Optimising generation and energy storage in the transition to net zero power networks

Abstract

As electricity networks plan to achieve net-zero emissions, the role of private behind-the-meter (BTM) generation and storage becomes increasingly important. Two key questions arise for planners: how much BTM will there likely be in the longer term; and what impact will this have on network generation and storage? The combination of high insolation and reducing cost of small-scale solar PV systems in Western Australia has led to a rapid and ongoing take-up of private generation which already supplies around 20% of demand (around one third of houses have rooftop solar), and declining midday network loads, which will likely become negative before 2030 at some times of day and year. However, the market operator has consistently underestimated the rate of private penetration, leading to inadequate planning for the future network. Most published research focusses on network scale renewable generation but neglects the impact of private generation and storage. In contrast, this article presents a model of the integrated system to 2050, projecting the likely scale of BTM generation and identifying the optimal form of network renewable energy and storage to achieve net zero emissions. By 2050 BTM generation will likely supply around 50% of the total annual demand of 54,000 GWh pa. Given the diurnal and seasonal shape of the resulting network load and projected renewable generation costs, onshore wind energy will be the most cost optimal generation source, supplemented by smaller capacity offshore wind, wave and solar PV facilities. Network storage in the form of batteries and pumped hydro will be required, but significant curtailment will still be necessary to optimally match supply with demand. Network generation and storage costs per MWh of network load into the future are likely to be similar to, or lower than existing costs (∼$85/MWh) with the range of technologies considered in this study.