Vistra on Tuesday said that it will idle units at its coal- and gas-fired Joppa Power Plant next year, three years earlier than planned.

The Texas-based competitive supplier also said that, pending passage of legislation in Illinois, it will invest more than $550 million to develop about 300 MW of utility-scale solar and 175 MW of battery storage at nine former plant sites across the state by 2025. Vistra said the buildout would more than triple Illinois’ utility-scale solar generation and double its battery storage capacity.

Vistra said the accelerated retirement timeline settles a 2018 complaint the Sierra Club brought before the Illinois Pollution Control Board. The environmental group alleged that the Edwards, Coffeen and Joppa plants contaminated groundwater in excess of state standards prior to Vistra’s acquisition of Dynegy.

The settlement also has Vistra paying a portion of its property taxes for three years following the closure of Joppa and installing additional groundwater monitors at Edwards and Joppa.

Vistra said that because of “mounting financial and legal pressures that now come from operating coal plants,” it’s calling for passage of the Illinois Coal to Solar and Energy Storage Act to help fund the repurposing of coal plant sites.

“We agreed to shut down the Joppa plant in light of the legal uncertainties and significant economic challenges facing the plant. First and foremost, we will work with our team members and the impacted communities to ensure a just transition, including our commitment to pay $1.1 million in incremental property taxes over three years,” Vistra CEO Curt Morgan said. “As part of this just transition, we remain focused on passing the Coal to Solar and Energy Storage Act, which will enable us to reinvest and repurpose sites like Joppa into zero-emission generation, using existing infrastructure, creating jobs and adding to the property tax base. We have a construction-ready plan to invest $550 million, including approximately $59 million at the Joppa location, to transform coal plant sites into renewable energy centers.”

Vistra said that if the bill passes, the Joppa site will house a standalone 45-MW battery storage facility. It said the land “does not have the site characteristics to support utility-scale solar.”

The approximately 65-year-old Joppa plant was included in a septet of retirement announcements from Vistra in October. (See Vistra Declares End of Midwest Coal Fleet.) The company initially said it would wind down Joppa’s six coal units (1 GW) and five gas units (239 MW) in 2025. The company’s seven-plant Midwest coal fleet will cease to exist by 2027, “or sooner should economic or other conditions dictate,” Vistra said at the time.

In its latest retirement announcement, Vistra again parceled out blame to a “dysfunctional” MISO capacity auction design that employs a vertical demand curve and prioritizes reliability over price signals.

MISO declined to comment on Vistra’s criticisms.

Morgan said the Joppa closure is an “unfortunate reminder that our remaining MISO fleet continues to face challenges and is at risk of rapid closure for a variety of factors, most notably legal and economic challenges — the latter due to the dysfunctional MISO market in Illinois and significant maintenance costs.”

The CEO said Vistra would like to “reinvest in and responsibly reuse its Illinois plant sites so local communities like Joppa and Massac County can economically benefit from the transition to renewable electricity generation rather than being left as a nonproductive former plant site.”

“The agreement will not only prevent millions of tons of dangerous air pollution from one of the oldest coal plants in Illinois, it will also require Vistra to install additional groundwater monitors that will help Sierra Club and our local members advocate for the safest coal ash closure plan under Illinois’ new coal ash regulations recently adopted by the Illinois Pollution Control Board,” Sierra Club Illinois Director Jack Darin said in a statement.

Darin also said the fast-tracked retirement spotlights the need for the Illinois legislature to pass the Clean Energy Jobs Act, which would help workers during Illinois’ transition from fossil fuels in the power sector.