In SolarCity's model of financing, homeowners and businesses lease the costs of the installation and maintenance of the system. By being able to prepay a certain amount and thus decrease the monthly payment rate, they can set up their lease rate to be less than their standard energy bills. To make it even easier for customers to make the switch to solar power, SolarCity also makes guarantees for the maintenance, warranty and the power output of the panels.
This is Google's largest investment in renewable energy projects so far, but the company's total investments in this sector are more than $680 million. In April 2011 Google invested $168 million in a Mojave Desert solar energy plant, and later that month, the company bought 20 years worth of wind energy to power one of its data centers in Oklahoma.
Check out a video describing the initiative below.