Dive Brief:

American Electric Power (AEP) will shutter a major coal-fired unit in Indiana by the end of 2028, notching the largest victory yet for Sierra Club's Beyond Coal campaign.

The environmental advocate launched its efforts to shut down existing coal plants in 2010, and the 1,300 MW Rockport Unit 1 is the largest single coal-burning unit to announce early retirement since.

The agreement allows AEP to avoid spending almost $1 billion to install flue gas desulfurization, or scrubbers, at the Rockport plant. Instead, the company will operate enhanced dry sorbent injection (DSI) technology, reducing the plant's sulfur dioxide (SO2) emissions by at least 58%.

Dive Insight:

Sierra Club tracks Beyond Coal "victories" and now tallies 792 coal units retired — with 487 units remaining open.

The group doesn't take credit for all of them, but in this instance the link is clear: AEP's commitment is the fifth modification to a consent decree originally reached in 2007 involving the company, the U.S. Environmental Protection Agency, several northeastern states, the Sierra Club and other parties.

The most recent modification was filed May 29, and alters a requirement that Rockport Unit 2 must be equipped with flue gas desulfurization technology to remove sulfur dioxide.

The Rockport plant is operated by AEP's Indiana Michigan Power (I&M). As a result of this modification, I&M will operate DSI equipment on both generating units beginning in 2021, to accelerate SO2 emission reductions and achieve a plant-wide emissions rate of 10,000 tons of SO2 or less a year.

The consent decree modifications will accelerate SO2 emission cuts from Rockport by eight years, the company said, while providing cost savings to customers.

"We invested nearly $9 billion in capital since 2000 to drastically cut emissions from our coal-fueled power plants," AEP Chairman, President and CEO Nicholas Akins said in a statement. "Today, our investments are focused on renewable generation and advanced technologies that enhance service for our customers."

The agreement also calls for AEP to provide $3.5 million to support projects that promote efficiency, distributed generation and pollution reduction measures.

"This agreement is a substantial step in the right direction, reducing emissions and ensuring the retirement of a significant source of pollution in Indiana,” Margrethe Kearney, senior attorney with the Environmental Law & Policy Center, and counsel for some citizen groups involved in the agreement, said in a statement.

Coal heavy-AEP, which has a goal of 80% CO2 emissions reduction below 2000 levels by 2050, has been taking steps to reduce its use of the fuel. In October, the company decided to close down its 1,590 MW Conesville coal generation facility in Ohio by May 31, 2020, two years ahead of schedule.

Sierra Club says the retirement of Rockport Unit 1 will eliminate annual emissions of 9 million metric tons of carbon dioxide.