Late last week, NRG Energy, Inc. announced that Ivanpah Solar Electric Generating System is in operation after six years of construction. Located in the Mojave Desert, 300,000 software-controlled mirrors and three 450-foot towers at full capacity can produce up to 392 megawatts of solar power. That will provide solar electricity for 140,000 California homes and will avoid 400,000 metric tons of carbon dioxide per year. The Ivanpah project received a guaranteed loan of $1.6billion from the US department of Energy’s Loan Programs Office, which became a joint investment made up of NRG Solar, Google and BrightSource Energy.
“Cleantech innovations such as Ivanpah are critical to establishing America’s leadership in large-scale, clean-energy technology that will keep our economy globally competitive over the next several decades,” said Tom Doyle, president, NRG Solar. Ivanpah accounts for nearly 30 percent of all thermal energy currently operational in the US and is the largest solar project in the world. This solar power tower technology is the first Ivanpah project to be used to produce electricity for company’s signed contracts with PG&E and Southern California Edison.
Solar thermal power plants use solar mirrors to heat water in boilers thus produce steam to turn the electricity generating turbines. This creates usable electricity by using large-scale magnification. The technology used in the Ivanpah plant comes from Bright Source and includes 173,500 heliostats that follow the sun’s trajectory, solar field integration software and a solar receiver steam generator.
Although solar thermal plants do require the use of water, as opposed to solar photovoltaic panels, this project utilizes dry cooling technology, which vastly reduces the amount of water needed. As Energy Secretary, Ernest Moniz says, “This entire facility will use roughly the same amount of water as two holes at the nearby golf course.”
Ivanpah produces solar power on a large scale rather than on rooftops. While some solar thermal power plants can store the sun’s thermal energy in the form of molten salt to produce energy when the sun isn’t out this project does not store energy after dark. BrightSource does plan to incorporate thermal storage in future next-generation designs.