Your solar sells at 4¢. You buy it back at 14¢.

Your estimate

The line item your power bill doesn't show you

Move the sliders above and this updates. It's an illustrative model built on Duke Energy Carolinas' published South Carolina rates — not a quote, and not a promise about your specific roof.

Estimated annual position

What your extra solar is worth — and what you're paid for it

$180/mo · 7.5 kW solar · Duke Energy Carolinas SC

Surplus solar you export to the gridPower your home doesn't use the moment it's produced —

What Duke pays you for itSC Solar Choice net-excess rate, about 4¢/kWh —

What that same power costs you back after darkDuke Energy Carolinas SC residential, about 14¢/kWh —

The gap a battery keeps in your house —

Illustrative. Production modeled at 1,300 kWh per kW per year for the Upstate; a battery is assumed to shift roughly a third of annual production from export to evening use, capped by what a single battery can cycle. Your real numbers depend on your roof, usage, tariff and equipment.

Over 10 years, rates rising ~6%/yr

—

What the same gap adds up to if electricity keeps climbing at the pace it has since 2021.

When the grid goes down

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of essentials — fridge, well pump, internet, a few lights and outlets — on one typical home battery. Without one, grid-tied panels shut off during an outage, sunny day or not.

Duke's approved increases

+13%

Two steps, both approved: +8.7% in August 2024 and +4.3% in August 2026 — about $222 a year more for a typical 1,000-kWh Upstate home.
Duke Energy / Public Service Commission of SC

Now the version for your actual roof

The model above uses Upstate averages. A free assessment replaces every assumption with your real numbers — and tells you plainly if a battery isn't worth it for your home.

Your actual tariff and export credit, pulled from your Duke account setup
Whether your existing inverter can take a battery, or needs an AC-coupled one
Which South Carolina and Duke programs your home is eligible for
Real installed cost, sized to what you want backed up

Your ZIP code

Do you have solar?

Free · no obligation · nothing to buy. Step 1 of 3

⏱ About 30 seconds · 📍 Greenville, SC · We'll say no if it's a no

The gap

Three things a rooftop panel can't do on its own

None of this makes solar a bad decision — it's still the best move most Upstate homeowners have made on their power bill. It just stops short in three specific places, and all three land at the same time of day.

Gap one · after sunset

Your panels clock out right as the house wakes up

Rooftop solar produces nothing after dark. Dinner, laundry, HVAC, the TV, the EV charger — the heaviest hours of a household's day run entirely on power you buy back at full retail price.

U.S. EIA / NREL residential load profiles

Gap two · in an outage

When the grid goes down, your panels shut down with it

Grid-tied solar is required to disconnect the moment the grid fails, so a lineworker isn't working on a line your roof is still energizing. Helene left parts of Greenville waiting days. Solar homes waited in the dark alongside everyone else.

UL 1741 / IEEE 1547 anti-islanding; U.S. DOE. Duke Energy, Hurricane Helene restoration, 2024

Gap three · every afternoon

South Carolina buys your extra power at a quarter of what it sells it for

Under Duke's SC Solar Choice tariff, whatever surplus you still have at the end of the month is bought at the net-excess rate — roughly 3–4¢ per kWh, against the ~14¢ you pay. If you enrolled between 2019 and 2021, your grandfathered full-retail credit runs out May 31, 2029.

SC Public Service Commission, Docket 2020-264-E (Duke Solar Choice); SC Office of Regulatory Staff; DSIRE

The spread, per kilowatt-hour

Duke Energy Carolinas, South Carolina residential · 2026

4¢

14¢

10¢ lost on every kilowatt-hour you sell at noon and buy back at eight. A battery doesn't sell it at all — it holds it until you need it, and you never pay the 14¢.

Same house, battery on

One sunny day, run twice

Identical home, identical sunshine, identical usage. The only difference is whether the surplus goes out to the grid at 4¢ or into a battery for the evening. Tap the toggle.

A 24-hour view of your power

Solar powering the house Battery powering the house Bought from the grid Sold to the grid at ~4¢

Bought from the grid—

Home runs on your own power—

Evenings run on—

—

Hour-by-hour model of one sunny day: ~7.5 kW rooftop solar, 16 kWh usable battery, typical Upstate household usage. Illustrative — a long cloudy stretch still leans on the grid. Rates: SC Solar Choice net-excess ≈ 3–4¢/kWh; Duke Energy Carolinas SC residential ≈ 14¢/kWh.

