This week the Environmental Protection Agency unveiled a new set of proposed regulations for existing coal-fired power plants.
The tax credits will benefit E-on Climate and Renewables and juwi, two energy companies building wind farms in Indiana.
Gregg says nuclear power is not a good option because it could take two decades to get a nuclear plant online.
A bill on its way to the Indiana House would mandate that 10 percent of Indiana power come from renewable sources by 2020.
Agriculture Secretary Tom Vilsack visited Indiana Tuesday, touting the growth of a new energy economy and some factories hit hard by the auto industry slowdown.