Will My VPP Enrollment Leave Me Without Backup? The Reserve Floor at Every Major US Program (2026)

In a Vermont storm outage, a homeowner enrolled in Green Mountain Power's battery program came home, lost grid power that evening, and expected their Powerwall to run the house through the night. It didn't. The utility had dispatched the battery during the day's peak event, and by the time the storm knocked out the grid, there wasn't enough stored energy left to carry the home until morning. The lights came back on with the grid, not with the battery.

That story — reported in Vermont press coverage of the state's battery program — is the most important thing to understand before you enroll in any virtual power plant. VPPs work. They pay well. In most states they're the single biggest post-purchase incentive a battery owner can earn. But the reserve floor — the percentage of your battery the utility is contractually barred from touching — varies from 10% at the low end to 50% at the high end, and the difference is roughly whether a family of four has power for three hours or for a full overnight outage.

This page lists the reserve floor for every major US residential VPP program, flags the programs that give the homeowner control and the ones that don't, and walks through the five settings to change before you enroll.

Shopping for a battery and want to know if the VPP math in your state actually pencils out? Get a free solar + battery quote →

How a VPP Interacts With a Grid Outage — The Three Scenarios

A grid outage and a VPP event are two separate things. Understanding how they interact clears up most of the fear homeowners bring to this decision.

Scenario 1: Outage during a VPP event

A VPP event is the utility signaling your battery to discharge onto the grid. The moment the grid itself goes down, that signal becomes irrelevant — your battery stops exporting to the grid, disconnects, and begins powering only your home as a normal outage would. The utility cannot continue to dispatch a battery whose grid connection is dead.

Scenario 2: Outage right after a VPP event

This is the real risk and the Vermont scenario. A utility dispatches your battery during a hot afternoon, draws it down to the reserve floor, and then — an hour later, four hours later, overnight — a storm takes out the grid. Your battery starts the outage at whatever the reserve was, minus whatever your home has used in the meantime. A 10% floor leaves roughly 1.4 kWh in a Powerwall 3 (13.5 kWh usable). A 40% floor leaves 5.4 kWh — more than enough to run essentials overnight.

Scenario 3: Outage during a PSPS or hurricane window

California's Public Safety Power Shutoffs and Atlantic hurricane season create periods of elevated outage risk that overlap with VPP dispatch season. California program terms require operators to manage dispatch so no participant battery is left below usable backup during a dispatch window, and a declared PSPS cuts distribution power directly rather than calling a VPP event. The safe practice is to raise your reserve to 80%+ (or 100% via Tesla Storm Watch) before a declared weather or PSPS warning.

Reserve Floor at Every Major US VPP Program (2026)

The table below lists the reserve floor each program applies by default on enrolled Tesla Powerwalls, which is the best-documented device across programs. Reserve behavior on other batteries (Enphase, Sonnen, Franklin WH, Generac) is handled through the same homeowner app in most cases but may follow slightly different defaults — confirm with your installer before enrolling.

Sources: Tesla program-support pages for each utility (tesla.com/support/energy/virtual-power-plant/<utility>), SMUD My Energy Optimizer Partner Terms and Conditions (04/03/26), Utah Public Service Commission filings for the Wattsmart Battery program, Xcel Energy Renewable Battery Connect FAQ, and ConnectedSolutions enrollment pages for each state. Verified October–November 2026. Programs update terms seasonally — confirm the floor in your enrollment docs before you sign.

For the full state-by-state picture of VPP payment rates and eligible batteries, see our main VPP guide. For Sacramento-specific numbers, see the SMUD battery rebate guide.

Case Study: What Actually Happened in Vermont

Vermont's Green Mountain Power runs one of the oldest home-battery programs in the country — launched in 2015, now covering thousands of Tesla Powerwalls. The program has a strong track record in outage events: during a 2019 statewide storm, 1,100 GMP-enrolled homes stayed on their batteries for an average of nine hours, with the longest-running household making it 82 hours before the grid came back.

But the program's design means the battery is actively dispatched, and the homeowner is responsible for the reserve setting. In one widely reported case, a customer discovered — after their home went dark during an evening storm — that the utility had drawn their Powerwall down during the day's peak event, leaving too little stored energy to carry the house through the outage. The grid came back the next morning before any serious harm was done, but the incident got the attention of Vermont legislators and the Tesla VPP community.

The lesson is not "don't enroll in GMP" — the program paid roughly $850/kW-summer in 2026, the highest capacity rate in the country. The lesson is raise your reserve before weather, and don't rely on the program default.

