SALISBURY — Duke Energy on Friday submitted a rate increase request that could raise residential power bills by 16.7 percent.

Including businesses, the rate increase would affect about 63,000 total customers in Rowan County. The increase would raise rates by 16.7 percent for residential customers, 11.4 percent for commercial customers and 9.9 percent for industrial customers.

Duke Energy says a typical residential customer — a household that uses 1,000 kilowatt-hours of electricity per month — would see monthly bills increase by $18.72 to a total of $122.68

A rate increase would help with costs associated with cleaning up coal ash, modernizing the electric grid, generating cleaner energy and improving service, Duke Energy said in a filing submitted to the N.C. Utilities Commission.

“Through smart investments in cleaner energy plants and renewable resources, safely managing coal ash, and the grid that powers our lives and improves reliability, we are focused every day on providing customers increasing value and laying the foundation for a smarter energy future,” said David Foundation, Duke’s North Carolina president, in a news release.

If approved by the Utilities Commission, the increases could go into effect by next spring, the company said. The utility requested April 1 to be the start date for a rate increase. It would be the first base rate increase since 2013, the company said.

In particular, the inclusion of coal-ash cleanup in rate hike request has prompted opposition. Before Duke made its filing official Friday, neighbors of the company’s coal-ash ponds filed a request to intervene and participate in the discussion about the matter.

Deborah Graham, who lives in Dukeville near Buck Steam Station, said Duke Energy has failed to responsibly manage its coal-ash waste.

“It would add insult to injury to have to pay more every month in my electric bill so that Duke can continue to earn a profit after decades of waste mismanagement,” Graham said.

In Rowan County, Duke Energy is required to excavate coal ash as a result of a settlement in a lawsuit with the Yadkin Riverkeeper. The company can either recycle its Rowan County coal ash or place it in a lined landfill away from the Yadkin River and groundwater, according to the settlement.

In addition to filing a request to intervene, Graham is also a plaintiff in a lawsuit against Duke Energy that focuses on a requirement that coal-ash neighbors give up their right to sue over well-water contamination if they also wish to want a financial settlement from the utility over concern that coal ash contaminated well water.

The company says cleaning up coal ash is part of the cost of providing power.

Asked recently about the rate increase, company spokesman Jeff Brooks said changes in state law that mandated the coal-ash cleanup could not have been anticipated.

The most prominent of state law changes — the Coal Ash Management Act — came in response to a massive coal ash spill on the Dan River. Brooks said the response to that spill would never be a reason for rate hikes. Fines and fees imposed on Duke Energy because of its handling of coal ash will also not be a reason for the increase, the company said.

Friday’s rate increase request came from Duke Energy Carolinas, which covers 62 counties in North Carolina, including Rowan, and 18 in South Carolina. A separate rate increase has been requested by Duke Energy Progress, which serves the eastern part of the state and an area near Asheville. Neighbors of coal-ash ponds have objected to rate increase requests by both divisions of Duke Energy.

The proposed base rate hikes would boost the company’s revenue by about $611 million, according to Friday’s filing.

A “grid reliability and resiliency rider” is also proposed to recover costs related to the “modernization of the energy grid,” the company said. The entirety of Friday’s request to the Utilities Commission would increase the company’s revenue by $647 million.

In its filing, Duke Energy said its current rates do not provide sufficient revenue to meet day-to-day operating expenses while also providing investors with a reasonable return.

Contact reporter Josh Bergeron at 704-797-4246.