Royal Dutch Shell Plc (RDSA) , Europe ’s biggest oil company, is considering retiring one of two coking units at its only refinery in as the company seeks to run lighter crude at the plant. The company has applied to county regulators for a permit to shut the flexicoker at the 156,400-barrel-a-day Martinez refinery northeast of San Francisco , a move that would shrink the plant’s reliance on heavy oils and cut its greenhouse-gas emissions by 15 percent, Destin Singleton, a Shell spokeswoman, said May 16. The unit helps convert the denser crude into more valuable products such as diesel and gasoline. Shell is considering the shutdown as hydraulic fracturing and horizontal drilling unleash record volumes of light oil from shale formations across the middle of the U.S. California’s refiners, lacking pipeline access to the growing crude supplies, are bringing in the most ever by rail as they work […]