Document renews debate over oil shale, water
Water remains a significant barrier to oil shale development in the arid Rocky Mountain West, an environmental organization said after gaining access to internal Chevron USA estimates.
“Yes, ex-situ (above-ground retorting) will use a lot of water, despite what we or others may have told you in the past,” was how Boulder environmental lawyer David Abelson characterized a report given to Western Resource Advocates by Chevron in a challenge to Chevron’s water rights. “This legal case puts to bed the argument of whether current oil shale plans will use large quantities of water.”
It’s long been known that mining and retorting is water-intensive, said Glenn Vawter, executive director of the National Oil Shale Association, who noted that more recent developments reduce water needs substantially.
Royal Dutch Shell, which last year abandoned its oil shale research program in northwest Colorado, discovered before it left that it could produce a barrel of oil from oil shale with about half a barrel of water, Vawter noted.
Shell was working to heat oil shale underground, with no mining or surface development, in what is known as an in-situ process.
Chevron had been working on its own in-situ process on a federal research, demonstration and development project, but gave up on the effort, also last year. The company, however, wanted to retain its water rights, and in its application to the water court Chevron said it could use a form of retorting called a “staged turbulent bed” process.
Such a process would require about 16,000 acre feet of water for a retort producing 100,000 barrels of oil per day. Additional demands could force the water requirement up to 24,000 acre feet per year.
An ex-situ oil shale operation producing 500,000 barrels a day of oil would require 120,000 acre feet of water, Western Resource Advocates said.
That’s enough water to serve more than 1 million people per year, and would put a strain on the existing system, the organization said.
By way of comparison, the Upper Colorado River basin is required to deliver at least 7.4 million acre feet of water on average annually to the lower-basin states.
Depending on the mix of methods, ranging from in-situ and above-ground techniques, along with modified techniques that involve retorting shale in earthen capsules, water demands could range from 16,000 to 29,000 acre feet for a 500,000-barrel per day industry, Vawter said.