Solar Energy Generating Systems

Solar Energy Generating Systems
Name	Solar Energy Generating Systems
Location	Mojave Desert, California
Status	Operational
Construction began	1984
Commissioned	1984–1990
Owner	NextEra Energy Resources
Solar farm type	Parabolic trough
Ps units manu	Luz Industries
Pthermal mw	354

Solar Energy Generating Systems. It is a collection of nine solar power plants located in the Mojave Desert of California. Developed by Luz International and constructed between 1984 and 1990, these facilities were the first commercial parabolic trough plants in the world and remain among the largest solar thermal energy installations. Owned and operated by NextEra Energy Resources, the SEGS plants have a combined generating capacity of 354 megawatts, providing power to the Southern California Edison grid.

Overview

The Solar Energy Generating Systems complex represents a pioneering achievement in utility-scale renewable energy. The project was spearheaded by the Israeli company Luz International under the leadership of Arnold Goldman. Its development was significantly aided by federal and state policies, including the Public Utility Regulatory Policies Act and favorable California tax incentives. The successful deployment of the SEGS plants demonstrated the technical and economic viability of concentrated solar power technology, influencing subsequent projects like the Ivanpah Solar Power Facility and installations in Spain.

Technology and Design

Each SEGS plant utilizes long rows of parabolic trough collectors, manufactured by Luz Industries. These mirrors concentrate sunlight onto a receiver tube running along the focal line, heating a heat transfer fluid, typically a synthetic thermal oil. The hot fluid then generates steam in a heat exchanger to drive a conventional steam turbine connected to an electrical generator. A key design feature is the integration of natural gas-fired superheaters to boost steam temperature and ensure consistent output during intermittent cloud cover, a hybrid approach that increases plant reliability. The plants also incorporate thermal energy storage in the form of molten salt systems in later units to extend operation.

Major Installations

The nine plants are designated SEGS I through IX, situated near the towns of Daggett and Kramer Junction in San Bernardino County. SEGS I and II, built near Daggett, have a combined capacity of 44 MW. The larger complexes, SEGS III through VII at Kramer Junction, provide 150 MW, while SEGS VIII and IX, located near Harper Lake, add another 160 MW. These facilities are strategically positioned in the Mojave Desert to maximize solar irradiance and are connected to the Southern California Edison transmission network. Other major parabolic trough plants globally, such as the Solana Generating Station in Arizona and the Andasol plant in Spain, have followed the technical precedent set by the SEGS installations.

Environmental Impact

The SEGS plants produce electricity without direct emissions of greenhouse gases during solar operation, displacing fossil fuel generation from plants like those operated by Southern California Edison. However, the auxiliary natural gas boilers do produce some carbon dioxide and nitrogen oxides. Land use in the arid Mojave Desert ecosystem and water consumption for mirror washing and steam cycle makeup are notable considerations. The facilities have a significantly lower impact on species like the desert tortoise compared to newer photovoltaic farms that cover larger areas, but site selection remains a critical issue overseen by the Bureau of Land Management.

Economic Aspects

The initial construction of the SEGS plants was made economically feasible by federal investment tax credits under the Energy Tax Act and long-term power purchase agreements with Southern California Edison. Although Luz International filed for Chapter 11 bankruptcy in 1991, the plants themselves have proven to be durable assets. Current owner NextEra Energy Resources benefits from stable operational costs and the valuable renewable energy credits generated in the California market. The levelized cost of energy from the plants has decreased over time, influencing financing models for later projects like the Crescent Dunes Solar Energy Project.

Future Developments

While the original SEGS plants are now decades old, ongoing projects focus on repowering and technology upgrades to improve efficiency and extend operational life. Research into replacing the original heat transfer fluid with molten salt or direct steam generation is being pursued. The success of SEGS continues to inform the design of next-generation concentrated solar power plants, including those incorporating power tower technology like the Ivanpah Solar Power Facility. Future expansion in the region may involve hybrid systems combining photovoltaic arrays with thermal storage, supported by initiatives from the United States Department of Energy.

Category:Solar power stations in California Category:Buildings and structures in San Bernardino County, California Category:Solar power in the United States