San Francisco Chronicle: The alternative energy business is starting to make real money. Worldwide sales for companies specializing in biofuels, wind farms, solar panels and fuel cells grew 40 percent in 2007 to reach $77.3 billion, according to an annual report issued by Clean Edge, a research firm that studies the green technology industry. That’s significant revenue for an industry crowded with startups, many of which don’t yet have finished products to sell. But other companies — including major …