Google.org, Google’s philanthropic arm, is investing in solar energy to meet its goals for promoting renewable energy. Google.org has the discretion to both make grants and invest in for-profit companies, and is currently taking advantage of the investment option.

One of the five goals Google.org has set for itself is developing renewable energy that is cheaper than coal. In pursuit of that goal, Google.org has invested in BrightSource Energy, a company developing solar thermal  power. BrightSource’s current round of Series C funding also brought in investments from BP Alternative Energy, StatoilHydro Ventre and Black River for a total of $115 million.

BrightSource sources report that the company is in the process of developing several solar power plants in the Mojave Desert, with actual construction planned to begin in 2009. The plants are planned on a large scale and are expected to deliver low price solar energy in either the forms electricity or steam.

BrightSource isn’t Google.org’s only solar investment, though. In November, 2007, Google partnered with eSolar to develop solar energy solutions. Other initiatives include encouraging plug-in vehicles, improving public services, supporting entrepreneurship and enabling rapid responses to emerging threats.