Wind Forecast

The system operator is preparing for a future with greater wind generation by trialling a wind forecast. Knowing in advance what wind generation the system operator can expect to turn up is key to ensuring a secure power system, providing accurate price signals, and facilitating outages.

There is already over 600 MW of wind generation on the system. As New Zealand transitions to a lower carbon economy the system operator expects this to increase, with a further 200 MW expected in the next few years and substantially more consented.

We have entered into a 12 month trial comparing the offered wind generation to a forecast supplied to the system operator by a forecasting specialist. This comparison is published below for North Island offered generation over 24 hours. We will also publish accuracy analysis each month.

Any wind generator interested in receiving a free 24 hour forecast specifically for their wind farm can contact market.operations@transpower.co.nz.

Monthly accuracy analysis

These charts compare the accuracy of the system operator trial wind forecasts and generator forecast of generation potential (FOGP) for September.

Chart A compares mean absolute error (MAE) in MW over a range of forecast horizons.  As reference points, the average North Island wind generation for September 2019 was 244 MW, and the installed North Island wind capacity is 577 MW.

Chart B compares the distribution of errors over 3 forecast horizons. 
The 36 hour horizon is the first time frame in which generators are required to make an offer.  
The 1.5 hour horizon is the last opportunity for participants to change their offers and bids outside gate closure.
The 0.5 hour horizon is the last opportunity for the system operator to carry out security checks