Commercial solar in New Zealand: costs, payback and how to decide
Michael Wilkins · Updated 13 June 2026
The short answer
Commercial solar in New Zealand costs roughly $1,400 to $1,800 per kW installed at 100 kW scale in 2026, with paybacks of four to eight years where most generation is used on site. The Investment Boost tax deduction returns about 5.6 percent of the cost in year-one cash for company taxpayers.
How much does commercial solar cost in NZ?
Installed cost falls fast with scale. As at mid 2026 we work to roughly $1,800 to $2,600 per kW at 30 kW, $1,400 to $1,800 per kW at 100 kW, and $1,100 to $1,500 per kW at 250 kW and beyond. These are the same bands our public calculator uses, and EECA's commercial guidance of $1,500 to $2,000 per kW (October 2024) sits inside them. The table below puts whole-project numbers on it.
Two things move you inside the band: roof complexity (steel trapezoidal roofs in good condition are cheapest; ground mounts add structure but can chase better angles) and how competitive the installer tender is. We run that tender across SEANZ-certified installers rather than taking a single quote.
From 22 May 2025 the Investment Boost deduction lets a business deduct 20 percent of a new solar system's cost immediately, with the remaining 80 percent depreciating as normal. For a company taxpayer at the 28 percent rate that is worth roughly 5.6 percent of the project cost in year-one tax cash. It is a deduction, not a discount, and we state it that way everywhere.
What payback should you expect?
Vendor marketing claims four to eight year paybacks and 15 to 25 percent returns for good sites. Treat those as the optimistic end. What actually decides your payback is the share of generation you consume on site: every kWh you self-consume avoids a loaded commercial rate of 25 to 45 cents, while every kWh you export earns a retailer buy-back of typically 7 to 17 cents. That three-to-one gap is the whole game.
Region matters too. Our modelled yields, derated 10 percent from satellite data to reflect real commercial installs, run from about 1,260 kWh per kW per year in Central Otago and 1,250 in Marlborough to 1,200 in Canterbury, 1,090 in coastal Otago and 1,010 in Southland. Sunnier sites generate more, but a Southland dairy shed with the right daytime load can still beat a poorly matched Central Otago site. Load shape beats latitude.
The full mechanics, including why export rates barely move the result, are in our guide to buy-back rates for businesses.
Is commercial solar worth it for your business?
The average commercial electricity price was around 21.3 cents per kWh excluding GST in 2024 (MBIE), prices rose roughly 12 percent through 2025, and lines charges are rising out to 2030 as transmission pricing shifts more cost onto commercial users. Solar is a hedge you own: it converts an open-ended operating cost into a fixed asset with a 30-year life.
The businesses where the numbers work hardest share three things:
- Daytime load: refrigeration, irrigation pumping, processing, compressed air or cool stores running while the sun is up.
- A usable roof or land: north-facing steel roofs in sound condition, or paddock corners for ground mounts.
- A planning horizon past five years, so the owner, not the next tenant, banks the savings.
If that sounds like your operation, the segment guides go deeper: dairy farms, wineries and vineyards, and orchards, packhouses and cold stores across the South Island.
How the buying process works
- 1
Analyse a year of usage
Half-hourly consumption data for 12 months, the method EECA recommends, shows exactly when you use power and how much a panel array would actually offset.
- 2
Independent feasibility study
Sizing, satellite irradiance for your site, costs from current bands, financing and incentives, and a 25-year cash flow with disclosed assumptions.
- 3
Arrange the financing stack
Green loans, the Investment Boost deduction and any live offers, stacked cheapest rate first. Claims like cashflow positive only get made when the whole cost is covered.
- 4
Tender and install
SEANZ-certified installers price the specified system competitively. Installation on a commercial roof typically runs days to a few weeks, not months.
What a proper study contains, and the red flags in free vendor assessments, is covered in our feasibility study guide.
