ERMUSR Misc Notes 04-11-2006 - Laserfiche WebLink

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U.S. ELECTRICITY GENERATION COAL NUCLEAR NATURAL GAS RENEWABLES OIL U.S. POWER PLANT COZ EMISSIONS coAL _ F NATURAL GAS OIL WHAT'S IN COAL SMOKE? SULFUR DIOXIDE NITROGEN OXIDES MERCURY CARBON DIOXIDE PARTICULATES The sulfur in coal forms this gas which The heat of power- plant burners turn The traces of mercury i l Coal produces more Particles from coal- , gives rise to acid rain s nitrogen from the n coa escape in power-plant exhaust. COz per energy unit than any other fossil burning plants can harm people who when it reacts with air into nitrogen Falling hundreds of fuel. COz is a green- have heart and water in clouds. Many plants control sulfur oxides, which can contribute to acid miles away in rain house gas, affecting breathing disorders. emissions by burn- rain and ground- or snow, the mer- curt' builds up in climate by trapping heat that would Soot and ash are captured before ing low-sulfur coal and passing the ex- level ozone. Pollution t l fish, making some otherwise escape to they go up the stacks, haust through scrub- con ro s on many plants limit nitrogen species unsafe for children and preg- space. Power plants today release all but finer particles can form later from tiers, which capture sulfur dioxide oxide emissions. Want women to eat. their COz into the , oxides of sulfur . atmosphere. and nitrogen. studies carbon dioxide management at Lawrence Livermore National Laboratory. But a new kind of power station could change that. A hundred miles up the Wabash River from the Gibson plant is a small power station that looks nothing like Gibson's mammoth boilers and steam turbines. This one resembles an oil refinery, all tanks and silvery tubes. Instead of burning coal, the Wabash River plant chemically trans- forms it in a process called coal gasification. The Wabash plant mixes coal or petroleum coke, acoal-like residue from oil refineries, with water and pure oxygen and pumps it into a tall tank, where a fiery reaction turns the mixture into a flammable gas. Other equipment removes sulfur and other contaminants from the syngas, as it's called, before it's burned in a gas turbine to produce electricity. Cleaning the unburned syngas is cheaper and more effective than trying to sieve pollutants from power plant exhaust, as the scrubbers at a plant like Gibson do. "This has been called the cleanest coal-fired power plant in the world," says Steven Vick, general manager of the Wabash facility. "We're pretty proud of that distinction:' The syngas can even be processed to strip out the carbon dioxide. The Wabash plant doesn't take this step, but future plants could. Coal gasification, Vick says, "is a technology that's set up for total COz removal:' The carbon dioxide could be pumped deep underground into de- pleted oil fields, old coal seams, or fluid-filled rock, sealed away from the atmosphere. And as a bonus, taking carbon dioxide out of the syn- gas can leave pure hydrogen, which could fuel a new generation of nonpolluting cars as well as generate electric power. The Wabash plant and a similar one near Tam- pa, Florida, were built or refurbished with gov- ernmentmoney in the mid-1990s to demonstrate that gasification is a viable electricity source. Projects in North Dakota, Canada, the North Sea, and elsewhere have tested the other parts of the equation: capturing carbon dioxide and seques- tering it underground. Researchers say they need to know more about how buried carbon dioxide behaves to be sure it won't leak back out-a potential threat to climate or even people. But Friedmann says, "For a first cut, we have enough information to say, `It's a no-brainer. We know how to do this: " Yet that's no guarantee utilities will embrace the gasification technology. "The fact that it's proved in Indiana and Florida doesn't mean 102 NATIONAL GEOGRAPHIC MARCH 2006 souaceerveacv wFOaMnnoN nommisrannoN, ooe. NCm War