Solar only

On the grid's schedule

Mornings, evenings and overnight you buy at full retail, same as a house with no panels at all.
Midday surplus leaves at ~4¢ and comes back at ~14¢.
An outage on a bright afternoon still leaves you sitting in the dark.

Solar + battery

On yours

Evenings and overnight run on the solar you already made that afternoon.
Only the true leftover gets sold — after the battery is full, not before.
The battery carries your essentials through an outage, and your panels recharge it the next morning.

See which of those two days your house would actually have

It comes down to your usage curve, your inverter, and what you want kept running. A free assessment answers all three.

Get my free assessment

What it costs, plainly

The number nobody puts on the website

So here it is. A battery is a real purchase, and whether it's worth making depends on numbers that are specific to your house. What follows is the honest version, including the part that got worse this year.

~$15,000

is roughly what a typical 13.5 kWh home battery runs installed, before any programs — the national average works out to about $1,128 per kWh, with real quotes spanning roughly $700–$1,300 per kWh depending on the equipment, how much of the house you're backing up, and what electrical work the panel needs. A smaller battery covering only essentials costs less; whole-home backup costs more.

EnergySage marketplace pricing, 2026

South Carolina

The 25% state solar tax credit

South Carolina's solar credit has no expiration date, caps at $3,500 a year or 50% of your state tax liability, carries forward for up to 10 years, and tops out at $35,000 over a lifetime. It's written as a solar credit — how it applies to storage depends on how your system is configured, which is one of the first things we check.

South Carolina

A property-tax exemption on the added value

The value a solar system adds to your home is exempt from South Carolina property tax, so improving the house doesn't raise the assessment. Whether paired storage is included depends on how it's installed and assessed — we confirm it rather than assume it.

Duke Energy

Utility programs that pay for flexibility

Duke runs demand-response and bill-credit programs that compensate customers for capacity the utility can call on. Terms and availability differ between North and South Carolina and change with each filing — we'll tell you what is actually open to a Duke Energy Carolinas customer in the Upstate right now, and what isn't.

Income-based

Help if your household qualifies

South Carolina's Weatherization Assistance Program, LIHEAP, and the federal Home Energy Rebates fund efficiency and electrification work for qualifying households. These aren't battery rebates — but for some homes they're the better first dollar spent, and we'll say so.

The part that got worse

The 30% federal residential credit is gone

The federal Residential Clean Energy Credit (Section 25D) was terminated for systems placed in service after December 31, 2025 under the law signed in July 2025. If you buy a battery outright in 2026, there is no federal residential credit — full stop. Anyone still advertising 30% off is quoting a rule that expired. It makes the state and utility programs that remain more important to get right, and it's why we lead with them.

IRS guidance on P.L. 119-21; SEIA

Find out which of these your home actually qualifies for

Eligibility comes down to your utility, your tax situation, your system, and your household — which is exactly what a free assessment sorts out. No cost, and no obligation to buy anything.

Check what I qualify for

Why this year

Your export credit stayed flat. Everything else moved.

Storage math is set by the spread between what you're paid and what you're charged. Both ends of that spread are being pushed apart at once — and the reason is showing up on Duke's own filings.

+13%

Two approved increases, both landed

Duke Energy Carolinas' South Carolina rates rose 8.7% in August 2024 and another 4.3% on August 1, 2026 — roughly $222 a year more for a typical 1,000-kWh home. Neither step raised what you're paid for exported solar.

Duke Energy; Public Service Commission of SC

3% → 10%

Data centers are now the demand story

Duke signed 1.5 GW of new data-center contracts in a single quarter, and expects data centers to go from 3% to 10% of its Carolinas commercial sales by 2028 — with regional demand growing about 8× faster than the previous 15 years. In Greenville itself, DartPoints is putting $125 million into expanding its data center for AI workloads.

Duke Energy 2025 Carolinas Resource Plan; SC Daily Gazette, 2025

1.25M

The Upstate does not have a quiet grid

Helene knocked out power to about 1.25 million South Carolina customers in 2024, with Greenville and Spartanburg among the hardest hit. Winter Storm Elliott forced the first rolling blackouts in Duke's history. January 2026's ice storm took out 30,000+ across the Upstate.

