How Ecotricity's Resi-Flex Peak Export Plan Works

Bottom line: Ecotricity's Resi-Flex plan is one of the highest peak-export buy-back offers in New Zealand. It pays solar exporters a premium rate during defined peak windows (typically weekday mornings and evenings) and a lower flat rate the rest of the time. It's designed for homeowners with a battery, because the value comes from storing midday solar and discharging it during those peak windows. If you don't have a battery (or a really well-timed EV setup), Resi-Flex isn't the right plan for you, and a flat buy-back retailer will probably net you more.

This article unpacks how Resi-Flex actually works, who it suits, the eligibility and regional rules to watch for, and how it stacks up against the other premium buy-back plans on the market. We won't quote live cents per kWh here, because those rates move; instead, point your eyeballs at our Dynamic Tariff & Buy-Back Engine for current figures across every NZ retailer.

This is part of our wider guide to NZ solar tariffs and retailers, written for Kiwi homeowners who want a clear-eyed read on which plan actually pays best for your setup.

What Resi-Flex Actually Means for NZ Homeowners

Ecotricity is a 100% certified carbon-zero electricity retailer based in New Zealand, and it's built much of its brand around supporting customer-owned solar generation. The Resi-Flex plan is its flagship offering for solar households who can shift export into peak demand windows.

The core idea is simple. The wholesale electricity market values power much more highly between roughly 7am and 9am and again between 5pm and 9pm on weekdays. That's when the grid is straining, when coal and gas peakers fire up, and when carbon intensity per kWh is highest. If you can push solar (or stored solar) into the grid at those times, you're displacing the dirtiest, most expensive generation, and Resi-Flex pays you accordingly.

It is, in plain terms, a time-of-use export tariff. It rewards behaviour, not just generation. Two households with identical 8 kW solar arrays could earn very different amounts under Resi-Flex depending on whether they have a battery and how they configure it.

How the Resi-Flex Pricing Structure Works

Resi-Flex splits the day into two export rate bands:

• Peak export window: a defined block of weekday morning and evening hours. Export during these windows earns the premium rate, which is among the highest in the country.
• Off-peak export: all other hours, including weekends and overnight. Export here earns a standard flat rate, generally similar to what other retailers offer for any-time export.

Import (the power you buy from the grid) is also priced on a time-of-use basis, so peak grid imports are more expensive than off-peak. That's important: Resi-Flex is a coherent product where both sides of the meter reward you for using your own solar at the right times, and selling the surplus at the right times.

For current peak and off-peak buy-back cents per kWh, check the live Buy-Back Engine. We update it as retailers move their rates, which they do more often than most homeowners realise.

Why a Battery Changes Everything Here

If you only have solar panels and no battery, your export pattern looks like a hill: nothing in the morning, peak production around midday, then nothing in the evening. You'll export almost entirely during the off-peak window because the sun is up when the grid doesn't need extra help.

A battery flips that pattern. You charge the battery from solar during the middle of the day (when peak rates are paying you nothing useful), then discharge into the grid during the morning and evening peak windows. That's where Resi-Flex's premium rate earns its keep.

The same logic applies, with some nuance, to households with an EV and a bidirectional charger, or to homes with smart hot water diversion and demand shifting. But for most Kiwi households today, the simple answer is: Resi-Flex pays best if you have a battery.

Eligibility, Region Locking, and the Fine Print

Resi-Flex isn't available everywhere, and that catches a lot of homeowners off guard. Here are the practical eligibility rules to be aware of.

Regional Availability

Ecotricity operates across most of mainland NZ, but Resi-Flex's premium export pricing depends on the local lines company and the wholesale node your home connects to. The plan is particularly well established in parts of:

• Canterbury (Orion lines), including Christchurch and surrounding districts. See our tariffs guide for how Christchurch homes typically structure their solar setups around Resi-Flex.
• Wellington (Wellington Electricity).
• Auckland (Vector), though plan terms can vary by zone.
• Selected regions on Powerco, Unison, and Aurora networks.

If you're outside those zones (parts of Northland on Top Energy, some West Coast areas, smaller rural lines companies), Resi-Flex may not be offered at all, or only on a modified flat-rate version. Always check directly with Ecotricity for your ICP number before you sign anything.

System Size and Inverter Limits

Like most NZ retailers, Ecotricity caps residential export buy-backs at a certain inverter size, typically 10 kW for single-phase connections and higher for three-phase. Above that size, you may be classed as a small commercial generator, which is a different conversation. Your lines company also has the final say on what's allowed to export.

