Today we want to talk about the Tenaska Westmoreland Generating Station, a two-turbine, 940-megawatt, natural gas-fired power plant located in South Huntington Township, Westmoreland County.
A little background: The facility’s construction and initial operation were authorized by an Air Quality Plan Approval issued in April 2015 by the Pennsylvania Department of Environmental Protection (DEP).
Although Tenaska Westmoreland is a major source of air pollution under the Clean Air Act and has operated for almost four years, it has never applied for or received a Title V Operating Permit.
And four years is a long time for a new source to operate “temporarily” under its plan approval. So we decided to find out why Tenaska Westmoreland has been permitted to operate subject to temporary authorizations recently after reading a notice in the Pennsylvania Bulletin announcing that the DEP was extending the facility’s authority to operate temporarily under its Plan Approval for another 180 days – the ninth such extension that DEP has granted.
What our legal staff learned is that Tenaska Westmoreland has had problems completing the initial compliance testing required by its Plan Approval.
*record screech* At this point we have to stop and explain a little bit of background and procedure: Under Pennsylvania’s air pollution regulations, a plan approval for a new source like Tenaska must require the source to demonstrate compliance with applicable emission limits before it can apply for, or be issued, an operating permit.
Plan Approvals must also authorize the temporary operation (for a period of up to 180 days) of the source pending issuance of an operating permit. If the construction or installation of the source is not complete before the authorized period of temporary operation ends, the source must apply for an extension of its authority to operate under its plan approval, for a maximum of an additional 180 days.
Tenaska Westmoreland’s Plan Approval sets emission limits for a host of pollutants including nitrogen oxides, carbon monoxide, volatile organic compounds, formaldehyde, particulate matter, sulfuric acid mist, sulfur dioxide, ammonia, and carbon dioxide.
The Plan Approval also requires DEP-approved testing within 180 days of the facility’s initial startup to determine compliance with the emission limits for all of those pollutants, excepting greenhouse gases - the facility must test for compliance with its carbon dioxide limits once every 25,000 hours of operation.
Tenaska Westmoreland performed its initial compliance test in January 2019, shortly after the plant became fully operational. However, the test showed that formaldehyde emissions from both of the plant’s turbines exceeded applicable limits by a factor of about 100 (that is not a typo!).
“Obviously, that was a problem, but retesting in March and May 2019 and December 2020 showed that formaldehyde emissions from the turbines were within limits,” GASP senior staff attorney John Baillie explained.
A Tenaska investigation into the cause of the failed January 2019 compliance test concluded that the exceedance of formaldehyde limits was caused by “potential off-gassing of formaldehyde from the heated sample line,” likely as the result of a large swing in the outside air temperature during the test.
In March 2022, the company scheduled yet one more compliance test for October 2022, proposing to use a different test protocol.
DEP rejected that test protocol in April 2022, as well as the previous compliance test results, and required Tenaska Westmoreland to develop a new test protocol.
From the documents that DEP provided us, it is not clear why DEP took more than three years to determine that the initial test protocol was inadequate. It also did not appear from those documents that Tenaska Westmoreland has submitted a revised, corrected test protocol, or scheduled a compliance test with such a protocol.
Also in April, DEP rejected a test protocol that Tenaska Westmoreland submitted to determine compliance with its CO2 emission limits. It appears that the company has yet to revise that test protocol to resolve DEP’s objections.
Where does that leave things?
“As things stand, no one can say for sure that Tenaska Westmoreland complies with its emission limits for formaldehyde and CO2, even though the plant has been operating for almost four years,” Baillie said. “GASP expects, DEP and Tenaska Westmoreland will be able to resolve this situation in the near future and without further delay.”
GASP will continue to monitor new developments as they occur and report when we know more.