Climate and electricity system

This project advances New Zealand's understanding of how climate variability and change affects electricity generation, demand, and transmission in New Zealand, and how best to manage and plan for climate-related opportunities and risks in the electricity system.

The problem

Recent dry years have highlighted the vulnerability of New Zealand's electricity system to a variable climate. There is a need to understand climatic influences upon the security of electricity supply, and how the dry year risk varies over time. If the electricity system is not adequately designed for this risk, security of supply will be compromised.

The solution

This research provides quantitative tools for generators and regulators to aid strategic planning by developing climate-electricity system models capable of handling both long-term and short-term climate variability. Knowledge of large-scale climate signals and how they affect New Zealand is built into models that simulate daily climate sequences (that can be aggregated into seasonal, annual, and longer sequences) for all of New Zealand. The modelling framework is based on physical as well as statistical considerations.

Climate sequences allow simulation of river flows, lake inflows, snow storage, and electricity demand. We are working with collaborators in the energy sector to help develop interfaces between models developed here and those employed by policy and industry users. Key questions to be addressed by this research include:

  • What does the current state of the climate imply about renewable electricity generation capacity over the coming season?
  • How does the dry-year risk vary on seasonal to decadal time scales, and how do we best adapt to changes in risk?
  • How will wind power potential vary on seasonal to interannual and longer time scales, how will that compare to hydro-generation potential, and how will the overall balance of renewables change as the climate changes?
  • What are the electricity transmission implications of variability and trends in wind power generation compared to hydro-generation?
  • What are the extremes of available renewable resources, and what level of renewable generation capacity can be guaranteed?
  • How may demand be influenced by climate, e.g. more use of electric vehicles on rainy days?
  • How will climate change affect the seasonality of inflows and snow pack, and hydro-generation capacity?
  • What are the optimum infrastructure requirements to maintain system robustness and integrity, and minimise risk?

The result

This present research programme has run for six years, and builds upon many years of research on understanding the climate of New Zealand and the Southern Hemisphere. We plan to expand the existing research programme to integrate climate and electricity system research. During the lifetime of the current programme, we have achieved a number of milestones:

  • Hosting a series of annual workshops, attracting a wide range of users from both government agencies and business sectors, plus other researchers. The programme team have provided advice to the Minister for Energy, and to central government agencies, on climate variability & change and security of supply.
  • Development of the concept of stochastic variable-length seasons into seasonally-varying weather generator models. This is on the leading edge of international research.
  • Increased robustness in weather generator design, including incorporation of spatial variability and the effects of large-scale signals such as the El Niño-Southern Oscillation (ENSO) and the interdecadal Pacific Oscillation (IPO).
  • Improved definition of the effects of ENSO on inflows into key South Island hydro-generation lakes (which informed a detailed analysis of the 2007/08 La Niña and its effects upon New Zealand hydro storage).
  • Enhanced capability of hydrological models to incorporate climate data and to model snow storage and melt in key Southern Alps catchments.

NIWA Contacts

Chief Scientist - Climate, Atmosphere and Hazards
External people involved: 
Martyn Clark
Rilke de Vos
Craig Thompson
Xiaogu Zheng
James Renwick
Peter Thompson, Statistics Research Associates Inc.
Page last updated: 
26 November 2019
Seventy-nine per cent of our electricity comes from the climate: rain, snow, wind and sun. What happens when that climate changes? Credit: Dave Hansford
Key transmission links with simplified capacity. Generation and consumption are highly dependent on climate.
Research subject: Hydrology