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It was a project that took five years to fight off critics and secure regulatory permits. But now the Sunrise Powerlink — a transmission line to ferry clean power like solar and wind from California’s desert to its southern coastal region — is done and live, according to its owner San Diego Gas & Electric on Monday.
The nearly $1.9 billion project erected giant towers and built both above ground and underground cables that now run over 110 miles from Imperial Valley to San Diego’s territory. The project required 28,000 flight hours from helicopters to complete nearly 75 percent of the towers along the way (see video). The project uses both 500-kilovolt and 230-kilovolt lines, and it will initially be able to carry up to 800 MW of electricity (eventually the transmission rate should hit 1,000 MW).
San Diego Gas & Electric plans to use the Sunrise Powerlink to transport wind and solar power, such as the eight projects totaling more than 1,000 MW that are set to rise in Imperial County, the company said.
The project was a hard-won victory for the utility, which faced critics who were worried about the project’s environmental impact and skeptical that the project would really be used to move renewable energy and not mostly electricity from fossil fuel power plants. Other similar transmission line projects have been tabled and cancelled because of such concerns.
The California Public Utilities Commission approved the project in December 2008 after rejecting a proposal from an administrative law judge to deny the project. The judge argued that the utility didn’t need the transmission line, which would cause significant environmental damage, to meet the state’s renewable energy mandate then. The commission also decided against a proposal from one of its own commissioners that would’ve required San Diego Gas & Electric to put in writing that it would use Sunrise mostly for moving renewable energy.
Clean power highways
Building new transmission lines, or upgrading existing ones, has come to be viewed as a necessity as more power plants are proposed and set to rise from remote regions where there is space to accommodate large-scale projects that could produce renewable energy more cheaply than smaller ones. For California, which has an aggressive goal of getting 33 percent of its electricity from renewable sources by 2020, many of the solar farms are materializing in the eastern part of the state, in arid deserts and on former farmland.
Utilities are largely turning to these large power projects to help them meet the state mandate. But the cost of building transmission lines – and the risks involved if the lines are knocked off line by stormy weather or other natural disasters – also has promoted the idea of building solar projects closer to where the electricity will be used.
The utilities commission approved a program in 2010 to require the state’s three largest utilities to hold auctions to buy renewable energy from projects no more than 20 MW in size. But 20MW still requires a big parcel of land, and some renewable energy proponents would like to see more solar equipment installed on commercial and residential rooftops instead. Those projects are more often kilowatt size.
Meanwhile, transmission line developers are looking at using newer technology to build projects that can carry a larger amount of renewable energy and do it more efficiently over long distances. China, which is building a lot of wind and solar farms, is where some of the world’s largest transmission projects are being built.
Photos courtesy of San Diego Gas & Electric