Yesterday GE announced that it will build what could be the largest solar panel factory in the United States. The plant will be the culmination of over $600 million worth of investment in cadmium telluride thin film solar technology over that past few years. The factory will produce 400 megawatts of solar panels a year. GE hasn’t yet picked a spot for it.

GE’s technology comes from its acquisition of PrimeStar, a startup that developed cadmium telluride thin film solar technology. Such solar panels less efficient than conventional crystalline silicon ones, even with the record 12.8 percent efficiency GE just announced (in contrast, conventional silicon solar panels are about 14 to 15 percent efficient). But they are cheaper to make. There’s already a big market for similar cadmium telluride solar panels made by a company called First Solar, which has become one of the world’s biggest solar panel manufacturers.

Other companies trying to break into the solar market say their panels will be significantly more efficient than GE’s panels, which could eventually allow them to offer lower costs per kilowatt hour for solar power. But they could have trouble scaling up to the level where they can realize low costs. GE has the money to do so quickly, and it has established connections that could help the company sell its new technology, says Travis Bradford, a solar industry analyst. GE has already announced orders for 100 megawatts of thin film products. PrimeStar currently manufactures solar panels at a 30-megawatt capacity facility in Arvada, Colorado.