Commercial solar is the laggard, which is the opportunity
Financing has also caught up: between the Investment Boost deduction and bank green lending, including dated offers like the ASB Smart Solar Loan for rural customers, most viable projects can now be structured so repayments sit below the power-bill savings for a sensible term. The financing guide compares the options honestly, including what happens when offers lapse.
| System size | Cost per kW | Indicative total | Suits |
|---|---|---|---|
| 30 kW | $1,800 to $2,600 | $54,000 to $78,000 | Small packhouse, workshop, dairy shed |
| 100 kW | $1,400 to $1,800 | $140,000 to $180,000 | Winery, cool store, processing site |
| 250 kW | $1,100 to $1,500 | $275,000 to $375,000 | Large processor, irrigation scheme |
| 500 kW | $1,100 to $1,500 | $550,000 to $750,000 | Industrial site, multi-shed operation |
Run your own numbers
Conservative assumptions, fully disclosed, no contact details needed.
Your indicative numbers
Conservative, ex GST, modelled not promised
System size
69 kW
Sized to your daytime load
Installed cost
$108,823 to $148,646
Confirmed with certified installers
Investment Boost, year one
about $7,209
A 20% immediate tax deduction, worth this in cash at the 28% company rate. Not a discount.
Estimated annual saving
$18,779 to $22,257
80% of generation used on site
Indicative payback
4.5 to 7.5 years
Net of the Investment Boost benefit
Asset life
25+ years
Panels keep producing long after payback
ASB Smart Solar Loan: 0% for 5 years
Your current bill
$4,000/month
Loan repayment
$2,146/month
Estimated saving
$1,710/month
Reverts to a floating business rate after five years.
On these numbers the monthly repayment of $2,146 sits at or below your current bill of $4,000 while the loan runs, and the power keeps getting cheaper after it ends.
How this is modelled (assumptions v2026-06-v3)
- Power valued at $0.25 to $0.30/kWh ex GST (savings are never valued at the top of the commercial tariff range).
- Export credited at $0.08/kWh, the conservative end of current buy-back rates.
- Installed cost interpolated from 30 kW ($1,800 to $2,600/kW) down to 500 kW ($1,100 to $1,500/kW), 2025/26 working ranges.
- Central Otago and Queenstown Lakes yield modelled at 1260 kWh per kW per year.
- Self-consumption capped by your daytime usage profile and held below typical vendor claims; sizing targets 90 percent of daytime load.
- Investment Boost stated as the year-one cash value of the 20 percent immediate deduction at the 28 percent company rate. It is a tax timing benefit, not a discount.
- No power price escalation and no panel degradation in simple payback; omitting escalation outweighs degradation, so the net effect is conservative.
Indicative only; not financial or tax advice. The feasibility study models your site from twelve months of actual bills.
Get these numbers checked properly
The real model is built from twelve months of your bills. Send your details and we will do it for you; we reply within one working day, no obligation.
Straight answers
How much does commercial solar cost in NZ?
As at mid 2026, expect roughly $1,800 to $2,600 per kW installed at 30 kW, $1,400 to $1,800 per kW at 100 kW, and $1,100 to $1,500 per kW at 250 to 500 kW. A 100 kW system therefore lands around $140,000 to $180,000 before the Investment Boost tax deduction. EECA's published guidance of $1,500 to $2,000 per kW sits inside these ranges.
What payback can a business expect from solar?
Vendors commonly claim four to eight years for good commercial sites. The honest answer depends on how much generation you use on site: self-consumed power offsets a 25 to 45 cent retail rate, while exports earn only 7 to 17 cents. High daytime loads in sunny regions sit at the fast end; we model conservatively and show the assumptions.
How long do commercial solar panels last?
EECA's commercial solar guidance puts panel life at 30 plus years with output declining around 0.8 percent a year, and inverter life around 15 years. We model 0.5 percent annual degradation, between vendor claims of 0.4 and EECA's conservative figure, and include an inverter replacement in the cash flow at year 13.
Does a business need a battery with solar?
Not to start. A battery shifts daytime generation into evening use and can keep critical loads running through outages, but it adds cost that often slows the headline payback. If your load is mostly in daylight hours, panels alone usually stack first. We model batteries separately so the numbers, not the bundle, decide.
What size solar system does my business need?
Size to your daytime consumption, not your roof. The aim is to cover most of what you use while the sun is up without exporting heavily, because exports earn far less than the retail rate you avoid. A monthly power spend of $2,000 to $5,000 with daytime operations typically points at 30 to 100 kW; a half-hourly analysis of 12 months of usage settles it.
For your industry and region
Put your own numbers on it
Two minutes in the calculator with conservative, disclosed assumptions, or book an independent feasibility study and get the full model.