Vector says more customers connected to its network over the past year, leading to an increase in the volume of power it distributed.
The number of people on its network increased 1% to almost 520,000.
The Auckland electricity lines company increased its volume of distributed electricity by 0.5%, in the three months to September.
But power supply was disrupted for 110 minutes for the half year to September, above its target of 104 minutes.
Vector says gas transmission volumes increased 2.7% due to increased industrial demand, while gas connections increased but distribution remained flat.
Gas liquids volumes decreased by 10% due to reduced demand.
Vector's profit dropped 30% to $1.6 million in the year to June.