Solar panels for farms: Solar sized to the loads your farm runs in daylight
The short answer
Solar panels pay on a farm when they are sized to the loads that run in daylight: milk chilling, cool stores, effluent pumps, water heating, and irrigation pumps run in the day. As at 2026 a farm system of 30 to 100 kW costs roughly $54,000 to $180,000 installed, and the Investment Boost returns about 5.6 percent of that in year-one tax cash.
Where it pays
The farm loads that suit solar
- Cool stores and packhouses
- Refrigeration peaks in the warm months, with the sun, and runs year round. Orchards and packhouses in Central Otago.
- Milk chilling and vat refrigeration
- Runs after every milking and through the day; solar carries the daylight share. Solar for dairy farms.
- Winery refrigeration and processing
- Cooling through summer and the vintage peak in autumn. Solar for wineries.
- Irrigation pumping
- A match by season, and by the hour only if the pump runs in daylight. Irrigation connections pay mostly for pump capacity and carry no other load, so solar saves less per kWh there and pays when pumping moves into daylight. Solar for irrigation.
- Water heating and effluent pumping
- Put cylinders and pumps on midday timers and they use generation that would otherwise be exported.
What does not suit: the pre-dawn milking peak, frost fans on cold clear nights and winter-only loads. A battery can shift some generation into the evening, but it rarely pays on its own: when a business battery pays.
Not a solar farm
Farm solar is not a solar farm
A solar farm is a utility-scale array that sells its power to the grid, usually built by a developer on land leased from a farmer; several are operating or being built across Canterbury. Farm solar is the opposite arrangement: panels on your shed roof or a paddock corner, sized to power your own operation, owned by you and paid for by the power you no longer buy.
If a developer has approached you about leasing land, that is a property deal for you and your lawyer. What we do is make your own farm cheaper to run.
The numbers
What farm solar costs and makes
| System size | Cost per kW | Installed cost | Investment Boost, year-one tax cash | Output a year, Canterbury |
|---|---|---|---|---|
| 30 kW | $1,800 to $2,600 | $54,000 to $78,000 | $3,000 to $4,400 | 39,000 kWh |
| 50 kW | $1,690 to $2,370 | $84,000 to $119,000 | $4,700 to $6,600 | 66,000 kWh |
| 100 kW | $1,400 to $1,800 | $140,000 to $180,000 | $7,800 to $10,100 | 131,000 kWh |
| 250 kW | $1,100 to $1,500 | $275,000 to $375,000 | $15,400 to $21,000 | 328,000 kWh |
Roof or paddock
Shed roof or ground mount
Most farm systems go on the roof of a dairy shed, implement shed or packhouse: the structure is already there and the connection is close. Ground mounts suit when the roof is small, shaded or due for replacement. They cost more for frames and trenching, but they can face due north at the best angle, and stock can graze around them.
Either way, every grid-connected system needs the lines company’s approval before it goes live, systems over 10 kW go through the fuller application, and the work needs a Certificate of Compliance and an independent inspection. We manage all of it, around your milking, harvest or irrigation calendar.
Paying for it
Rural finance and the Investment Boost
The Investment Boost lets a farming business deduct 20 percent of a new system’s cost immediately, worth about 5.6 percent of the cost in year-one tax cash at the 28 percent company rate. It is a deduction, not a discount. What it is actually worth.
ASB Smart Solar Loan: 0 percent for 5 years on up to $150,000 for ASB rural customers’ on-farm solar and battery. Reverts to a floating business rate after five years. Terms checked against asb.co.nz on 8 October 2026.
The worked example above sets the loan repayment next to the saving, so you can see the monthly position while the loan runs, not just the payback. The options, including PPAs, are compared in solar finance for NZ businesses.
By industry and region
Farm solar where you are
- WineriesMarlborough1,390 kWh per kW a year
- Orchards, packhouses and coolstoresNelson Tasman1,330 kWh per kW a year
- Cold stores and packhousesCanterbury1,310 kWh per kW a year
- IrrigationCanterbury1,310 kWh per kW a year
- Dairy farmsCanterbury1,310 kWh per kW a year
- Orchards, packhouses and cold storesCentral Otago1,220 kWh per kW a year
- Dairy farmsCoastal Otago1,220 kWh per kW a year
- WineriesCentral Otago1,220 kWh per kW a year
- Dairy farmsSouthland1,140 kWh per kW a year
Your numbers
Run your farm's numbers
Your farm or business
Your indicative numbers
Conservative, ex GST, modelled not promised
Measure
- Power used
- 188,235 kWh a year
- Your spend at 25.5c a kWh ex GST, the national commercial average.
- Power bill
- $48,000 a year
Design
- System
- 39 kW
- Sized to your daytime load.
- Generates
- 51,090 kWh a year
- Used on site
- 55%
- The rest exports at 8c a kWh.
- Installed cost
- $68,194 to $97,389
- Confirmed with certified installers.
Finance
- Investment Boost, year one
- about $4,636
- A 20% immediate tax deduction, worth this in cash at the 28% company rate. Not a discount.
- ASB Smart Solar Loan
- $1,380 a month
- 0% for 5 years. Reverts to a floating business rate after five years. Terms checked against asb.co.nz on 8 October 2026. ASB may change or withdraw the offer; the calculator only shows it while it matches.
- Estimated saving
- $691 a month
- Mid estimate, set against the repayment while the loan runs.
Outcome
- Saving
- $7,572 to $9,005 a year
- Payback
- 7 to 12 years
- Net of the Investment Boost benefit.
- Emissions avoided
- 2.1 t CO₂e a year
- Asset life
- 25+ years
- Panels keep producing long after payback.
How this is modelled (assumptions v2026-10-v7)
- Power valued at $0.20 to $0.26/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.
- Canterbury yield modelled at 1310 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.
Next step
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
The questions farmers ask
Can I power my shed with solar panels?
Yes. A shed roof is the most common home for farm solar, and the panels power whatever runs on that connection in daylight: pumps, chillers, workshops and lights. Size to the daytime load rather than the roof area, because exports earn 7 to 17 cents per kWh against the 20.4 to 25.5 cents our model values power you use yourself at.
How big a solar system does a farm need?
It follows the daytime load. A typical dairy shed system is around 30 kW, while packhouses and the pumps on large pivots can justify 100 kW or more. Twelve months of power bills, ideally half-hourly data, show how much of your use falls in daylight and settle the size.
Does farm solar qualify for the ASB Smart Solar Loan?
ASB's Smart Solar Loan is for ASB rural customers financing on-farm solar and battery systems. Whether it is available, and on what terms, is shown in our calculator, which checks ASB's page daily and hides the offer the moment its terms change. Other banks' green lending suits larger projects or customers of other banks.
Is farm solar the same as a solar farm?
No. A solar farm is a utility-scale array that sells power to the grid, often built on land leased from a farmer. Farm solar powers your own operation from a shed roof or paddock corner, and you own it.
What happens to farm solar in winter?
Output in most South Island regions falls to roughly 40 to 60 percent of summer in mid winter. The case is built on the high-use irrigation, chilling and processing months, and our model counts the full seasonal shape month by month.
Do I need a battery on a farm?
Not to start. A battery shifts daytime generation into the evening and can keep critical loads running in an outage, but it adds cost that usually slows the payback. Size panels to the daytime load first and model a battery as a separate decision.
Send a year of farm bills. Get the model.
An independent feasibility study on your own numbers: system size, cost, savings, payback and the finance to fund it. No obligation, and yours to keep.