Duke Energy Carolinas solar in 2026: the clock is real

Two Dukes today, one Duke on January 1, 2027

North Carolina has two Duke utilities with different rates, different riders, and different rate cases. Duke Energy Carolinas covers the western half of the state, including Charlotte and the central area. Duke Energy Progress generally covers the eastern half, plus the Asheville area. The scale gap is real: EIA's 2024 data counts 1,919,372 DEC residential customers in North Carolina buying 22,664,575 MWh at an average 13.94 cents per kWh, against 1,356,079 DEP residential customers at 15.54 cents. For context, the North Carolina statewide residential average was 14.74 cents per kWh in June 2026. This page covers DEC only. If your bill says Progress, most numbers below do not apply to you.

The split has an expiration date. Duke filed a joint application on August 14, 2025 with the NCUC, the PSCSC, and FERC to merge DEP into DEC, creating one utility serving both states, under NCUC dockets E-7, Sub 1332 and E-2, Sub 1383. All three approvals are in: FERC on January 30, 2026, the PSCSC on April 30, 2026, and the NCUC on May 1, 2026, consistent with a comprehensive settlement. The targeted effective date is January 1, 2027. Duke projects more than $1 billion in retail cost savings through 2038, and the settlement requires guaranteed savings over a 14 year period to offset identified customer impacts, with NC retail customers making Share the Benefits contributions to South Carolina customers for six years beginning 2030.

What it means for a solar buyer: nothing changes for customers on January 1, 2027 itself. The two sets of rates get integrated over time through future rate cases at a pace regulators control. So the DEC tariff stack on this page keeps governing DEC territory after the merger closes, until a later proceeding says otherwise. Do not let a sales pitch use the merger as urgency; the rider deadline in the next sections is the real urgency.

Sources: EIA Table 6, 2024 utility bundled residential sales; EIA Electric Power Monthly, table 5.6.A; Blue Ridge Public Radio, May 2026; Duke Energy SEC regulatory matters disclosure; merger docket announcement; and Duke Energy savings projection release.

Schedule RSTC: the TOU rate Solar Choice requires

Here is the part most quotes gloss over. Rider RSC requires the customer to be served on a time-of-use rate with critical peak pricing, specifically Schedule RSTC or RETC. So choosing Solar Choice is really choosing a different rate for every kWh you buy, not just a compensation scheme for exports. Schedule RSTC is NC Eighth Revised Leaf No. 136, effective for service on and after January 1, 2026, and its price spread is enormous.

Source: Schedule RSTC, NC Eighth Revised Leaf No. 136.

The critical peak mechanics deserve a close read before signing anything. On designated Critical Peak Days the on-peak hours become Critical Peak Hours, Duke may shift them one hour earlier or later, and customers are notified by 4:00 pm the prior day by phone, email, or text, though notice can come as late as one hour before the critical peak period. Miss the text and run the dryer at the wrong hour, and that hour costs roughly three and a half times the standard RS energy rate. This is why batteries and load shifting, not raw export volume, drive payback under the new structure. A system that can ride through critical peak windows is protecting you from 42.7695 cent power; a system that just exports at midday is earning 4.53 cents.

Sources: Schedule RSTC tariff leaf and Rider RSC tariff leaf.

Rider NMB: the bridge closes January 1, 2027

Rider NMB, the Net Metering Bridge, NC Fifth Revised Leaf No. 143, effective July 1, 2026 under the same June 2026 NCUC orders as RSC, is the alternative worth understanding before it is gone. Its tariff states plainly: this Rider will be closed to new participants on and after January 1, 2027. Enrollment is capacity limited, first come, first served, with a spot reserved upon submission of a valid interconnection application. The 2026 annual capacity is 38,700 kW AC, up from 35,100 in 2025, 31,900 in 2024, and 7,250 in 2023.

Source: Rider NMB, NC Fifth Revised Leaf No. 143.

Why anyone cares: NMB is the last enrollment window that lets a residential customer avoid the mandatory critical peak TOU rate. Same 4.53 cent excess credit, same $1.01 per kW charge, same $22 minimum bill, but without being forced onto RSTC and its 42.7695 cent critical peak exposure. The catch is the queue. Your spot is reserved when your valid interconnection application lands, the statewide DEC pool for 2026 is 38,700 kW AC, and the door shuts January 1, 2027 regardless. If NMB fits your situation, the interconnection application date is the deadline that matters, not the installation date.

