The U.S. Environmental Protection Agency (EPA) announced Nov. 24 a proposed action to reduce emissions of SO2 from coal-fired power plants in Texas to improve visibility at parks and wilderness areas in Texas and Oklahoma.
EPA has proposed to partially approve and partially disapprove the state of Texas' regional haze plan intended to meet federal Clean Air Act requirements for improving visibility and reducing haze. EPA is proposing to approve the part of Texas' plan as meeting the Clean Air Act requirement that shows certain older, industrial sources meet existing requirements for best-available retrofit technology (BART) to reduce harmful emissions.
Because parts of Texas' plan did not meet federal Clean Air Act requirements, EPA has proposed to disapprove parts of the state's plan for reducing haze pollution from specific power plants in Texas. EPA said its proposal requires “cost-effective controls,” consistent with treatment used at power plants across the country. The federal plan would be effective until the state replaces it with an approvable state plan.
Under EPA's proposed plan, 15 units at eight coal-fired facilities in Texas will be required to reduce SO2 as part of the national long-term strategy for improving visibility. These pollution controls will be very much like those already in place for almost all similar power plants in other states, EPA said. No facilities in Oklahoma will be affected by this action. Oklahoma has already committed to haze-preventing pollution controls at three generating plants and submitted an approvable state plan to partially replace the EPA's federal plan in that state.
After being published in the Federal Register, the proposed plan will be open to a 60-day public comment period. EPA will also hold a public hearing in Austin on Jan. 13, 2015, and one in Oklahoma City on Jan. 15, 2015.
Said the Texas Commission on Environmental Quality in a Nov. 24 statement: "The proposed EPA Regional Haze FIP would target 14 Texas coal-fired power plant units, at a cost of more than $2 billion, for a negligible increase in visibility in Class One areas, such as national parks and wildlife areas. These costs would invariably be passed on to consumers, either directly or indirectly, and could have consequential impacts on the state's power grid. It would require seven power plants to install additional emissions controls on specific units within a 3-5 year window. The power plants are Sandow 4 (1 unit); Martin Lake (3 units); Monticello (3 units); Limestone (2 units); Big Brown (2 units); Coleto Creek (1 unit), and Tolk (2 units). It would require San Miguel power plant to limit capacity to 94 percent. The TCEQ maintains that its 2009 SIP meets all the EPA's criteria for approval. The TCEQ will evaluate the EPA's proposal and will provide additional comments to the EPA during the upcoming formal comment period." The affected plants and units that would need SO2 scrubber upgrades under the EPA plan are: Sandow Unit 4, Martin Lake Units 1-3, Monticello Unit 3, Limestone Units 1-2, and San Miguel. The plants and units needing scrubber retrofits under this proposed rule are: Big Brown Units 1-2, Monticello Units 1-2, Coleto Creek Unit 1 and Tolk 172B and 171B.
“We propose that those sources whose emission limits can be achieved by conducting scrubber upgrades must comply with the emission limits within three years of the effective date of our final rule, except for San Miguel, for which we
propose compliance within one year because that unit has been recently meeting our proposed emission limit,” EPA noted.
The agency later added: “The SO2 control technologies we considered in our analysis - [dry sorbent injection] and scrubbers - are in wide use in the coal-fired electricity generation industry. Both technologies add spent reagent to the waste stream already generated by the facilities we analyzed, but do not present any unusual environmental impacts."
The agency gave estimated costs for each of the units needing new scrubbers/DSI for each of the possible technologies - wet scrubbers, SDA scrubbers and DSI.
Scrubber installations would have varying benefits in protected areas
EPA proposes to find that installing either wet FGD or SDA scrubbers on five of these units would yield significant visibility improvements at the Wichita Mountains. These five units are: Big Brown 1 and 2, Coleto Creek, and Monticello 1 and 2. It proposes to find that scrubber installations on Big Brown 1 and 2 would also yield significant benefits at both Guadalupe Mountains and Big Bend, and that a scrubber installation on the Coleto Creek unit would also yield significant visibility benefits at Big Bend.
In comparison to those five units, EPA proposes to find that the visibility benefits from installing scrubbers on the W. A. Parish 5-7 units; and Welsh 1-3 units would not yield large enough visibility benefits to be considered at this time.
It also evaluated the visibility benefits of installing scrubbers on Tolk units 171B and 172B, limiting its analysis to SDA. The visibility benefits of SDA scrubbers on the Tolk units are projected to occur mainly at the Guadalupe Mountains. EPA noted that the deciview visibility benefits projected at the Guadalupe Mountains from controls on the Tolk units are smaller than those from scrubber upgrades at W. A. Parish or Welsh for impacts at the Wichita Mountains.
However, when it evaluated other metrics, such as extinction benefit or percent of extinction benefits, EPA believes that the overall visibility benefit for installing scrubbers on the Tolk units was superior to either the W. A. Parish or the Welsh units. In particular, the Wichita Mountains has a much higher total extinction for the baseline and the 2018 projection than the Guadalupe Mountains, so the relative improvement in extinction levels is higher when the Tolk units are controlled for the Guadalupe Mountains, than if the W. A. Parish or the Welsh units were controlled for the Wichita Mountains. Therefore, considering all the visibility benefits relative to the respective Class I areas, EPA proposes to find that the visibility benefits from installation of dry scrubbers on the Tolk units would be significant and beneficial towards the goal of meeting natural visibility conditions at the Guadalupe Mountains.
EPA proposes that the existing scrubbers for Sandow 4, Martin Lake 1-3, Monticello 3, and Limestone 1-2 be upgraded to perform at a 95% control level.
“We propose that compliance with these limits be within five years of the effective date of our final rule for Big Brown Units 1 and 2, Monticello Units 1 and 2, Coleto Creek Unit 1, and Tolk Units 171B and 172B," EPA wrote. "Although this is not a BART action, this is the maximum amount of time allowed under the regional haze Rule for BART compliance. We based our cost analysis on the installation of wet FGD and SDA scrubbers for these units, and in the past we have typically required that scrubber retrofits under BART be operational within five years.
“We propose that compliance with these limits be within three years of the effective date of our final rule for Sandow 4; Martin Lake Units 1, 2, and 3; Monticello Unit 3; and Limestone Units 1 and 2. We believe that three years is appropriate for these units, as we based our cost analysis on upgrading the existing wet FGD scrubbers of these units, which we believe to be less complex and time consuming that the construction of a new scrubber. We solicit comments on alternative timeframes, of from two years up to five years from the effective date of our final rule.
“We propose that compliance with these limits be within one year for San Miguel. We believe that one year is appropriate for this unit because we based our analysis on scrubber upgrades that San Miguel has already performed, and because it has demonstrated its ability to meet this emission limit.”