A massive solar plant in the Mojave Desert officially began operation today after years of construction, testing, and development. Co-owned by Google, NRG Energy, and BrightSource Energy, the Ivanpah Solar Electric Generating System is said to be ready to generate nearly 30 percent of all solar thermal energy produced in the United States. NRG says that the nearly 5.5-square-mile plant is the largest solar project of its type in the world, and that it will be able to provide clean energy to 140,000 neighboring California homes. But thought its owners see Ivanpah as a beacon for clean energy sources, the plant has not been without its controversies.