NEW YORK ( TheStreet) - When the U.S. government stepped in to rescue banks in the 2008 financial crisis, it was Warren Buffett'sBerkshire Hathaway ( BRK.A) that invested billions into the likes of Goldman Sachs ( GS) and General Electric ( GE), in a cornerstone investment that gave investors the confidence to put money back into the banking system. Quietly, in the wake of President Obama's $50 billion earmark to the renewable energy industry as part of the 2009 billion stimulus bill, Berkshire Hathaway is again playing the role of savior investor. This time in the crisis-stricken solar energy sector. After a Wednesday deal with California-based solar giant SunPower ( SPWR) for ownership of the world's largest solar plant, Berkshire Hathaway's energy subsidiary MidAmerican Energy now has stakes in three of the largest U.S. solar power plants - two plants are built by First Solar ( FSLR) -- as the industry undergoes transformation and tries to survive without government financial support. When the three plants are completed by 2015, MidAmerican Energy will become a top utility in the U.S. and the world when it comes to "green energy" generation. For investors who want to put their dollars behind renewable energy investments, Berkshire Hathaway by way of its MidAmerican Energy unit is in an enviable position. However, Warren Buffett's sprawling investment conglomerate and MidAmerican are far from a pure-play bet on the renewable energy sector. If Buffett wants to be the cornerstone investor to the renewable energy sector - as he was to the banking industry in his crisis-time Goldman investment and a big holding in Main Street lenders like Wells Fargo ( WFC) - it's time for the 'Oracle of Omaha' to consider spinning off MidAmerican Energy to public markets. As a publicly traded standalone, MidAmerican's renewable strategy might get the investor attention it deserves, as the likes of SunPower and First Solar attempt to transform their business models to meet a post-stimulus reordering of the green energy business in America. Meanwhile, the company's traditional energy businesses could stand as an investor buffer. A MidAmerican spinoff would also give investors a safer, Buffett-like investment in renewable energy after publicly traded solar and wind energy stocks in the U.S. were battered by commodity price fluctuations, political wrangling and pricing pressure from highly subsidized international players, particularly in China. Putting MidAmerican on public markets would, however, have to appeal to Buffett's charitable instincts and a seemingly increasing role in public policy debates such as taxation and investment. MidAmerican Energy is the classic Buffett business with high capital expenditure needs that make use of billions in cash that Berkshire generates every year, and it provides stable, predictable returns. Outside of Berkshire's insurance businesses and a recent $26 billion takeover of railroad Burlington Northern Santa Fe, MidAmerican Energy is the company's third largest business by revenue and profitability, as of 2011. Last year, Berkshire said it would invest $100 billion in MidAmerican over the next 10-15 years To understand why Buffett should consider a MidAmerican IPO, it's important to know how the company gained what is arguably the strongest green energy position in the U.S., and possibly the world. As solar giants like SunPower and First Solar transition from manufacturing and selling solar energy panels on wholesale markets to building large plants with multi-decade purchase agreements with utilities, MidAmerican Energy appears to be the biggest backer of such projects. In late 2011, when First Solar broke ground on its Topaz and Agua Caliente projects to take advantage of the final throes of a Department of Energy loan guarantee program, MidAmerican Energy stepped up to invest in the plants and the corresponding return that will be generated over the life of their power purchase contracts with utilities like Southern California Edison and NRG Energy. Other large utilities like Exelon ( EXC) have also joined the mix. While the solar plant business of First Solar and SunPower is still uncertain in the absence of DoE loan guarantees, their Antelope Valley projects outside of Los Angeles and similar ones in California's Mojave desert will be a test as to whether the U.S. solar business survives and gets a new round of investment. In the new ordering of the solar world, First Solar or SunPower break ground on projects with a power purchase agreement in place, sell the plant to the likes of MidAmerican, and get contracted to maintain the plants over their lifespan. The strategy is to move away from competing against highly subsidized Chinese panel manufacturers, who've pushed panel prices lower on wholesale markets. The transition comes at a time when states like California will essentially force regional utilities to become a big investor in solar or other renewable energy generation, as they try to meet a state mandate of a one-third renewable energy mix by 2020. With stakes in three of the nation's largest solar plants, MidAmerican appears to be in a leading position in California as the plants come online in 2014 and 2015.