The times they are a changin’: Current and future trends in electricity demand and supply

Abstract

The increasing penetration of variable renewable electricity generation in Australia's National Electricity Market over the past decade has led to a sustained change in the shape of electricity demand. In particular, intra-day demand has become more volatile, with demand in some Australian regions increasingly resembling the widely-cited ‘duck curve’ or more appropriately the ‘emu curve’. The changes in demand have, in turn, economically driven out generators whose technical characteristics are ill-suited to supplying this demand profile: high capacity-factor, slow-start plant. In this article, we describe the changes to date in the profile of electricity demand, and draw on other studies to argue that these trends are likely to accelerate going forward based on projected future uptake of variable renewables. In combination with technological and policy developments, these trends imply that flexible plant, such as peaking gas, hydro, and dispatchable storage, are likely to be better suited to the changing profile of demand, in contrast to slow-start and relatively inflexible technologies such as coal and combined-cycle gas plants. These trends are based on the flexibility of different generation technologies and their interaction with emissions considerations.