Solar power just hit the big time in the US -- BrightSource Energy has confirmed that the world's largest solar thermal plant, the Ivanpah Solar Electric Generating System in California, is up and running. The array, also backed by Google and NRG Energy, produces a total 392MW of power through 173,500 multi-mirror units. That's enough to power 140,000 nearby homes, and it represents 30 percent of all the solar thermal energy in the US. The Ivanpah harvester has its drawbacks; with roughly 5.5 square miles of mirrors, it's creating trouble for birds and other nearby wildlife. Even so, it represents an important breakthrough for delivering clean energy on a grand scale.