Power plants that burn wood to produce electricity emit comparatively more pollution than modern coal-fired power plants, according to a group that advocates tougher rules on the growing biomass-power industry.
The issue is relevant in Kentucky because of a proposed wood-burning power plant near Hazard, called ecoPower Generation, the state's first.
In a study released early Wednesday, the Massachusetts-based Partnership for Policy Integrity said wood-fired plants are not as clean as advocates claim, putting more carbon dioxide and other pollutants into the atmosphere than coal or natural-gas plants when judged on the ratio of pollution to energy produced.
For example, biomass plants emit nearly 50 percent more carbon dioxide — which traps heat in the atmosphere — per megawatt hour of electricity produced than coal plants, the study concluded.
One reason is that wood doesn't burn as hot as coal, so the same level of emissions produces less power. Another is that wood contains a lot of moisture, so it is a less efficient feedstock than coal or gas.
The study also said loopholes in regulations governing biomass plants mean lax controls on what goes out their smokestacks, even though they emit many of the same pollutants as fossil-fuel plants, according to the study by Mary S. Booth, director of the Partnership for Policy Integrity.
"What emerges from our analysis is a picture of an industry that despite loudly and continually proclaiming itself clean and green, is in many respects still one of the dirtiest corners of the energy industry, an industry where avoidance of pollution restrictions is tolerated, and even encouraged, by state and federal regulators," the report said.
The proposed ecoPower plant in Perry County would burn low-grade logs and waste from sawmills to produce enough electricity for 30,000 homes.
Company executive Gary Crawford did not return a call Tuesday, but the ecoPower website says it would provide a market for low-quality timber — making room for higher-quality trees to grow — and would be environmentally friendly.
Burning wood to make power means no net increase in carbon dioxide in the atmosphere because the trees soaked up carbon while they were growing, advocates say, though critics argue it takes decades for that cycle to even out, if in fact it ever does.
Acting under a state law designed to favor ecoPower, the state Public Service Commission approved a request by Kentucky Power last year to buy the company's electricity even though it would be relatively expensive, potentially adding about more than $100 annually to the bill of the average residential customer..
Backers say the project would provide jobs during construction and about 30 permanent jobs to run the plant, as well as jobs in associated industries.
The report released Wednesday singled out the ecoPower plant as an example of lax regulation.
The plant and scores of others across the country have been allowed to use industry standards in estimating their emissions of hazardous air pollutants such as hydrochloric acid, rather than using standards approved by the U.S. Environmental Protection Agency.
The industry standard significantly underestimates hydrochloric acid emissions, according to Booth's report.
The report alleged that ecoPower went a step further — that it "invented" its own standards to estimate total emissions of hazardous pollutants. Its level of emissions would have been higher even using the suspect industry standards, the report said.
Booth said in an interview she is skeptical that many biomass plants will actually emit a low enough level of pollutants to be considered minor sources, and that there are no enforceable limits on hazardous emissions in many permits.
John Lyons, the assistant secretary for climate policy at the state Energy and Environment Cabinet, said the permit Kentucky issued to ecoPower was designed to adequately protect air quality. He was head of the Division for Air Quality during the state's review.
Lyons said state regulators often consider pollution estimates submitted by industry in vetting permits, but don't use them if they're not valid.
The permit for ecoPower requires the company to test to make sure it does not exceed limits for sulfur dioxide and other major pollutants, and it has to continuously monitor for hydrochloric acid, Lyons said.
The company is required to burn only clean wood, so there should not be concerns about hazardous pollutants that can come from burning other types of fuel, such as construction debris, Lyons said.
If the company gets caught burning anything else, he said, "there would be swift enforcement action."
The Biomass Power Association disputed Booth's report, saying the industry turns material that would otherwise have no use into power.
"Biomass is a clean, renewable energy source that our nation relies upon to reduce our dependence on fossil fuels," said Bob Cleaves, the association president.