It comes as the government considers changes to make rooftop solar more accessible, and legalising plug-in solar panels.
The Science Media Centre asked six experts about benefits and limitations of solar in NZ. Read on for the full quotes, and feel free to use these comments in your reporting. 
Is solar the silver bullet of energy? 
“In short, no. But it an important element in our mix of generation technologies towards carbon neutrality for our nation and the world. The main advantage of solar is investment costs. It is an affordable option for many populations around the world, costing anywhere from a few dollars to million dollar investments. Hence it is popular and will continue to be popular as new solar generation technologies emerge. Compared to other technologies that need detailed planning, residential solar only needs a solid roof that is north facing (in NZ).
“The falling costs of solar panels and related technologies will generate a lot of opportunities; a situation we see in NZ with several large solar farms being installed. For our smaller Pacific neighbours, solar provides a carbon friendly and cheaper (?) option where, historically, fossil fuels are the main source of energy. Solar can be easily scaled too; from using a small solar panel to charge our phones to large farms that run the airports.
“However, the limitations are many. No generation after the sun sets and less generation when cloudy. It is this intermittency that demands incorporation of other technologies such as batteries, hydro power, nuclear/ thermal power and other non-intermittent technologies into our power systems.
“Lately, the world’s transmission grids are also facing several challenges due to inclusion of large scale solar and wind in their networks. Examples are outages in USA, Ireland, and Spain/Portugal over the last year. With tremendous interest on large scale solar lately, usage of arable land for the purpose has become an issue.
“So solar is a star batsman in cricket who says ‘I only bat between sunrise and sunset’. To win, we need the whole team.”
What factors could determine whether solar becomes widely adopted in NZ?
“Unlike many countries, New Zealand already generates most of its electricity from renewable sources, largely hydro and geothermal. This means solar is not replacing large amounts of coal-fired generation in the way it does elsewhere. Instead, Solar’s value increasingly comes from:
“So for wide adoption in NZ, there needs to be:
“Using the cricket analogy, the question is not “Is solar a good batsman?” but rather “Will New Zealand select it in the playing XI?”
Which innovations are most likely to make a practical difference for NZ over the next decade or so?
“Each innovation in the following areas will make practical difference for NZ:
What does plug-in solar power mean for NZ households?
“This is one of the more interesting developments in NZ energy because it potentially changes who can participate in solar, not just how much solar gets installed.
“Non-solar installed household renters, apartment dwellers and households who are not interested in investing in roof-top solar can benefit from this development. Is it worth it? Possibly, but it is important to consider some issues:
What is one aspect of solar energy in NZ you think is overlooked or misunderstood?
“That ”New Zealand isn’t sunny enough”. New Zealand isn’t Australia, but it’s far from a poor solar country. Wellington receives 2,094 hours of sunshine, Auckland receives over 2,100 sunshine hours a year, while Nelson and Blenheim receive around 2,500. That’s significantly more sunshine than many European countries that have built world-leading solar industries.
“Solar performance depends not only on sunshine hours but also on the intensity of sunlight. Commercial reports note that New Zealand receives approximately 4 kWh/m²/day of solar energy on average, making it a viable solar market.
“NZ has:
“So, solar panels can perform surprisingly well even when total sunshine hours are lower than in parts of Australia.”
Is solar the silver bullet of energy?
“Nothing is a silver bullet, but solar will likely form the backbone of future electricity systems. It’s abundant, clean, deployable almost anywhere, and is now one of the cheapest ways to generate electricity in history.
“The limitation is obvious—there’s no solar at night. But for a country like New Zealand, that pairs well with our hydro lakes, which can act like giant batteries by storing water while the sun does the work. As home batteries get cheaper and the grid gets smarter, many of solar’s current limitations will shrink.”
What factors could determine whether solar becomes widely adopted in NZ? 
“The technology is already here—the real question is how fast we choose to embrace it. New Zealand is falling behind Australia, where more than 35% of homes have rooftop solar compared with around 4% here. That’s partly because Australia has more sunshine, but more importantly because of strong government incentives.
“The biggest factors are cost, policy and how easy it is to install. Falling solar costs, rising power prices and better financing are making solar increasingly attractive, but the upfront cost—typically around $10,000-$15,000—remains the biggest barrier. For most households, the biggest return comes from using your own power, not selling it back to the grid.”
Which innovations are most likely to make a practical difference for NZ over the next decade or so?
“The next decade will be exciting. Perovskites—new printable solar cells—and tandem solar cells could deliver cheaper, higher-efficiency panels that generate more power from the same roof.
