ENERGY

Exxon, Mitsubishi to Study Pipeline: The largest U.S. oil company said it will join with Japan’s Mitsubishi Corp. and a Chinese firm to study the possibility of building the world’s longest natural gas pipeline. The group will examine whether a pipeline can be built from the gas-rich republics in central Asia, such as Turkmenistan, across some of the most rugged terrain in the world to China and eventually to energy-starved South Korea and Japan. While some analysts say it is unlikely that gas prices will ever be high enough to justify a pipeline that is longer than the United States is wide, the formation of a study shows how desperate East Asian nations are to get energy.