The U.S. Environmental Protection Agency (EPA) on March 28 finalized updates to emission limits for new power plants under the Mercury and Air Toxics Standards (MATS). The rule includes emission limits for mercury, particulate matter (PM), sulfur dioxide (SO2), acid gases, and certain individual metals.

The standards affect only new coal- and oil-fired power plants that will be built in the future. The EPA said the update does not change the final emission limits or other requirements for existing power plants.

The agency said the updates, signed by EPA Acting Administrator Bob Perciasepe, were “based on new information and analysis that became available to the agency after the rule was finalized,” and characterized them as “largely technical in nature.” They will have no impact on standards already set for existing power plants. It said the updates “ensure that emissions limits are achievable and that pollution levels can be measured continuously.”

Seth Jaffe, an attorney with the Foley Hoag law firm, in a note to clients, wrote that the most significant change was to revise the mercury emissions standard from 0.0002 lb/GWh to 0.003 lb/GWh. He said the change was made in response to comments suggesting that the more stringent standard simply wasn’t attainable. The EPA said that reaching the 0.003 lb/GWh standard will still require installation of the same types of pollution control equipment.

The agency said the updates are calculated from data about the emission rates achieved by the best performing source for each of the air toxics or surrogates.

The environmental agency also amended the definition of coal in an effort to make it clear that coal-derived synthetic natural gas is considered to be coal under MATS. In addition, in recognition of the fact that emissions from the burning of desulfurized coal-derived synthetic natural gas are similar to those from the burning of natural gas, the EPA amended opacity and SO2 monitoring provisions. Facilities burning desulfurized coal-derived synthetic natural gas now will have opacity and SO2 monitoring requirements similar to those of facilities burning natural gas.

The EPA also revised its definition of integrated gasification combined cycle in its Utility New Source Performance Standards to make those standards consistent with MATS. As a final step, the agency adopted technical corrections to the PM standards for facilities that began construction before March 1, 2005, and for facilities that began modifications after May 3, 2011.

Also on March 28, the EPA proposed stricter rules on gasoline and vehicle emissions and updated the agency’s 2012 performance standards for storage tanks used in oil and natural gas production. The proposed updates to the oil and gas storage tank standards reflect recent information showing that more higher-volume storage tanks will be coming online than the agency originally estimated, the EPA said. The updates would also provide storage tank owners and operators additional time to comply with a requirement to reduce volatile organic compound emissions while equipment to reduce those emissions is being manufactured.

The EPA said it will take comment on its proposals for 30 days after they are published in the Federal Register and will hold a public hearing if requested.

Sources: POWERnews, EPA

David Wagman, Executive Editor (@EPContentDirect)

This story was first published April 2.