Frequency keeping

The frequency of the New Zealand power system is maintained within a narrow band around 50 hertz. Frequency keeping refers to the ancillary service used to maintain the frequency of the power system within the desired band.

Frequency keeping generation plant increase or decrease generation in response to short-term supply and demand imbalances to ensure that frequency is kept at or near 50 hertz. Generators offer in to the wholesale market their willingness to supply frequency keeping services. These offers are then dispatched, or cleared, by the frequency keeping selection tool prior to the energy and reserves dispatch being determined by SPD, the market clearing engine.

All frequency keeping offers and the offers actually dispatched to supply frequency keeping services are available for download on a daily basis.