Smart Meter Required

Time-of-use export pricing only works with a half-hourly smart meter that reports both directions. The vast majority of NZ homes already have one (the rollout is essentially complete per the Electricity Authority), but a small number of older properties may need a meter upgrade first. Ecotricity will arrange this if needed.

Contract Terms

Ecotricity's plans are typically no fixed term for residential customers, which means you can switch away if a better offer turns up. That's worth knowing because the NZ buy-back market is competitive and rates move. There's no penalty for trying Resi-Flex and switching later if your circumstances change.

The Key Numbers: What You Could Actually Earn

Let's get practical with a worked example. Imagine a Christchurch household with an 8 kW solar array, a 10 kWh battery, and a moderate household load.

On a typical day, that system might:

• Generate around 35 kWh of solar in summer, 12 kWh in winter (per NIWA-derived irradiance averages for Canterbury).
• Use roughly 15-20 kWh of that solar directly during daylight hours.
• Charge the battery with surplus solar during the off-peak middle-of-day window.
• Discharge battery into the grid (or into the house) during the 7am-9am and 5pm-9pm peak windows.

The exact dollar return depends on the current Resi-Flex peak rate and how much energy you can reliably push through the battery into the peak window. For a battery-equipped Canterbury home, this kind of setup can meaningfully outperform a flat 12c per kWh buy-back, especially across the longer summer days.

For an actual calculation tied to your roof, system size, and consumption pattern, use our Buy-Back Engine, which models Resi-Flex against every other live plan in NZ.

What This Means for You: By Persona

For the ROI Pragmatist

Resi-Flex is worth your attention only if the maths works on your specific setup. The premium peak rate is real, but you have to actually export during the peak window to capture it. Without a battery, you're unlikely to beat a simple flat-rate retailer.

If you're considering a battery anyway (and they're now part of the calculation for most new NZ solar quotes), Resi-Flex shifts the battery payback equation in your favour. Run the numbers carefully: a battery adds roughly $8,000-$15,000 to the install, and the payback comes from a mix of avoided peak imports and premium peak exports.

For the Tech-Savvy Optimiser

This is your tariff. Resi-Flex rewards exactly the kind of dispatch logic you'd want to build anyway: charge battery off solar at midday, discharge into peak windows, schedule EV charging at off-peak overnight. Most modern hybrid inverters (Sungrow, Fronius GEN24 with BYD, Goodwe ET) support time-of-use export logic via their app or third-party integrations.

It's worth comparing Resi-Flex against the Octopus OctopusPeaker plan, which uses a similar dispatch-rewarding logic but with different windows and slightly different mechanics. The "best" plan depends on your battery size and how aggressive you can be with discharge.

For the Eco-Conscious Family

Ecotricity is one of the few NZ retailers that has gone the distance on carbon-zero certification, and Resi-Flex genuinely encourages exporting during the times when your power displaces the dirtiest grid generation. That's not greenwashing; it's a real carbon impact.

If your priorities lean towards environmental outcomes alongside dollar returns, Resi-Flex with a battery is one of the more aligned setups available in NZ today. Pair it with smart hot water and an EV on off-peak charging and your household sits near the top of the residential decarbonisation league.

How Resi-Flex Compares to Other NZ Buy-Back Plans

The NZ solar buy-back market has tightened up significantly in the last two years. Here's where Resi-Flex sits relative to the main alternatives.

• Octopus Energy NZ offers similar peak-rewarding logic via OctopusPeaker, with strong dynamic tariff integration. See our OctopusPeaker vs OctopusFlexi breakdown.
• Meridian Energy offers a flat buy-back that's competitive for households without batteries. See Meridian's solar plans explained.
• Power Edge is a smaller specialist offering longer-term buy-back contracts at fixed rates. See our Power Edge contracts review.
• Genesis, Mercury, Contact all offer flat buy-back plans, generally at lower rates than the specialist solar retailers but with the benefit of larger company stability and bundled services.

The honest summary: if you have a battery, look hard at Resi-Flex and OctopusPeaker. If you don't, a flat-rate plan from Meridian or one of the big three is usually the simpler, higher-earning choice.

Common Pitfalls: What Installers Won't Always Tell You

Here's where the trust-proxy hat goes on. We've seen homeowners make these mistakes more than a few times.

1. Signing up for Resi-Flex without a battery. Some installers will mention "premium peak buy-back" as a selling point during the quote without explaining that you need a battery to actually capture it. Read your export profile carefully before switching plans.

