Duke Energy aims to more than double the wind, solar and biomass energy in its portfolio by 2020, according to its 2012 sustainability report.
Duke Energy Renewables, a nonregulated unit, now owns most of the companys renewable generation about 1,700 megawatts.
Most of the generation is from wind projects in six states, but the unit has seven solar farms in North Carolina and others in Texas, Arizona and Florida.
The business is growing fast, in part because of federal tax credits.
Duke Renewables added 647 megawatts last year alone.
Dukes regulated businesses contract for another 900 megawatts.
Duke aims to total 6,000 megawatts of renewable energy by 2020.
By comparison, Duke now operates about 10,000 megawatts of nuclear capacity.
The report says Duke also aims to reduce its carbon dioxide emissions. It sets a goal of reducing carbon dioxide emissions 17 percent by 2020 compared to 2005, from 169 million tons to 141 million tons a year.
Cleaner-burning natural gas, which Duke and other utilities are adopting as fuel prices drop, accounts in part for U.S. carbon emissions dropping to 20-year lows in 2012.
More use of gas means less burning of coal, a powerful source of greenhouse gases.
Duke has brought 2,760 megawatts of natural gas generation online since 2011 and will add 625 megawatts in 2013.
It will have retired 3,400 megawatts of coal capacity by the end of this year.
Still, Dukes nearly 135 million tons of carbon dioxide emissions in 2012 were second-highest among U.S. investor-owned utilities, the report said.
Its carbon intensity releases per unit of energy ranked 14th among those utilities.
Henderson: 704-358-5051; Twitter: @bhender