By Gwen Bristol

The nation is wondering if clean coal technology is real.

With more than 50 percent of the country’s electricity coming from coal, it’s no wonder that the question has come up. In the past year, the issue has been visited by prominent media businesses, including Newsweek and CBS News. Recent television advertisements have pushed the idea that clean coal technology is a myth.

Chris Kling, public relations director of Ottertail Power Company, said there is no bright line defining clean coal technology. One definition by the EPA describes clean coal technology as a new generation of energy processes that reduce emissions from coal-fired power plants. Kling said Ottertail Power uses an IRS definition called ‘advanced coal base generation technology.’

In North Dakota, where abundant research and development for clean coal technology continues, questions are geared toward how to make current and upcoming technologies more economically feasible and reliable.

“Obviously there is such a thing as clean coal technology,” said John Harju, associate director for research with the Energy and Environment Research Center, located at the University of North Dakota. “Government investment in clean coal technology has been significant and sustained,” he said later.

North Dakota is making its own investments in clean coal technology. Private companies and government agencies are studying issues like carbon sequestration, coal gasification and coal drying. The end result could be that the state could plan for long-term coal usage while developing renewable fuels as well.

One of the hottest buzz phrases in the state associated with clean coal technology is carbon sequestration. According to Harju, this means reducing or offsetting carbon dioxide emissions.

There are two ways to do this. Terrestrial or indirect carbon sequestration means planting trees and other vegetation that use carbon dioxide. Geological or direct carbon sequestration captures carbon dioxide from man-made sources and stores it someplace else—usually underground.

While both methods work for keeping carbon dioxide out of the air, the geological method is most often associated with clean coal technology in North Dakota. Carbon dioxide is already captured from some fossil-fuel energy facilities in the state, and it appears that North Dakota is an ideal place for storing them, as well.

Harju said there are places in North Dakota where sedimentary rocks run 16,000 feet deep. Within these rock formations are layers of permeable and less-permeable stone. Oil can sometimes be found in the permeable rocks trapped between layers of less-permeable rock, but not always.

The permeable traps make terrific carbon sinks, or storage vessels for carbon dioxide. It’s possible that in the future, people in North Dakota could make money from allowing carbon dioxide to be stored in sinks below their land.

As an added bonus, inserting carbon dioxide into an oil field can extend the life of the oil wells. Carbon dioxide is used most often where production is dwindling and where other methods like inserting water into the wells have already been exhausted. The carbon dioxide makes the oil flow better, increasing the production of the wells.

According to Floyd Robb, vice president of communications and marketing support at Basin Electric, it’s a good situation for both oil companies and other energy companies that produce and capture carbon dioxide.

Robb said prior to the time Basin Electric had a market for carbon dioxide, the company incinerated it. In the late 1990s the company developed a contract with an oil company now called EnCana. The Canadian company uses the carbon dioxide to help get more oil out of oil fields that were developed in the 1950s.

“EnCana was seriously considering closing that field down because there was just no way to get more oil out of it,” Robb said. “Now that they’re injecting carbon dioxide they expect that those oil fields will be productive for at least another 20 to 25 years.”

Robb said Basin Electric sees western North Dakota, particularly with the development of the Bakken oil formation, as another potential market for carbon dioxide. Not everyone has the same feelings about the situation, though.

“A lot of the sequestration that people are talking about, especially in North Dakota is to help with oil recovery,” said Wayde Schafer, a spokesman from North Dakota’s Sierra Club. “How much are you really saving?”

Schafer pointed out that putting carbon dioxide into the earth to help bring another fossil fuel out to burn could defeat the purpose of sequestering it in the first place. Harju disagrees.

“Any oil that we would produce using sequestered carbon would certainly be a positive compared to oil produced without carbon dioxide,” Harju said.

The Sierra Club is a member of the Reality Coalition, a group of environmental organizations maintaining the viewpoint that there’s no such thing as clean coal. Besides producing a recent television ad supporting that claim, the coalition advocates switching from fossil fuels to renewable fuels as soon as possible.

“We should be getting off coal and putting our research efforts and dollars in renewables that we know won’t put carbon dioxide into the atmosphere,” Schafer said. “If we were talking about this ten or fifteen years ago, we would have had more time to maneuver. We just don’t have the time to be exploring sequestration and other clean coal technologies.”

Schafer said if the earth reaches a tipping point of about 450 parts per million of carbon dioxide in the atmosphere, a chain reaction could occur. Global thawing would release methane, another greenhouse gas that is currently stored in tundra areas buried beneath snow and ice.

Current carbon dioxide levels in the atmosphere sit at about 383 parts per million.

