Solar Power for All These brothers have set big goals, but that's the only way to make big change.

Lyndon and Peter Rive, 32 and 34, respectively, never tire of meeting new customers. "It's great to see the smiles on their faces when their utility meter starts spinning backward," says Lyndon.

The South Africa-born brothers are the founders of SolarCity, and they've made it their mission to make solar power accessible to everyone. "In the past, solar was typically only available to the wealthy--with a price tag of about $60,000 to install," says Lyndon. "We've designed a system that allows someone to go solar without putting down that money."

The brothers' solution is a leasing program for solar panels: Their Foster City, California, company puts up the capital to install the panels on homes and then rents them to residents. The beauty of the system is that clients' savings on their electricity bills offset the cost of the lease, so residents usually end up spending less per month. Even more money is saved when neighborhoods work together and all residents go solar simultaneously.