Modelling Australia’s transition to a low carbon electricity system with optimised transmission networks and renewable energy exports

© 2020 Changlong WangIn order to meet the Paris Agreement and pursue efforts for a 1.5 degrees Celsius target, the electric power system worldwide must undergo a fundamental transformation as the main pillar for decarbonisation. The decarbonisation will almost certainly be driven largely by the massive adoption of variable renewables. The objective of this PhD project is to develop a co-optimisation model with the ability to perform comprehensive analysis to simultaneously explore the least-cost configurations of generation, storage and transmission over large geographic regions to facilitate the transition to a low carbon power system. Although applicable to any region, the capacity expansion model we developed focuses on Australia’s National Electricity Market. The capacity expansion calculated by the model satisfies prescribed demand projections and emission abatement targets from 2020 to 2050, subject to constraints including resource adequacy, system inertia and reliability, unit commitment, economic dispatch and transmission capacity. The model also takes into account the decommissioning of the existing fossil fuel generation fleets and explores a great range of renewable generation and storage options. The transmission model employs a Direct Current power flow approximation with 21 major load centres over the eastern states of Australia. We have used the model to examine various carbon abatement scenarios for Australia. We show that wind turbines and solar PV technologies combined with pumped hydro energy storage dominate the solutions, and that gas is unlikely to be a transition fuel towards a 100% renewable system by 2050. The 100% renewables systems simulated are not only technically feasible but also economically achievable. Australia’s vast wind and solar resources become increasingly valuable assets as the world decarbonises. Not only does this study consider meeting local requirements for electricity demand, but also the potential for export of green energy. Our research confirms the very real and great potential for Australia to produce cost-competitive hydrogen. In the pathways to carbon neutrality, we demonstrate there are substantial synergies between renewable hydrogen export and domestic energy transition in Australia. In particular, we show if the hydrogen industry co-locates within the National Electricity Market with shared renewable generation facilities (i.e. sector coupling), not only can the hydrogen industry produce cost-competitive hydrogen, but also that domestic electricity consumers could enjoy lower electricity costs, thereby benefiting the whole economy in the long run. Besides hydrogen export, we also conducted the first detailed least-cost optimisation studies of power system decarbonisation planning for both Australia and Indonesia that considers HVDC interconnections. We show direct electricity export to Indonesia could also benefit Australia’s domestic energy transition as any wind and solar energy not used by Indonesia could then be fed to the National Electricity Market. This could help both countries to achieve decarbonisation. Overall, our modelling suggests that a long-term system-wide perspective and orientation are critical for the design of energy policies that can secure broad energy system benefits. If planned well, Australia could become a major supplier of green hydrogen, direct renewable electricity and energy-intensive products as energy vectors in the global market. Particularly, this could be driven and strengthened by a robust commitment to “net-zero by 2050”