Ivanpah, the giant “power tower” concentrating solar project backed by a government loan guarantee and Google, among others, is apparently ready to rock ’n’ roll.

Lead owner NRG Energy announced on Tuesday that the 377-megawatt power plant in California’s Mojave Desert, which uses giant mirrors to shine sun power on receivers atop towers, heating water to generate electricity, had “produced its first output of energy when the Unit 1 station was synced to the power grid for the first time.”

ivanpah solar
‘First Sync’ at Ivanpah Unit 1 (image via NRG Energy)

“Given the magnitude and complexity of Ivanpah, it was very important that we successfully complete this milestone showing all systems were on track,” Tom Doyle, president of NRG Solar, said in a statement.

A 29-MW version of co-developer BrightSource’s concentrating solar technology began operating in Coalinga, Calif., in late 2011 to provide steam for enhanced oil recovery at a Chevron oil field. There had been earlier power-tower demonstration projects in the U.S., and Spain has three plants functioning. In addition to Ivanpah, before the end of the year SolarReserve’s Crescent Dunes plant in Nevada, which comes with molten-salt energy storage, is expected to begin producing energy as well.

But Ivanpah is the big daddy of them all, covering some 3,500 acres of public land and using three 459-foot-tall towers encircled by a total of 173,500 garage-door-sized mirror sets.

The government-backed project has drawn criticism from some environmentalists, most notably for its impact on fragile endangered desert tortoise habitat and recently for dust problems linked to the development.

Google joined NRG and BrightSource as an equity investor in the project with a $168 million investment in April 2011.

“At Google we invest in renewable energy projects that have the potential to transform the energy landscape. Ivanpah is one of those projects,” Rick Needham, director of energy and sustainability at Google, said in a statement. “We’re excited about the project achieving this first sync – a landmark event along the path to completion. Congratulations to the many people who have worked so hard to get this far.”

Ivanpah will be the world’s largest solar thermal plant once it begins full operations, sending power from units 1 and 3 to the Pacific Gas & Electric and from Unit 2 to Southern California Edison, under long-term power purchase agreements. When exactly full operations will commence was unclear, with NRG saying only that “proof-of-concept testing will also be conducted at Unit 2 and 3 in the coming months.”