The Five Settings to Change Before You Enroll

1. Pick your reserve floor against a worst-case outage, not an average one. For a 13.5 kWh Powerwall, 20% is 2.7 kWh — about 3–6 hours of fridge, lights, Wi-Fi, and phone charging. 40% is 5.4 kWh — closer to 8–14 hours. If you live in a hurricane state, a PSPS county, or an area where overnight outages are routine, start at 30–40%.
2. Turn on Storm Watch (Tesla) or the equivalent. Tesla Storm Watch automatically charges Powerwalls to 100% when the National Weather Service issues a severe weather alert within range of your property. It overrides the reserve setting for the duration of the alert. Enphase, Sonnen, and Franklin WH each have a comparable manual "backup mode" — confirm yours is enabled in the app.
3. Set opt-out rules for severe weather days. Most programs let you opt out of individual dispatch events. In season, if a storm is in the forecast, opt out that morning.
4. Confirm the program-fixed floor matches your tolerance. If you're in Rocky Mountain Power's Wattsmart territory, the floor is 10% and the program reserves the right to override even that — if that bothers you, the Wattsmart economics may not be worth the risk of an overnight outage during August dispatch season.
5. Make sure your battery is actually wired for whole-home or partial-home backup. A battery on the market can be installed grid-tie-only (no islanding hardware, no backup). If your installer wired the system without a backup gateway or backup load panel, no reserve setting will help — the battery simply can't power the home during a grid outage. Confirm in writing before enrolling in any VPP.

What a 20% Reserve Actually Buys You

Translating reserve percentages into real backup hours — for a Tesla Powerwall 3 (13.5 kWh usable capacity), a reasonable "critical loads" setup (fridge + freezer + a few LED lights + Wi-Fi router + phone charging + occasional microwave use, drawing about 400–700 watts average):

• 10% reserve = 1.35 kWh = roughly 2–3 hours of essentials. Enough to get the fridge through a short outage and charge phones.
• 20% reserve = 2.7 kWh = roughly 4–6 hours. Gets a family through dinner, bedtime, and the first few hours of overnight — not a full overnight.
• 30% reserve = 4.05 kWh = roughly 6–10 hours. A reasonable overnight if your loads are tight.
• 40% reserve = 5.4 kWh = roughly 8–13 hours. A full overnight for most essentials-only households.
• 100% reserve (Storm Watch) = 13.5 kWh = roughly 20–30 hours on essentials-only, or 8–12 hours if HVAC is on the backup panel.

These are essentials-only ranges. Running central air conditioning, electric heat, an electric water heater, or an EV charger during the outage cuts these numbers by 2–5×, depending on the load. If your installer did not break out which circuits are on the backup panel, that conversation needs to happen before you enroll.

Which Programs Are Actually Homeowner-Friendly

Ranking the programs covered here by how much control the homeowner has over the backup/payment trade-off:

1. Most control: ConnectedSolutions (MA, RI, CT, NH, ME), PG&E ELRP, Green Mountain Power. Homeowner sets the reserve in the battery app with no program-imposed floor.
2. High default + homeowner control: Xcel Renewable Battery Connect (40% default, adjustable), USVI (50% default), SDCP (20–40% band).
3. Standard 20% default: SMUD, PSE, PSEG Long Island, NYSEG/RG&E (25%). Default works for most households, adjust up before storms.
4. Program-fixed floor, no override: Rocky Mountain Power Wattsmart (10%), CoServ (20%), GVEC (30%).

If you're buying a battery and weighing whether to enroll, the ranking above matters more than the headline payment rate. A $400/kW-summer program that keeps you dark during a November storm is a worse product than a $275/kW-summer program that keeps your fridge running overnight.

Frequently Asked Questions

Will enrolling in a VPP leave me without power during an outage?
Not if you set a reserve you can live with and your utility honors it. Every major US VPP program holds a reserve floor the utility can't dispatch below. The floor ranges from 10% (Rocky Mountain Power Wattsmart) to 50% (USVI), and some programs — including ConnectedSolutions in the Northeast — let you set your own. If your reserve is 20% of a 13.5 kWh Powerwall, you keep about 2.7 kWh — roughly 3–6 hours of running a fridge, lights, Wi-Fi, and a phone charger.

Can a utility drain my battery right before an outage?
It has happened at least once publicly. In Vermont, a Green Mountain Power customer reported that the utility drained their Powerwall during an evening dispatch event, and when a storm outage followed the same night, their home went dark until service was restored the next morning. All major programs now cap dispatch at a reserve floor, but the floor is not the same in every program, and an aggressive dispatch followed by a surprise outage is the real risk to understand before enrolling.

