{"id":478048,"date":"2026-06-15T07:41:10","date_gmt":"2026-06-15T07:41:10","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/478048\/"},"modified":"2026-06-15T07:41:10","modified_gmt":"2026-06-15T07:41:10","slug":"calder-stewart-to-invest-110m-in-rooftop-solar-and-battery-rollout","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/478048\/","title":{"rendered":"Calder Stewart to invest $110m in rooftop solar and battery rollout"},"content":{"rendered":"
The systems are expected to generate about 4.2 gigawatt hours of electricity a year, equivalent to the annual power use of more than 500 homes.<\/p>\n
Christchurch-based Calder Stewart director Sam Stewart told the Herald that \u201cbig sheds\u201d were very much the firm\u2019s bread and butter.<\/p>\n
The company often undertakes study tours overseas.<\/p>\n
\u201cWe saw where things were going in Europe and in California especially,\u201d Stewart said.<\/p>\n
\u201cIt was like, what do we do now to get ahead of this rooftop solar thing that\u2019s happening everywhere else but in New Zealand.\u201d<\/p>\n
The move towards solar started with strengthening buildings to become solar-ready but without necessarily installing it at the time of construction.<\/p>\n
The firm then reserved the rights to those roof spaces through an easement structure.<\/p>\n
\u201cWe did that for a few years before I came back from the UK and said we should do something with this.<\/p>\n
Calder Stewart is investing $110 million in rooftop solar. <\/p>\n
\u201cIt started with retrofits but now it\u2019s every single building as they come through the pipeline,\u201d he said.<\/p>\n
The firm is now checking out the battery side of the equation, particularly as battery prices fall.<\/p>\n
Initially, solar worked out well for building owners as it would supply power to them during the day, helping to avoid the morning and evening demand peaks.<\/p>\n
Now the firm is eyeing batteries.<\/p>\n
\u201cIt\u2019s probably not something that makes absolute commercial sense now, but we are planning for the future,\u201d Stewart said.<\/p>\n
\u201cIt\u2019s something that we need to understand a bit more.\u201d<\/p>\n
Calder Stewart has completed a distribution centre for Fonterra in Christchurch, a facility for Briscoe Group at Drury in Auckland and another one for NZ SafetyBlackwoods on the same site.<\/p>\n
In general, the price per kilowatt installed is coming down, and that\u2019s a multi-year trend, Stewart said.<\/p>\n
Calder Stewart\u2019s first solar installation provided 50 kilowatts (kW).<\/p>\n
Now, the firm will not do anything under 100kW and often 500kW plus.<\/p>\n
Stewart said adoption of rooftop solar across the country\u2019s industrial sites could save millions of dollars in transmission and distribution-related costs, while reducing the need for additional grid investment.<\/p>\n
He says network losses typically add around 5% to 10% to the amount of electricity users pay for, meaning industrial businesses are effectively paying for more power than they consume onsite.<\/p>\n
Ben Krieble, Calder Stewart\u2019s energy manager, says the company\u2019s model allows tenants to access cheaper solar power without needing to fund or own the solar infrastructure themselves.<\/p>\n
Because the generation is on the roof, there are no lines charges, no network transmission losses and no levies attached to that portion of the electricity.<\/p>\n
\u201cThat allows us to undercut the normal retail power cost because we are generating the power where it is being used,\u201d he said.<\/p>\n
The planned battery rollout would allow more solar power to be used onsite and help reduce demand from the grid during morning and evening peaks.<\/p>\n
Data from the Ministry of Business, Innovation & Employment (MBIE) showed renewables generated 94.5% of all electricity in the March quarter, up from 83.2% in the same quarter last year.<\/p>\n
A favourable mix of strong hydro inflows, increased wind output, and a 50% year-on-year increase in solar generation helped keep renewable electricity generation high in the quarter.<\/p>\n
Record solar generation of 373GWh reflected rapid growth in new capacity, including large-scale solar farms such as P\u0101mu R\u0101 ki Whitianga, and Te Herenga o Te R\u0101 near \u014cp\u014dtiki, alongside strong summer solar conditions, MBIE said.<\/p>\n
Jamie Gray is an Auckland-based journalist, covering the financial markets, the primary sector and energy. He joined the Herald in 2011.<\/p>\n