Douglas McFarlan (at left), president of Midwest Generation, raises his hand as he is sworn in to testify during an Illinois Pollution Control Board hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

Douglas McFarlan, president of Midwest Generation, testifies during an Illinois Pollution Control Board hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

Will County Executive Larry Walsh (top center) addresses the Illinois Pollution Control Board during a hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

State Sen. Pat McGuire (right) addresses the Illinois Pollution Control Board during a hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

State Rep. Larry Walsh, Jr., (below), addresses the Illinois Pollution Control Board during a hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

A crowd is gathered for the Illinois Pollution Control Board hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

A crowd gathers for the Illinois Pollution Control Board hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

Members of the Illinois Pollution Control Board (top right) listen to testimony during a hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

Sandy Burcenski, (center), a director for Citizens Against Ruining the Environment, listens to testimony during an Illinois Pollution Control Board hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media

Members of the Illinois Pollution Control Board (top right) listen to testimony during a hearing on Midwest Generation's request on a variance to operate its local plants at the Health Professions Center at Joliet Junior College Tuesday, Jan. 29, 2013, in Joliet. | Matthew Grotto~Sun-Times Media