Fracking for natural gas being powered by it, too - Article Photos 5/7

In this photo made on Thursday, Jan. 17, 2013, Universal Well Services fracturing engineering team leader Mike Michaelson opens the cover of a display panel before he starts the 16 cylinder diesel engine sfor the first time since it was converted to run on a blend of diesel and natural gas at the Cummins Bridgeway facility in Gibsonia, Pa. Since there was no natural gas available at this facility, the engine would run on diesel fuel alone this day. Oil- and gas-field companies from Pennsylvania to Texas are experimenting with converting the huge diesel engines that operate pumps that propel millions of gallons of water, sand and chemicals down a well bore in the fracturing process to break apart rock or tight sands that trap natural gas. (AP Photo/Keith Srakocic)