Stage around cashflow
Build the highest-return plane first, prove the model against a year of monitoring data, then extend. The second stage is always better designed than the first.
Installation types
Five ways to mount
Five ways to mount
an array. Each one
changes the answer.
Where the array goes drives the structural work, the consent path, the cost per watt and the yield. Before anyone talks about panel brands, this is the decision that matters. Here is the honest trade-off on each of the five.
Type A
Roof-mounted, pitched metal
The cheapest watt you can install. Rails clamp to the existing purlins with minimal penetration, the array follows the roof plane, and most installations of this type need no building consent.
- Best for sheds, workshops, warehouses and implement barns with a well-oriented slope.
- Watch for roof age, cladding condition and purlin capacity — a 30-year array on a roof with 8 years left is a false economy.
- Yield is fixed by the roof. East–west planes still work; south-facing generally does not.
- Programme is the fastest of the five — days rather than weeks on most sites.
Type B
Roof-mounted, low-pitch or membrane
Tilt frames set the array angle independently of the roof, on ballast or mechanical fixings. Better yield per module than a flat lay, at the cost of a structural check and more careful waterproofing detail.
- Best for large flat commercial and industrial roofs, coolstores and packhouses.
- Row spacing has to clear winter self-shading, so usable capacity is well below the raw roof area.
- Added dead and wind load must be verified — ballast in particular is heavy.
- Penetrations through membrane need detailing that keeps the roof warranty intact.
Type C
Ground-mounted
Driven pile or ground screw on land that isn’t earning anything else. You get optimal tilt and orientation, easy access for cleaning and maintenance, and the strongest bifacial gain of any mounting type.
- Best for farms with sidling, gully margins or unproductive corners, and for sites where the roof is unsuitable.
- Highest yield per kWp — you choose the angle rather than inheriting it.
- Bifacial gain off pasture, gravel or light ground cover is real and worth designing the clearance height around.
- Costs more in steel, civils and cable run, and generally carries a consent path.
Type D
Carpark and yard canopy
A structure in its own right, with foundations, a building consent and a real steel cost. It earns that back by sheltering vehicles, stock or staff and by carrying EV charging on something that is already there.
- Best for sites where the roof is full, leased, shaded or structurally unsuitable.
- Dual purpose — the shelter has value whether or not you count the generation.
- EV provision designed in from the start avoids a second switchboard job later.
- Highest cost per watt of the five, and the longest consent path. Worth it when the shelter is wanted anyway.
Type E
Agricultural and growing structures
Arrays elevated over crops, greenhouses, races and water storage. The land does two jobs at once, and the layout becomes a light-transmission problem as much as an electrical one.
- Best for horticulture, greenhouses and stock that benefits from partial shade.
- Row gaps and clearance height are set by what has to grow and what has to drive underneath.
- Shared land use — generation without giving up productive area.
- Most site-specific of the five. There is no standard layout; it is designed around the crop and the machinery.
The same five types, on the ground.
Installations delivered by The Green Valley and our manufacturing partners. Select any image to see it larger.
Most sites end up with two of these, not one.
A packhouse roof plus a ground mount on the back paddock. A shed roof now and a carport when the EV fleet arrives. Staging is normal and usually cheaper than one large commitment made too early.
Design the switchboard once
Sizing the AC side and the grid application for the eventual system, not just stage one, avoids paying an electrician twice and re-applying to the network.
Mind the export limit
Your lines company sets an export cap for the connection. It applies across the whole site, so stage two has to fit inside the same envelope — or need a fresh application.
References
Ask us for the numbers, not the photos.
A photo of an array tells you nothing about whether it paid off. What matters is modelled yield against measured yield, self-consumption against forecast, and what the power bill actually did afterwards.
We can share monitoring data and financial outcomes from comparable New Zealand installations, and put you in touch with owners running systems of a similar size and load profile.
- Modelled vs. measured yield over a full twelve months of operation.
- Self-consumption rate achieved against what the feasibility study predicted.
- Actual capital cost including consent, structural work and switchboard upgrades.
- Payback tracking against the original financial model.
- Owner contacts for sites of a comparable size and sector, with their permission.
Next step
Find out what your roof is worth.
Send us twelve months of power bills and a roof plan. We come back with a yield model, a layout, an indicative price and an honest view on whether the numbers work.