City-scale assessment of stationary energy storage supporting end-station fast charging for different bus-fleet electrification levels

Fast-charging electric buses at bus end-stations can lead to high peak-demand charges for bus operators. A promising method to reduce these peak-demand charges is combining the fast charging station (FCS) with a stationary energy storage unit (SES). This work analyses the potential cost reduction for installing optimally-sized SES at bus FCS on a city scale for different levels of bus-line electrification. Results show that the cost-reduction potential reduces with increasing levels of bus-line electrification. For a case study based on the Singapore bus network, installing an SES at FCS can reduce the total costs by 1.8% on average when 30% of the bus lines are electrified, while the average cost reduction in a fully electrified bus network is 0.4%. A comparison of the results with previous studies showed that the cost reduction potential is highly sensitive to the peak demand pricing method.