The owner of eight coal-fired power plants in central and southern Illinois lobbied the Illinois Environmental Protection Agency (EPA) to propose rules that would loosen pollution regulations, according to the Chicago Tribune. Instead of limiting the rate of pollution from the coal plants, the state would set an annual cap on how much sulfur dioxide (SO 2 ) and nitrogen oxide (NO x ) those eight plants could emit collectively—and those caps are higher than what the coal plants have collectively emitted annually for several years.

The proposed amendments to state rules come just months after the state of Illinois approved subsidies for the continued operation of Excelon nuclear energy plants in December 2016. According to the Tribune, Dynegy saw its opportunity to open discussions with lawmakers after its competition received a boost. Although Illinois Governor Bruce Rauner denied Dynegy’s request for comparable subsidies, e-mails seen by the Tribune suggest the state’s EPA had been talking with the Dynegy’s lobbyist about changes to emissions rules “since at least November.”

The Tribune wrote that the Illinois agency is working “to keep the financially struggling coal plants open by giving Houston-based Dynegy more flexibility to operate individual generating units, several of which are not equipped with modern pollution controls.”

The push to keep struggling coal plants open reflects the rhetoric coming out of the federal Department of Energy recently. Energy Secretary Rick Perry commissioned a grid reliability report back in April to study the effect of coal and nuclear energy plant closures on the reliability of the energy grid. The memo requesting the report seemed to beg the question that emissions standards and renewable policies had caused coal plant closures. When the report was finally published, it mainly found that the cheap price of natural gas was the culprit behind coal and nuclear closures. The report also noted that the US electricity grid was not more unreliable than it was before coal and nuclear closures, although it did recommend additional study of grid resilience in the face of weather events and fuel-price shock.

Still, the Trump-appointed chairman for the Federal Energy Regulatory Commission (FERC) has hinted that he will push for new regulations to compensate coal plants for their reliability outside of market forces, a move that would likely de-prioritize pollution concerns.

In Illinois, the proposed amendment imposes a 55,000 tons/year SO 2 cap for Dynegy’s eight plants, as well as a 22,000 tons/year cap for NO x emissions. Ars reached out to Dynegy, and spokesperson David Byford offered that, under the new plan, “SO 2 emissions from the fleet would be reduced from 70,000 tons per year to a cap of 55,000 tons per year—a greater than 20 percent reduction.” (In an e-mail, the Illinois EPA told Ars that the current estimated emissions limit for SO 2 under the rule today is approximately 66,354 tons per year.)

On paper, it seems good that the total emissions limit is being lowered, but Dynegy’s eight coal plants are already emitting far less SO 2 and NO x than either the current or new emissions ceilings allow, according to the US EPA Acid Rain Database. Currently, the state allows coal plants to emit SO 2 and NO x at an average rate, so three of Dynegy’s cleanest coal plants emit an average rate of 0.05 pounds of SO 2 per million BTUs, while five other plants emit 0.43 pounds of SO 2 per million BTUs—a rate that’s above current state limits but less than state limits when averaged over the fleet. The current rate-based emissions program incentivizes the company to close down its dirtier plants, even though these plants might be cheaper to operate. The rate-based emissions plan also becomes more and more stringent over the next decade.

The general cap on emissions, on the other hand, won’t be ratcheted down over the years or reevaluated if plants are closed or taken offline, according to the Tribune. This suggests Dynegy is incentivized to keep its cheapest plants open, even if they pollute more, as long as they stay under the emissions cap. Or Dynegy could potentially even reduce emissions controls on new plants that have more sophisticated emissions-scrubbing technology if it’s more cost-effective to operate the plant without them and the plant won’t cause the company to hit the emissions cap.

Hitting the emissions cap shouldn’t be too much of a worry for Dynegy—its eight Illinois coal plants have released far less than 50,000 tons of SO 2 every year since 2013 and less than 20,000 tons of NO x since 2010, according to the US EPA Acid Rain Database.

Rauner’s administration pushing to change limits on lung-damaging pollution from coal-fired plants https://t.co/wKlLYcpyOc via @scribeguy pic.twitter.com/R3i6rqUGTH — Tribune Graphics (@ChiTribGraphics) September 27, 2017

Ars reached out to the Illinois EPA, and a spokesperson said that the current rules aren't great because they don't prevent an emissions increase if demand for energy increases (because currently, emissions allowances are set per million BTUs provided), while the new rules protect against emissions increases if demand increases dramatically in the future. The agency did not immediately respond to a followup question about the relative impact of increasingly strict emissions-per-BTU rates that are prescribed in the current rules. A spokesperson for the agency also told the Tribune that the proposed rule change would still offer tougher standards than those prescribed federally.

Now, the proposed rule change goes to the Illinois Pollution Control Board, which will invite a public hearing. Even if the proposed amendments are enacted, Dynegy’s coal plants will still have to compete with cheaper natural gas plants, whether or not emissions reduction costs are slashed. But if the price of natural gas increases over the next year, as the EIA expects it to, looser coal regulations could offer the fuel a temporary comeback in Illinois.