Modelling Electricity and Heat Supply with Renewable Infeed and Seasonal Storages on a Local Level using Multi-Period Optimal Power Flow

In this paper, an optimal power flow model for electricity and heat distribution in district networks is demonstrated. The algorithm is based on the AC power-flow equations and solves problems with a time horizon of up to an entire year with the intention to size and operate generation and storage equipment. The interior-point solver PIPS, that allows to include non-linear and linear constraints and variable bounds is used to solve the problem. To decrease computational effort, an algorithm for time series aggregation is introduced, that allows to maintain the seasonal, as well as the hourly characteristics of the time series while significantly reducing the computation time. Besides the electrical network, a district heating network is modelled. This allows various couplings through generation or storage equipment to be integrated into the model. It could be shown, that, with a joint consideration of electricity and heat in the model, a high self-sufficiency of a district energy system can be achieved while at the same time the costs can be lowered. As a side effect, other operating parameters, such as voltage stability, are significantly improved.