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Comment by Chilko | Hacker News Reader

I found this really interesting as well as here in New Zealand that relationship is inverted - we don't typically have residential air conditioning yet use a lot of electric heating so our peak demand is in the mornings and evenings, and most intense in the winter. This makes the business case for solar a lot trickier here as the periods of max generation (daytime during the summer) coincides with low demand and subsequently low wholesale energy prices.

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It makes we wonder if something like the Australia-Asia power link would make sense. 2.2GW would be enough to cover current Gas, Coal and Diesel generation for NZ. With sufficient storage (Batteries, Pumped Hydro), you could recharge in the day, carry load into the evening peak, before switching to stored power.

Initial cost would be higher, but long term cost of Solar is ridiculously cheap.

> It makes we wonder if something like the Australia-Asia power link would make sense.

There is the AAPowerLink project which proposes exactly this. It's a ~20GW solar farm in Australia with battery storage and a 4500km HVDC undersea cable to export power to Singapore. Seems currently in a planning and Project seems to be in a planning and exploration stage with funding not fully secured though.

Doesn't New Zealand have tons of hydro? Is it possible summer solar could be used to pump up a mountain reservoir somewhere with that energy sold 6 months later at a premium?

Getting only one cycle per year out of your storage solution is hard to justify economically. Regular pumped hydro gets 200-365 cycles per year, and there's already a substantial difference between day and night electricity prices.

I've seen this idea elsewhere, but for latitudes like NZ it makes sense to tilt panels in a way that it optimises for winter & morning/evening sun.

Also wonder how much kWh batteries one would need for winter heating (generate at day, use at evening). Kinda feel NZ, especially north island should have enough. Over in Eastern Europe you can get recycled batteries for $150/kWh!

Wind should work better than. Especially offshore. Tends to be much more expensive than solar in a sunny place like Texas, but also much more reliable/stable.

In the end, you'll always need a mix of supply. Or simply better insulation and efficient heat pumps rather than wasting electricity on heating at above freezing.

People need to realise that not all forms of renewable generation are good solutions in all parts of the world, just because they're renewable. I hate the "green energy" cults that shout you down for suggesting solar might be bad idea for these sorts of reasons.

Well, bad idea for now. If we can start storing up solar energy for the winter, then it might start making a lot of sense. The sand battery that can store thermal energy for months seems pretty interesting in this aspect.

https://www.bbc.com/news/science-environment-61996520

Getting one discharge per year and being less than 30% efficient is a major limitation for any kind of construed thermal battery.

A more viable though still impractical approach is to store energy in rocks underground. Essentially trading the need for a multi km deep borehole for geothermal with the need to provide your own heat.

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