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Utah scientists, like their peers around the world, are grappling with ways to address global warming, a charge made more urgent by last week's authoritative report holding humans largely responsible for the problem.
University of Utah engineers and scientists are working to make coal a more environmentally friendly option for producing power. At Utah State University, a team hopes to turn substances such as pond scum into biodiesel.
One group is trying to make the best of the world's reliance on fossil fuels; the other anticipates a time when untapped parts of nature can be harvested to produce cleaner fuels. Carbon emissions from spent fossil fuel are singled out as the key culprit behind global warming in the report released Friday by the Intergovernmental Panel on Climate Change, which said humans are 90 percent likely to be driving global warming. The report predicts hotter temperatures and rises in sea level "will continue for centuries no matter how much humans control their pollution" but emphasizes that solutions must be sought regardless.
Environmental groups call for heavier use of renewable resources, such as solar and wind power, but no matter how you consider the future mix of power generation, coal appears poised to remain a player, said Adel Sarofim, a U. researcher who is part of the Clean Coal Center.
"You need coal in any scenario you look at today to solve the problem," he said.
Renewable energy can only go so far, added JoAnn Lighty, a U. researcher who oversees several research groups, including the Clean Coal Center. "We can't replace all of our fossil energy with solar power; that's not going to resolve the issue," she said.
Many environmentalists consider coal a dirty word, but its abundance and low cost may make it a bridge to future solutions. While gas and oil supplies dwindle, coal is projected to remain available for the next few centuries, Lighty said. Even if the U.S. somehow finds a way to eliminate coal power from the mix, other countries will persist and even expand its use.
Part of the U. team's goal is to find ways to sequester carbon dioxide, a major culprit in global warming. U. researchers have connections with industry and schools in China, with the goal of lessening that nation's effect on carbon emissions, said Jost Wendt, who is part of the U.'s Institute for Combustion and Energy Studies.
In traditional coal plants, carbon dioxide is released into the atmosphere, which contributes to the heating of the lower atmosphere. Available technologies turn carbon dioxide into a liquid that can be pumped deep underground for storage, Sarofim said.
The challenge is obtaining pure carbon dioxide that can be liquefied. Most coal plants use air to fuel the fires that burn the coal, but the output is a mix of nitrogen and CO2. Nitrogen cannot be turned into a liquid and is not easily removed from the exhaust product.
U. researchers want to create coal plants that use pure oxygen to fuel the fire, thus eliminating nitrogen from the output, Sarofim said.
In an industrial part of downtown Salt Lake City, a U. team is building a test boiler to determine the best method for adding oxygen to the burning process. The two-story, green metal cylinder is still under construction, and team members hope to fire it up in the coming weeks.
The U.'s test boiler could be installed in an existing coal plant to allow utility companies to store their carbon dioxide in saline aquifers deep underground.
This technology could also benefit China, which plans new coal plants, said Eric Eddings, another member of the U.'s Institute for Combustion and Energy Studies.
"It's very important that these developing nations be on board with whatever technology, or regulations, that the more-developed countries are having to withstand," he said.
Jingwei "Simon" Zhang, a doctoral student from China, helped build the prototype. He hopes to one day take this knowledge back to his homeland to help create more environmentally responsible power plants.
"In my country, people are using too much coal," he said. "This is a serious problem when it comes to pollution."
The U. researchers will meet with Chinese representatives in May in Park City to share knowledge about coal technology, including sequestration methods.
Storage of CO2 is only one of the potential uses for sequestration. One idea would be to pump the gas into deep coal veins, which are not feasible to mine, to force up methane, which can be used as a fuel. Carbon dioxide also can be pumped into oil wells to make it easier to raise the heavy oils that may remain.
Several groups are examining the Aneth oil field on the Navajo Reservation in southeastern Utah as a potential place to test sequestration technologies, storing carbon dioxide in old oil wells. While the U. team looks to coal as a bridge to the future, USU's team is working on a natural fuel source that could help replace fossil fuels.
But coal actually inspired part of USU's new Biofuels Initiative.
Byard Wood, who came to USU in 2003, had worked on an idea involving growing algae as a way to sequester carbon dioxide streaming from coal-fired power plants.
Algae, which grow by photosynthesis, need sunlight, carbon dioxide and nutrients to survive. Funneling the carbon dioxide to mass quantities of pond scum, or other algae, would prevent the carbon from finding its way into the atmosphere.
Eventually, Wood and others took this idea a step forward and realized that the right kind of algae could be farmed and eventually turned into a fuel known as biodiesel, an environmentally friendlier version of fossil-fuel-based diesel.
Pond scum and other types of algae could be grown and harvested to create a fuel that burns cleaner and puts out less carbon dioxide than regular diesels.
The process involves solar collectors-receivers that resemble shiny satellite dishes. Sunlight is concentrated and sent through fiber-optic cables, which can redirect the light, to reach the algae growing inside a nearby building.
As the algae reach maturity, they are washed off the screens and processed into a biofuel. That fuel can either power a turbine to create electricity or be used to fuel diesel cars and trucks.
These facilities, known as bioreactors, need a source of carbon dioxide. Wood said they could be placed near a coal plant or any source that emits carbon dioxide.
Competing sources of biofuel come from soy or canola oil. Assuming a climate that can yield two harvests a year, each acre of canola field can produce 280 gallons of biofuel.
Because the algae are grown on vertical walls, more product can be grown in each acre. Estimates are that 10,000 gallons of biodiesel per acre could be pulled from the right algae farm.
Right now, the key is to find algae that grow fast while having enough fat content to create biodiesel, he said.
An advantage to this process is that the algae can be grown on desert land that is often unsuitable for agriculture.
There is no question that the technology is there, but the team is taking a business-oriented approach to the problem, Wood said.
"It's gonna take us three to five years to really determine whether we can do what we want to do economically," Wood said. "We know we can do what we want to do technically."
Both Utah research groups are looking to a future when humans send less carbon into the atmosphere. Each team realizes that the projects will not solve the whole puzzle, but they hope they can contribute to the solution.
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* GREG LAVINE can be
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