A U.S. EPA proposal could lower the emissions standards for ethanol plants, aligning the facilities with standards for corn milling plants that produce products for human consumption, according to John Millett, EPA spokesman.

Currently, plants producing fuel are subject to review under the Prevention of Significant Deterioration permitting program at 100 tons per year of air pollution. If the proposal passes muster, all corn milling facilities, whether food or fuel, would both be subject to a permitting review at the point when the plants emit more than 250 tons per year of air pollutants.

If the change goes through, it would be positive news for Pacific Ethanol Inc., said Sharon Sturm, who handles the plant's technical services. The company, which is headquartered in Fresno, Calif., is a marketer and producer of renewable fuels. With a limit of 250 tons per year, more plants could be classified as a minor source of air pollution rather than a major source, which requires stricter controls. "A lot of ethanol plants want to stay a minor source," she said.

The change could also mean larger ethanol plants. "By increasing this to 250 tons, the plants can more easily get bigger, or you can build bigger from the beginning," she said.

The rule change wouldn't mean the end of regenerative thermal oxidizers (RTO) and scrubbers, however. Instead, it likely will mean the control measures could be loosened and emissions abatement equipment could be operated at less stringent efficiencies.

Todd Potas, principal for Natural Resource Group (NRG), said he, like others, had been asking the EPA to consider this rule change for some time. On Jan. 23-24, he attended a U.S. DOE and EPA Bio-Fuels Permitting Workshop. NRG does environmental permitting for the energy industry, including ethanol plants, and this rule change was one of the suggestions Potas made to help alleviate permitting issues for ethanol plants.

If the proposed change is finalized, it would allow minor-source ethanol plants to increase their output of criteria pollutants including particulate matter, NOx, sulfur dioxide, volatile organic compounds and carbon monoxide, Potas said. He also felt the change would likely support the trend for larger ethanol plants. "I think it will allow people to potentially expand their ethanol plants, and it will allow new ethanol plants to be permitted as minor sources," he said.

On the other hand, whether the change is implemented or not, there could be other site-specific factors, such as regional or state rules, that could supersede the emissions standard. But in areas that don't have current air-quality concerns, increasing the emissions to 250 tons per year would be appropriate. "If the air shed can handle the higher emissions, it isn't a concern," Potas said.

At the same time, the EPA proposed an overhaul of emissions standards in another area. It includes new benzene standards for gasoline, hydrocarbon emissions standards for passenger vehicles at cold temperatures and evaporative standards for fuel containers, Millett said. The proposed Mobile Source Air Toxic regulations, if approved, would be phased in with full implementation by 2030.

For more information on the plant emissions standard proposal or to make a comment before the May 8 deadline, go to www.epa.gov/nsr/actions.html.