Towards techno-economic evaluation of renewable hydrogen production from wind curtailment and injection into the Irish gas network

This paper presents the results of techno-economic modelling of hydrogen production from otherwise wasted wind energy in the Republic of Ireland (ROI), and its transportation to the natural gas network, for injection. The model includes the production of hydrogen by electrolysis powered by curtailed and constrained (wind curtailment) wind energy at every wind farm in the ROI, compression to 300 bar, and transportation by tube trailer to the nearest potential injection point to the natural gas grid. This system is referred to as a wind-hydrogen system (WHS). The model does not currently include the costs of converting the hydrogen to methane or injecting the hydrogen/methane into the grid. The WHS model selects an optimum electrolyser size for each wind farm that minimises levelised cost of hydrogen (LCOH) from that farm. Compressors and storage tanks for each wind farm are scaled to the farm’s electrolyser. Central to the WHS model is a correlation that relates optimum electrolyser size to each wind farm’s power capacity (CP), annual capacity factor (CF) and percentage wind curtailment (%CW). This correlation was developed from hourly CW time series data for 75 wind farms in the ROI. Capital, operating and other costs were obtained from literature. Results show that not all wind farms in ROI are suitable for WHS, as indicated by high LCOH at farms of capacity <1 MW. However, 6 kilotonnes of hydrogen, equivalent to 204 GWh or 1% of ROI’s natural gas demand, are producible from 209 wind farms in the ROI. 76% of WHSs, accounting for 79% of renewable hydrogen capacity, are located less than 100 km from their nearest grid injection point. LCOH for hydrogen production and transportation to the nearest grid injection point are in the range 26-46 €/kg excluding injection tariff.