the world's total energy supply. Since solar radiation is intermittent, solar power generation is combined either with storage or other energy sources to provide continuous power, althoughfor small distributed producer/consumers, net metering makes this transparent to the consumer.


Concentrated solar power (CSP) systems use lenses or mirrors to focus a large area of sunlight onto a small area. Electrical power is produced when the concentrated light is directed onto photovoltaic surfaces or used to heat a transfer fluid for a conventional powerplant.


Photovoltaics are arrays of cells containing a solar photovoltaic material that converts solar radiation into direct current electricity. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, microcrystalline silicon, cadmium telluride, and copper indium selenide/sulphide.
Due to the growing demand for renewableenergy sources, the manufacture of solar cells and photovoltaic arrays has advanced dramatically in recent years

Photovoltaic production has been doubling every 2 years, increasing by an average of 48 percent each year since 2002, making it the world’s fastest-growing energy technology.At the end of 2008, the cumulative global PV installations reached 15,200 megawatts.

Driven by advances intechnology and increases in manufacturing scale and sophistication, the cost of photovoltaics has declined steadily since the first solar cells were manufactured


The solar power tower:

The solar power tower (also known as 'Central Tower' power plants or 'Heliostat' power plants or power towers) is a type of solar furnace using a tower to receive the focusedsunlight. It uses an array of flat, movable mirrors (called heliostats) to focus the sun's rays upon a collector tower (the target).

• A parabolic trough:

A parabolic trough is a type of solar thermal energy collector. It is constructed as a long parabolic mirror (usually coated silver or polished aluminum) with a Dewar tube running its length at the focal point. Sunlight is reflected bythe mirror and concentrated on the Dewar tube. The trough is usually aligned on a north-south axis, and rotated to track the sun as it moves across the sky each day.


• Advantages :

-Once solar panels are installed, they produce energy without generating pollution.
-They operate with little maintenance .
-Competitive where grid...
tracking img