AWARDS FINALIST: Calder Stewart, Endless Energy and Ecotricity – Reverse 144 national solar roll-out
A partnership between Calder Stewart, Endless Energy and Ecotricity has created a new model for commercial rooftop solar development.
Their "Reverse 144" model speeds up commercial solar installation, which is often limited by tenant energy use and delayed by the complexities of negotiating power-purchase agreements with them.
The partners say Reverse 144 flips that model. Instead of supplying energy to the building's occupants, these rooftop systems export electricity directly to the national grid - with no capital from the building owner and no tenant involvement.
The name "Reverse 144" is a nod to New Zealand's historic "144" tariff, under which large users were paid to reduce demand.
Roof rights
Ecotricity says this model does the opposite: it injects renewable solar energy into the local grid to meet rising demand and support decarbonisation.
The roll-out is being implemented across Calder Stewart's extensive portfolio of industrial buildings. Thanks to a unique easement structure, Calder Stewart retains roof rights even after buildings are sold, enabling long-term solar deployment without disrupting ownership or tenancy.
Designer and installer Endless Energy manages the full asset lifecycle - from design and installation to metering and maintenance - while Ecotricity purchases the exported power and handles market settlement.
The project is a technical first for New Zealand. Each site features dual metering - one for the tenant, one for the solar export - requiring close collaboration with network operators.
The systems are designed for maximum export, not on-site consumption, and are future-proofed for battery integration and virtual power plant participation later on.
Revenue
Commercially, Reverse 144 is just as innovative. With fixed export rates secured through Ecotricity, Calder Stewart Energy funds the installations, while building owners enjoy a revenue-share without any capital outlay.
The model is modular, scalable and replicable, with almost 10 megawatts under development across more than 40 sites.
The partners say the benefits extend beyond the balance sheet. The project has upskilled contractors, introduced new technical standards and fostered collaboration with lines companies.
The annual Energy Excellence Awards will be held in Wellington on 13 August. The Energy Project of the Year Award is sponsored by Bluecurrent.