Storage End Effects: An Evaluation of Common Storage Modelling Assumptions

High temporal resolution modelling of energy systems often requires modelling a number of sub-periods, with the end condition of one sub-period being used to seed the next. When storage is modelled a challenge is to keep the model from draining the stored energy at the end of each sub-period. A common approach is to model extra-long sub-periods and to discard this end effect, increasing computation time. Another approach is to require refilling for each sub-period but this introduces a stored energy jump between sub-periods. This paper compare these methods to the alternative of assigning a monetary value to the stored energy at the end of each sub-period using an economic dispatch energy system model. Overall, effective storage modelling is challenging and both the choice of model structure and the value of stored energy impacts storage operation.