Security of supply.

Mercury’s ability to generate electricity reliably is vital to our business and is directly connected to our economic performance. Active management of our assets over the long term is fundamental to this.

Across our organisation we apply an integrated approach to asset management involving tailored risk management frameworks to optimise reinvestment. This results in a dynamic plan that responds to asset and market conditions to maintain reliable and efficient generation from our renewable assets.

We routinely commission independent expert reviews focusing on how we manage our assets.  This year our reviews considered safety-critical equipment and critical major spare equipment.  Our commitment to industry-leading practice and innovation sees our infrastructure teams regularly participate in local and global industry forums.  

Reliable hydro generation

A programme of major maintenance and reinvestment projects across our vital hydro assets is well underway with a number of upgrades commenced or completed this year.

The successful rehabilitation of the first of four units at the 60-year-old Whakamaru Hydro Station has now been completed. The station upgrade, scheduled for completion in 2020, involves an intensive programme of work where all of the turbines, generators and governors will be replaced. This will increase the station’s capacity by 24 MW to 124 MW. 

Similar preparations are well advanced for an upgrade of the Aratiatia Station, with on-site activity scheduled to start in October 2017. The rehabilitation programme includes the replacement of all three generators, governors and one turbine, along with an extensive refurbishment of the station. Completion is expected mid-2020. 

hydro station 96

» NZ Winter Energy Margin

The NZ Winter Energy Margin is an assessment produced by Transpower that estimates the level of new generation required to reliably meet expected winter demand.  It does this through combining the expected winter energy contribution of existing and committed generation plant across the entire electricity industry and comparing it to projected winter demand (with an allowance  for security).  Mercury recognises that we have a part to play in keeping New Zealand’s electricity supply secure and stable and we contribute  through our efforts to maintain reliable and efficient generation assets.


security and supply graph