Orchard and Packhouse Solar Nelson Tasman: Size it to the quiet months, not the harvest

Tasman grows 23 percent of New Zealand's apples by planted area and 38 percent of its pears (Stats NZ), and most of that fruit goes through a packhouse and a coolstore. Refrigeration is the big load, up to 85 percent of a coolstore's energy use (EECA). The catch for solar is timing: the harvest runs from February to mid May and the stores run down by early summer, so a packhouse is busiest when the sun is lower and quietest when it is highest.

We are not an installer. Involve Energy models the system against your own load, arranges the financing stack and project-manages SEANZ-certified local crews through to commissioning, so you own the asset with an independent model behind it and one point of accountability.

The apple year against the solar year

On a typical 10 degree packhouse roof, the harvest months from February to May get 31 percent of a Nelson array's year and November to January 36 percent. Tilting the panels to 39 degrees on frames evens the year out (33 percent and 30 percent), at the cost of the frames and wider row spacing.

That sets the size. An array whose December output fits under what the site draws on December days uses most of its power in every month; one sized to the harvest exports much of its summer output for a low buy-back rate. A feasibility study models it month by month against twelve months of your bills, so the quiet months are priced in rather than averaged away.

What solar saves on Network Tasman

Network Tasman's lines charges are low, and its discount, credited through your retailer twice a year, is paid on the electricity you take from the network, so a kWh from your panels saves the charge but forgoes its discount. Weighted by when a Nelson array generates, solar saves about 3.3 cents a kWh of lines charges on a 20 to 150 kVA connection (T-2) and 2 to 2.5 cents over 150 kVA (T-3.4), where days from October to April cost 0.56 cents. In Nelson city, on the former Nelson Electricity network that amalgamated with Network Tasman on 31 March 2026, a 20 to 150 kVA connection pays 4.5 cents on weekdays and 1.7 cents at weekends, with no discount.

So the saving per kWh is mostly your energy rate, which your retailer sets and your bill shows. Nationally, MBIE puts the average price, lines and fixed charges included, at 17.7 cents a kWh for food processing and 25.5 cents for commercial customers in the year to March 2026. Our calculator values solar used on site at 20.4 to 25.5 cents, the commercial average and that average less a fifth for fixed charges; on Network Tasman fewer of those cents are lines charges, so the table below prices the worked example from 16 to 28 cents. It assumes power used across the day, because refrigeration runs around the clock.

How it works

1. 01

   Feasibility

   Send twelve months of power bills, ideally half-hourly data. We model system size, generation against your actual load, self-consumption, cost, savings and payback on your numbers, not industry averages.

2. 02

   Financing

   We apply the Investment Boost deduction and match the remainder to the best available green or interest-free business lending, sized so the repayment sits at or below your current bill wherever the numbers support it.

3. 03

   Installation

   Certified local crews install and commission the system on the packhouse or coolstore roof, or on frames alongside. We manage the Network Tasman connection approval, the electrical certification and the programme around your harvest so packing and the cold chain are never at risk.

4. 04

   Monitoring

   Once live, we watch performance, flag anything underperforming and report your actual savings against the model, year after year.

Start from the worked example below, then send a year of bills for the month by month version. The wider picture is in our cold store and packhouse guide, alongside our pages for Central Otago orchards and packhouses and Canterbury cold stores.