The significant disadvantage of solar systems is their dependence on daylight. In Chile, solar power plants are to be built, which still provide electricity at night or in bad weather.
In addition to wind and hydropower, solar energy is the great hope for climate-friendly electricity production. Particularly in warm regions with high solar radiation the potential is enormous.
However, a crucial weak point in the sun-dependent electricity production has been the fact that less or no electricity can be produced at night and in bad weather. The exclusive supply of a region with solar power is therefore difficult.
This makes possible a storage solution in the form of a liquid salt solution. It should circulate during the day and heat up. At night, it is stored in tanks at a temperature of 566 degrees Celsius.
In the case of energy supplies, the hot salt water is heated. The resulting steam drives a turbine, which in turn produces electricity. Up to 5.8-gigawatt hours can be stored for 13 hours. The largest of the three planned plants in the Chilean province of Tamarugal is to be able to deliver 450 megawatts around the clock.
The installations consist of up to three solar towers, surrounded by several thousand mirrors, which bundle the sunlight and return to the towers. In this way, the salt solution circulating therein is heated. A similar facility is under the name Ashalim Project is just in the Israeli desert. The 250-meter high Solturm tower is the highest of its kind.
The Chilean government has recently given the green light to the construction of two of the three facilities. The construction work for the Tamarugal power station and another in Copiapó can theoretically start according to the SolarReserve, but an approval for the third facility in Antofagasta is still pending. Until the new solar power plants actually deliver energy, however, it could still take quite a while.
First, SolarReserve needs to find customers for solar power. Contracts with potential buyers are to be signed at a public auction in October. It is then necessary to attract investors for the construction of the facilities.
The implementation of the Solar Power Plants in Tamarugal alone will cost 2.6 billion dollars. If all negotiations are proceeding as planned, construction work is scheduled to start at the end of 2018.
The principle used by SolarReserve is not new. In Arizona and Las Vegas, similar plants are used, which also store energy in the form of heated salt. However, both power plants use an additional transfer liquid in the form of oil to heat the salt.
SolarReserve is the first company to heat the salt directly. The company has already implemented and commissioned a first small plant in Nevada with promising results.
The power plant produces more electricity than expected; the yield is 105 percent of the contractually secured electricity. Other comparable facilities are lagging behind their set goals.
The goal for projects in Chile is to be able to compete directly with coal and nuclear power plants. The plants should work for 30 years without having to resort to fossil fuels or to have to exchange the liquid salt.
SolarReserve can also be used as a fertilizer. The company wants to restore the environment with its power plants as little as possible. To do this, work with local communities is carrying out extensive studies before construction. The selection of the sites and the use of water-saving technology are also taken into account during planning.
The introduction of 24-hour solar power plants could be a major step in the spread of renewable energies. In any case, it is another sign of global efforts to make electricity production climate friendly.
Europe is also on a right path in this regard. In the North Sea, for example, an artificial island for electricity generation by wind power is to be created, which would supply electricity to several surrounding countries.