Model Based Dispatch Optimisation for Residential Districts – Analysing the Integration of Electricity Storage Systems and their Environmental Impact

Abstract

In the European Union, residential districts consume a high share of the total electricity, which is still mainly generated by conventional power plants. Consequently, utilising renewable energy carriers is necessary to mitigate climate change. Electricity storage systems are needed to address the fluctuation and the temporal shift between power generation and consumption, caused by a switch to energy carriers like solar and wind. To assess the electricity generation and the storage operation a techno-economic bottom-up model is applied. The goal is the dispatch optimisation of the analysed residential district in on-grid and off-grid cases considering an increasing application of battery electric vehicles. The combination with a Life Cycle Assessment allows the valuation of the environmental impacts of the applied electricity storage system. Gained results show that the operation of a lithium-ion-ironphosphate (LFP) or a vanadium-redox-flow (VRF) battery system with an installed capacity of 182 kWh is resulting in an increased utilisation of generated photovoltaic electricity. A reduction up to 17,968 kWh of grid supply is possible by utilising the LFP in scenario I. Higher installed capacities are dependent on electricity generation and demand. In the analysed energy system model increasing demand due to battery electric vehicles makes higher installed capacities of LFP meaningful. The off-grid system exhibits high degrees of self-supply and autarky, when the installed capacity of LFP accounts for 2850 kWh. But a self-sufficient operation is not possible. The low amount of charge and discharge cycles is indicating that calendric aging is more important than cycle life for stationary electricity storage systems. The valve-regulated-lead-acid battery is not operated due to its low cycle life, furthermore it exhibits the highest amounts in all analysed impact categories when discharging 1 MWh of electricity. The operation of VRF shows higher impacts in climate change and freshwater ecotoxicity than the LFP but results in lower values in the impact category resource depletion. Model based dispatch optimisation for residential districts – analysing the integration of electricity storage systems and their environmental impact