Solar buy-back rates in New Zealand explained

A solar buy-back rate is what your electricity retailer credits you for surplus power your panels export to the grid. New Zealand has no single government-mandated feed-in tariff for homes. Each retailer sets its own rate and plan rules, and those numbers change.

That is why this guide does not publish a frozen retailer price list. Instead it explains how buy-back works, why self-consumption usually matters more, how to read plan fine print, and where to check live rates before you switch.

If you only remember one idea: a kilowatt-hour you use yourself typically avoids a much higher retail import price than the credit you earn by exporting it.

Import price versus export credit

Households often pay roughly three to four times more to import a kilowatt-hour than they receive to export one, though exact gaps depend on your plan and region. EECA’s consumer material emphasises using your free solar first; selling surplus is the secondary benefit.

Example logic, not a personal quote: if you avoid buying power at about 30–40c/kWh by running the hot water cylinder at noon, that saved unit is worth far more than exporting the same unit at a lower buy-back credit. Shifting loads beats shopping for a slightly higher export rate in many homes.

What shapes the credit you actually earn

Headline cents per kilowatt-hour are only the start. Plans may use flat rates, time-of-use windows, seasonal peaks, system size caps, or fixed-term conditions. A high peak rate that applies only on winter weekday evenings does little for sunny midday surplus in January.

• Flat vs peak/off-peak export pricing
• Whether GST is included in the advertised figure
• Maximum system size or export volume the plan allows
• Contract length, exit fees, and signup credits
• Daily charges and import rates on the same plan

How to compare plans without getting trapped

Compare the whole bill, not only buy-back. A plan with a flashy export rate can still cost more if daily charges or import rates are poor for your night-time use.

Check current published solar rates on Powerswitch’s solar rates tool: https://www.powerswitch.org.nz/solar-rates. Retailers change offers, so verify on the retailer’s site before you switch, and keep a copy of the terms that applied when you signed up.

Self-consumption tactics that beat rate chasing

Timer hot water to the middle of the day when it is safe and suitable for your cylinder controls. Run dishwashers, washing machines, and dryers while generation is high. Charge an EV on a daytime schedule if your travel pattern allows.

Heat pumps and controlled loads can often be nudged without hurting comfort. The goal is not to make life awkward — it is to move flexible loads into sunshine hours so fewer kilowatt-hours are bought after dark.

Meters, networks, and export limits

Exporting usually needs an import/export capable meter and acceptance from your lines company through the distributed generation process. Your installer typically lodges that application. Until approval lands, the system may be limited even if panels are on the roof.

Some networks set export limits. That can influence array size and whether a battery helps store energy that would otherwise be clipped. Ask the installer what limit applies at your address and how the design respects it.

Batteries and buy-back

A battery is not a substitute for a good retailer plan, and a good plan is not a reason to skip storage if you truly need backup. Financially, many homes still do better exporting modest surplus and avoiding battery cost — especially when evening loads can shift.

If you cannot shift loads and export credits are low, storage becomes a more serious conversation. Model both paths with the same usage data rather than buying both maximum array and maximum battery by default.

Common mistakes

Do not size a system only to maximise export. Do not switch retailers on buy-back alone. Do not assume last year’s blog table is still accurate. Do not ignore daily charges. Do not forget that winter generation falls while evening lighting and heating rise.

Also do not expect export credits to zero the bill. Lines charges and night imports remain. Solar reduces what you buy; it does not erase the network’s fixed costs.

How credits appear on your bill

Export is usually credited in kilowatt-hours multiplied by the plan’s buy-back rate, then netted against what you owe for imports and daily charges. You may build summer credit and draw on it in winter, depending on the retailer and your usage shape.

Read the bill line items for a few cycles after switch-on. Confirm the export volume looks plausible against your inverter app. Discrepancies are easier to fix early than after a year of wrong assumptions.

Policy and market context without the hype

Retail buy-back sits inside a wider electricity market that continues to evolve. Occasional policy discussions about fairer export rewards do not replace today’s plan terms. Design your system for the rates and rules you can verify now, and treat future reforms as upside, not as the base case.

Installer marketing that leans on a speculated future tariff should be challenged. Ask for savings modelled on current retailer options you are willing to use.

Worked thinking example

Suppose your panels export 2,000 kWh in a year at a modest flat buy-back while you still import heavily after 6pm. Improving self-consumption by moving 500 kWh of hot water and laundry into daylight can outweigh finding a buy-back rate a couple of cents higher — because those 500 kWh avoid the full retail import price.

That is why this site’s cost and worth-it guides hammer daytime use. Buy-back is the cleanup mechanism for surplus, not the core business case for most homes.

Practical next steps

Read your last twelve months of usage if the retailer app allows it. Note when you use power. Check live buy-back options on Powerswitch, then ask solar quotes to model self-consumption for your roof. Decide array size first, retailer plan second, battery third.

Home Solar Installation NZ can introduce you to a local installation partner for a written generation estimate. The form is free and there is no obligation to proceed.

For EECA’s framing of savings through using your own solar first, see https://www.eeca.govt.nz/for-homes/solar-for-homes/solar-costs-and-savings/

Switching retailers after solar

You can usually change electricity retailers after solar is installed, but you must check that the new plan accepts your system size and export arrangement. Some offers look generous until you find a kilowatt cap or a fixed term that clashes with your goals.

Before switching, export your generation and usage history, note your meter type, and confirm the new retailer can continue export credits without a long re-commissioning drama. Ask solar-aware retailers how they handle existing distributed generation customers.

Keep the installer’s documentation handy. Retailer call centres move faster when you can quote system size, inverter make, and the date export began.

Export caps and clipped midday surplus

If your lines company limits export, your inverter may reduce output when the house cannot absorb the power and the export cap is reached. From the footpath the system looks idle; in reality it is obeying network rules.

That is another reason not to size purely for export revenue. Capacity you cannot export or store has limited value. Discuss caps before you buy a larger array than the connection can use.

Batteries and load shifting are the two practical responses. Neither is mandatory, but both beat pretending the cap does not exist when you read the annual yield estimate.

Reading Powerswitch without drowning

Use Powerswitch’s solar rates tool as a living directory, not as a one-time screenshot you keep for a year. Note the date you checked, the plan name, and any system size cap. Then confirm the same details on the retailer site before you switch.

If two plans look close on buy-back, compare daily charges and night import rates next. The plan that wins on export alone can still lose on the rest of the bill for an evening-heavy home.

Keep export in proportion

Export credits are real money, just smaller money than avoided imports. Celebrate a good buy-back plan, then go back to timers, hot water scheduling, and right-sized arrays. Households that obsess over one cent of export while ignoring evening heaters usually leave larger savings on the table.

Revisit your plan annually or when your retailer emails a change. Rates move. Your roof does not have to.

Bottom line on buy-back

Treat buy-back as a helpful credit on surplus power, check live rates before you switch, and put most of your effort into using solar while the sun is up. That order of priorities matches how New Zealand household bills actually improve after a well-sized install.