Genesis Energy lost $136 million in the year to June, a turnaround from last year's profit of $99 million.
The State-owned thermal generator attributes the loss to a fall in the value of its aging Huntly power plant.
The company says underlying earnings were $82 million.
Despite the loss, it will still pay the Government a dividend of $10.4 million, taking the total payout to $20.8 million for the year.
