Heliostats
Atwhat are known as tower power plants, thousands of mirrors directthe sun’s rays onto a central receiver at the top of a tower.
Theprerequisite for high yields is direct solar radiation, whichoccurs mainly in the Earth’s sun belt. A particularly high numberof CSP plants have been and are being built in countries such asSpain and the United States, as well as the Middle East and NorthAfrica. In these plants, the energy captured by concentrating solarpower can be boosted further by large heat reservoirs containingliquid salt, that holds in the heat already obtained – for timeswhen the sun does not shine.
Thermal energyfrom solar power
What is billions of years old and still full of power? The sun.Photovoltaic and solar thermal power technologies use the Earth’sclosest star as a literally inexhaustible source of energy. Whilephotovoltaic uses solar cells to convert sunlight directly intoelectricity, solar thermal power technology produces thermalenergy. In private homes, solar thermal power is used mainly toprovide hot water and well-heated rooms. Meanwhile, concentratingsolar power – CSP for short – can produce electricity on a largescale: a solar thermal power plant such as Noor I in Morocco has acapacity of 160 megawatts (MW) and supplies electricity for 350,000households. Thousands of mirrors concentrate the sunlight and warmup a liquid. This source of heat then turns water into steam, whichsubsequently produces electricity through a generator. Fourdifferent types of collectors are used to concentrate the sun’srays:
New investment anda jobs boom?
According to the study “Solar Thermal Electricity – Global Outlook2016,” countries such as Morocco are thus making an importantcontribution to reducing emissions of green-house gases. By 2020the countries in the “sunbelt” – those located between 40° northand south of the equator – could avoid 32 million metric tons ofCO2 byusing CSP. At present, Spain and the United States are top of thetable for CSP capacity, but other countries are catching up. Chinaaims to commission solar thermal power plants with a total capacityof 10 gigawatts (GW) by 2020, and Saudi Arabia is planning a CSPcapacity of 25 GW by 2032. The study, which was commissioned bySolarPACES, a technology program of the International Energy Agency(IEA), Greenpeace and the European Solar Thermal ElectricityAssociation (ESTELA), also found that the use of thisclimate-neutral energy source in these countries would createinvestments worth €16 billion by 2020 and 70,000 new jobs in thefuture.
