Electricity guide · New Zealand
Solar Self-Consumption vs Export NZ
Understand why using solar electricity at home and exporting it to the New Zealand grid have different values, and calculate the effect on solar payback.
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
Two values for generated solar energy
Self-consumed solar avoids buying a kWh at the applicable retail usage rate.
Exported solar earns the retailer’s buy-back rate, subject to the plan and metering arrangement.
When the retail rate exceeds the export rate, increasing useful daytime self-consumption generally increases financial value.
Value of 1,000 solar kWh
Avoided imports are worth the retail variable rate; exports earn the buy-back rate. This example uses 30 cents imported and 12 cents exported.
| Check | Used at home | Exported | Annual value |
|---|---|---|---|
| 30% self-consumed | 300 kWh × $0.30 | 700 kWh × $0.12 | $174 |
| 50% self-consumed | 500 kWh × $0.30 | 500 kWh × $0.12 | $210 |
| 70% self-consumed | 700 kWh × $0.30 | 300 kWh × $0.12 | $246 |
| Value of shifting 200 kWh | Avoids import instead of export | Difference is 18c/kWh | $36 |
A solar unit used at home replaces a retail purchase
If imported electricity costs 30 cents per kWh and export earns 12 cents, a self-consumed solar kWh is worth 18 cents more than an exported one. That gap—not an abstract percentage—is the reason daytime use matters.
Fixed daily charges usually remain, so self-consumption value comes mainly from avoided variable imports. Do not credit every generated kWh with the full average bill rate.
Shift flexible loads into sunshine
Dishwashing, laundry, hot-water heating and EV charging can often move into the middle of the day. Automation is more reliable than expecting someone to remember every sunny Tuesday.
Move existing consumption before inventing new consumption. Running an appliance unnecessarily because the power feels free does not improve household economics.
Related: solar buyback rates and payback Related: peak off peak electricity rates Related: electricity rate per kwh
A battery buys timing, not free energy
A battery can store surplus for the evening and lift self-consumption, but it adds cost, conversion losses and eventual replacement risk. Its value depends on the import/export spread, usable capacity and cycles actually used.
Price resilience separately from financial payback. Backup power can matter to a household even when the spreadsheet return is weaker.
Frequently asked questions
Is it better to use solar power or export it?
When the avoided retail rate is higher than the export rate, useful self-consumption generally has more direct value per kWh.
What is a solar self-consumption rate?
It is the percentage of generated solar electricity used on site at the time it is produced.
Does solar remove the daily power charge?
Usually not while the home remains grid connected under a plan with a fixed daily charge.
How do I value exported solar?
Multiply exported kWh by the current buy-back rate and apply any relevant plan conditions or fees.
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.