San Diego Gas & Electric says its Sunrise Powerlink energy transmission line that was put into service a year ago is performing as expected, boosting reliability of the grid while acting as a catalyst for renewable power production.

The 117-mile power line moves electrical power generated from wind and solar sources in Imperial County to San Diego. It was built by SDG&E at a cost of about $1.9 billion.

Jessie Knight, SDG&E’s chief executive officer, said the transmission line is more valuable today than when it was originally planned because of the closure of the San Onofre Nuclear Generating Station.

“It not only adds another major transmission artery to our local transmission grid, it is bringing a significant amount of imported power to our region during the summer months to compensate for the loss of power from SONGS (San Onofre),” Knight said.

Since 2011, SDG&E signed 36 renewable contracts with energy generating firms that are now in development, totaling nearly 1,750 megawatts of electrical capacity. When the projects are all operational, they will produce enough energy to power about 750,000 homes and offset more than 300,000 cars from the roads, SDG&E said.

Of those contracts, 10 are in Imperial County. One of those, Pattern Energy’s 265-megawatt Ocotillo Wind project, was shut down while the company determines the cause of wind turbine blade breaking off and falling in May. Pattern said it expects to return operating the wind turbines by the end of this month.

SDG&E said several other solar projects under construction in Imperial County are expected to be activated this year and next year.

In 2011 and 2012, SDG&E said it obtained about 20 percent of the energy it delivers from renewable sources. The business said it is on its way to meeting or exceeding the state-mandated 33 percent goal by 2020.

— Mike Allen