Environmental Protection

Burden Index Weighs Coal-fired Plant GHG Reductions

Coal-fired power plant operators can make substantial reductions in actual greenhouse gases and huge reductions in other emissions, according to a report, "Power Plant Environmental Burden Analysis," by McIlvaine Company. Operating costs would be reduced while the cost of electricity and life cycle costs would not increase. The large investment to accomplish this would greatly boost the U.S. economy.

Robert McIlvaine, president of the company, said, "We do not have to wait until CO2 capture technologies are commercialized. CO2 and other equivalent emissions can be reduced 85 percent with a low-cost but innovative holistic approach. By adopting the European strategy of replacing old coal-fired plants with new efficient ones, we can have our cake and eat it too: a better environment and a better economy and no rise in electricity cost."

The concepts of eco-efficiency and sustainability require the assignment of numerical values to a range of environmental burdens. McIlvaine has created an index that includes a range of air pollutants and greenhouse gases. Most decisions to reduce air pollutants result in greenhouse gas increases. The energy required to remove NOx from stack gases results in added electricity consumption and, therefore, increased CO2 emissions. The reverse is occasionally true as well. Increases in particulate emissions will lead to global cooling. However, the harm caused by the increased particulate emissions would far outweigh the greenhouse gas benefits.

All air pollutants have been numerically equated based on the burden (harm) they cause. Air toxics have been ranked based on the U.S. Environmental Protection Agency's draft "Lesser Quantity Emission Rate (LQER)." NOx, SO2, and particulate have been ranked based on a variation of the LQER. This equates particulate with the most benign toxic and equates NOx and SOx at 1/10 the most benign toxic.

Present total emissions from U.S. coal-fired plants for all pollutants have then been quantified based on their actual emissions in tons multiplied by the environmental burden index.

Environmental Burden In Millions of Tons For U.S. Coal Plants CO2
CO2 value at $20/ton
CO2 value at $10/ton
Pollutant
Percent emissions
Best present cost-effective technology
Cost-effective holistic approach
Present emissions
Bes present cost effective technology
Cost-effective holistic approach
CO2
2,000
1,400
840
1,000
700
420
Particulate
1,000
100
95
1,000
100
95
SO2
900
30
28
900
30
28
NOx
400
40
38
400
40
38
Mercury
500
25
25
500
25
25
Air Toxics
500
25
25
500
25
25
Total
5,300
1,620
1,051
4,300
920
631
Reduction
69%
80%
79%
85%

Actual CO2 emissions are less than two billion tons, but the burden of other emissions is 3.3 billion tons when CO2 is valued at $20/ton. Since NOx trades at $2,000/ton the burden of a ton of NOx is assumed to be 100x that of a ton of CO2.

European coal-fired boilers routinely replace up to 15 percent of the coal with biomass. Several plants make byproduct hydrochloric acid. One coal plant in the United States will achieve 66 percent equivalent thermal efficiency by providing the waste heat to make ethanol. This holistic approach is low in cost and immediately employable. It would reduce the environmental burden by 80 percent. An additional capital investment of $200 billion would be needed for this holistic approach, bringing the total investment requirement to $650 billion. The reduced coal consumption, reduction in operating costs, and sale of byproducts would offset the depreciation increases.

Coal plants using the best available control technology can burn waste with lower net emissions than dedicated waste combustors. Gasified chlorinated waste injected above the primary firing zone in coal-fired boilers reduces NOx and oxidizes mercury. This soluble mercury compound is then efficiently captured in the SO2 scrubber.

These benefits are based on a trading value of CO2 at $20/ton. Early programs in the U.S. are pegging allowances at $3/ton. With this value, the environmental burden reduction would be more than 90 percent. Even at $10/ton, there would be an 85 percent burden reduction.

More information on this analysis is available in the McIlvaine publication "Power Plant Air Quality Decisions." A comprehensive analysis will be provided in the soon to be released Power Plant Greenhouse Gas Decisions. To learn more about these services click on www.mcilvainecompany.com.

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