Source: Paul Sabelman, Ameren Portage De Sioux Plant, 2016, https://www.flickr.com/photos/pasa/24107569613.
Client: Sierra Club
Authors: Tyler Comings
September 2025
Principal Economist Tyler Comings provided testimony before the Missouri Public Service Commission on the utility's proposed return on equity (ROE) and economics of its coal units. Mr. Comings found that the utility's proposed ROE of 10.25 percent was too high, finding that using more reasonable assumptions and methods would lead to an ROE between 9.25 and 9.5 percent. He also argued that the Sioux coal units were costly and unreliable which should lead Ameren to consider their earlier retirement.