“For consumers though, the bigger near-term shift will come from storage. Affordable batteries let households move cheap midday solar into the expensive evening peak, solving one of solar’s biggest weaknesses. Smarter grids and electricity pricing will make that even more valuable.”
What does plug-in solar power mean for NZ households? 
“While not legal yet, the Ministry for Regulation has recently recommended legalising plug-in solar. Once allowed—with the right legislation, safety standards and approved inverters—it could be a genuine step forward, as countries like Germany, and increasingly the UK, have shown have already shown. It lowers the upfront cost and opens solar to renters and apartment dwellers who have traditionally missed out.
“A typical unit won’t power an entire home, but it could offset around 7–15% of a household’s daily electricity use. That’s a modest but worthwhile saving and a simple way for more New Zealanders to start generating their own electricity.”
What is one aspect of solar energy in NZ you think is overlooked or misunderstood?
“The biggest misconception is that because New Zealand’s electricity is already around 82–85% renewable, we don’t need more solar. The opposite is true. As we electrify transport, heating and industry, we’ll need much more electricity, and solar is one of the quickest and cheapest ways to build it.
“The flip side, worth being honest about, is that solar’s biggest benefit in New Zealand is often economic rather than carbon. Because our grid is already highly renewable, a panel displaces less coal than say one in Australia. Its biggest payoff is lower power bills, greater energy security and helping meet our growing electricity demand.”
Conflict of interest statement: “I declare no conflicts of interest”
Is solar the silver bullet of energy? 
“We need a symphony of renewables and storage. Solar, like wind, is a variable resource. Without backup at the point of generation, or elsewhere in the grid, it typically can’t meet the demand.”
What factors could determine whether solar becomes widely adopted in NZ? 
“We need to enable prosumers to participate more actively in the electricity market. They need to be able sell electricity at reasonable prices, preferably at the wholesale market price, so they can earn a decent revenue.”
Which innovations are most likely to make a practical difference for NZ over the next decade or so?
“The solar tech is mature. There will be efficiency improvements, but it won’t be major. The real innovation is around storage – thermal, flywheels, electrochemical (batteries). As they become more affordable it will strengthen solar to supply electricity when it is needed.”
What does plug-in solar power mean for NZ households?
“It means you don’t need to install it, which is really good for rentals, as you can take it with you when you change your address. But I question the real value. The generated electricity will seldom meet the household demand, especially the morning and evening peaks.”
What is one aspect of solar energy in NZ you think is overlooked or misunderstood?
“It should not be considered in isolation.”
Conflict of interest statement: “I have no conflict of interest.”
Is solar the silver bullet of energy?
“Solar represents the lowest cost new generation opportunity, and the only practical generation that scales to the household level. It is safe, reliable, quiet, long-lasting, and has minimal ecological impact. Across NZ we see adoption by grid-scale enterprises, businesses and households.
“However, it is an intermittent energy source that depends on sunshine, so it is not well matched to the demand profile in NZ that is dominated by winter heating. The recent cold snap is a great illustration, with record electricity demand causing generation stress between 7.30-8.30am and 6-7.30pm – when no solar was contributing.
“Solar alone won’t be the silver bullet for our increasing electrification load, it needs to be backed by energy storage, such as batteries. It also needs to be scaled to cover our winter peaks, which will mean an oversupply in summer – but this could present new opportunities for energy intensive summer activities.”
What factors could determine whether solar becomes widely adopted in NZ?
“Electricity supply is a complex balancing act of generation and demand. As a nation we are facing increasing electricity demand through electrification of transport and the move away from coal and gas. At the same time, new generation options really only consist of solar, wind, and geothermal. Both wind and solar are intermittent, depending on sunshine and wind.
“At the moment, as more solar comes online, we face an oversupply on sunny summer days, and don’t fix our shortage on cold dark winter mornings. Oversupply drives down the value of generation, which in turn will throttle investment. Energy storage, such as batteries, pumped hydro, or thermal-electric, will unlock the continued investment. As could market settings to favour using our intermittent energy over stored hydro energy when the sun shines. Regulation changes to encourage and better use home batteries would also be an advantage.”
Which innovations are most likely to make a practical difference for NZ over the next decade or so?
“Without a doubt the biggest innovations will be in energy storage. Being able to store energy through cloudy moments, overnight, and between seasons will allow us to even out electricity supply from intermittent renewable sources such as solar and wind to cover our highest demand peaks.
“Batteries are currently too expensive for systemic uptake, and have unsolved environmental concerns, but it is certain new battery innovations will solve these issues. Other promising innovations exist with NZ innovators investigating concepts such as thermal-electric storage, which heats sand or bricks when, for example, the sun shines, and then uses the stored heat for creating steam or hot water for industry processes later. Large scale storage, such as pumped hydro (‘NZ Battery Project’), could also contribute to interseasonal stability.”
