LATROBE VALLEY, Australia -- Oct 10 - McClatchy-Tribune Regional News - Laurie Goering and David Greising Chicago Tribune

Beneath the rolling green hills of Australia's Latrobe Valley lies a deposit of brown coal so enormous it seems almost endless. After nearly a century of mining, more than 95 percent of the 35-mile-long, 600-foot-deep coal seam is still in place, ready to fuel Australia's energy needs for generations.

But burning brown coal produces vast amounts of carbon dioxide, the major culprit in global warming. So Australia is trying out an ambitious idea: capturing carbon dioxide emissions and pumping them into storage in natural reservoirs below ground.

Carbon storage has been experimented with for more than a decade. But the Latrobe Valley effort under development would dwarf all existing projects. Its scale is a reflection of the dramatic global need to find clean ways to continue using coal.

In a world in which more than 80 percent of energy comes from fossil fuels, finding a way to catch greenhouse gas emissions and lock them away permanently could dramatically reduce climate change. The International Energy Agency says the technology, if proven effective, could provide 15 percent to 20 percent of the total greenhouse gas cuts needed worldwide to stabilize the climate, making it potentially a more important contributor than any other technology.

Just as important, underground storage would allow nations that depend on major coal deposits, among them the United States, China and Russia, to continue burning coal, dodging both economic slowdowns and criticism for wreaking environmental havoc.

On Tuesday, the U.S. Energy Department committed $197 million over 10 years to three new carbon-storage projects around the country, in what it called a significant step in developing a new tool against global warming. A project based in Illinois is among four expected soon to receive commitments for an additional $250 million in government funding.

Scientists are trying to determine whether carbon dioxide emissions can be safely and effectively locked away underground for thousands of years. Complex issues of ownership and liability for storage sites remain to be worked out. But governments, corporations and environmentalists are all pushing ahead to explore what could be one of the biggest technological means to stem global warming.

"If it works, it will be very, very, very big. It has massive potential," said Greg Bourne, head of the Australia office of the World Wildlife Fund, which has in recent years made finding ways to slow climate change a key part of its environmental mission. "It's a big solution."

Around the globe, businesses, governments and people are searching for solutions to the vexing problems presented by climate change. One of the most promising is carbon sequestration, the process of injecting carbon dioxide emissions, usually from power stations or industrial plants, into permanent storage, mainly in depleted oil or natural gas fields or salty aquifers at least a half-mile underground.

The technology is at the same time revolutionary and common. Since the late 1970s, oil and natural gas companies, trying to boost output from wells, have tapped into naturally occurring deposits of carbon dioxide and then pumped the gas into their oil and gas fields, where it helps strip oil from rocky deposits and bring it to the surface. Texas alone has more than 1,500 miles of carbon dioxide pipelines stretching across the state to boost oil recovery at its wells.

Pumping carbon dioxide underground as a way to reduce concentrations in the atmosphere is a newer idea. But Norway's state oil company, faced with paying a tax on its carbon dioxide emissions, has since 1996 injected about a million tons of the gas each year into storage in a reservoir below the North Sea. Similar small-scale projects are under way in Algeria and on the U.S.-Canada border, and scientists are studying how to make central Illinois a major focus of U.S. efforts to sequester carbon dioxide.

Australia, a coal-rich nation of just 21 million people, is fast becoming an international leader in carbon sequestration. The country is among the most advanced in the complicated process of developing legislation to license and monitor storage facilities, and is home to four of the world's largest proposed demonstration and commercial-scale storage projects, more than any other country.

The biggest is in the Latrobe Valley, where a joint venture of mining giant Anglo American and Shell Oil company aims to begin turning brown coal into high-quality diesel fuel and then pumping the carbon dioxide produced into a vast and increasingly depleted oilfield 50 miles offshore in the Bass Straits that separate mainland Australia from Tasmania.

The proximity of the massive coalfields and the big oil field, considered a top potential carbon-storage site, means the companies should be able to sequester 50 million tons of carbon dioxide a year, making it the biggest project in the world.

