The south island lakes are still incredibly empty (exception being Tekapo but that is because of a generator fault at Tekapo B power station which has meant Genesis hasn't been able to move as much water as they wanted) and so the prices are going to remain higher than normal.
The counter side to being a renewable dominant system is that when the clean energy can't be generated (no water or lack of wind) it has to be supplemented by gas/coal plant (and this is why the greens vision of a 100% renewable is faltering) which are priced higher over here than in other countries. The reason is in other countries they'll be running something flat tack all the time in NZ with the cheaper renewable energy sources they don't run flat tack so when they are needed to get the returns the generators will price them at a premium.
To be honest, I don't see the prices being sustained low for a while, the snow packs have been exhausted and past experience is the storage will take at least a year to recover back to normal levels from where we are.
Flick pass through the wholesale cost of electricity, traditional retailers like Genesis, Meridian hedge this by working out an average price and billing that (some months they'll be in the money, sometimes they won't) and essentially take on the risk for you. With Flick you are exposed to that risk.