Techno-Economic Optimisation of Wind Curtailment Utilisation with Battery Storage Dispatch to Electricity and EV Charging Markets

This research examined whether battery energy storage could economically utilise event-conditioned curtailed wind energy by optimally allocating stored electricity between wholesale grid export and EV charging. The analysis focused on a 43.2 MW onshore wind farm in Central Greece. Expected non-curtailed generation was estimated from ERA5 100 m wind data and the Vestas V117 power curve, calibrated against measured non-event production, and compared with measured output during IPTO-reported curtailment-event hours. The estimated recoverable curtailed energy was treated as the sole BESS charging source, and three scenarios were evaluated: grid-only discharge, EV-only discharge, and joint grid-plus-EV allocation. The dispatch and sizing problem was formulated as an MILP-based, NPV-oriented optimisation including an explicit no-investment alternative and was assessed over a 20-year FCFE horizon using Monte Carlo simulation and sensitivity analyses. The calibrated model reduced holdout nRMSE from 21.92% to 17.83% and mean bias from −4.309 to 0.117 MWh. Under the base scenario, 1537 event hours yielded positive estimated curtailment, corresponding to 10.26 GWh. The no-investment option was the global NPV-maximising solution in all baseline scenarios. The best non-zero BESS Pmax/Emax was 0.25 MW/0.5 MWh, with expected NPVs of −332.6 k€, −356.3 k€, and −321.0 k€ for grid-only, EV-only, and grid-plus-EV operation, respectively. EV-premium breakeven required 1207.5 €/MWh for EV-only and 1186.4 €/MWh for grid-plus-EV operation. The results show that market diversification improves curtailed-energy utilisation, but curtailed-energy-only BESS investment remains financially unattractive under the observed conditions.