Posted on Tue, Jul. 29, 2008
last updated: July 28, 2008 05:53:45 PM
WASHINGTON — Oil shale in the American West might contain three times the oil of Saudi Arabia, but getting it out of the ground would require much more energy than drilling for conventional oil does, and the result would be more greenhouse-gas emissions.
Department of Interior Secretary Dirk Kempthorne announced proposed regulations last week to start a commercial oil-shale program on public lands in Colorado, Utah and Wyoming. He said that with gasoline around $4 a gallon, "we need to be doing more to develop our own energy here at home, through resources such as oil shale."
President Bush started speaking about the prospects for oil shale in June, when he said that Congress shouldn't block regulations that would allow exploration to proceed. Congress last year blocked final regulations through September.
Bush "wasn't speaking to emissions. He was just talking about expanding more American energy," White House spokesman Scott Stanzel said. The amount of emissions would depend on what kinds of energy are used to obtain fuel from the shale, he said.
There's been some long-range thinking about using nuclear power or wind energy to convert oil shale into hydrocarbons. But over the next few decades, fossil fuels probably would supply the energy, according to a 2005 study by the policy research group RAND Corp.
The Department of the Interior estimates that it'll be several years before the technology is ready for commercial oil-shale development. The government has given oil companies leases for five demonstration projects in Colorado and one in Utah.
Adam Brandt, a graduate student at the University of California at Berkeley's Energy and Resources Group, has analyzed the greenhouse gas emissions from converting oil shale to liquid fuels.
Oil shale is a type of rock that contains kerogen, a fossil organic material. Kerogen can be heated to produce oil and gas.
Brandt said that most companies had abandoned the idea of aboveground processing, which requires open pit mining and cooking the crushed rock in huge drums. Instead, they're looking at what's known as "in situ" — in place — processing, in which electricity is used to heat the underground rock slowly, while a "freeze wall" is built around the area to keep water out. Then wells are drilled to pump the oil.
Either way, the greenhouse gas emissions would be higher than conventionally produced petroleum-based fuels. They'd probably be roughly the same if nuclear power were used to convert the oil shale, Brandt said.
Brandt's research looked at oil-shale production with electricity powered by coal and natural gas. He found that over the full "life cycle" of the fuel — from its production to its combustion to power a car — fuels from oil shale produced greenhouse gas emissions that were 21 percent to 47 percent higher than those from conventionally produced petroleum fuels if the oil shale is heated underground, and about 50 percent to 60 percent higher if it's mined and heated aboveground.
By comparison, fuel from the oil sands of Alberta, Canada, has greenhouse gas emissions from "well to wheels" that are about 15 percent to 20 percent more than conventionally produced petroleum fuels.
When only fuel production and transportation is examined — not the use of the fuel in a vehicle — oil shale and oil sands produce several times more greenhouse gas emissions than conventionally produced petroleum fuels do.
Most emissions are produced when the fuel is used to power a vehicle, regardless of where it came from.
"I think the proper way is to compare the total emissions," Brandt said. "The total insult on the environment."
Another environmental factor is water.
"If there's a deal stopper in here, it's probably the water," Brandt said. Oil shale processing would use large amounts of water, and it would produce toxic chemicals that would have to be isolated from drinking water.
The Argonne National Laboratory, part of the Department of Energy, analyzes greenhouse gas emissions from many kinds of fuels, including gas from oil sands and ethanol from various sources. Michael Wang of the lab's Center for Transportation Research said his team hadn't done an analysis of oil shale.
McClatchy Newspapers 2008