Solar panels with trees in the background.
A portion of a 43 MW solar array near Bladenboro, North Carolina, which sells power to Duke Energy. Credit: Riley Harwood / U.S. Dept. of Energy

North Carolina regulators have approved a controversial green tariff proposal from Duke Energy, rejecting protests from critics who argue it won’t bolster the company’s transition to zero-carbon electricity. 

Originally designed as a way for large electric customers to chip in extra for renewable energy projects Duke is already mandated to build, an amended tariff offered in April could allow some customers to speed up construction of new solar farms by about two years.

The revision appeared to help sway the Utilities Commission. The change, the panel said in its Jul. 31 order, is an “improvement” because the change “adds additional accelerated capacity” of renewable energy. 

The revised tariff, called Green Source Advantage Choice, has backing from the Carolina Industrial Group for Fair Utility Rates, an association of some of Duke’s largest customers. The utility says it plans to formalize the program soon in the wake of the regulators’ order. 

“The [commission] didn’t give us a deadline but asked that we do so when reasonably feasible,” spokesperson Logan Stewart said over email, “so it will be in the coming weeks. In conjunction, we will be working on updating the Green Source Advantage public webpage to include the new program details.” 

A question of ‘regulatory surplus’ 

For large customers with 100% clean energy commitments, a green tariff is a necessity in North Carolina, where Duke has a monopoly and cities, data centers and the like can’t buy clean energy directly from solar farms.  

In theory, a green tariff allows a company such as Google or Amazon to spur a new supply of clean energy equal to their electric demand, with Duke acting as an administrative go-between. An earlier iteration of Green Source Advantage more or less did just that. 

But the accounting got more complicated in 2021, when a bipartisan state law required Duke to cut its carbon pollution at least 95% by 2050. If the company is legally required to build scores of solar farms anyway, can a large customer legitimately claim its sponsorship of one project makes a difference? 

This question of “regulatory surplus” sparked a flurry of arguments and counter-arguments before the commission for some 18 months. Duke initially claimed such “additionality” was neither feasible nor necessary, and some businesses said chipping in to support the clean energy transition was good enough for them. More than a dozen local chambers of commerce and potential customers wrote regulators in support of the original program.  

But Google, the U.S. Department of Defense, and other large customers joined clean energy advocates to flag the problem of regulatory surplus, as did the Center for Resource Solutions, the nonprofit that certifies voluntary renewable energy purchase programs. Duke University, which has no connection to the utility, said it wouldn’t participate in the tariff.  

‘A small step in the right direction’ 

The debate, along with prodding from commissioners, prompted Duke to add a “resource acceleration option” to its proposal. The alternative allows large customers to advance about 150 megawatts of solar energy each year by sponsoring projects not selected in the company’s annual competitive bidding process. Every two years, Duke gets retroactive credit for this “extra” solar as part of its compliance with the 2021 law.

Clean energy advocates believe the new option is a “small step in the right direction.” But they note it accounts for 1 gigawatt of clean energy over ten years, a fifth of the entire program. Customers who lay claim to the remaining 4 gigawatts would not be impacting the state’s transition to clean electricity, they say. 

“If you’re the customer of a business who claims to support our state’s clean energy transition by participating in the program, you’re going to expect that business to be making a difference – not just subsidizing what Duke was going to do anyway,” said Nick Jimenez, senior attorney at the Southern Environmental Law Center. 

The Carolinas Clean Energy Business Alliance, a group of clean energy suppliers, also criticized the acceleration option. And though the Carolina Utility Customers Association, another group of large industrial customers, didn’t oppose the amended proposed tariff, it registered skepticism. 

“[Our] members have little interest in the Resource Acceleration Option,” the group said in a letter to regulators, “which would deliver electricity at a premium cost without providing the benefit of regulatory surplus-based environmental attributes that would be useful in meeting corporate environmental, social, and governance goals.” 

Cause for hope? 

While advocates see little good in the commission’s approval of the Green Source Advantage Choice program, they still have some faint cause for hope. 

One is the so-called Clean Transition Tariff, which Duke could propose later this year. An outgrowth of a May agreement between the utility and Amazon, Google, Microsoft, and Nucor, that program could allow participating customers to spur new projects, such as solar-battery storage combos or small nuclear energy, that provide carbon-free electricity around the clock. 

“This is not within the order,” said Jimenez, but the May memorandum of understanding, “is the big opportunity for something better.” 

Duke says the Clean Transition Tariff would be another voluntary option for customers, not a replacement for the one just greenlighted. “We see the approval of Green Source Advantage Choice as a first step,” the company’s Stewart said, “enabling us to move forward with new tariffs like the Clean Transition Tariff.” 

Maggie Shober, research director at the Southern Alliance for Clean Energy, agrees the memorandum of understanding is cause for some optimism. But she also notes that it’s only “an agreement to talk about something. It could be an opportunity,” she said, “or it could be a missed opportunity. “ 

And no matter what, the Clean Transition Tariff won’t cater to municipalities and other midsize customers with climate commitments. If these customers decline to pursue Green Source Advantage Choice, their only option is to wait for Duke to adjust.  

Commissioner Jeff Hughes pointed to that possibility in a concurring opinion. 

“Once the program offerings are launched, it will quickly become clear whether the program is as attractive as Duke asserts,” Hughes wrote. “If concerns continue and interest is modest from the outset, it is my hope that Duke will work quickly on new programs that will have a greater impact.”

Based in Raleigh, North Carolina, Elizabeth has covered the state’s clean energy transition for the Energy News Network since 2016. She has also produced features for Environmental Health News and SEJournal, the news magazine of the Society of Environmental Journalists. A former communications director for the nonprofit Environment America, Elizabeth brings over two decades of environmental and energy policy experience to her reporting.