March 29, 2009

MSU part of $79 million study on storing greenhouse gases emissions underground

By KARL PUCKETT
Tribune Staff Writer

BOZEMAN — Lee Spangler holds up a small sandstone rock that he says could suck up carbon dioxide like a sponge.

Rocks like this could play an important role in the fight against climate change, he says. At the same time, the technology could help out the coal industry, one of the biggest emitters of CO2.

"That's where you put the CO2, in something that feels like solid rock," said Spangler, a physical chemist who runs Montana State University's Energy Research Institute in Bozeman.

Spangler heads the Big Sky Carbon Sequestration Partnership, which is studying the viability of storing liquefied CO2 from industrial facilities such as coal-fired power plants in porous rocks thousands of feet below the surface in Montana and five other Western states.

Sequestration is not putting CO2 in underground caves, a common misperception, he says. Invisible holes in rocks are the storage grounds.

"It's important to look carefully to see if this can be part of the solution," Spangler said. "Right now, I would say the evidence is pretty good that it could be."

Since 2003, $79 million in federal funds have poured into the U.S. Department of Energy-backed sequestration project, which involves mapping potential sequestration sites and CO2 sources and conducting tests on how well rocks will trap the pollution indefinitely. MSU's is one of eight regional sequestration research efforts nationwide.

The technology isn't ready for prime time but large-volume test injections of more than 1 million tons are in the works.

4 millions tons of CO2 a year

As a rule, a 500-megawatt coal-fired power plant produces about 4 million tons of CO2 a year.

"I think everybody agrees carbon sequestration is not a silver bullet," said John Talbott, deputy director of the Big Sky Carbon Sequestration Partnership. "It's a temporary solution to a long-term problem."

Worldwide, an estimated 31 billion tons of man-caused CO2 are emitted each year, up from an insignificant amount 200 years ago. The United States accounts for about 7 billion tons of the total.

The CO2, along with other so-called greenhouse gases, acts like a blanket and absorbs sunlight radiating off the Earth's surface. Most scientists believe it is accelerating climate change.

In the long run, cleaner cars and power plants are needed to reduce global warming emissions, Big Sky experts say.

But they add that CO2 storage is a way to stabilize CO2 already in the atmosphere while serving as a bridge to the future.

The DOE estimates coal will continue to dominate power generation for the next 25 years in the United States and longer in the developing world because it's cheap and abundant.

"To get to your end goal, and not have a big economic impact, you have to look at things that make coal more climate friendly," Spangler said. "And that would be sequestration."

MSU is ground zero for the Big Sky research, where 15 employees coordinate projects by universities, national laboratories, private companies and others in Montana, Wyoming, Idaho, South Dakota and eastern Washington and Oregon.

The goal is to develop technologies by 2012 for safe and cost-effective long-term carbon storage.

"You may get people who run cement plans and power plants contracting with other people to dispose of it," Spangler said.

Companies with subsurface experience, such as oil and gas companies, are likely to jump into the sequestration business, he said.

Montana has a lot of coal

Montana, which has 6 percent of the world's coal reserves, has a lot riding on the outcome of the research.

Of the total CO2 emissions in the Big Sky Partnership region, 81 percent, or 107 million tons, comes out of the stacks at coal-fired electric generation facilities. Facilities in Montana and Wyoming account for 70 percent of those emissions.

Federal carbon regulations are looming that would penalize the industry for emitting greenhouse gases, possibly through a "cap-and-trade" system.

"There's a very large storage capacity in our region that can definitely handle storage for a very long time," Spangler said.

The region's stationary sources of CO2 — cars are non-stationary emitters — produce an estimated 131 million tons of CO2 a year.

The partnership estimates the region's saline formations alone, which are located below 750 million acres in the six states, including large swaths in Montana, could hold 441 billion tons of CO2.

Research is focusing on how CO2 will migrate and react in certain kinds of rock formations after it's injected into the ground via wells.

Groundwater contamination and the leaking of gas through existing wells are concerns. So is the reaction of the CO2 with some kinds of minerals in the ground.

CO2, which results when oil and coal are combusted, can react to minerals in the ground when it's injected.

"If you pick the sites properly, you will not have these issues," Spangler said.

"Just in case" and monitoring technologies are in the development stage, Spangler said.

One potential bad reaction would be dissolved rock. One pilot test, however, has shown that injecting CO2 into basalt rock can produce more rock, a good sign.

"If it turns to rock, it's not going to cause other issues," Spangler said.

A small-scale CO2 injection test into basalt formations is now under way in southeast Washington to see if the reaction in the lab will be replicated on a larger scale. Basalt is common in the Pacific Northwest.

The 750 million acres of saline formations below the six-state region also offer potential as storage sites because they have layers of porous rock, which is saturated with salty water.

Shelby area formations ideal

The Kevin Dome near Shelby is an example.

Ideal reservoirs not only have porous rock layers but also connected pores allowing the gas to migrate throughout the formation, experts say.

These spongy layers of sandstone also need impermeable layers of cap rock such as shale, which prevents CO2 from escaping, said David Bowen, a MSU geologist who serves as the partnership's geologic team leader.

"You want it to migrate up and hit that cap rock," he said.

At the Kevin Dome, Big Sky researchers have discovered that large volumes of naturally trapped CO2 have existed naturally for millions of years 4,000 feet below the surface.

Since it hasn't escaped, the dome is potentially an ideal CO2 injection site, Bowen said.

Other attractive locations are oil and gas reservoirs in Wyoming and Montana, such as the Sweetgrass Arch in north-central Montana.

Montana alone has more than 500 oil and gas fields.

"You're getting economic benefit from capturing and storing the C02," said State Geologist Ed Deal, director of the Montana Bureau of Mines and Geology, which has studied sequestration sites for the governor's office.

Injecting CO2 helps liberate the oil from the rock, he said.

"We're not dealing with technologies that are completely, radically new," Bowen said.

MSU got $67 million grant for test

Recently, MSU received its biggest grant yet — $67 million over 10 years — to launch its biggest test: Injecting up to 3 million tons of CO2 from a Cimarex Energy gas processing plant in southwest Wyoming 11,000 feet into sandstone.

The $67 million grant was the largest research grant ever awarded to any institution in Montana, Spangler said. "You couldn't do this work without a large budget," he said.

The commercial-scale test will involve drilling, injecting and monitoring wells.

With an existing pipeline in the area, the CO2 will then be shipped to oil fields where it will be injected to enhance oil recovery.

The idea behind carbon storage is to locate potential "sinks" near the CO2 sources, such as the Colstrip-fired coal plants in Montana, to minimize transportation costs, Bowen said.

"What you would like to do is find a number of these regional sites," he said.

The Wyoming test area underlies 1,000 square miles. The layer of sandstone where the gas will be injected is 550 feet thick. The cap rock above it is 75 feet thick.

If other layers in the formation were tapped as well, it's estimated that the site could potentially store 50 billion tons of CO2, Spangler said.

That would be seven year's worth of storage for the United States or 100 year's worth for the region.