Dominion Energy South Carolina has proposed updates to its time-of-use (TOU) rates that, if approved by the Public Service Commission, would take effect July 1, 2026 and apply to bills issued on or after that date. If you're on a TOU plan like Rate 7 — or thinking about switching — these changes matter, because they move the windows your whole strategy is built around. Here's the plain-English read.
Note: as of this writing these are proposed changes pending PSC approval. Dominion has said final approved rates will be posted on its Rates and Tariffs page on July 1, 2026. Confirm the live periods there before making decisions.
What's proposed to change
Three things stand out for residential customers:
- New rate-period hours. Dominion is proposing to change the hours that count as on-peak, off-peak, and super-off-peak. The exact new windows are part of the filing — so the on-peak hours you may have read about (today's summer window is late afternoon, winter is morning) could shift. Don't assume the old hours carry over.
- An additional winter super-off-peak window. Today there's a super-off-peak band overnight (roughly 1–5 a.m.) year-round. The proposal adds another super-off-peak window in winter — so the colder months would have more than just the overnight band, giving you extra cheap hours to shift usage into and charge a battery.
- Weekends and holidays treated like weekdays. This is the big one. Today, weekends and major holidays are off-peak. Under the proposal, they'd be treated the same as weekdays — meaning the on-peak window would apply every day (holidays still excluded), not just Monday through Friday.
What it means if you have a battery
Counterintuitively, the weekend change makes a properly sized battery more valuable, not less. Right now, if you slip and pull heavy load during a Saturday afternoon, it doesn't matter — weekends are off-peak. If weekends become on-peak, that protection disappears, and covering the window seven days a week becomes part of the job. A battery that already carries your house through the weekday peak just extends the same behavior to weekends automatically. Manual load-shifting, on the other hand, gets harder — now there's no weekend break from watching the clock.
The additional winter super-off-peak window is also good news for battery owners: another cheap stretch to charge in during the months when the on-peak period shifts to the morning.
What to do right now
- Don't lock in the old hours in your head. If you're optimizing around specific on-peak times, wait for the confirmed July 1 periods before hard-coding anything (thermostat schedules, battery discharge windows, EV charging timers).
- If you're about to switch to Rate 7, ask Dominion which periods will be in effect when your switch takes hold. See how to switch to Rate 7.
- If you're sizing a battery, size it to cover the window comfortably — the every-day change means there's less slack for a system that can only just cover the weekday peak. More on that in what size battery you need.
The bottom line
The headline is "the cheap-vs-expensive windows are moving, and the expensive one may apply every day." That doesn't change the core strategy — charge cheap, cover the peak — it just raises the bar on doing it consistently, which is exactly what a battery is for. If anything, it strengthens the case in is a home battery worth it on Dominion Rate 7.
I'll update this post once the final periods are confirmed on July 1.