One square kilometer of land holds the capacity – depending on the specifities of location – to generate as much as 100 gigawatt hours (GWh) of electricity per year through solar thermal technology. To make it clear, this amount is enough to run 50,000 residents.
One option to produce this energy is the solar power tower, which is a type of solar thermal plant that uses a tower to receive the sunlight, focused upon it via an array of flat, movable mirrors (ie. heliostats). These focused rays heats the water and the steam produced powers a turbine. As you see, no pollutants are emitted in producing the electricity.
Today liquid sodium is commonly used instead of water to store the energy before using it to run turbines.
- A major advantage: Solar thermal plants produce electricity whose current and future costs are known.
It is a fixed-cost generation resource know to the consumer in advance and it decreases consumers’ exposure to market fluctuations and the volatile cost of natural gas (which solar thermal typically replaces in the portfolio).
- A major disadvantage: Solar thermal power plants are huge
It uses a lot of land. With respect to the electricity output versus total size, they land more effectively than coal plants or hydroelectric dams, though. The best locations for solar power plants are on land, such as deserts, for which there might be few other uses; but again, then comes the problem of how to provide the necessary water.