As the volume of ethanol blended into the US gasoline supply increased from 3% to 10% over the past two decades, the fuel’s energy density decreased by 3%, according to the EIA. In an interesting example of how energy/environmental issues are often characterized by tradeoffs, greater volumes of ethanol added to gasoline decreases air pollution but also decreases the number of miles driven per gallon. However, advances in engine technology have also significantly increased fuel efficiency. “While these additives reduced air pollution, they also resulted in lower heating value compared with conventional gasoline, translating to fewer miles per gallon, because they have lower energy density.” [EIA]

Williams is merging with Access Midstream Partners in a $50 billion deal that will create one of the largest US natural gas pipeline companies. “Williams this year called a surge in domestic energy production and demand for new pipelines an “ongoing energy infrastructure super-cycle.” [Bloomberg]

The Khafji oilfield operated jointly by Saudi Aramco and Kuwait Petroleum Corporation was reportedly shut due to technical reasons, though some speculate political disagreement could have influenced the closure. “The halt of oil production in the divided zone is due to purely technical, rather than political reasons,” he said, adding that production could not resume until the technical matters were addressed. [Reuters via Rigzone]