By GARY D. ROBERTSON Associated Press
RALEIGH, N.C. (AP) — Environmental and renewable energy groups have challenged the proposal by Duke Energy Corp. subsidiaries on how to reduce greenhouse gases in North Carolina in the next decade, saying it relies too much on natural gas and unproven technologies to succeed.

The groups, in filing a formal response to the proposed electricity-production shifts the utility offered in May to the state Utilities Commission, also make an alternate proposal to reduce carbon dioxide emissions by 70% by 2030 as compared to 2005 levels. They say it would require more solar and wind power and battery storage use than Duke’s plan.

The coalition says its plan would do better with energy savings through efficiency initiatives than what Duke proposes to comply with the landmark 2021 state law that mandates the 70% reduction as well as zero-net CO2 emissions by 2050.

According to a report filed with the commission July 20 prepared by an outside firm hired by the coalition, the mandates can also be met at a lower cost for customers, who are expected to pay higher bills for these shifts.

“Duke’s carbon plan is deeply flawed,” said Luis Martinez, director of Southeast energy at the Natural Resources Defense Council, one of the groups that filed written comments by a deadline July 15. “But this modeling shows that a less costly plan, which also significantly reduces emissions, is possible for North Carolina.”

The law directs the Utilities Commission to tell Charlotte-based Duke Energy how to meet these reductions by the end of the year, and says the seven-member panel can examine “the latest technological breakthroughs to achieve the least cost path,” among other considerations. The commission is holding in-person hearings this month and online meetings next month to take public comment.

Duke spokesperson Bill Norton said July 21 that the utility’s priority remains “to produce the most efficient, reliable, least-cost way to deliver the clean energy our customers deserve and expect” and that Duke looks forward to reviewing proposals and “providing constructive feedback” to the commission.

The coalition, which also includes the North Carolina Sustainable Energy Association, Southern Alliance for Clean Energy and the Sierra Club, is also critical of Duke Energy’s plan because it wants four energy-portfolio alterations it proposed approved, not just one. The utility says that would provide more flexibility and time to evaluate emerging electricity sources.

All four portfolios do envision retiring Duke Energy’s remaining coal-fired power plants in North Carolina by 2035. They also would rely on hydroelectric power storage; an emerging form of small nuclear power plants; and additional natural gas-powered plants, which can provide energy on cloudy or high-demand days.

Natural gas burns cleaner than coal and is considered a bridge fuel while other alternate energy sources are ramped up. But critics say the methane contained in natural gas and that can leak is disproportionately more damaging to the climate than carbon dioxide.

Three of the four portfolios don’t reach the 70% reduction target by 2032 or 2034, but the utility said those plans would result in slightly lower average annual increases on retail power bills through 2035.

The law gives the commission the ability to delay the 2030 target by up to two years, and even longer if regulatory and construction delays for nuclear or wind energy facilities arise, or if the electric grid’s performance is questioned.

Still, “the commission has an obligation to develop a plan to achieve the required carbon reduction requirements set forth in law,” the coalition’s written comments say, calling Duke’s proposal a “Choose-Your-Own Adventure Carbon Plan.”

The utility’s plan covers activities in North Carolina and South Carolina, but the 70% reduction only applies to North Carolina. Duke Energy Carolinas and Duke Energy Progress serve 4.4 million customers in the two states. The coalition said its proposal could trim anticipated higher costs for ratepayers by 2% to 7% through 2030 compared to Duke’s plan.

This post appeared first on Power Engineering.