What does plug-in solar power mean for NZ households? 
“Plug-in solar is not yet legal in NZ. This has been hugely successful internationally, particularly in Germany, allowing renters to offset their energy use without requiring their landlords to invest. Plug-in solar will not significantly offset electricity bills due to the limited amount of electricity they generate, but for low-income families it will certainly be a meaningful contributor.
“However, while proven safe in other jurisdictions, the NZ and German home wiring systems are very different. Plug-in solar feeds power into the house behind the overload protection systems, and in older NZ homes with retrofitted insulation, it is possible that the additional power injected behind the protection could overheat the wiring and even present a fire risk. There is also some evidence that it could ‘blind’ the electrocution protection as well. We are currently doing some tests on this.”
What is one aspect of solar energy in NZ you think is overlooked or misunderstood?
“Solar is very sensitive to even the slightest shading. The rooftop panels you see are actually made up of a series of smaller cells connected in a string. And the panels themselves are also connected in together in a long string. If we use the water-in-a-hose model of electricity flow, even the shadow of a TV antenna or a small branch on just one panel is like standing on the hose – the flow drops dramatically over the whole system.”
Conflict of interest statement: “Hamish has no conflict of interest in producing these responses.”
Is solar the silver bullet of energy? 
“Solar is not a single solution to all energy problems. However, the big potential and opportunities are real.
(1) Solar energy is free once the system is installed. It works in a much wider range of locations than some other energy sources, e.g., wind, since you just need reasonable sun exposure.
(2) The maintenance is relatively low, compared to other generation technologies, and it suits distributed generation well, e.g., household and businesses can generate their own power rather than fully relying on the main power grid.
(3) Environmentally friendly. Solar system has no emissions.
“Limitation:
(1) The biggest issue with solar power system is intermittency. Solar systems can only generate electricity when the sun is out, and that brings mismatch between the peak generation (mid-day) and demand peaks (usually morning and evening).
(2) There are also seasonal and latitude variations in NZ. NZ spans a large range of latitudes, so the irradiation is totally different from North to south, which cause significant solar system performance difference by region.”
What factors could determine whether solar becomes widely adopted in NZ?
“Policy and electricity price will be the key factors that could determine that, since the electricity price determines the payback and policy shapes the rules people decide. The regulatory framework is still unclear at this point, especially around how the distributed generation, like how household solar can feed back into the grid, will be compensated. This uncertainty makes it harder for people to make the decision.
“Other practical factors include things like the rooftop orientation, the strength of the mounting infrastructure for individual installations, also broader factors like installer availability and access to finance support at a wider market level.”
Which innovations are most likely to make a practical difference for NZ over the next decade or so?
“NZ is quite unique and special. We have already got around 90% of our electricity from renewables, mostly hydro and geothermal. So the core question in NZ is not how to decarbonise electricity, it is more about how to meet growing demand without falling back on fossil fuels for the gap.
“One possible innovation is floating photovoltaic systems where the panels are installed on the existing reservoirs behind hydro dams. These hydro-floating systems can reduce evaporation from the reservoir, which can actually help the hydro system reserve more water, especially during the dry seasons or dry year.
“Apart from the technical aspects, government financial support will be most likely to matter, and with the right support NZ could reach a similar market share to Australia’s.”
What does plug-in solar power mean for NZ households? 
“Plug-in solar power refers to small-scale, portable photovoltaic devices that can be connected directly into a household’s existing wiring. In NZ, the residential electricity price is relatively high, so the users of such plug-in solar power can get benefit from reducing electricity bills.
“Whether it is worth depends on the user’s electricity usage. For household with high electricity usage, I would say it is worth to have one such plug-in solar power. When buying these devices, people should check the regulation and confirm it is allowed to be plugged in and to feed electricity into the household circuit or grid.
“Also, site irradiation also matters: if the installation location doesn’t get enough irradiation, the electricity output will be low.
“Finally, the buyers should also check their physical mounting and supporting hardware for the panels is robust enough for outdoor conditions.”
What is one aspect of solar energy in NZ you think is overlooked or misunderstood?
“Solar is not automatically the best solution for every household. This is overlooked by some consumers. It depends on your using time, electricity usage pattern and sometimes storage cost.
“Payback years are usually based on high self-consumption, using most of what the PV panels generate during the day. If you use little power during the daytime, selling the generated electricity back to grid at a low rate and buying it during the evening peak with a high rate, the payback takes longer. A storage system can fix that, but it will also increase the upfront cost.”
