Electricity guide · New Zealand
Solar Buy-Back Rates and Payback NZ
Learn how New Zealand solar buy-back or export rates affect annual credits and payback, what to check in a retailer plan and why self-use also matters.
Reviewed 26 August 2026
Reviewed by KiwiTools editorial team — NZ energy researchers using Electricity Authority and EECA sources
General planning information. Electricity prices, time bands, appliance performance and solar export terms vary by address, retailer, installation and usage.
Key points
Solar export rates in a payback model
Buy-back rate is the price credited for each eligible kWh exported to the grid.
Annual export credit = exported kWh × buy-back price in dollars per kWh.
A high export rate should be compared with import prices, daily charges, eligibility, contract terms and the amount actually exported.
Payback sensitivity for a $14,000 solar installation
Simple payback divides installed cost by annual bill benefit. It excludes financing, maintenance, degradation and opportunity cost.
| Check | Annual solar benefit | Simple payback | What could produce it |
|---|---|---|---|
| Conservative | $1,000 | 14.0 years | Lower self-use or tariffs |
| Middle case | $1,400 | 10.0 years | Balanced self-use/export |
| Strong case | $1,750 | 8.0 years | High daytime use |
| Very strong case | $2,000 | 7.0 years | High prices and optimised use |
Buy-back is one line in the solar return
Retailers credit exported kWh at their published terms. From July 2026, large retailers must offer fair pricing for exports at busy times, but plans, time bands and eligibility still vary.
A generous export rate can sit beside expensive imports or daily charges. Compare the entire electricity plan using the home’s import and export profile.
Simple payback is useful when its assumptions are visible
A $14,000 system saving $1,400 a year has a ten-year simple payback. At $1,000 it is fourteen years. Those clean figures exclude finance cost, degradation, maintenance and the return the cash might earn elsewhere.
Run conservative and strong cases instead of publishing one heroic answer. EECA notes that high daytime use and local electricity prices materially change household results.
Related: solar self consumption vs export Related: electricity daily charge vs kwh rate Related: electricity rate per kwh
Bigger is not automatically better
Panels sized far beyond daytime consumption export more at the lower buy-back value. The cheapest cost per panel can still produce a slower household payback.
Use interval consumption, roof orientation, shade and network export limits. A reputable quote should show generation, self-use and export separately rather than valuing all production at the retail import rate.
Frequently asked questions
What is a solar buy-back rate?
It is the price a retailer credits for each eligible kWh of surplus solar electricity exported to the grid.
Is there one solar export rate in NZ?
No. Rates and conditions differ by retailer and plan and can change.
How do I calculate solar export credits?
Multiply exported kWh by the buy-back rate expressed in dollars per kWh.
Does the highest buy-back rate mean the best power plan?
Not necessarily. Compare import prices, daily charges, eligibility, discounts and the household’s import/export profile.
Put the guide into practice
Continue with related KiwiTools calculators
Test your own numbers, compare scenarios and return to the guide to check assumptions and limitations.