Frequency keeping and instantaneous reserve sharing

Transpower – Frequency keeping and instantaneous reserve sharing

Transpower and the Electricity Authority have engaged in a multi-year joint initiative to make the power system more efficient and save consumers millions of dollars by reducing the cost of ancillary services.

In 2014, Transpower completed the award-winning upgrade of the HVDC inter-island link. The project increased the transfer capacity between the North and South Islands to 1200 MW, while new control systems enabled the sharing of reserves between the North and South Islands and more efficient frequency keeping.

The Reserves and Frequency Management (RFM) programme was run jointly by Transpower and the Electricity Authority. It capitalised on the tools in new ways to allow the simultaneous transfer of energy and reserves in both directions, significantly reducing reserves procurement and frequency-keeping costs. These innovations also improve the overall reliability of the power system.

The two organisations say they are unaware of reserve sharing and frequency keeping being used in this way anywhere else.

The new system means North Island providers can compete in the South Island and vice versa. It has also reduced the volume and cost of frequency keeping, saving an estimated $22 million, which will ultimately be passed onto consumers.

Sustained instantaneous reserve sharing has reduced the volume of reserves needed and the cost of reserves by an estimated $1.3 million a year.

Transpower says a key element of the project’s success was the active collaboration that was maintained with the industry and interested parties so that they could participate and provide feedback into decision-making and solution designs.

That gave the teams a better understanding of the commercial implications of their work, and enabled them to take an all-encompassing approach to reserve sharing and frequency management.

Transpower says staff working in the nine interrelated but overlapping projects also had to collaborate closely to deliver such a large and complex programme of work.

Importantly, they did not wait until all the project controls and components were in place. When they saw opportunities to deliver ‘quick wins’ and keep the programme moving they came up with innovative interim solutions to do so.

Six elements of the project were progressively commissioned by late 2015. Another four elements will be completed by the end of the year.

In October the total volume of reserve able to be shared between the North and South Islands will increase from 60 MW to 220 MW in both directions. 

The Innovation in Energy award category is sponsored by Gentrack