California’s largest electric utility Southern California Edison (SCE) is getting onboard the solar train as today it inked a deal with Pasadena, Calif.-based eSolar to help it secure an additional 245 megawatts of solar power by 2013 for its customers in what the companies say is the nation’s first commercial effort using power tower solar thermal technology.

What exactly is power tower solar thermal technology anyway, you ask? Well, according to the companies, each pre-fabricated module (pictured left) consists of several solar towers each associated with thousands of heliostats, or mirrors, which precisely track the sun over the course of the day and reflect light to a receiver at the top of each tower. Then, the concentrated light boils water in a central receiver, routing the steam to a traditional turbine to – viola! - produce electricity.

eSolar purports that its solar thermal technology is unique because it uses shorter towers, small mass-manufactured mirrors and advanced tracking software, allowing it to achieve economies of scale within a minimal footprint and easy connection to transmission lines.

SCE, which claims to be the nation’s leading purchaser of solar energy, said its project will be built in the Lancaster area of California (i.e., in the middle of nowhere—trust me on this, I’ve driven through), and is expected to begin delivering energy in 2011, with a total of 105 megawatts of renewable solar power by 2012, ramping up to 245 megawatts by 2013.

In April, eSolar closed a $130 million round of funding led by Idealab, Google.org, and Oak Investment Partners.