Life Cycle Climate Change Impact of a Cost-optimal HVDC Connection to Import Solar Energy from Australia to Singapore

This paper aims to evaluate the life cycle greenhouse gas (GHG) emissions of importing electrical power into Singapore, generated from a large-scale solar photovoltaic (PV) power plant in Australia, through a long-distance subsea high-voltage direct current (HVDC) cable. A cost optimization model was developed to estimate the capacities of the system components. A comprehensive life cycle assessment model was built to estimate emissions of manufacturing and use of these components. Our evaluation shows that, for covering one fifth of Singapore's electrical energy needs, a system with an installed capacity of 13.1 GW PV, 17.3 GWh battery storage and 3.2 GW subsea cable is required. The life cycle GHG emissions of such a system are estimated to be 109.5 gCO₂eq/kWh, with the majority coming from the manufacturing of solar PV panels. Cable manufacturing does not contribute largely towards GHG emissions. By varying full-load hours (FLH) and cable lengths, it was assessed that sites closer to Singapore might provide the same energy at the same or a lower carbon footprint and reduced cost, despite the lower insolation as compared to Australia. However, if land-use change emissions are considered, the tropical regions of Southeast Asia might fare poorly in terms of emissions.

Life cycle assessment, Cost optimisation, HVDC cable, Photovoltaics, Australia, Singapore

10.3390/en14217178