Multi-Objective Optimization of a Power-to-Power System with Hydrogen Storage in Solid Materials at Room Temperature

The increasing deployment of variable renewable energy sources calls for scalable and long-duration energy storage solutions. This study investigates the integration of hydrogen storage via physisorption in microporous materials into a Power-to-Power system operating under ambient conditions. A dynamic model is developed to simulate power flows and component interactions, and a multi-objective optimisation is used to minimise both the levelized cost of electricity (LCOE) and grid dependency, with a reference scenario fixed at 20% external electricity withdrawal. Results show that bulk density is the key adsorbent property affecting system performance, while pore volume has a negligible effect. At a material cost of 3.5 € kg−1, high-density metal-organic frameworks (e.g., IRMOF-1 at 500 kg m−3) enable seasonal storage operation at low pressure, achieving LCOE values as low as 0.707 € kW−1 h−1 and specific hydrogen storage costs of 7.1 € kW−1 h−1, below the target of 10 $ kW−1 h−1. Conversely, elevated material costs (35 € kg−1) lead to capacity constraints, operation at 350 bar, and increased compressor demand, raising the LCOE to over 0.73 € kW−1 h−1. Only selected combinations of material cost and density, such as IRMOF-1 at ≤10 € kg−1, meet cost targets, while MSC-30 remains uncompetitive due to lower hydrogen uptake. These findings underline the importance of reducing MOF synthesis costs and improving packing density. The system exhibits a dual operational role—short-term cycling or seasonal buffering—depending on storage capacity.