Huntly Power Station (NZ) – Hydrodynamic Modelling
Huntly Power Station is the largest thermal power station in New Zealand and is situated on the banks of the Waikato River in Huntly. The original four generators were built between 1973 and 1985, and upgraded with a gas turbine plant in 2004. A further upgrade in 2007 increased the station’s production of power from an original 1000 megawatts (MW) of electricity to 1485 MW. The station supplies about 17% of the country’s electrical power.
Water Technology was commissioned by the Genesis Energy to develop both a near field (3D) and a far-field (2D) hydrodynamic model of the Waikato River at the Huntly Power Station. The modelling investigation was undertaken in order to more accurately describe the Station outfall discharge plume and to gain an understanding of the fate of chemicals discharged with the Station cooling water. The models were used to undertake scenario modelling of the Station cooling water outflows and various discharge chemical concentrations for a range of river flow conditions, with a view to informing improved management decision of the Station operation and the assessment of performance against Resource Consent conditions.
A detailed bathymetric description of the river from upstream of the Power Station to approximately 5km downstream was developed, which can be enhanced in future with improved survey information. The model was calibrated to local conditions and the 3-dimensional model used to assess the initial mixing of the heated water from the power plant. The model was used to inform the power station operators of the current dilution and transport of process waters with river flows, particularly under low flow conditions, which are critical to operation of the station under their Resource Consent conditions. The models can also be further developed to describe sediment transport conditions and the effect of existing Iowa Vane structures upstream of the outfall.
Key Services Provided
- Hydrodynamic Modelling—2D and 3D
- Advection-Dispersion modelling of the discharge plume and discharge chemicals
- Assessment of discharge chemical fate