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The Future of Solar Energy- Current Research

08/06/2010

Solar energy is appreciated for its environmental qualities and meets the demand for diversified energy resources. It has shown promising performances, thanks to research advances.

As part of its sustainable development policy, Total Coal South Africa (Pty) Ltd supports the Kosmos Childcare Association, which helps abused and orphaned children (April 2007). © Total / Zylberman Laurent

A Popular Energy Source

With growing demand for energy and the increasing rarity of fossil fuels as an energy source; and the need to combat global warming, solar energy provides a solution for the energy mix of tomorrow in Europe and elsewhere in the world.

Also, solar energy's rapid growth creates many jobs. In 2012, over 15,000 jobs could be created in the French photovoltaic industry¹. Finally, this locally available resource helps states achieve energy independence when used as an additional energy source alongside imported energy sources (as is often the case with hydrocarbons).

Photovoltaic energy is developing more rapidly than other renewable energy sources.

It is a popular energy source, and the sector's development has the support of both governments and economic stakeholders in industry and construction. For example, in the United States, California is investing in solar energy. About a hundred photovoltaic start-ups were set up in 2008 with funding from the federal government and a vast state-sponsored program, which has earmarked $ 3 billion to fund solar panels for one million buildings².

Improving Existing Photovoltaic Technologies

Engineers and researchers are working together to upgrade existing photovoltaic equipment. The main focus is on reducing their environmental impact and increasing their output. In theory, photovoltaic cells can convert up to 85% of light into electricity. To attain this theoretical rate, scientists are exploring a number of areas, such as:

• Combining different cell types to design equipment that is sensitive to the entire solar spectrum

• Using innovative materials to enable panels to convert even more light particles (photons) into electrically charged particles (electrons)

• Testing new manufacturing and assembly processes

In Germany and the United States, new concentrated solar power (CSP) technologies are being developed. These technologies increase the amount of energy generated by photovoltaic panels by concentrating solar radiation received through lenses or mirrors on tiny high-output photovoltaic cells.

Finally, researchers want to reduce the amount of silicone used to manufacture photovoltaic cells because it is expensive. To do this, they are testing other procedures (thin films) and organic polymers.

Highly Promising Plants

Large-scale solar power plants are expanding rapidly because they provide economies of scale compared to smaller plants. In 2010, the United States, China, and France planned to build new photovoltaic power plants with a generating capacity of over 100 MWc³.

Large-scale plants that concentrate solar radiation to obtain heat or electricity are very recent.

False. The Odeillo solar furnace in the French Pyrenees was commissioned in 1970. With a generating capacity of 1000kW, it was used up to the mid-1980s to carry out experiments that were later used to design solar plants. Nowadays it is used for scientific purposes to test the reactions of certain materials when subject to extreme temperatures.

Since the start of the 1980s, and more particularly since the turn of the century, new experimental thermodynamic solar power plants that concentrate solar radiation using mirrors have been tested in the United States and Spain. This is often referred to as concentrated solar power (CSP).

In these plants, solar heat is used to heat a liquid (oil, eutectic salts or water) to produce steam. As with a traditional power plant, the steam turns a turbine, which drives an alternator, which produces electricity. There are several types of thermodynamic power plants, including:

   • Parabolic trough systems, which have semi-cylindrical mirrors that open up to 6 meters and redirect radiation to a tube located in the center of the collector.

   • Solar power towers, where flat mirrors concentrate solar radiation on the same point located at the top of a tower.

   • Photovoltaic panels, which use a 10-12m diameter swivelling parabolic collector that directs solar radiation to a Stirling engine that converts the heat into electricity.

Contrary to photovoltaic power plants, the new thermodynamic power plants can store the generated electricity if it is not used immediately. The advantage is that thermal storage today is much cheaper than electrochemical storage (i.e. batteries).

These plants can also use solar energy in conjunction with other fuels (gas or biomass) in hybrid plants.

These advantages explain why these plants are rapidly expanding in regions with high levels of sunshine such as the United States, North Africa, the Middle East, South America, and desert regions.