Modelling the impacts of electric vehicle recharging on the Western Australian electricity supply system

This study investigates the potential impacts of EVs on the Western Australian electricity grid, the constraints on the system’s capacity to supply electricity for EV recharging and the options for managing those potential impacts and constraints. Western Australia is geographically isolated and the electricity network has no interconnection with neighbouring regions. The State energy and vehicle markets are independent of issues occurring in neighbouring states. Western Australia is a relatively clean sample space. This study eliminates uncertainty in vehicle adoption rates from analysis by assuming that all new vehicles are EVs. This gives a worst case scenario in terms of load growth and shows that it will over 200,000 EVs, which represents 10% of the fleet, before there is any significant impact on peak demand even if charging behaviours are left unfettered. The study also shows, however, that the electricity supply and transmission industry can achieve significant short- and long-term benefits if vehicle charging behaviours are managed from the outset, through, for example, demand management or structured tariffs. In the short-term, providing incentive for off-peak recharging increases utilisation of existing transmission capacity, and cheaper, more efficient base-load generation infrastructure. In the long-term, investment in more underutilised capacity can be avoided.