A cleaner source of coal power

A cleaner source of coal power

The new, cleaner coal technology “integrated gasification combined-cycle” – better known as coal gasification – holds promise as part of Wisconsin’s next generation of baseload power plants, a state report concludes.

The Department of Natural Resources and the Public Service Commission have been studying coal gasification, which is being pushed by environmentalists but has elicited a generally wary response from utilities, since 2005. The report is a final version; a draft was released last June 1.

Gasification uses high pressure and temperature to transform coal into a gas prior to combustion. The gas can be cleaned of pollutants prior to firing in a turbine. Conventional coal technology burns coal in a boiler, and pollutants must be stripped out after combustion in the exhaust, which is an expensive and difficult process. Gasification also results in lower emissions of sulfur dioxide, which contributes to haze, acid rain and the formation of fine particulate pollution.

The report shows that if Congress enacts legislation limiting carbon dioxide emissions from power plants, the cost of electricity generated from a gasification plant is competitive with the cost of electricity produced from conventional coal plants. Carbon dioxide is the primary greenhouse gas and is emitted mainly from power plants and automobiles.

“Controlling carbon dioxide is the wild card in this analysis,” Al Shea, DNR air and waste administrator and co-chair of the study group, said in a statement. “Both in terms of our understanding of technology options and federal regulations – these factors have the potential to change the draft results dramatically.”

Utilities such as Alliant Energy see gasification as a risky investment that increases plant construction costs. The utilities have said that emissions and performance of experimental gasification plants have failed to meet consistent standards.

The report notes that there are just two coal gasification plants in the country and the technology still is experimental, so it may not be financially feasible for one utility to take on the costs of constructing a coal gasification power plant in Wisconsin.

Alliant’s Wisconsin Power & Light Co. unit announced last April plans to ask state regulators for permission to build a 300-megawatt coal-fired power plant at its Nelson Dewey Generating Station in Cassville. The company rejected gasification, instead choosing to feature “circulating fluidized bed” technology that can burn many different fuels, including renewables such as dedicated energy crops, woody biomass, agricultural waste, and paper production waste.

The report also found that Wisconsin is not rich in sites to store the carbon dioxide that is captured in the coal gasification process, so transportation options to viable storage sites would probably need to be developed.

PSC commissioner Mark Meyer, who served as co-chair of the study group, noted that baseload power plants are long-term investments that will serve for 50 years.

“The investment has to make sense for ratepayers and fit into future environmental strategies to contain carbon,” Meyer said.

DNR Secretary Scott Hassett said global warming is at the “forefront” of what the agency is doing.

“What we do to combat global warming makes a difference,” Hassett said in a statement. “Under Gov. Doyle’s leadership, Wisconsin is moving forward in developing new technologies and investing in renewable energy. This report is another resource we can use in our efforts to curb global warming.”

The report is available at: http://psc.wi.gov/CleanCoal/comments.htm.

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