Solar Energy

The cleanest form of energy for our planet also renews itself daily. Historically the challenge has been its efficiency rate, i.e. the energy output compared to the solar energy input, which has been uncommercially low. This is now changing as new materials yield substantial improvements. As a consequence the interest quickly grows for solar energy as a serious alternative source of energy and manufacturers of solar energy panels, such as REC, are consequently experiencing steep increases in demand for their products. Commercial applications are now appearing also in relatively sun-poor countries like Germany and Norway. Presumably the sunshine in the Sahara deserts could be used to build large solar cell facilities that can produce great quantities of energy, free from pollution. If only 4 % of the world's deserts could be covered with solar cells, theoretically the whole global energy consumption could be satisfied. The problem is the cost. Solar cell facilities are expensive and most users live far away from deserts. It's expensive to lay wire or build high voltage lines. Unstable political relations are further reasons why the sahara still has no solar cell facilities, but they probably will come. The International Energy Agency, IEA, has formed a group to analyze solar cell plants in the saharan desert. The first attempts at large solar cell areas in the desert are now being tested. A 644 MW-facility in the Nevada desert in the USA was opened in June 2007 and in the United Arab Emirates a plant is built to provide 10 000 homes with power. These solar energy plants are facilities using solar energy to generate electricity with turbine-driven generators (thermal solar plants) or with solar cells. In thermal solar plants sunlight is used to generate current with conventional steam turbine technology. To reach high temperatures sun-following large mirrors are used on statives (heliostater). The mirrors reflect and concentrate the direct sunshine to an absorber on top of a solar tower. There water is heated to high temperatur and generates steam. Alternatively a so-called parabolic collector with steam pipes can produce the steam. The steam is then led to a turbine connected to a generator where electronic current is finally generated. So far the largest thermal solar plants were built in California where 2.7 billion square meters of parabolic collectors are gathering 430 MW (megawatt) electronic current. Production of current for the electronic power grid from thermal solar plants or solar cell based plants that lead to profitability is still far despite the large growth in the solar cell market. In the beginning of the 21st century the solar cell market grew about 25 % every year on average and in 2005 the production capacity rose above 1000 MW corresponding to 10 million square meters a year. The largest market is in Germany which through legislation created incentives to invest in new facilities where anybody can become producer of electronic power. 60 % of the solar cells were installed in Europe and 30 % in Asia. Currently solar electricity from solar cells is about five times costlier than conventional electricity from the net, but the gap is decreasing due to increasing electricity prices and decreasing production costs for solar cells.