The proportion of the nation's electricity supply generated from renewable sources jumped from 64% in the June quarter, to 73% in the September quarter.
The figures are included in key energy statistics in the Ministry of Business, Innovation & Employment's quarterly energy update.
A ministry spokesperson says the increase is due to a 28% lift in hydro generation from July till the end of September.
He says the increase also meant a 3% drop in greenhouse gas emissions.
But overall power generation over the September quarter also dropped by 3%, largely due to reduced demand because of milder weather patterns this year, and lower production at the Tiwai Point Aluminium Smelter.
