Duke Energy delivers electricity to some 25 million people in the Southeast and Midwest, making it one of the U.S.’s largest utilities, as well as one of its biggest coal burners. Since Good took over in 2013, she’s packed more renewables than ever into that portfolio. Some 40% of the energy Duke delivered in 2015 was carbon-free, and Good has upped investments in solar and wind, planning to spend another $3 billion over the next five years. That’s in addition to the $4.9 billion acquisition of Piedmont Natural Gas, expected to close before the end of this year.