Solar Energy Facts
Solar thermal collectors use the solar radiation falling on them to heat tap water. They can also serve for space heating.
Different types of photovoltaic modules convert solar radiation directly into electricity. Such modules are increasingly integrated in buildings, and can, for example, be used as roof tiles.
Different types of solar thermal power plants use solar heat by concentrating solar radiation – such as through mirrors focused on a solar power tower or by means of parabolic troughs – to heat up water and conveying the steam to a turbine.
And very simple mirror-based systems can help in saving gas, kerosene or wood through solar cooking.
A growing trend
These various solar technologies are growing in scale. Total PV capacity amounted to 16 GW in 2008, and large plants (over 50 MW) have been built in several places.
Solar thermal power plants are mushrooming in the US and in Spain, and China takes the lead in solar heating with 70% of existing global capacity.
Solar heat holds a great promise for cities, where air pollution can be a big problem. And in many sparsely populated off-grid areas, passive solar design, solar heating, cooking and photovoltaics are starting to be used.
WWF envisages a future where large-scale solar electricity plants are connected to super grids to meet energy needs throughout the world.
In theory, the entire present energy consumption of the world could be met by an area smaller than 1% of the world’s deserts if they were covered with solar thermal electric plants.