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Photovoltaics: generating electricity from the sunUpdated 01/20/2014, published online 08/06/2010
Solar radiation can be converted directly into electricity using special collectors, known as photovoltaic collectors. This solar photovoltaic energy can be used to supply public or private buildings both in urban or isolated environments. All over the world, it offers the means for development to people who cannot be connected to conventional power grids.
© Total / Daniels William
The advantages of photovoltaic electricity
Since 2000, the global production capacity of photovoltaic electricity has risen 35% per year. This success is based on a number of advantages:
• Limited environmental impact. Solar photovoltaic panels have a short energy payback time: the time it takes for the panels to generate as much energy as was required for their manufacture and transportation is between 6 months and 2 years. Furthermore, photovoltaic electricity generation does not emit any pollutants or greenhouse gases and a large proportion of the panel components are recyclable, particularly for the most widespread technology on the market – silicon-based panels. Solar photovoltaic energy emits 15 times less greenhouse gases than conventional energy sources in Europe.
• Photovoltaics offer an alternative to the rapidly dwindling stock of fossil fuels as they require no fuel.
• They can supply the power grid through solar power plants or rooftop installations, but also rural areas with no power grid. They are easy to install, require little maintenance and will provide energy for 20-30 years. It is easy to upscale the systems when local energy demand rises. This is why photovoltaic technology is ideally suited to developing countries such as South Africa, Morocco, Senegal, India, Bangladesh and Thailand.
A wide variety of different applications
Photovoltaic technology can be used in a wide variety of situations.
- Plants connected to the power grid produce electricity that is fed back into the grid (purchased by electricity companies) or used on-site. These plants can be building-integrated systems or systems installed on private or public buildings (increasingly common across the globe), or ground based solar power plants (or solar farms). They comprise rows of photovoltaic panels aligned over several hundred hectares, producing electricity that is usually fed back into the power grid.
- Stand-alone plants that are not connected to the power grid are used to supply satellites, radio relay stations, time stamp machines and devices, public lighting, and signage systems, or are used to supplement oil and gas power plants. These plants also provide energy to mountain refuges and to isolated schools, dispensaries and villages in developing countries.
Access to energy in emerging and developing countries
1.3 billion people in emerging and developing countries have no access to a power grid. Stand-alone photovoltaic systems and solar systems providing decentralized rural electricity are one way of providing access to electricity for these people.
In African countries such as Morocco and South Africa, and in Asian countries such as India and Bangladesh, these systems supply energy to isolated villages, thus providing them with new systems and facilities:
- Telecommunications systems (radio, television and telephone booths);
- Cooling systems (refrigerators);
- Solar pumping of underground water (for drinking water and irrigation);
- Electrical devices (cell phones and sewing machines).
In India, the number of households with photovoltaic panels practically tripled between 2000 and 2012, growing from 500,000 to 1.4 million. Over 3,000 villages use only this form of energy for their electricity supply and Indian businesses are making substantial investments in photovoltaic research.