New Zealand's electricity market has undergone a major turnaround compared with a year ago, when hydro storage lakes were low and there were fears of an electricity shortage.
This year, electricity prices are far lower, hydro storage lakes are above average and the South Island is sending electricity to the North Island.
M-co, the electricity market analyst company, produces a seven-day summary of the spot electricity market and its latest - the week ending last Sunday - shows a big transformation compared with the corresponding period last year.
That is because of heavy rain in hydro lake catchments at the end of April and again on May 16 and 17, which over-filled South Island hydro lakes.
Meridian Energy's Waitaki lakes system, which makes up more than 50% of New Zealand's hydro storage, has been spilling water to lower lake levels, at the same time generating as much electricity as possible, depending on demand.
The excess water and high lake levels for this time of year mean lower spot market prices.
Over the seven days until last Sunday, the New Zealand-wide electricity price index ranged from 4.21c a kilowatt hour (c/kWh) to 6.63c/kWh.
In the corresponding week last year the price index ranged from 27.98 to 30.77c/kWh.
However, most consumers will not benefit from the very low spot market prices because electricity retailers buy on long-term contracts, which even out the high and low fluctuations in spot market prices.
