Photovoltaics

Solar energy can be used in photovoltaic shape to produce electricity. In 1998, the photovoltaic industry has provided 0.04% (1.2 TWh) of global electricity production.

Historically developed in North America (0.9 TWh in 1998), it is experiencing significant growth in the developing world where it seems like the best solution from a technical point of view (simplicity of implementation, autonomy, maintenance reduced) and cost to meet the basic electricity needs of rural populations.

It also increased in industrial countries, mainly for food sites too isolated to be connected to the network but also, as in Japan and Germany, as part of the major programs of grid-connected photovoltaic roofs.

In France, as in developing countries, the EDF Group is involved in the development of this mode of production.

A development factor

More than 2 billion people worldwide lack access to electricity, especially in rural areas. In these areas, solar energy is a factor of development that meets the basic needs of families and health care facilities and to ensure the supply of drinking water or irrigation (solar pumps).

As part of its agreements with ADEME, EDF Group participated in a group of industrialists in a pilot scheme for the electrification of three villages in Burkina Faso. The electricity produced is used to pump water, light a communal space and power a rural telephone, a TV and a refrigerator for medicines and vaccines.

This group has been active in Benin and Chad as well as Mali where two projects are underway: one to equip four villages (which will replace kerosene lamps and save 600 tonnes of CO2 per year) the other for twenty villages, approximately 80,000 (8,000 tonnes of CO2 saved per year) residents.

In 2000, EDF signed a memorandum with the government of the state of Bahia in Brazil to power 15,000 homes with photovoltaic systems. Purpose: 50 000 people to plug in lamps, small appliances as well as a radio or a television. This program, one of the largest to be conducted in the world, to save $ 16,000 tons of CO2 per year. It is led by a French consortium of EDF, and TotalEnergie TotalFinaElf, the world's photovoltaic assembler that combines since 1997 EDF and Total in many achievements in Indonesia, Vietnam.

The three partners also have a project for 20,000 households in Morocco in rural areas to sparsely populated.

An effective solution for remote sites

In France, photovoltaics can power sites too isolated to be connected to the grid under satisfactory economic conditions. 3000 homes are affected in France and more than 7,000 in the DOM.

EDF and ADEME provide financial and technical support for equipment of approximately 1,000 sites per year, mainly in the DOM for a 1 MW peak (the peak watt is the maximum power of the PV modules). In late 2000, nearly 4,000 homes, shelters and sheep-grid had been electrified.

As part of the agreement signed in 1999 with the French Alpine Club for three years, EDF provides technical and financial support to install, extend or improve the photovoltaic equipment over a hundred shelters CAF and to maintain . In 2000, the refuge Platé was equipped with a device (28 photovoltaic modules, a battery bank and an electronic controller operation) providing winter and summer, energy independence (lighting, cooling, water pumping small appliances). Other embodiments of the year: the shelters Cover, Shark and Albert 1er.

The energy of the light

Sunlight arrives in the form of particles, photons, on panels made of "modules", small square of semiconductor material, usually silicon. These photons dislodge electrons in the material thereby producing an electrical current. Without light so it can be no current. We must therefore store electricity generated during the day in batteries. Finally, if a bulb is working directly with the direct current produced by the sun, this is not the case for many appliances (washing machines, hair dryer ...) that require AC power. Thus branch to the output panel or battery, an inverter that handles the conversion.

Energy on any surface?

Generated by photovoltaic cells electric current is proportional to the illuminated surface and the light intensity received and watt-peak (Wp) is the unit characterizing the photovoltaic power. In order of magnitude, a panel of 0.5 m² with a capacity of 50 Wh 50Wc happen if it receives full sunlight midday sun for an hour.

Larger and more sophisticated applications

Mostly used for rural electrification and pumping drinking water (50%), photovoltaics has seen its scope of application to extend the pace of technological progress: flashing lights indicating the work on highways, terminals relief emergency telecommunications systems, maritime signals (like 90 buoys in the Gironde estuary) and even power plants chlorinating water towers (eg six Corsican towns).

In Japan and Germany, they have undertaken major programs to install photovoltaic panels on the roofs of existing buildings or integrated facades in new buildings. These systems are connected to the electricity grid, the corresponding spaces are powered by it when their needs exceed the production supplied by photovoltaic panels: the days of limited sunlight, at night of course, winter ...