Here's how Mosaic works: Investors contribute a minimum of $25 to a project. Over the next 5 to 10 years—depending on the project—the investors will make that money back, plus interest. The return on the investment ranges from 4.5 to 6.4 percent annually, depending on the project. They can support projects in any state, but right now only accredited investors and people in New York and California can invest in the projects, due to regulatory barriers in other states. In order to qualify, projects must be for organizations that are financially stable, have adequate insurance, and benefit the wider community in some way. Recent projects include affordable housing projects, a convention center, several nonprofits, a grocery store, and a Native American reservation.

Mosaic's founders want to do for solar energy what Kickstarter has done for bands and independent films, or what Kiva has done for upstart projects in the developing world. But Mosaic's model goes beyond most other crowdsourcing sites, by not only allowing supporters to invest in the solar project but also make a profit doing so.