Accounting for renewable energy supply intermittency in energy systems modelling

We report on the development and application of an integer programming model for simultaneously proposing electricity transmission system augmentations and the selection of electricity generation projects over multi-year time horizons. Undertaking network design while simultaneously addressing renewable energy supply variability over time and space is a difficult proposition. It was however a key design requirement for this model, due to the model's intended use as part of studies of plausible scenarios for Australia's energy future to 2050. The model has been successfully utilised within a multi-stage modelling workflow, being preceded by an economic model of the energy sector and followed by a high resolution simulation of the national electricity market. Together the three models flesh out the details of electricity systems of the future, in terms of the location and technologies for individual power plants, the magnitude of transmission line capacity expansions, and the energy and financial flows in the resulting networks. We present the results from various analyses that have been undertaken using the model, with emphasis on the integration of renewable and fossil-fuel supply options to meet end-user demand, and also describe some of the mathematical and systems-development work that was required in order to yield a model which was sufficiently detailed, solvable in reasonable time, and able to be embedded in a powerful yet easy-to-use GIS and database system.