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Coal-Fired Power Remains Most Polluting
So-called clean coal technology still years away
The combination of higher fuel costs and restricted pipeline space has conspired to temper enthusiasm for building new natural gas-fired power plants, the technology of choice for new generation in the Northwest for more than ten years. And while the count of proposed gas burners continues to climb, the number that eventually get built may be limited not by demand for electricity, but by access to competitively-priced gas.
Conservation and renewable energy proponents believe the forces limiting potential development of new gas plants should be driving the Northwest down the clean energy path. And the boom of proposed wind facilities in the region is ample evidence of this effect. But deterrents to gas plant development are also fuelling renewed interest in coal-fired generation which remains the most polluting way to produce electricity. "There's a happy middle here where gas prices are high enough to bring a lot of new wind power online but not so high as to open the door to more coal," said Phil Carver , senior policy analyst with the Oregon Office of Energy .
Portland -based PacifiCorp , which has electric customers in six western states, including Washington and Oregon, is considering plans to expand its coal generation capacity by as much as 2,000 megawatts. Under the Western Governors Conceptual Western Transmission Plan , the company would add that capacity in southwest Wyoming and Utah using Best Available Control Technology (BACT ).
BACT or "new" coal technology produces roughly 75 percent less sulfur dioxide (SO2) and nitrogen oxide (NOx) than the current average for all coal generation in the U.S. which is dominated by old coal technology (see chart on page 2 for emissions comparisons).
But new coal plants offer little benefit in the form of reduced carbon dioxide (CO2) emissions over their old coal counterparts. And they still produce 700 times as much SO2 and 13 times as much NOx as high-efficiency gas-fired generators. The sulfur content of coal does affect the amount of SO2 emitted by old coal-fired generators, but makes no appreciable difference in BACT plants. New coal cleaning technology hasn't yet proven effective at removing mercury.
Beyond BACT is so-called "clean" coal technology. Despite receiving $2.75 billion of taxpayer-funded research since the early-1980s clean coal is still entrenched in the design phase and is years away from being competitive with established fossil fuel and other conventional generation.
The Wall Street Journal reported in May that not a single commercial order has been placed for a plant using Integrated-Combined Cycle (IGCC ) technology, the clean coal process which chemically converts coal to a synthetic gas for use as a boiler fuel. "There have been a lot of experiments with gasification but it's just never been very economic to do it," says Tony Usibelli , senior policy analyst with the Washington Office of Trade and Economic Development .
The potential environmental gains IGCC technology offers remains questionable. Polk County , Florida-based Tampa Bay Electric Co . built an IGCC plant with $140 million worth of help from U.S. Department of Energy . And while the Tampa facility does emit less SO2, NOx and particulate pollution than a conventional coal-fired generator, it doesn't cope any better with mercury or CO2 emissions.
The West Coast energy crisis has intensified the debate over how much the U.S. should turn to its most abundant fossil fuel and prompted a new look at the relative impacts of different coal generation technologies. Mining, exploration, transportation and refinement of coal also remain controversial those impacts are tallied in a recently completed study by the Boston-based Clean Air Task Force , From Cradle to Grave: The Environmental Impacts from Coal .
Critics charge that despite some advances, coal technology remains essentially a relic of the 19th century. A coal-fired power plant built today will release less of some dangerous pollutants but poses the same health and environmental threats as a plant built 30 years ago.
Mark Glyde