Of the 144 operable U.S. refineries recorded by the EIA Refinery Capacity Report, 134 were operating and 10 were idle as of January 1, 2012. A refinery is considered idle if the atmospheric crude oil distillation unit (ACDU) is not in operation and not under active repair, but capable of being placed in operation within 30 days; or the ACDU is not in operation, but under active repair that can be completed within 90 days. Based on the definition above, refineries are considered to be idle if on January 1 they are not in operation for any number of reasons including routine maintenance, unplanned maintenance, or market conditions.
Refinery sales in 2011 included the merger of Holly Corp with Frontier Refining and Marketing, bringing HollyFrontier Corporation's total refinery capacity to 470,350 bbl/d. Murphy Oil Corporation sold both of its U.S. refineries last year. Valero Energy Corporation purchased Murphy's Meraux, Louisiana refinery, and Calumet Lubricants purchased its Superior, Wisconsin refinery. On May 1, 2012, ConocoPhillips split into two stand-alone, publicly traded corporations. The downstream operations and nine refineries in the lower 48 states will be owned by Phillips66, and the refinery in Prudhoe Bay, Alaska will remain under ConocoPhillips.
With the purchase of the Meraux refinery, Valero is once again the largest U.S. refiner, with total capacity of 1.863 million bbl/d as of January 1, 2012. ExxonMobil was a close second with 1.856 million bbl/d. ConocoPhillips fell to third largest while BP PLC and Marathon Petroleum Corporation ranked fourth and fifth, for the third consecutive year. These five companies make up 45 percent of total U.S. refining capacity.
On a PADD level, the top rankings by corporate capacity are mostly unchanged from the last two years. With the closure of Sunoco's Marcus Hook refinery, PBF Energy Corp now leads the East Coast (PADD 1) with 29 percent of its capacity. Marathon Oil Corporation leads in the Midwest (PADD 2) with 17 percent. ExxonMobil Corporation has 16 percent of the capacity in the Gulf Coast (PADD 3). In the Rocky Mountains (PADD 4), Suncor Energy Inc. leads with 17 percent of capacity, while Chevron Corporation has the most capacity in the West Coast (PADD 5) with 18 percent.