Life cycle environmental analysis of a hydrogen-based P2P storage system for remote applications

Climate change, mainly caused by the GHG emissions increase, is threatening our planet and a huge energy transition is needed, including the decarbonisation of energy sources, a larger and larger penetration of renewables (with the dramatic growth of wind and solar intermittent energies) and the necessary development of energy storage technologies. The integration of RES in hydrogen-based P2P storage systems is the most credible option with medium/long-term capacity and H2 can be also used as a clean energy vector, flexibly transportable across different sectors and regions. In particular, islands and remote areas can become isolated mini-grids based on RES and P2P systems, avoiding more expensive and impacting solutions, such as submarine electric connections or on-site diesel generators, and having a huge global development potential. In this framework, the European Remote project takes place, aiming at demonstrating the technical and economic feasibility and the energy and environmental advantages of hydrogen-based P2P energy storage systems, designed and implemented in four remote demo cases, creating smart micro-grids almost totally relying on local RES. The aim of this thesis is to provide an environmental analysis of the complete system of the demo case 4, located in the harsh environment of the Norwegian Froan Islands and composed by PV panels, wind turbines, a diesel generator (covering 5% of the load), the H2 storage system (water electrolyser, H2 tank and PEM fuel cell) and Li-ion batteries. The impacts of this system are assessed in comparison with the ones of different scenarios, such as a reference fossil fuel case, with on-site diesel generators, or the actual situation, in which the Norwegian mainland electricity is transmitted through submarine cables. The climate impacts of each component or subsystem, mainly evaluated from literature data, are studied in a holistic view, according to a Life Cycle Assessment philosophy and methodology, in terms of Global Warming Impact (CO2 equivalent emissions with time horizon of 100 years) per MWh of electricity generated or carried by sea cables. The Diesel case has very high GHG emissions (1,031.9 kgCO2eq/MWh), more or less 7 times the ones of the Remote scenario (145.7 kgCO2eq/MWh). The Cable case, instead, presents a lower impact (120.8 kgCO2eq/MWh), because of a lower contribution of the diesel generators (2%), the relatively small distance from the mainland and the very low carbon intensity of the Norwegian electricity, almost totally produced from RES (98%). Further scenarios are also studied through sensitivity analyses, in which some relevant parameters are modified, in order to evaluate their relative contribution to the total GWI. Among the additional scenarios, the Remote-2% case, in which a lower contribution of generators is assumed for the demo case 4 (2% as in the Cable scenario), presents the lowest GWI (119.5 kgCO2eq/MWh), while the Cable additional scenarios, in which a double connections length and a higher electricity carbon intensity are considered, reveal larger GWI (from 211.4 to 595.2 kgCO2eq/MWh), showing the high sensitivity of the final results to these parameters. In conclusion, apart from the very low GWI of the Cable scenario in the particular Froan Islands situation, the application of H2-based P2P storage systems in remote isolated micro-grids offers high climate change benefits in comparison with other scenarios, especially with fossil fuel ones.