The world’s largest concentrating solar plant is now sending electricity to the grid from California’s Mohave Desert – Ivanpah Solar Electric Generating System.
Spread out over 3,500 acres, the 377 megawatt (MW) project will supply electricity to 140,000 households in California each year, and more than twice that during peak hours of the day.
The electricity is being sold under a long term power purchase agreement to California utilities, PG&E and Southern California Edison, helping them meet California’s Renewable Portfolio Standard of 33% renewable energy by 2020.
Each of three units has a 459-foot high tower containing water that’s heated by the circular array of 170,000 mirrors (heliostats) that surround it, tracking the sun throughout the day. When water in the tower is heated, it produces steam which spins turbines that produce electricity. Water consumption is minimized by using a technique called dry cooling to condense steam, important in a desert.
At peak construction, the project employed about 2725 people (more than would be needed to build the Keystone pipeline).
Imagine seeing this in the desert:
“Given the magnitude and complexity of Ivanpah, it is very important that we successfully complete this milestone showing all systems are on track,” says Tom Doyle, President of NRG Solar, which owns the project.
Sync testing will continue for each of the units over the coming months, after which the entire project comes online.
This is BrightSource Energy’s first commercial project, which proves its concentrating tower technology. NRG is the lead investor and Google is a major investor in the $2.2 billion project. Bechtel is charged with engineering, procurement, construction and commissioning. The project received a $1.6 billion loan guarantee from the Department of Energy and sits on public land leased from the Department of Interior.
Construction started in 2010, but two of three units were temporarily halted because of concerns about endangered tortoise habitat.
“Ivanpah is the showcase project for BrightSource’s power tower technology and technical expertise. Validation at this scale demonstrates the viability of our technology as BrightSource increases focus on international markets and applications for concentrating solar power,” says David Ramm, Chair of BrightSource. Last year, Brightsource raised another $80 million, bringing its total to about $615 million.
An even bigger concentrating solar plant begins construction this year, the 500 MW Palen Solar Electric Generating System in Riverside, California. Its two towers will be much higher – 750-feet tall. It is being built by Brightsource and Abengoa.
Solar tower technology requires less land than solar PV because heliostats can be very close together, and it also cuts water use by half.
Rather than scraping the land of all vegetation, the solar field can be built around the natural contours of the land, retaining native vegetation under the mirrors, and avoiding areas of sensitive vegetation. Heliostats sit on poles placed directly into the ground without concrete foundations.