What's the lowest backup reserve any US VPP program allows?
Rocky Mountain Power's Wattsmart Battery program in Utah and Idaho sets the reserve at 10% and reserves the right to dispatch "at any time and to any level," though the company states it tries to respect the customer reserve. That is the lowest documented floor of any major US residential VPP as of 2026, and the terms give the utility the broadest dispatch rights of any program covered here.

What backup reserve do most Tesla VPPs default to?
20% is the most common default across Tesla VPP programs. SMUD, PSE, PSEG Long Island, and CoServ all start at or fix the reserve at 20%. Xcel Energy Colorado's Renewable Battery Connect starts at 40%. GVEC uses 30%, NYSEG/RGE 25%, and the US Virgin Islands program 50%. Some programs — San Diego Community Power, for example — let you adjust between 20% and 40%.

Does a VPP dispatch run during a grid outage?
No. When the grid is down, a properly configured solar-plus-battery system islands — it disconnects from the grid and powers only your home, and the utility cannot signal or dispatch it. The risk is the reverse: a VPP event finishing shortly before an unexpected outage, leaving the battery closer to its reserve floor than you planned. The reserve setting is what protects you in that scenario.

Can a VPP event happen during a PSPS or hurricane evacuation?
In California, program terms require dispatch to be managed so that no participant's battery is drained below usable backup during a dispatch window, and PSPS events are a separate utility mechanism that cuts distribution power rather than calling for battery discharge. In practice the safest move during a declared storm or PSPS warning is to raise your reserve in the app before the event window. Tesla's Storm Watch feature automatically charges Powerwalls to 100% when the National Weather Service issues a severe weather alert in your area.

Should I raise my reserve before a storm?
Yes. Every major battery app — Tesla, Enphase Enlighten, Sonnen, Franklin WH — lets you raise the reserve manually or opt out of individual dispatch events. Raising the reserve to 80% or 100% when a storm is forecast costs you one potential VPP event's earnings and buys you a full battery heading into the outage. Tesla's Storm Watch automates this for severe weather alerts; other brands require a manual change.

What happens if my battery is already below the reserve when an outage hits?
A Powerwall below 5% stored energy will not power the home when grid power is lost — the system needs a minimum charge to inverter cleanly onto home loads. Above 5%, the battery discharges normally until it reaches 0% or the outage ends. The reserve floor is what keeps the battery above that 5% danger zone in the first place.

Do VPP programs cover me if a utility dispatch leaves me without power?
No. Tesla's program terms explicitly state the company is not liable for reduced device charge during a power outage. Utility program terms are similar. The protection is the reserve floor plus your own pre-storm override — not a warranty or indemnity if the sequence goes wrong.

Which VPP programs give the homeowner the most control over the reserve?
The ConnectedSolutions family (Massachusetts, Rhode Island, Connecticut, New Hampshire, Maine) is the most homeowner-friendly on reserve control — the program does not fix a floor, so you set the reserve in your battery app and the utility dispatches above it. San Diego Community Power lets you adjust between 20% and 40%. The strictest programs are Rocky Mountain Power (10% fixed) and CoServ (20% fixed).

Bottom Line

A VPP is not a trap. For most homeowners in most programs, the trade is excellent: a few hundred to a few thousand dollars a year in exchange for the utility borrowing a slice of your battery on hot afternoons, with the rest held back for you. The failure mode is specific — a dispatch that finishes just before an unexpected outage — and the fix is specific: set your reserve against your worst outage, turn on Storm Watch (or the brand equivalent), and opt out when weather is forecast.

Read the reserve floor in your program's enrollment terms before you sign, and if it's lower than you can live with, pick a different battery brand or skip that program.

Shopping for a battery and want to know if the VPP math in your state actually pencils out? Get a free solar + battery quote →

Sources and verification

Tesla VPP program-support pages (reserve defaults per program): SDCP, Xcel, PSE, NYSEG/RGE, RMP Wattsmart, GMP BYOD, SMUD, CoServ, GVEC, PSEG LI, USVI, PG&E. Tesla Storm Watch: tesla.com Storm Watch support. Tesla Backup Reserve behavior: tesla.com Backup Reserve support. SMUD My Energy Optimizer Partner Terms and Conditions (04/03/26): smud.org MEO Partner T&C. Rocky Mountain Power Wattsmart tariff and DPU comments (2020): Utah PSC tariff, DPU comments. Green Mountain Power storm case study (1,100 homes, 2019): greenmountainpower.com storm outage. Vermont Powerwall-dispatch incident background: Seven Days VT, "Charging Forward," sevendaysvt.com. Xcel Renewable Battery Connect: SolarEdge program FAQ, solaredge.com. Verified November 11, 2026.