MADISON, Wis. -

A settlement reached Friday between a local branch of the Alliant Energy Corporation and several federal agencies will require the Wisconsin company to commit more than $1 billion to reduce air pollution from its power plants.

The Wisconsin Power and Light Company announced it reached a Clean Air Act settlement with the Environmental Protection Agency, the Department of Justice and the U.S. Attorney’s Office. According to a DOJ statement, the settlement will invest more than $1 billion between 2012 and 2016 in pollution control technology to limit emissions from three coal-powered plants in Portage, Sheboygan and Cassville. It will also require WPL to spend $8.5 million in environmental projects to address damage from the company’s emissions.

According to the statement, WPL will retire or refuel four coal-powered units at its Edgewater and Nelson Dewey plants under the agreement. The Wisconsin company will also pay $2.45 million for previous alleged violations of the CAA settlement.

An Alliant Energy statement said the EPA notified WPL of violations in 2009 that alleged the company failed to comply with pre-construction review and permits for its Edgewater, Columbia and Nelson Dewey plants. According to the statement, WPL maintained it followed regulations but entered into settlement negotiations to avoid further costs to its customers.