The most consequential fact in New Zealand's renewable energy boom right now has nothing to do with megawatts. The evidence coming out of the underwriting market points to a broker's file, not the underlying engineering alone, increasingly deciding whether a client keeps standard insurance terms or gets pushed into higher deductibles and restricted cover.
That is the practical result of a shift now under way across solar, wind and battery underwriting, and it is playing out in New Zealand at an awkward moment: grid-connected solar capacity stood at 247 megawatts in early 2026, with the Electricity Authority expecting another 783MW by 2026/27, quadrupling total capacity to just over 1,000MW.
Most of that build sits in construction or commissioning right now, the same phase in which two Australian solar sites, Raywood and Mannum, caught fire since 2024, according to John Rae, Willis's renewable energy leader for the Pacific.
"If the responses from the insureds are not adequate in relation to mitigations from these types of losses, the insurers first response will be to increase deductibles and at worst they will look to put sub limits or restrictions on coverage," he said.
The technology causing the losses, in other words, isn't what separates a clean renewal from a restricted one. The documentation is.
That documentation increasingly comes from the broker, not the client. Rae described using Willis's own global loss database as a working tool in client conversations: "We can look at how many inverter fires that we've seen in our solar projects globally through our renewable energy loss database and advise that to our clients.”
Armed with that benchmarking, a broker can turn a defensive renewal conversation into a practical one about maintenance schedules, critical spares and engineering fixes, rather than leaving the client to explain a loss with no context.
On larger New Zealand and Australian projects, underwriting judgement is often made in London, and Rae's advice to brokers is to go there and make the trip count.
"You've got to go there and talk to underwriters and get their comfort around your experience of risk and mitigations and allows them to go under the bonnet which creates a closer connection to the underwriters/insurance market," he said.
That relationship-building work sits with the broker, and it is now presented as a competitive differentiator rather than a courtesy call.
Battery storage adds the same dynamic to nearly every renewable placement now, not just standalone storage projects.
"I've actually seen the battery market improving quite dramatically," Rae said, pointing to newer designs generally.
Tesla's newest Megapack 3, for instance, is built "so when they do go on fire that they collapse inwards," Rae said, rather than triggering the thermal cascade that used to worry underwriters most.
That specific design isn't yet the one installed at Contact Energy's Glenbrook Ohurua Battery, a 100MW facility built from 56 Tesla Megapack 2XL units in South Auckland that came online within weeks of a comparable Australian project reaching full grid sign-off, but Glenbrook still gives brokers on both sides of the Tasman a live, operating example of the wider containment gains Rae describes, rather than a theoretical one.
The catch is scale: "Every single one of my projects that I'm working on right now has some form of battery associated with it," Rae said.
A broker who could once treat battery risk as a niche conversation confined to standalone storage now has to carry a current, documented mitigation story into almost every renewable file they place.
Five years ago the goal was simply getting projects built, says Aon's Shannon O'Brien, executive director of construction, power and renewables. Now developers, investors and lenders want to know how those assets will hold up "in an increasingly complex and uncertain operating environment," and O'Brien puts the underlying question bluntly: "Are we simply building renewable infrastructure faster, or are we building it to withstand the next 30 years?"
Answering that question with anything more than reassurance is, in practice, the broker's task: it is their file, their site data and their underwriter relationships that turn a client's long-term confidence into an actual placement.
O'Brien argues that resilience needs to be treated "as a design principle, not an afterthought," and points to site selection, engineering design, equipment specification, grid connection, maintenance and contractor choice as the decisions that determine how a project copes with disruption later.
Those are exactly the details a broker now has to gather and present, not simply pass along.
Lockton Pacific chief executive Marcus Pearson has argued that submitting granular, site-level data and using current catastrophe modelling is becoming essential, a shift from a sector-wide pitch to risk differentiation between individual sites.
Earth Sciences New Zealand estimates more than 750,000 people and roughly $235 billion of buildings sit within one-in-100-year rainfall flood zones today, the scale of exposure that makes a single site's specifics, not a broker's general claims about the sector, what insurers now price against.
New Zealand's own hazard profile compounds the problem. An earthquake can knock out a generation asset and the transmission line beside it at once; heavy rain can flood a site and wash out its access road for weeks; a storm can hit several assets across a region in one afternoon.
IAG New Zealand has found natural hazards have cost the country at least $64 billion over 15 years, with around 95% of that spent responding to and recovering from events rather than reducing risk beforehand, a finding drawn from more than 50 practitioners across engineering, infrastructure, finance, government and academia.
Risk advice has traditionally turned up near a project's end, O'Brien says, but its value is usually delivered earlier, before risk gets built into the asset and before a broker is stuck placing cover on a design that was never built with underwriters in mind.
Getting that right reduces future losses, builds insurer confidence and eases financing; insurance becomes "an enabler of infrastructure development," not just a backstop arranged at the last minute.
Willis's 2026 Renewable Energy Market Review found pricing cuts of 20% to 30% for well-engineered, high-premium accounts, 10% to 15% for the next tier down, while loss-affected programmes still face renewal terms tied to the scale of their loss.
Rob Hale, global power and renewable energy leader at Willis Natural Resources, said the underwriting behind those numbers is becoming more demanding, not less: "Competitive advantage is shifting towards renewable energy projects that can demonstrate strong engineering standards, robust maintenance practices and credible, data-driven risk insights," he said.
The softening market rewards the broker who curates that evidence and penalises the one who doesn't.
O'Brien makes a similar point from the client side: developers who get involved early, share information and take a long-term view on risk stand apart from those who treat resilience as a box-ticking exercise. That distinction runs through the broker relationship as much as it does through the developer's own planning.
Willis's wider market review found that battery fire risk, transmission constraints and elevated reinsurance costs are pushing renewable underwriting across the Tasman toward project-by-project assessment rather than sector-wide appetite.
As Rae summarised it: "Capacity remains available, but deployment and pricing are increasingly influenced by project location, technology type, and overall risk quality. In this environment, achieving optimal insurance outcomes increasingly depends on strong risk presentation, robust technical design, and a strategic, well-structured approach to insurance programme placement."
Strong risk presentation is broker work. O'Brien's own summary of the underlying challenge, "building faster is important, but so is building smarter," applies just as much to how a broker builds a file as to how a developer builds an asset.
As New Zealand's solar and battery capacity multiplies over the next few years, the brokers who build that presentation early, and keep it current, are the ones deciding which of their clients renew on standard terms and which ones don't.
