Enhancing distribution hosting capacity in urban microgrids: A coordinated DSM and storage framework for Wellington's Kilbirnie network

Abstract

The Wellington Electricity distribution network confronts escalating operational challenges from ageing assets, seismic vulnerabilities, and localised capacity constraints amid decarbonisation. This study proposes and validates a coordinated demand-side management and distributed storage framework to enhance distribution hosting capacity, using quasi-dynamic Power Factory simulations of the Kilbirnie network across three scenarios: baseline operations, passive PV-battery saturation, and active demand orchestration. ​ Passive PV-battery integration across residential, retirement home, and industrial bus depot feeders yielded substantial self-consumption, notably 38% at high-occupancy sites, yet triggered critical transformer overloads reaching 90% utilisation during evening peaks. Active demand-side management, synchronising flexible loads like hot water cylinders and EV charging with solar generation, dramatically alleviated these stresses, slashing residential transformer loading to 25% and creating thermal headroom for rigid night-time industrial demands. ​ Key findings underscore that residential load shifting not only restores daytime reverse power flows but also accommodates electric bus depots, which otherwise would risk severe peaks. High-occupancy commercial loads demonstrated inherent flexibility, further amplified by orchestration. Overall, the framework unlocks latent network capacity, defers reinforcement, and bolsters seismic resilience without physical upgrades. ​ Recommendations advocate mandating active control for residential interconnections, prioritising PV in flexible sectors, rightsizing transport storage for arbitrage, and deploying cross-sector dynamic tariffs. This Wellington-specific approach offers a blueprint for urban distributors balancing affordability, reliability, and electrification under N-1 standards.