Conflict of interest statement: No conflict of interested declared.
Is solar the silver bullet of energy? 
“It’s not a silver bullet, but for the New Zealand energy mix, it is the most obvious and fastest way to provide lower cost, more resilient power and it works particularly well alongside our hydro generation (especially in a dry year). Rooftop solar is the lowest cost energy most households and businesses can get, including the upfront cost and interest. It also helps lock-in lower costs for the long term as you pay today’s prices for 30 years of power from your roof.
“The biggest opportunities are bill reduction, resilience and speed of deployment. Australia’s biggest power plant is 3.2GW, yet their total rooftop solar is around 30GW. We are a long way behind, but the same will be true here eventually and the biggest power plants of the future will be owned by our communities.
“Historic weather analysis shows the sun shines more than enough to significantly lower bills and provide extraordinary service to our energy system. One short-term limitation is the workforce required to scale solar up, but we should be looking at this as a huge job creation opportunity at a time of high unemployment.”
What factors could determine whether solar becomes widely adopted in NZ? 
“‘Not everyone can afford solar’ is a common refrain, but this misses the forest for the trees. Technically, everyone can afford solar because it will create savings – the problem is that not everyone can access those savings due to the high upfront cost.
“When new power poles in your street need to be built, it costs hundreds of thousands and that money will be charged to your bill in increments each year over the life of the asset. The energy system was designed to make paying for big investments on consumer bills simple, but the regulation has not kept pace with technology.
“Our Electric Homes and Vehicles research shows that if you could buy solar in the same way and finance it over the long-term it would save about $1,000 per year net for an average home. That means your bills would drop by $1,000 rather than increase while also paying off the asset. Subsidies are not necessary because the economics stack up so well, but subsidies do speed adoption up, as we’ve seen in Australia with solar and now batteries.
“There are some who say the grid won’t be able to handle it, but New Zealand is at around 3% adoption while Australia is at over 40% (and in some areas it’s over 80%, so these issues have already been addressed next door. ”
Which innovations are most likely to make a practical difference for NZ over the next decade or so?
“As solar drops in price, it becomes economic in more places. For example, today it’s at a point where even if it’s in the shade for half the day or even mounted along a fence it can still produce electricity cheaper than most people can buy it from the grid. So as the technology improves, it just increases the amount of feasible homes and buildings where it’s an economic win. Even today, a roof does not need to face north for solar to be economic.
“Alongside this, falling battery prices will make solar and battery combos far more common, as we are already starting to see, and batteries are to electricity as refrigeration was to food. Around 50% of systems in New Zealand now also have a battery installed and Australia installed over 1GW of home batteries in one month alone. For context, that is equal in output power to New Zealand’s largest power plant (Huntly).”
What does plug-in solar power mean for NZ households? 
“Plug-in solar systems are quite small and won’t be able to run high draw appliances, but they will be great for renters and apartment owners and some estimates suggest they could reduce grid electricity consumption by up to 20%. One of the biggest things with plug-in solar is it gives people a simple pathway to have some agency in their energy future – and it could be a gateway drug to more electrification.
“Bigger savings are available with a full sized rooftop system but plug-in solar and plug-in batteries will be a quick and easy way for people to lower bills and increase resilience and it will enable far more dinner table conversations about energy, which is a great thing. ”
What is one aspect of solar energy in NZ you think is overlooked or misunderstood?
“How often the sun shines is often overlooked. The free nuclear fusion reactor in the sky is a pretty reliable power plant. People mistakenly believe the sun doesn’t shine enough to help in winter, for example, or that it would help with our dry year. That is flat out not true. You can do the historic weather analysis to show this and it’s quite rare to have many days in a row without sunshine.
“New Zealand already has over a month of energy storage and as far as we know there’s never been a month without sunshine. There’s a lot of nuance to energy system design, but it’s safe to say the positive energy system ramifications of solar are often overlooked by companies with an interest in overlooking them and regulators and officials continue to underestimate the popularity of solar (as well as batteries and EVs). In that same respect, what’s overlooked is that solar and battery systems give households and businesses independence and agency in the power system.”;
Conflict of interest statement: “Rewiring Aotearoa is an independent charity working on energy, climate and electrification research, advocacy and education. The New Zealand-based team consists of energy, policy, communications and community outreach experts and it is funded by New Zealand-based philanthropists including Sir Stephen Tindall and Urs Hölzle. While we are selling the achievable dream of a more secure, resilient, productive, affordable and renewable energy system, we do not financially benefit from sales of solar, EVs or any of the electric technologies we advocate for.”

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