24 Hour Solar Power
July 13, 2016
The solar power company SolarReserve is making waves in the solar energy industry. Its concentrated solar plant, Crescent Dunes in Nevada, has become the world’s first solar power plant that can continuously supply power for 24 hours a day. Furthermore, it produces absolutely no emissions. The technology utilized by the plant is based on the heating of molten salt (solar thermal technology). The generated heat is then transferred into steam to power a traditional steam turbine. The salt also has a high heat retention rate, allowing it to hold the heat for a long time and disperse the energy overnight.
Previously, solar power plants had depended on back up energy plants powered by carbon emitting fuels because a solar system’s peak generation hours do not coincide with the utility’s peak load hours after 5 p.m. Low sunlight meant low energy generation, and this challenge scaled back the environmental benefits of solar plants. Building or using a second power plant (powered by fossil fuels) paired with every solar plant, to produce energy for the night energy demand, was not an ideal solution. With the solar thermal technology that issue has been overcome. The Crescent Dunes facility has 10 hours of full load storage that allows for reliable on-demand energy production. It currently produces energy for around 75,000 local homes with more than 500,000 MW-hours of energy that it produces annually.
While this is a great development for the growing demand for clean energy, it’s not perfect. SolarReserve has entered into a 25-year power supply contract with NV Energy supplying power at $135 per MW-hour, but new natural gas plants are able to supply power for less than half that price ($52 per MW-hour). However, this technology would be more economically efficient in areas where natural gas and other conventional fuels are more expensive. There have also been reports that the project might be dangerous for birds. In its testing, biologists on site reported seeing multiple birds killed by vaporization when flying near or into the solar flux created by the mirrors aimed at the tower. The birds are attracted to the area supposedly by a “desert mirage,” the false appearance of water caused by the heat and mirrors in the desert basin, but since the vaporization incidents, the mirrors have been re-angled to create a less intense, non-lethal solar flux to mitigate the number of bird casualties.
There are still many ways that solar power can be improved, but this new 24/7 solar thermal plant (and the other two concentrated solar plants SolarReserve is constructing in Africa and Chile) is leading a clean energy revolution, critical progress in the diverse environmental movement.