If electricity prices were to ever reach that (random?) high price it would make the case for a PV installation with battery storage a no-brainer.
Northland has good sunlight levels and those price levels justify installing a storage battery to isolate yourself from any disruptions to grid supply, if you even wanted to remain grid tied. The flow battery technology coming out of Australia is worth keeping an eye on. Essentially a zinc based liquid system that is like a mini galvanising plant that doesn't have the drawdown limitations of a Li-Ion battery unit.
https://redflow.com/products/redflow-zcell/