Duke Energy's Clean Transition Tariff Proposal Fails to Materialize
Duke Energy's proposed clean transition tariff for large customers in the Carolinas has been omitted from its final rate plan.
A major utility has finalized a new rate structure for large power users without a promised mechanism to fund novel clean energy. Separately, a leading solar manufacturer is making a significant bet on a more efficient photovoltaic technology.
Duke's Tariff Proposal
Duke Energy filed the final version of its large load tariff proposal this week, a framework developed with Amazon, Google, Microsoft, and Nucor to address massive data center growth in the Carolinas. The tariff requires large loads to cover the total cost of dedicated new infrastructure, provide letters of credit for transmission upgrades, and sign 10-15 year contracts. It has the support of those major customers but does not include a previously discussed clean transition tariff (CTT). Duke told regulators that no party has presented sufficient detail to support a CTT program at this time, arguing proponents need to provide extensive detail on program design, pricing, and credits to ensure other customers are not harmed.
The utility's 2024 memorandum of understanding with the hyperscalers regarding a CTT is now essentially dead, according to Nick Jimenez, a senior attorney at the Southern Environmental Law Center. After initial fanfare, about 18 months of discussions failed to produce a formal proposal. Duke has since urged the North Carolina Utilities Commission to decline including CTT provisions in the current proceeding, suggesting its existing green tariff program should be fully explored first. That existing program allows large users to procure renewable energy and accelerate some solar and storage projects, but critics argue it subsidizes projects Duke was already likely to build. A CTT is intended to fund newer technologies like enhanced geothermal or long-duration storage.
Qcells' Tandem Solar Plans
Solar manufacturer Qcells aims to open a gigawatt-scale factory to produce next-generation tandem solar panels in 2029. The company is currently testing full-size tandem panels in the field, which pair traditional silicon cells with layers of perovskite crystals to achieve higher efficiency. Qcells set a tandem efficiency record in 2024, with an independent body confirming a rate of 28.6% for a standard-size cell, a significant jump from the current high-performance panel average of around 24%.
The move heats up competition to commercialize perovskite tandem technology, which has struggled with durability outside the lab. Qcells has been developing the cells since 2016 and launched a 40-megawatt pilot line in South Korea in 2024 to produce full-size panels. Other companies are also racing toward mass production. Tandem PV is targeting 2028 for a gigawatt-scale factory, while Chinese company GCL said it opened a 1-GW factory last year. Danielle Merfeld, Qcells' Global Chief Technology Officer, expects further process improvements once tandem technology hits mass production. Success could allow for more power generation in the same physical footprint, accelerating solar adoption.
