The U.S. Forest Service (USFS) on Tuesday approved a San Diego Gas & Electric (SDG&E) 120-mile transmission line from remote areas in southern California’s Imperial Valley to residences and businesses in the San Diego area.

After a rigorous environmental review, the USFS issued a Record of Decision (PDF) approving the construction, operation, and maintenance of a 19-mile segment of the Sunrise Powerlink transmission line through the Cleveland National Forest (CNF). When completed in 2012, the 500-kV Sunrise Powerlink electric “superhighway” will have the capacity to carry at least 1,000 MW of power—mostly from renewable sources.

The decision for the $1.9 billion project joins key prior approvals from the California Public Utilities Commission (CPUC) in late 2008 and the Department of the Interior’s Bureau of Land Management (BLM) in early 2009. It now signals the imminent start of the project’s construction.

SDG&E said in a release that the permitting process and environmental reviews for the Sunrise Powerlink represent the most comprehensive completed for a power line in California history.

“California has two dozen renewable energy projects looking to break ground this year alone that will create thousands of jobs and billions of dollars of investment in our state. But, many of these projects will be built in remote locations in the desert, and we need more transmission lines, like the Sunrise Powerlink, to transport this renewable energy to population centers,” said Calif. Gov. Arnold Schwarzenegger.

The line has drawn heated opposition from the beginning, with rural advocates, conservationists, and consumer groups alleging the line would bring fossil power in from Mexico, that it’s dangerous, and too expensive.

SDG&E has issued public notices in response to these allegations. In one instance, it refuted the claim that enough solar panels installed on roofs would eliminate the need for the transmission line, saying: “San Diegans would pay 10 percent of the $1.9 billion Sunrise Powerlink. If we rely exclusively on rooftop solar panels instead, SDG&E customers would pay the entire estimated cost of $20 billion and receive little improvement to energy reliability.”

It has also stated that California’s best bet to met power demand is to build more transmission lines. “The U.S. Department of Energy says San Diego’s energy corridor is one of the two weakest in the nation,” SDG&E says on its website. “The Imperial Valley has some of the largest potential renewable energy supplies in the country, but we need to be able to transmit the energy here. That’s why the Sunrise Powerlink is so urgently needed.”

According to the CPUC, California’s three large investor-owned utilities—SDG&E, Pacific Gas & Electric Co., and Southern California Edison—are struggling to meet a state law that mandates they procure 20% of their retail electricity sales from clean energy sources by the end of 2010. The three utilities are likely to end this year with a combined 18% of their retail sales coming from renewables, the agency says.

“It’s highly unlikely that they’ll make the exact number by the end of this year," Commissioner James D. Boyd with the California Energy Commission told the Los Angeles Times last week. "I hate to be a naysayer, but … even though many contracts have been entered, the actual construction and thus the delivery of electricity has lagged."

The newspaper noted that the utilities have been moving aggressively to meet the target, but renewable power producers with which they have inked deals have run into an assortment of problems, including difficulty securing financing during the economic downturn. Other issues include technological difficulties, permitting roadblocks, and transmission bottlenecks.

Sources: SDG&E, POWERnews, Los Angeles Times