A major advance in innovative alternative electric power generation was achieved this past September with the opening of the Ivanpah Solar Electric Generating System on about 5.5 square miles of public land in the Mojave Desert of California. The system deploys concentrated solar power (CSP) technology, concentrating reflected sunlight via special mirrors called heliostats in a process to heat water into steam for running turbines to create electric power.
Jointly owned by NRG Energy, Inc., BrightSource Energy, Inc., and Google, the Ivanpah facility, with an investment cost of $2.2 billion (and a $1.6 billion loan guarantee by the U.S. Department of Energy), is a project of BrightSource Energy and Bechtel. It’s designed to generate 377 megawatts of power, enough electricity on some days to power over 200,000 homes. The facility’s power output will be sold to two Californian utilities, Pacific Gas & Electric and Southern California Edison.
The Ivanpah complex, currently considered the world’s largest CSP installation, consists of three solar thermal power plants, each with a vast array of heliostats focusing and concentrating sunlight on a special receiver in each central water tower. In the towers, the water is heated, creating high-temperature steam that is then piped to run turbines connected to electric power generators. The three arrays together deploy a total of 173,500 heliostats.
According to the main Ivanpah solar facility website,
The entire Ivanpah project features an industry-leading low-impact design, resulting in maximum land-use efficiency. Our heliostat technology places individual mirrors onto metal poles that are driven into the ground, which allows vegetation to coexist underneath and around our mirrors; reduces the need for extensive land grading; and uses far fewer concrete pads than other technologies.
A particular advantage of the Ivanpah design over other solar thermal designs, according to BrightSource, is its use of a dry air-cooling system, allowing the power complex “to reduce water usage by more than 90% over competing solar thermal technologies using conventional wet cooling systems.”
A major drawback to CSP systems such as Ivanpah is the requirement for huge expanses of acreage and the effects of open-air heating, and the impacts of both of these on the immediate environment. In the case of Ivanpah, there are complaints of disruption to wildlife habitats, and birds have been harmed by the intensely concentrated solar radiation from the heliostats.
On the other hand, there are major benefits such as a significant reduction in greenhouse gas emissions and the near-elimination of raw material consumption for ongoing power production. According to the Ivanpah Solar website,
More than 13.5 million tons of carbon dioxide emissions will be avoided over the 30-year life cycle of the plant, equivalent to taking 2.1 million cars off the road. This solar complex also cuts major air pollutants by 85% compared to new natural gas-fired power plants.
For additional information on the Ivanpah facility, see: