You gotta dream big when you dream about oil shale
by Ed Quillen
Things have quieted in the oil patch, and you don't hear as many chants of "Drill, baby, drill" as we did last summer. Even so, there remains considerable interest in developing oil shale, as evidenced by a recent report from the Center of the American West in Boulder.
America's biggest deposits are roughly centered where Colorado, Wyoming and Utah come together. Producing useful oil from those rocks means converting an unpopulated area into an industrial zone of roads, retorts, power lines and refineries. No one who cherishes open space and clean air wants to see that. But there may be a way to minimize those effects if that oil shale ever gets developed. This is my solution: Mine it here, but process it somewhere else.
It's the processing, after all, that requires one to three barrels of water for every barrel of oil, and if there's one thing we don't have a lot of here, it's water.
Technically, oil shale is neither oil nor shale. The "shale" is a sedimentary rock known as marlstone, and the "oil" is a waxy solid called kerogen. A ton of marlstone contains 20 to 50 gallons of kerogen. To extract the kerogen, you crush and heat the marlstone. The leftover marlstone takes up about 30 percent more volume. So you can't just fill in the hole you mined because you'll have a big pile of leftovers. As for the kerogen, it has to be refined to make useful products like diesel fuel.
So here's a pipe dream for producing oil shale: We start with open-pit mines, with the drills and gargantuan shovels operated by electricity. Mine haulage will be by rail, like the Bingham Canyon pit in Utah, and the carloads of marlstone will also moved to some place that has plenty of water, already has a petrochemical industry, and could even use the waste rock that remains after the kerogen is extracted. In other words, Louisiana. There's abundant water at the mouth of the Mississippi, and it rains 60 inches a year, as opposed to maybe 12 up here.
As for the waste rock, Hurricane Katrina underlined the fact that much of New Orleans is below sea level. This is clearly a place that could use fill -- crushed marlstone by the cubic mile.
The rail route from Shale Country to Bayou Country would be electrified, and thus it could produce energy. When an electric train that draws its power from overhead wires rolls downhill, it can feed power back into the line. Thus a marlstone train, dropping to sea level after crossing the Rockies, could function like a big hydroelectric plant, powered by rolling rock instead of falling water. Granted, some of this energy would be need to haul the marlstone up to the Great Divide before starting down to generate power. But it should be at least a break-even proposition.
Is it possible to move enough rock by rail? Consider the Powder River Basin of Wyoming, where immense coal mines fill trains to fuel distant power plants, as a model. On an average day in 2005, 63 "unit trains" left the basin. The typical unit train is 130 cars long, with each car holding 110 tons. Assume 30 gallons of oil per ton, and that works out to 643,500 barrels a day.
Mining that much rock -- 900,900 tons a day -- would not cause a population boom in Shale Country. The rule of thumb for a big open-pit operation is 250 tons per employee per day. Thus we're looking at only 3,604 workers, hardly enough to cause boom-town woes. So here's a way to satisfy the "drill here, drill now" crowd while solving some of the Gulf of Mexico's problems. It would also follow our Western tradition of supplying cheap raw materials with the "value-added" processing done elsewhere.
It is true that in 2008, the United States imported more than 11 million barrels of oil a day, and my gargantuan rail-haul system would replace less than 6 percent of that. To replace all our imports with shale oil would take more than 1,000 trains a day.
In other words, oil shale seems unlikely to bring America energy independence. But hauling rock downhill does make more sense than trying to process the stuff here. Producing just those 643,500 daily barrels in arid Shale Country would require at least 27 million gallons of water every day.
As the old joke goes, "Oil shale is the fuel of the future -- and always will be." Maybe we just need to wait a few million years until the kerogen has a chance to turn into crude oil.
Ed Quillen is a contributor to Writers on the Range, a service of High Country News (hcn.org). He writes in Salida, Colorado.© High Country News