2. Oversizing the system for the wrong reason. A 12 kW system on a household with a 5 kWh battery doesn't earn 2.4 times what a 5 kW system earns on Resi-Flex; it just exports more during off-peak hours at the lower rate. Size the system to your peak-window export capacity, not just your roof space.

3. Not configuring the battery properly. Default battery settings on most inverters prioritise self-consumption, not grid export. To capture Resi-Flex peak rates, you need to actively configure the battery to discharge into the grid during peak windows, not just into the house. A good installer will set this up; some won't, and you'll need to ask.

4. Ignoring the import side of the tariff. Resi-Flex's import rates are also time-of-use, so if you're running a heat pump full-bore at 6pm in winter, you're paying peak prices for that. The plan suits households who can shift load (dishwasher, washing machine, EV charging) to off-peak windows.

5. Assuming the rates won't change. All NZ retailers can and do adjust buy-back rates. Resi-Flex's headline peak rate today may not be the headline peak rate in 18 months. The Buy-Back Engine tracks these changes; check it before signing and check it again annually.

Frequently Asked Questions

Is Ecotricity's Resi-Flex the highest paying solar buy-back in NZ?

During the defined peak windows, yes, Resi-Flex is consistently among the top one or two NZ peak-export rates. For total annual earnings, however, the "highest paying" plan depends entirely on whether you have a battery and how much you can export during peak hours. A flat-rate plan can out-earn Resi-Flex for solar-only households.

Do I need a battery to be on Resi-Flex?

No, you don't need a battery to sign up, but you almost certainly need one for the plan to pay better than a flat-rate alternative. Without a battery, your solar exports happen mostly outside the peak window, so you'd earn the lower off-peak rate on most of your generation.

Is Resi-Flex available in my region?

Resi-Flex is available across much of Canterbury, Wellington, Auckland, and selected regions on Powerco, Unison, and Aurora networks. Availability depends on your specific ICP and lines company. Enter your address with Ecotricity directly to confirm before you commit, and check our Buy-Back Engine for region-specific comparisons.

What inverter size limit applies?

Ecotricity typically caps residential export at 10 kW for single-phase and higher for three-phase connections, in line with most NZ lines company rules. If your inverter exceeds this, you'll either need to export-limit it or move to a small commercial arrangement.

Is there a fixed-term contract?

Residential Resi-Flex plans are generally no-fixed-term, which means you can switch away if a better offer turns up. Always confirm the current terms with Ecotricity at sign-up, as retailer T&Cs change.

How does Resi-Flex compare to OctopusPeaker?

Both plans reward exporting during peak demand windows, but the specific hours, rates, and dispatch mechanics differ. OctopusPeaker integrates with Octopus's broader dynamic tariff ecosystem (good for EV households), while Resi-Flex sits inside Ecotricity's carbon-zero retail proposition. See our full Octopus tariffs breakdown for a side-by-side.

Will Resi-Flex's rates stay the same?

No retailer guarantees long-term buy-back rates in NZ outside of specific fixed-term products (like some of Power Edge's offerings). Resi-Flex peak and off-peak rates can be adjusted with notice. Our Buy-Back Engine tracks current rates across the market.

Can I get on Resi-Flex if I already have solar installed?

Yes. You don't need to install new equipment to switch to Ecotricity Resi-Flex (provided your existing system meets the standard NZ grid-connection requirements). The switch is a retailer change, not a hardware change, and your half-hourly smart meter handles the time-of-use reporting automatically.

Does Resi-Flex pay extra in winter?

The rate structure doesn't change seasonally, but the earning opportunity shifts. In winter, peak windows are darker and longer, so battery dispatch into peaks becomes more valuable per discharge cycle. In summer, you'll have more total export volume but a smaller proportion lands in peak windows.

Where to Go From Here

If you've got a battery (or are planning one) and you're in a Resi-Flex-eligible region, the plan is genuinely worth modelling against your alternatives. The premium peak rate is real, and the carbon-zero credentials of Ecotricity are a meaningful bonus for households who care about that side of things.

Your next steps:

• Run your numbers in the Dynamic Tariff & Buy-Back Engine with your system size, battery capacity, and export pattern.
• Compare against the Octopus peak-export options and the Meridian flat-rate plans.
• If you're a long-term thinker, also check Power Edge's fixed-term contracts.
• Read our wider NZ solar tariffs and retailers guide for the full picture.

And if you haven't yet installed solar (or are sizing up a battery upgrade), the single best move is getting honest, comparable quotes from installers who know how to set up a system properly for time-of-use export plans like Resi-Flex.