The 2025 Ancillary Services Tender is now open!
We invite tenders for Instantaneous Reserve, Multiple Frequency Keeping, Back-up Single Frequency Keeping and Black Start (North Island only).
The tender documents and information on the tender process is available here.
Ancillary Services in the NZEM
There are currently five ancillary services we can procure:
- Frequency Keeping (Multiple Frequency Keeping and Back-up Single Frequency Keeping)
- Instantaneous Reserve
- Over-frequency Reserve
- Voltage Support
- Black Start
If you would like to offer or have any questions about Ancillary Services, please contact [email protected].
Ancillary Services Procurement Plan
The Procurement Plan sets out the mechanisms we use for procuring these services, as well as the technical requirements and key contractual terms applying to each service. We are required to use reasonable endeavours to both implement and comply with the Procurement Plan.
We enter into contracts with market participants (generators, distributors, large load providers and demand aggregators) via a closed tender process conducted between August and November each year. We may also enter into contracts outside this tender period when appropriate. Our standard contract terms are updated annually. Samples of our standard contract terms for all ancillary services are linked below.
Prior to entering into contracts, new providers must demonstrate the capability of their equipment to provide the service through testing. Some services also require regular testing during the term of the contract. Guidance on testing is set out in the Companion Guide for Asset Testing.
We procure ancillary services either:
- on a “firm quantity procurement” basis, where we procure services on a fixed quantity or fixed price basis, regardless of whether the ancillary service is dispatched or not (eg over frequency reserve, voltage support and black start); or
- through a half-hour clearing market process, where contracted ancillary service providers submit offers and are dispatched via a market for that service (eg instantaneous reserve and frequency keeping). That market is then priced and settled via the Clearing Manager.