A storage solution…700 feet underground
Some 700 feet below Marathon Petroleum Corporation’s (MPC’s) refinery in Robinson, Ill., a cavern is being mined in a layer of shale to store butane. To put that in context, the Gateway Arch in nearby St. Louis is just 630 feet at its tallest point. At this depth, the cavern will have a 1.4 million barrel capacity to hold all of the butane excess produced by the refinery throughout the summer, plus space for additional purchases to supplement the winter gasoline-blending needs at both this refinery and MPC’s refinery in Detroit, Mich.
“The economic incentive for the cavern construction is the seasonal variation in butane pricing,” notes Ben Hill, project manager. “Historically, Robinson has exported about 1 million barrels of butane in the summer and imported even more than that in the winter.”
The cavern, which is funded by the master limited partnership MPLX LP, is 28 feet high in the center, descending to around 20 feet on the sides. All mined rock will be brought to the surface, creating a rock pile approximately 20 acres in diameter and 18 feet tall. The butane cavern is scheduled for completion in 2018.