What a commercial solar feasibility study includes, and when you need one

What a proper study includes

1. 1

   Half-hourly consumption analysis

   Twelve months of usage, half-hourly where your retailer provides it: the method EECA's commercial solar guidance recommends, because when you use power decides what solar is worth.

2. 2

   Site-specific generation model

   Satellite irradiance for your actual coordinates, panel orientation and shading, derated 10 percent for real-world commercial installs rather than laboratory conditions.

3. 3

   Sizing to self-consumption

   The system is sized to cover most of your daytime load, not to fill the roof, because self-consumed power is worth two to four times export.

4. 4

   Costs from current bands

   Installed cost from the same published bands as our calculator, then tested against a competitive tender across SEANZ-certified installers if you proceed.

5. 5

   Financing and incentives

   Live offers stacked cheapest rate first, the Investment Boost deduction stated at your entity's tax rate, and any uncovered remainder shown plainly.

6. 6

   A 25-year cash flow you can audit

   Payback, IRR, lifetime savings and emissions, with degradation, opex and an inverter replacement included, and every assumption version-stamped and disclosed.

Why half-hourly data matters

Two businesses with identical $4,000 monthly bills can have opposite solar economics: one runs refrigeration all day, the other runs night shifts. Monthly bills cannot tell them apart; half-hourly interval data can. EECA's commercial-scale solar guidance recommends exactly this analysis over a 12-month period before sizing anything, and it is the foundation of our model rather than an optional extra.

What it costs, and why independence is the point

Our study is a fixed fee, credited against the project if you proceed with us, and the fee buys the answer rather than the sale: if solar does not stack on your site yet, the study says so with the numbers attached. We sell the analysis and the delivery management; we do not sell panels, so the model has no reason to flatter the system size.

On co-funding: EECA supports feasibility studies at 40 percent up to $50,000, but only for organisations spending more than $1.5 million a year on stationary energy. That is meat processors and large manufacturers, not owner-operated farms and wineries, so our study is priced for the businesses the scheme misses.

Red flags in free vendor assessments

• Vendor-claimed yields with no derate: laboratory output survives neither bird droppings nor a Southland winter.
• Self-consumption assumed, not derived: the single number that most decides payback, presented without interval data behind it.
• No degradation, opex or inverter replacement in the cash flow, flattering year 15 onwards.
• Residential buy-back rates applied to a commercial-scale export profile.
• Investment Boost presented as a 20 percent discount rather than a deduction worth about 5.6 percent in year-one cash at the company rate.

Every one of those is checkable against this site: our cost and payback guide publishes the bands and the method, and the calculator publishes its assumptions, version and all.