Jim Cramer is getting behind an alternative energy stock that has a big name investors and leading politician already long the name. The stock Cramer likes is Clean Energy Fuels (CLNE), a company that builds and operates natural gas fueling stations.. He explained that a recent Wall Street Journal article reported that House Speaker Nancy Pelosi owns somewhere between $100,000 to $250,000 of the stock. T. Boone Pickens is also the largest shareholder of CLNE. Cramer believes that Pelosi’s ownership is big because without government incentives, gas stations with natural gas pumps will see little activity. “So her investment in CLNE is the clearest possible endorsement of natural gas as a transportation fuel,” Cramer said. He pointed out that the stock should benefit from a ballot initiative in California, which is asking for $5 billion to be earmarked for the purchase of 70,000 trucks and 150,000 cars in the state to be converted over to natural gas and other clean fuels. Cramer said the passage of the bill would have a huge impact on the shares. The “Clean Tech” sector is poised to be the biggest gainer in 2008. See what our analysts rank as the #1 opportunity today