One of the biggest impediments to growing the adoption of residential solar power is the high cost of marketing to homeowners and installing the panels and supporting equipment. SolarCity, the fastest growing installer in California, is leveraging the power of community to get neighborhoods to sign up for solar en masse at discounted rates.

By meeting with community members and encouraging word of mouth marketing, SolarCity can reduce the cost of buying a solar array by up to 30 percent, according to spokesman Brad Sullivan. The neighborhood by neighborhood approach reduces the number of installers in the field, he said. As more homeowners and businesses agree to add solar and a goal of installed PV in an area is met, the price for everyone goes down, Sullivan says.

The company also has a school program where for every 15 kilowatts of solar panels are installed in a neighborhood, 1 kw is donated to the school. The sign-up period for receiving the discount lasts between 2-3 months.

Peer pressure is aiding SolarCity's success as neighbors ask each other to join together for the good of the environment and in the hopes that solar will be cheaper than coal or natural gas powered electricity in the long run. Some have criticized the tactic, but it is no different than the "keeping up with the Joneses" mentality that has neighbors buying new cars or spending on their lawns for appearence's sake.