Scientists believe the Bass Straits reservoir is so big it could permanently capture between 2 billion and 6 billion tons of carbon dioxide, the equivalent of all of Australia's greenhouse gas emissions from every man-made source for the next five to 15 years, or the world's production for up to a year.

"It's world-class," said Scott Hargreaves, a spokesman for Monash Energy, the Anglo-Shell joint venture. The vast sandstone reservoir, more than a kilometer below the ocean floor, "stored oil and gas, so, all things being equal, you should be able to put something else down there," he said.

Promising as the idea may be, the technological risks of storing carbon dioxide are sizable too. The gas, which becomes a fluid when under pressure below ground or in a pipeline, is acidic and can in high concentrations cause asphyxiation. In 1986, volcanic activity under Lake Nyos in the African nation of Cameroon released a geyser of naturally occurring carbon dioxide. A 150-foot-high cloud of the gas poured down into populated valleys near the lake, killing more than 1,700 people in a matter of hours.

Small leaks of carbon dioxide, the same gas used to put bubbles in soft drinks, present no real health risks, experts say. But scientists say any potential storage site, which would hold vast quantities of the gas, must be meticulously studied to rule out risks from geologic faults, seismic activity or breaches in the top sealing layer of rock and clay that could allow concentrated carbon dioxide to escape.

At the Weyburn oil field in Canada's Saskatchewan province, workers since 2000 have been injecting carbon dioxide piped from a synthetic fuels plant in North Dakota, both as a way of improving oil output and testing the soundness of carbon-storage technology. One big worry there is whether injected carbon dioxide might leak, like helium from a balloon, from any of 720 oil wells drilled through the shale rock that seals the oil reservoir.

"It was a good container before the wells," said Ray Knudsen, director of an $80 million, eight-year study to monitor the movement of below-ground carbon dioxide, an effort carried out at Weyburn by the Petroleum Technology Research Centre, a consortium funded by oil companies and the U.S. and Canadian governments. "What will it be like after we walk away from it? We need to know where the CO2 is going to be in 30 years or so and predict where the CO2 is going to be over several hundreds of thousands of years."

Australia's Bourne, a former British Petroleum executive, believes any hint of leakage should rule out a site as a potential storage reservoir.

"You can't talk about 1 percent escape," he said. "It's either all down there for a million years or it's not." That said, if sites are well chosen, "you can put it down and keep it down there for all geological time. I have no doubt about that," he said.

In the search for places to sink carbon dioxide emissions, researchers have looked first at the places they know best: depleted oil and gas fields. The fields, intensively studied during years of exploration and pumping, are the most attractive potential storage sites because their geology is well known, they successfully contained oil and gas reserves for millions of years, and scientists generally have an idea of how much gas or oil came out, giving some indication of how much carbon dioxide might fit in.

Injecting carbon dioxide into the fields is roughly the reverse of pulling out oil: Pressurized gas, which becomes a fluid, flows into the pores of rocks that once held oil or natural gas. Over time, and depending on the geology, scientists say, some of the fluid may react with minerals in the rock to form a stable solid, some of it may dissolve into salt water within the formation, and some may pool below the solid cap rock that isolates the reservoir.

Scientists say decades of close monitoring of the process will be crucial to ensuring that reservoirs aren't overfilled, creating pressure that could break the seal. But most potential storage fields are so vast, and the projected rate of injection so relatively small, that the projects will be the equivalent of pumping air into a massive tractor tire with a bicycle pump, Bourne said.

That is particularly true of what may be one of the biggest possible storage sites in the United States, the St. Simon aquifer, which covers vast tracts of central Illinois. The U.S. Department of Energy, which has picked the site for one of its seven carbon-storage projects, believes the salty reservoir, more than two miles below ground and up to a half-mile thick, could hold up to 109 billion tons of carbon dioxide, enough to store all of the country's carbon dioxide emissions for 100 years.

