The sun over
Owned and operated by the Spanish energy company Acciona Solar Power, the Nevada Solar One plant contains parabolic mirrors with a total length of 76 kilometers. These mirrors focus and direct solar rays onto a receiving tube containing a special thermal oil that heats the concentrated solar energy to a temperature of approximately 400 degrees Celsius. After this, a heat exchanger uses this energy to heat water, and the resulting vapor is then used to drive the turbine. With its installed capacity of 64 megawatts, the facility can generate around 134 million kilowatt hours of power each year, while at the same time saving about 80,000 tons of carbon dioxide emissions in terms of the global energy mix.
The steam turbine from Siemens Power Generation (PG) had to meet very specialized requirements for use at the solar facility. For one thing, a solar-thermal power plant depends on the sun, and it’s run up and shut down daily when the sun rises and sets. This is why the turbine has two turbine sections — a high-pressure section and a low-pressure section, which also makes more flexible turbine operation possible. Siemens’ success has made it the world market leader in this area, and plans already call for two new solar-thermal facilities to be built in Andalusia in