| 19.95kW Total Solar Array | $4,525 Year 1 Savings | 42 Panels |
Project Overview
Commercial solar NZ installation projects don’t often achieve a perfect match between generation and demand, but KFC’s restaurant at 167 Cavendish Drive, Papatoetoe, Auckland comes close. Future Energy installed a 19.95kW solar array projected to produce an estimated 24,706kWh a year, and modelling shows the restaurant is on track to self consume effectively 100% of that generation, with only a fraction of a kilowatt hour exported to the grid on an average day. Facing an annual electricity bill of around $20,592, the system is projected to deliver $4,525 in savings in year one, paying for itself in 6 years and 5 months, with a 16.62% internal rate of return over the system’s 25 year life.
The Challenge
Fast food restaurants run long hours with a heavy, near constant electrical load from fryers, ovens, refrigeration and HVAC, which makes them a different sizing problem to a typical office or home. Rather than the usual challenge of avoiding an oversized system that exports too much power for too little return, the goal at Cavendish Drive was to size an array that could be almost entirely absorbed by the restaurant’s continuous baseline draw. With weekday energy charges as high as 30c per kWh against an export credit of only 13 to 14c per kWh, every kilowatt hour kept on site and self consumed is worth roughly double what exporting it would earn.
The System
42 × Longi Hi MO X10 LR7-54HVH 475M Panels – 19.95kW Total
42 Longi Hi MO X10 475W panels were selected for this commercial solar installation, delivering a combined array capacity of 19.95kW across two south west facing sub arrays at 3 degree tilt. The Hi MO X10 is Longi’s flagship commercial grade PV solar panel, featuring BC cell technology with up to 24% module efficiency, less than 1% first year power degradation, and 0.35% annual degradation from year two – meaning the system maintains strong output across its full 25 year product warranty period. With a 30 year linear power warranty and TUV, IEC, and CSA certifications, the Longi panel is purpose built for commercial solar power systems where longevity and performance consistency matter.
Sungrow SG20RT – 3 Phase Commercial Inverter
The Sungrow SG20RT is a 20kW three phase multi MPPT string inverter designed specifically for commercial solar NZ and commercial scale applications. With two independent MPPT inputs handling the split 18 panel and 24 panel sub arrays across the roof, the inverter optimises generation from each array section independently – maximising output despite the dual array configuration. The SG20RT achieves up to 98.5% efficiency, includes built in Type II DC and AC surge protection, 24/7 live monitoring via Solar Analytics connected to the site’s mains 400A controller, and carries a C5 anti corrosion rating suited to the Auckland urban environment. The inverter is wall mounted on the roof block wall, keeping the installation clean and accessible.
Dual South West Array – Engineered for the Site
The 42 panel array is split across two south west facing sections at 245 degrees azimuth – SW1 carrying 18 panels at 8.6kW and SW2 carrying 24 panels at 11.4kW. A 500mm access gap runs through the middle of the array as required by the PV plan, with 500mm clearance maintained from the gutter line. DC cabling runs surface mounted on the roof with no cable tray, connecting to the Sungrow inverter before feeding into the HVAC switchboard AC connection. Solar Analytics monitoring is live from commissioning, giving the site real time visibility of generation performance.
System Specifications
- 19.95kW nominal PV array – 42 × Longi Hi MO X10 475W panels
- Sungrow SG20RT 20kW three-phase inverter with dual MPPT
- SW1: 18 panels at 8.6kW – SW2: 24 panels at 11.4kW, both at 245° azimuth, 3° tilt
- Max DC voltage: 757.7V – Max DC current: 30.06A
- AC output: 3-phase, 20kW max, 31.9A – connected to 200A HVAC switchboard
- Solar Analytics monitoring connected to 400A mains catch controller CTs
- Smart meter installed – full generation and consumption visibility from day one
Frequently Asked Questions
Is commercial solar a good investment for a fast food restaurant?
Yes – and commercial kitchens are particularly well suited to it. Fast food restaurants typically trade during daylight hours when solar generation is at its highest, meaning on site generation aligns closely with peak consumption. Rather than exporting surplus at a low rate, the solar energy goes directly into running the site. For a business with high, consistent daytime energy use like KFC Papatoetoe, commercial solar NZ delivers a strong return from day one and compounds over the 25 year life of the system.
How does a 3 phase inverter differ from a standard residential inverter?
A three phase inverter like the Sungrow SG20RT is designed for commercial solar power systems connected to a three phase electrical supply – standard for commercial premises in New Zealand. It distributes solar generation evenly across all three phases, handles significantly higher power outputs (20kW in this case), and is engineered for the reliability demands of commercial operations. For a site like KFC Papatoetoe with a 200A HVAC switchboard and 400A mains supply, a three phase commercial inverter is the correct choice.
Can commercial solar be installed without disrupting an operating business?
Yes. Future Energy regularly installs commercial solar NZ systems on active commercial sites. Careful project planning, sequenced installation, and close coordination with site management means most commercial solar installations can be completed without disrupting trading hours. At KFC Papatoetoe, the system was designed and commissioned with minimal footprint – surface run DC cabling, roof mounted inverter, and a clean AC connection to the existing switchboard.
What monitoring comes with a commercial solar system?
This system includes Solar Analytics monitoring connected to the site’s mains 400A catch controller CTs – providing real time generation data, consumption tracking, and performance reporting from commissioning. A smart meter is also installed, giving complete visibility of grid import, solar generation, and export. For commercial operators, this data is valuable not just for tracking savings but for understanding energy patterns and identifying further efficiency opportunities across the site.
Looking at commercial solar NZ for your business? Future Energy designs and installs commercial solar systems across New Zealand – from single site commercial installations through to multi site rollouts. Talk to us about what the right commercial solar power system looks like for your operation.