Perhaps the hardest part of sequestering carbon is creating a regulatory framework to do it, and then finding someone to pay for it. Few countries outside of Europe tax emissions of carbon dioxide, which means power plants, industrial facilities and drivers of cars, trucks and other vehicles pay no price for emitting the gas and have no incentive to pay the cost of capturing and storing it.

Australia, however, like a growing number of countries, is making plans to enact a carbon tax aimed at cutting greenhouse gas emissions. Once that happens, companies will have a financial incentive to pay firms like Monash to help them catch and store their emissions. For now, though, governments and industry giants like Anglo and Shell are footing the hefty bills to prove the technology.

For Shell, "it's an opportunity to get in at the ground floor of what could be a huge technology for the 21st Century," Hargreaves said.

An equally difficult part is regulating the technology. Many nations, including Australia, are writing guidelines for carbon capture, storage and monitoring into oil industry legislation, since the two industries often use the same fields and are so closely linked.

Australia is expected to pass its first national laws governing offshore carbon sequestration within three years, putting rules in place before the Monash project would begin operating. Several of its provinces have passed rules for onshore storage, which in Australia is regulated under state law.

But legislators in Australia and elsewhere are still struggling to decide major issues, including what are appropriate monitoring processes for carbon storage, how to handle turnover of ownership of the would-be reservoirs from oil companies to carbon storage firms, and, crucially, who would be financially liable if something goes wrong over the multithousand-year life of the facilities.

"Governments will have to come to terms with the reality that industry of this scale won't happen without [financial] help," said Roger Bounds, a Shell Oil official acting as director of the Monash Energy project. Trying to get market financing for pilot projects is "very hard," he said, and government willingness to assume much of the liability risk will be crucial to making large-scale carbon storage a reality.

Australia's government, well aware that its energy security and economic well-being depend on being able to continue mining coal at places like the Latrobe Valley, has been largely supportive of carbon capture and storage efforts. Australia's Cooperative Research Center for Greenhouse Gas Technologies, funded by government and industry, is a leader in carbon-storage research and in August won state Environmental Protection Agency approval to begin injecting carbon dioxide into a depleted natural gas field in Victoria province, a test that should get under way before the end of the year.

In the U.S., the federal government's involvement in seven regional research projects is not its only sequestration effort. An additional focus is FutureGen, a $1.5 billion project to develop a plant to convert coal into gas, use it to produce power, and store the carbon dioxide emissions below ground. Tuscola and Mattoon in Illinois are among four finalists vying for the plant.

Carbon-storage technology is so new and vaguely understood by the public that little in the way of grass-roots opposition has emerged.

Environmentalists are divided on the technology. Some fear potential catastrophic failures and argue there is little way to accurately test whether carbon dioxide can be safely held underground for thousands of years. But many others, including big environmental groups such as the World Wildlife Fund, appear increasingly eager to embrace sequestration as a key to holding the line on climate change and preventing other sorts of resulting worldwide environmental disasters.

The more worrisome opposition, at least in Australia, may come from the oil companies that own the rights to oil fields envisioned as storage sites. Exxon Mobil, for example, which operates the Bass Straits oilfield that Monash Energy hopes to take over, has been reluctant to consider turning over the field, insisting it holds massive usable reserves. That opposition may prove a major obstacle in Monash's efforts to get its carbon-capture and storage facility in commercial operation, a process company officials hope will take about 10 years.

Climate-change scientists say the key to proving the technology and sorting out its issues, from liability to ownership, is to get many small-scale test projects functioning around the world as quickly as possible. Effectively battling climate change, they say, will require finding as many kinds of solutions as possible, from conserving energy to growing renewable fuel, then rapidly putting the most effective of them into large-scale operation around the world.

"If [carbon sequestration] is going to work, it's going to be amazingly important from a technology and environmental point of view, and we need to know that quickly. And if it's not going to work, we need to know that even more quickly," Bourne said. "If wind [power] fails, it's a relatively small part of the solution. If solar fails, it's a relatively small part. But if carbon sequestration fails, it's a real problem."

lgoering@tribune.com

dgreising@tribune.com