NZ also doesn't have anywhere near enough hydro storage to properly use large scale solar. Storage is only in the region of a few weeks to a month of generation capacity. Meaning a big storm can easily fill the lakes. While a dry year can still cause a winter power shortage, even if the lakes were full in April.
We would need hydro storage equivalent to around 6 months of demand for large scale solar to be useful. We would probably need a lake of similar size to Lake Superior in the USA for that to happen.
And is solar still economic to install if grid power cost around 10c per unit? How about 5c per unit? And if you give subsidies to solar, is that actually the best way of reducing carbon emissions? Is such money better spent on say subsidies for buying EVs?
Either way, something needs to change. As high power prices are a subsidy for fossil fuels. As they are cheaper in comparison. And are also an unnecessary extra cost on EV charging.
Does that still apply if you have an alternative like wind generation? Wind increase during winter, when electricity demand increases.
I don't see EVs as an alternative to solar to reduce emissions. I see EVs and home solar and PowerWall as to symbiotic technologies which, for the energy consumer, multiply the cost savings available from each separate technology. Batteries allow time-shifting of consumption away from time of generation. So a home solar generation system charges batteries which can then be used for energy at peak load times. And, given sufficient solar generation, to also supply power to charge your car for use the next day.
The big problem with both solar and wind is that you can't command them to output power when you choose. And they can't be used to provide reserve capacity. Also bear in mind that there is a lot of run of river hydro and geothermal generation in NZ also. If you run them at less than max capacity, you are just throwing away energy, in the form of spilled water or steam. So lake fed hydro is far more valuable than other sources of power. As the only other sources of large scale energy generation with storage are fossil fuel generation.
Home batteries are extremely expensive, as each time you put the battery through a charge and discharge cycle, it's lifetime reduces. This means that the equivalent power cost for electricity delivered from a home battery can be as high as 50c per unit. Even if the power used to charge the battery was completely free.
Agree that solar and EVs can both be done at the same time. But if subsidies are going to be paid, then they should only be used for what would give the biggest emissions reduction. This is a big problem with solar. As getting solar installed reduces the amount of lines fees that you pay. But because solar doesn't reduce peak demand, the cost to supply your house doesn't reduce. So lines fees have to increase. And low income people are forced to pay the bulk of those increases.