Source: Rider NMB tariff leaf.

Interconnection: $100, the NCIP ladder, and a fee caveat

DEC interconnection runs under the North Carolina Interconnection Procedures, NCIP, approved by the NCUC. Rider RSC itself requires a Request to Interconnect, an application fee, and compliance with NCIP liability insurance requirements. The process ladder: certified inverter-based systems no larger than 20 kW file under the simplified NCIP Section 2 review, which is where most residential projects land; larger certified systems use the Section 3 Fast Track, published by Duke as covering more than 20 kW up to 2 MW; and projects that fail screens go to the study process. Applications go through Duke's online interconnection portal, reached from the Apply for Grid Connection page, which routes new connections, ownership transfers, and status checks.

The fee for the residential tier is $100, a nonrefundable processing fee filed with the NC standard Interconnection Request Application Form for systems no larger than 20 kW, or $50 if the request is solely a transfer of ownership. One honesty note on sourcing: that $100 figure comes from a county government posted copy of the NC standard form, because Duke's own generate-your-own page lists no fee amounts and a Duke published NC fee schedule page was not located in this research. A newer form for facilities over 20 kW posts Fast Track fees of $750 for over 20 kW to 100 kW and $1,000 for over 100 kW to 2 MW, so fee levels above the residential tier are in flux and should be verified per project.

Sources: Rider RSC tariff leaf; NCIP process summary; NC standard Interconnection Request Application Form, county posted copy; Duke Apply for Grid Connection page; and the over 20 kW application form with Fast Track fees.

What is still moving at the NCUC

The big open item is the DEC rate case, Docket E-7, Sub 1329, filed November 20, 2025. It proposes performance based regulation with a two year multiyear rate plan, residential decoupling, performance incentive mechanisms, and an earnings sharing mechanism. The initial request was about $1,002 million, roughly 15.0 percent over two years, on a 10.95 percent ROE and 53 percent equity. Duke's rebuttal on June 19, 2026 cut the ask to about $622 million, roughly 9.3 percent, at a 10.48 percent ROE. A partial settlement with the Public Staff was filed July 2, 2026, the evidentiary hearing commenced July 7, 2026, and Year 1 rates were requested effective no later than January 1, 2027. Public hearings ran in Morganton April 28, Charlotte April 29, Winston-Salem May 6, and Durham May 12, 2026.

Here is what we cannot tell you, stated plainly: the NCUC hearings list shows the E-7 Sub 1329 order described as Order Accepting Stipulations, Granting Partial Rate Increase, with no order date and no amounts posted on that page. A partial increase was granted, but the final approved dollar and percentage figures were not posted on any page fetched for this research. Verify the final numbers from the order itself before quoting bill impacts. The parallel DEP case, Docket E-2, Sub 1380, filed the same day, also requested 10.95 percent ROE; the last approved ROEs were 10.10 percent for DEC and 9.8 percent for DEP. Also on the calendar: E-7, Sub 1330, a certificate hearing September 9, 2026 for an 850 MW simple cycle combustion turbine in Rowan County, and DEP rider hearings September 15, 2026 in E-2, Subs 1397 to 1401. The merger dockets, E-7, Sub 1332 and E-2, Sub 1383, are approved and covered above.

Sources: Duke Energy rate case exhibit, July 2026; NCUC hearings list; Third Act NC public hearing schedule; EQ Research ROE comparison; and the merger docket announcement.

What we could not verify

As of August 28, 2026, four gaps remain. First, the E-7 Sub 1329 rate case order grants a partial rate increase, but the approved dollar and percentage figures were not posted on any page fetched for this research; the NCUC hearings list shows the order title without a date or amounts. Second, PowerPair remaining capacity and any end date are unpublished by Duke; the scarcity claims circulating come from third party marketing sites and are unverified against Duke or NCUC sources. Third, the $100 residential interconnection fee comes from a county government posted copy of the NC standard application form because Duke's own NC fee schedule page was not located, and fees above 20 kW appear to be in flux. Fourth, no current NC residential solar income tax credit was located, a searched-and-not-found result rather than a confirmed absence. Each of these stays a gap until a primary source closes it.

Sources: NCUC hearings list; Duke Energy PowerPair page; NC standard interconnection form, county posted copy; and Duke Apply for Grid Connection page.