OAK CREEK — The Wisconsin Department of Natural Resources has submitted to the Environmental Protection Agency a revised version of the pollutant discharge permit for the Oak Creek Power Plant, which officials stated was shaped by the more than 600 public comments the agency received.
“Public participation is essential to the permitting process, so we appreciate that so many people shared their thoughts,” stated Jason Knutson, DNR wastewater section chief in a press release.
Three sizable changes were made to the proposed permit since the public hearing that was held on Feb. 11.
- It sped up the timeline for the plant to change from one type of ash handling to another which does not discharge ash into waterways.
- It lowered the limit of mercury that can be discharged.
- It also sets a limit for discharging arsenic, although the DNR states the plant currently discharges at below ambient lake levels.
“We appreciate the DNR’s thorough review and proposed permit,” We Energies spokesperson Brendan Conway stated in an email.
“As the DNR notes, overall, the water our facility returns to the lake has lower levels of mercury and arsenic than the lake itself and this permit will help continue that practice.”
A wet ash handling system uses water to remove ash at a coal power plant and dispose of it, in Oak Creek’s case into Lake Michigan. With a dry ash handling system, the dry ash is removed and typically sent to a landfill. Ash disposal is regulated because it contains heavy metals such as mercury, cadmium and arsenic.
Initially the proposed permit set the deadline for the plant at 11060 Chicago Road to go from a wet ash handling system to a dry ash handling system was Dec. 31, 2023.
The revised discharge permit has moved the deadline for the Oak Creek plant to convert to dry ash up to Dec. 2021, with an up-to six-month variance if We Energies has to apply for construction authorization through the Public Service Commission.
Addressing heavy metals
In the press release, the DNR responded to a report by The Clean Power Coalition of Southeastern Wisconsin, a local clean energy group, that showed elevated levels of heavy metals in surface water near the Oak Creek site.
The samples were collected by UW-Parkside students and tested at the University of Wisconsin Laboratory of Hygiene and indicated unsafe levels of boron, arsenic, copper, lead, manganese and other metals.
“Multiple programs at the department continue to review the data and will conduct an investigation to the identify the source,” the DNR stated.
“The Oak Creek Power Plant/Elm Road Generating Station does not discharge wastewater to these surface waters under its (discharge) permit, and elevated metals concentrations have not been linked to the facility.”
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Retiring the plant?
Sierra Club spokesperson Dana LaFontsee said the updated timeline could increase pressure for We Energies to retire the coal plant.
Last month the environmental group filed a testimony before the Public Service Commission stated that both the plant on Chicago Road and the Elm Road Generating Station have lost money for the utility.
Utility analyst Paul Chernick stated We Energies has lost an average of $98 million a year since 2014 operating the Oak Creek plants, and WPS Corp. lost about $40 million.
We Energies filed a testimony in response that Conway stated refutes Sierra Club’s claims on cost.
“Our system has long relied on fuel diversity, plants like Oak Creek and other coal-fueled units operate all year long to provide safe, reliable and affordable energy to customers,” Conway wrote. “They are especially important when other units are constrained due to supply or weather. For example, coal-fueled plants ensured energy to customers during this year’s polar vortex when natural gas prices were high and wind turbines were shut down by extreme cold.”
“We remain committed to working with the Sierra Club as we transition to a cleaner energy future without putting our customers’ comfort or lives at risk,” Conway continued. “Unfortunately, the Sierra Club’s suggestion that we retire our fossil plants immediately is premature and impractical.”
New and lower discharge caps
The revised permit also lowered the discharge variance from 4.1 parts per trillion to 3.7 parts per trillion, “setting the first-ever cap on mercury from the outfall.”
“The cap will serve as a backstop to prevent an increase in mercury loading from (Oak Creek Power Plant) until it is brought into compliance with the monthly average wildlife water quality criterion of 1.3 parts per trillion,” the release stated.
In the DNR’s response to public comments on the permit, it sites one commentator who notated that there are methods, though experimental, for removing mercury from water, making discharge below 1.3 ng/L, which is considered the floor for this type of disposal, theoretically possible. The department said it reached out to other entities to learn about these methods but “they did not provide documentation or studies demonstrating consistent attainment for this types of wastewater as requested.”
However the department did state that, “if one of these technologies proves feasible, the permit may be reopened to require installation of the technology at full scale and compliance with the final limit of 1.3 ng/L.”
The release also mentioned a variance for water quality standards for arsenic, though it was unclear what the variance would be. According to the DNR the plant’s arsenic discharges are already lower than the concentration of arsenic in the lake; Lake Michigan water has an average concentration of 0.92 parts per trillion and the plant discharges water with an average of 0.43 parts per trillion.
The EPA has 60 days to review the permit and make a decision. If approved, the permit would be reissued and take effect starting this fall.