Electricity

Solar power has been rapidly growing in New Zealand with the total installed capacity increasing fivefold over the last few years. Most of the growth has taken place in the residential sector. Auckland Council has a goal of 970 MW installed capacity of solar photovoltaics by 2040. To assess this in number and size of rooftop solar installations we need to assess the solar energy potential on Auckland buildings. In this research project we have used LiDAR data to develop a digital surface model of the city, including topography, buildings and trees. With this model the ArcGIS solar radiation tool has been used to calculate the annual solar radiation on each square meter of roof area, taking into account latitude, time of year, time of day, average climatic conditions, surface orientation and slope, and shading from nearby buildings and trees. The results show a roughly 5% under-estimation in comparison with NIWA’s SolarView tool for north-facing unshaded surfaces and a roughly 10% underestimation for east or west-facing surfaces, which should be taken into account when planning a solar PV investment. This research has been made public via a webtool that can be used as an educational tool for a first approximation of solar potential on a rooftop.

Solar energy can also been play an important part in designing resilient energy systems in small, isolated island states. A research project on ‘Polynesian Pathways to a Future Without Electricity Grids’ investigates the feasibility of solar energy with and without batteries at different levels of the transmission grid. The report presents opportunities and challenges in transforming to a decentralised energy system, and economic assessment shows that differences in outcomes are mainly due to local energy prices and costs. There is need for a systematic optimisation approach to help design the most economic pathway to transition to a low-carbon, decentralised energy system.

Research team: Kiti Suomalainen, Vincent Wang, Basil Sharp

Studying the correlation between the seasonal patterns of wind, hydro, electricity demand and prices is important in a country like New Zealand, which depends on hydro power availability and has experienced high price volatility due to low levels of hydro availability in dry seasons. Whether wind power development will help balance the situation or not depends on its seasonal availability, particularly during those critical periods.

In our approach, we separate daily deviations from the expected seasonal value, and show that for some locations it is the anomalies that have a more significant correlation with electricity prices than the seasonal patterns themselves. This indicates that the correlation results for anomalies from different wind sites across the country can give valuable information on wind resource availability in these critical periods of the year, and thereby enable the identification of  sites that can most optimally balance price volatility during these periods, while potentially also maximising profits to investors.

The work has been developed in R-software. The data and R-code are available on request.

Research team: Kiti Suomalainen, Geoff Pritchard, Basil Sharp, Golbon Zakeri

Researchers at the Centre recently explored the use of a stochastic auction to clear electricity markets with large amounts of wind. The research for this project is largely complete. In 2019 Javad Khazaei will give several presentations on the results to audiences in New Zealand and overseas, and we will submit the research for publication.

This year Ben Gusson, an Honours student, has elected to work on the impact of expanding wind generation on pricing and dispatch in the existing New Zealand market. This research will use the NZEM Simulation model developed by David Young.

Research team: David Young, Javad Khazaei, Golbon Zakeri (EPOC), Steve Poletti, David Young, Ben Gusson

The research aims to understand why existing markets may not provide adequate security of supply. A model of imperfect competition in both the retail and wholesale markets is used to analyse the impact of market power on security of supply. Preliminary work describes conditions where the optimal level of supply may be achieved. Market power tends to exacerbate security of supply issues.

Research team: Steve Poletti, Julian Wright (National University of Singapore).

In 2018 we created an agent-based simulation model of the New Zealand electricity market. The software for this model is complete, but the underlying transmission, demand, and generation data could be improved. In 2019 we will be working to calibrate the model with real NZEM data, and write a paper discussing the model. This work will be presented at the INFORMS conference in Austin, Texas, in November of this year.

Alex John, an honours student in engineering science, is doing a research project to determine which simplified model of the National Grid gives prices and dispatch closest to reality. This is jointly supervised by Dr Golbon Zakeri (EPOC) and David Young. The results of this research will determine the underlying transmission model used by the software.

Two other economics honours students will be incorporating this software into their projects this year. Ben Gusson is using it for wind integration in New Zealand (see above), and Kin Chong will be studying the use of electric cars in New Zealand.

There are plans for Tony Downward, a postdoctoral scholar in engineering science, to start simulations incorporating hydrology this year. The start date of this will be determined by when he finishes his PhD, and no outputs are expected this year.

Research team: David Young, Alex John, Golbon Zakeri (EPOC), Tony Downward

In 2018, Tony Downward, David Young, and Golbon Zakeri submitted a paper to the Energy Journal on the impact of asset swapping on wholesale electricity prices. This year we plan to continue this research by explicitly including the retail market in our model to examine the impact on retail pricing. Additionally, the three researchers are co-supervising an honours student, Veselina Pencheva, who is working to modify the wholesale model used in last year’s paper with more realistic generator data.

Research team: Tony Downward, David Young, Golbon Zakeri (EPOC), Veselina Pencheva

We have had discussions with industry over how ETS obligations should be assigned in the electricity market. If these discussions prove fruitful, we may write a research report on the issue. This is still provisional.

Research team: Bart van Campen, Rob Kirkpatrick, David Young (provisional)

New Zealand has gone through three dry year ‘crises’ and one near-crisis in less than a decade. The government has recently introduced changes to the electricity market design that is aimed in part at managing dry year security of supply concerns. The project will investigate alternative market designs that focus on firm energy payments to ensure security of supply. A market design for such a scheme will be developed specifically for New Zealand.

Research team: Bart van Campen, Steve Poletti and Robbie Turner

We examine the social welfare implications of consumers switching to real time pricing plans (and away from traditional contracts where consumers pay a flat rate per unit of electricity consumed whether or not it is consumed during the peak period) in a setting where there is imperfect competition. With perfect competition expected efficiency gains are large; however this is far from clear once markets are modelled as imperfectly competitive.

Research team: Steve Poletti

The national energy strategy of 90% energy generation from renewable sources has significant implications for the location and development of wind farm sites, geothermal and marine resources. Continued, and increased, use of water resources for hydroelectricity generation is now facing increased competition from other users, notably agriculture. It is remarkable that very little peer-reviewed literature is available on the economics of renewable sources of electricity generation. At a more applied level, Environment Court decisions have signalled a lack of economic analysis that could be used to guide decisions. This research programme will apply a range of economic models to renewable sources of electricity.

Research team: Basil Sharp, Bryce Hool