Thanks to innovative business models, the off-grid solar market from sub-Saharan Africa to India has not only been growing, it's picking up serious momentum. But many of the first organizations to bring solar to the poor were nonprofits, which have had a hard time raising enough capital to satisfy the huge demand. That's why the California-based d.light, a for-profit social enterprise, is so important. The off-grid solar lighting specialist has lined up a stellar group of investors for an $11 million investment round, which brings d.light's total to $40 million. This milestone sends a message about the ability of companies in this part of the world to successfully sell products that improve the lives of the poor. (The video is a case history.) After serious due diligence, investors saw that d.light already made more than 500,000 solar lights a month, thanks to its first big customer: the French oil and gas company Total, which sells d.light's product line throughout Africa as part of its "Access to Energy Program." With growth rates similar to the early days of mobile phone expansion, d.light serves over 40 countries through over 10,000 retail outlets, and has sold 6 million solar power products. So as more companies raise the money they need, the world will begin to move meaningfully toward ending energy poverty.