Vectren Energy North says the recent cold snap will cost its natural gas customers about 30 percent more than a year ago.
Northern Indiana Public Service Co. says it's committed to improving its operations.
The study finds cheap natural gas and declining power demand are driving coal and nuclear power plant closures.
Indianapolis Power and Light plans to replace its current coal-fired power plant near Martinsville with a new natural gas plant.
This week the Environmental Protection Agency unveiled a new set of proposed regulations for existing coal-fired power plants.
The Perry K Steam Plant is converting from coal to natural gas to comply with new Environmental Protection Agency emission standards.
Some states like Ohio and Pennsylvania use a heavier hand when regulating natural resource extraction on state-owned land.
Researchers at Purdue found natural gas is a cheaper and cleaner way to fuel city buses.
It stays lit because of gas that seeps out of shale deposits deep underground and provides the flame constant fuel.
Once completed the natural gas plant would employ about two dozen people, approximately the same number as the coal plant.