“We really need to be reducing it to about 350 parts per million,” Schafer said. “This is a global problem and we’re not alone, but we should be leading by example.”

According to Harju, developing clean coal technology is an investment that could buy some time to work on renewable energy issues.

“Clean coal technology provides a way of building our experience base and building an infrastructure that can be used as we move to a carbonmanaged future,” he said.

A third area where Reality Coalition members clash with proponents of clean coal technology is whether the carbon dioxide stored in geological sinks can stay put.

According to Harju, the fact that oil has been trapped in sinks for millions of years is one indication that carbon dioxide would stay trapped, too. Computer models run in the second phase of a three-phase research project for carbon sequestration, overseen by the Plains Carbon Dioxide Reduction (PCOR) partnership, back up that assertion.

Harju said that sequestered carbon dioxide would be under tremendous pressure and high temperatures, putting the gaseous compound into a supercritical phase where it would have properties of both a gas and a liquid. The computer models show that, in this state, carbon dioxide could be sequestered in geological sinks for “thousands of years to indefinitely,” Harju said.

“Every indication that we’ve gotten so far in the research is that the carbon dioxide stays there,” Robb said. “It forces the oil out but it stays in the formation.”

PCOR is just beginning the third phase of its efforts to develop carbon sequestration in a commercial scale demonstration project that partners with Basin Electric. PCOR will use about 1 million tons of carbon dioxide annually in its carbon sequestration field tests.

The carbon dioxide will be captured from Basin Electric’s coal-fired Antelope Valley power plant. Capturing carbon dioxide at a power plant and sequestering it in the ground could eventually pay off with big results both monetarily and environmentally.

Besides being able to sell captured carbon dioxide for enhanced oil recovery, the project could result in greater capabilities to capture carbon dioxide from a power plant and store it in the ground.

It’s a possibility that packs a lot of promise, especially if it could be combined with more efficient power plants than the state has seen in the past. Robb said comparing a coal-fired power plant built 50 years ago is like comparing an Edsel to a Porsche.

“The technology that is implemented today in a state-of-the-art coal based power plant is light years ahead of the technology that was implemented when the plants were originally built in the 50s or 60s,” he said.

Gasification processes are evolving, too. About seven different gasification technologies have already been developed, but they don’t all work with the same efficiency or the same kinds of coal.

“One of the problems that you run into is you hear people talk about gasification as sort of a one-size fits all technology,” Robb said, adding that what works for one kind of coal may not work for another.

Robb described how North Dakota’s lignite coal, high in sodium, doesn’t work in a transport gasifier technology that’s showing some promise. Another coal gasification facility in Florida works well at sea level but has problems because of pressure at higher altitudes.

“There are all kinds of technical issues that you run into when you’re trying to develop a new technology,” Robb said. “You’ll hear many people saying IGCC, Integrated Gasification Combined Cycle, is the future of coal. I think that it is, but it’s not here yet.”

GCC technology works first by using a coal gasification process to break the coal down to a low btu gas. The gas is then captured and run through a combustion turbine, which works like a jet engine. When the gas goes through the turbine, it creates electricity. Heat from the turbine is captured and used to generate steam that drives a second turbine.

That’s the combined cycle,” Robb said.

According to Robb, a study done by the Electric Power Research Institute (EPRI) shows that coal combustion with combined carbon dioxide capture could be commercially viable by 2020. By 2030, implementation could be broad.

It’s always a moving target,” Robb said. “It’s always getting better. We believe that the future of clean coal technology is technology itself.”

Technology can be applied to the coal as well as to the processes that burn it. Lyndon Anderson, North Dakota communications director with Great River Energy, said the company is adding four coal dryers to both of the two units at its’ Coal Creek power station.

Carbon dioxide emissions from coal that is refined in those dryers will be reduced by 4 percent. The refined coal has a 28 percent moisture content compared to regular North Dakota lignite, which contains about 37 percent moisture.

This means power plants burning refined coal will use about 10 percent less of the fossil fuel. According to a fact sheet published by Great River Energy, if power plants totaling just 10 gigawatts were using the coal drying technology on a lignite fuel, carbon dioxide emissions would be reduced by 3.4 million tons per year.

For the coal industry, it’s a step in a long walk to meet the highest clean air standards possible. It may not be completely clean coal yet, but it’s clean-er, and it’s one way the state can tell the country that clean coal technology isn’t just a myth.

“Although you may feel that we are at odds all of the time, the fact is that we both have the same goal, and that is eventually to have a coalbased facility that has zero emissions,” Robb said. “The debate is on how we get there and how quickly we get there.”