Seems strange. An Internet company speculating in energy trading. A few years ago there was a famous energy company that speculated in Internet broadband trading.
I don't believe they have the same auditing firm, at least Arthur Anderson is not around anymore. Google got into the energy business by trying to be energy efficient and locating their power hungry servers at the most cost effective locations (with server farms that are so energy-sucking that they suck as much electricity as the city of Tacoma, Washington).
Two words... 'Server Farms'. Massive energy consumption for both machine power and cooling systems. Companies like Google, Microsoft, Amazon, etc. spend enormous amounts of time, effort and money to design, build, and locate facilities for maximum energy savings. It's easy to see them trading to hedge / speculate on those costs.