Bloom Energy has an attractive and in-demand technology, but investors have already priced in a lot of good news.Shares of Bloom Energy (BE 0.31%) have risen more than 700% over the past year. That's a very large change in a very short period of time. But it makes sense, given Bloom Energy's business, which makes solid oxide fuel cells. Over the past year, this clean energy company has become a story stock. It isn't the first time that this has happened.What does Bloom Energy do?Bloom Energy makes solid sta ...