Duke Energy; SC Office of Regulatory Staff; SC Daily Gazette

The sources behind these figures

Duke Energy — “New rates approved for Duke Energy Carolinas customers in South Carolina.” news.duke-energy.com
SC Public Service Commission, Docket 2020-264-E — Duke Solar Choice tariff and the net-excess energy rate. ors.sc.gov (PDF)
Duke Energy — 2025 Carolinas Resource Plan (data-center contracts and load growth). investors.duke-energy.com
SC Daily Gazette — DartPoints' $125M Greenville data-center expansion. scdailygazette.com
SC Office of Regulatory Staff — Winter Storm Elliott inspection & examination report. ors.sc.gov
Duke Energy — Hurricane Helene restoration updates, 2024. news.duke-energy.com
U.S. DOE — Homeowner's Guide to Going Solar (grid-tied behavior during outages). energy.gov
IRS — FAQs on the termination of §25D under P.L. 119-21. irs.gov
DSIRE — South Carolina 25% solar tax credit (SC Code §12-6-3587). dsireusa.org
EnergySage — home battery pricing, 2026. energysage.com

We keep a longer, fully-cited write-up of the grid side of this story — data-center load growth, capacity markets, reliability filings — on a separate page: read the full research →

Straight answers

The questions solar owners actually ask us

Can I add a battery to the solar I already have?

Usually yes. If your inverter is battery-ready (hybrid), a battery connects directly. If it isn't — which is common on systems installed before about 2019 — an AC-coupled battery goes alongside it and your existing panels and inverter keep working exactly as they do now. Neither route means replacing your panels. Which one applies to you comes down to the model on the side of your inverter, and that's the first thing an assessment checks.

Will it actually pay for itself?

Depends on the house, and we're not going to pretend otherwise. On bill savings alone, the payback on a battery is long — the estimate at the top of this page shows you roughly what the export-versus-retail gap is worth at your usage level, and for most homes that number alone doesn't cover a battery in a few years. What changes the math is everything stacked on top: rates that have risen 13% here in two years, a mandatory time-of-use tariff, the state credit, utility programs, and the value you put on your house staying powered through a multi-day outage. Some homeowners look at that and it's an easy yes. Some look at it and it isn't. We'll tell you which one you are.

How much of my house will one battery run?

A typical 13.5 kWh battery covers essentials — refrigerator, freezer, well pump, internet, lights, outlets, and usually a mini-split or a portion of your HVAC — for somewhere around 12 to 20 hours, then recharges from your panels the next morning. Running central air, an electric range, and a water heater at full tilt drains it far faster, which is why systems are sized around what you actually want kept alive rather than around the whole panel.

Is there still a 30% federal tax credit?

No. The federal Residential Clean Energy Credit ended for systems placed in service after December 31, 2025. If you buy a battery outright this year, you don't get it. Anyone telling you otherwise is quoting an expired rule. South Carolina's 25% state credit and the utility and income-based programs are what's left, and they're worth getting right.

Does adding a battery change my net metering?

Adding storage generally requires a new interconnection application with Duke, and that is the moment to look closely at your tariff. If you enrolled between 2019 and 2021, you're grandfathered at full retail credit until May 31, 2029 — you don't want to trip out of that by accident. If you're already on Solar Choice, you're on the net-excess rate now, which is exactly what a battery is designed to route around. Either way, we check your enrollment before anything gets filed.

What does the assessment involve, and what happens after?

A conversation — usually 20 to 30 minutes, by phone or at the house. We look at your last 12 months of usage, your inverter, your panel, and what you want backed up, then give you real numbers: installed cost, what programs apply, and what it does to your bill. If a battery isn't the right spend for your home, we say so — sometimes the honest answer is a load-shifting change or an efficiency fix first. There's no cost and no obligation, and we don't sell or share your information.

Who is GridShift?

GridShift is a home solar and battery program serving Upstate South Carolina — so yes, we have a commercial interest in this: if a battery makes sense for your home, we'd like to be the ones who install it. We publish the numbers and the sources anyway, because homeowners who understand the tariff make better decisions and become better customers. The longer, fully-cited research behind the grid side of this page lives at gridshiftprogram.com/grid. Questions: support@gridshiftprogram.com · (800) 555-0144.

Free assessment

Find out what your solar is leaving on the table

Three quick questions. We come back with your real numbers — the tariff you're on, whether your inverter takes a battery, what one would cost installed, and which South Carolina programs apply. If the answer is that you shouldn't buy one, that's what we'll tell you.