Assessing the effectiveness of hydrogen pathways: A techno-economic optimisation within an integrated energy system

With the world still far off-track from averting relentless global warming, and most countries struggling in meeting their self-imposed goals, hydrogen can potentially play a crucial role in tackling the major challenge of decarbonising the global economy in the framework of a sustainable development. Capable to store, carry, and convert energy in a variety of ways, hydrogen can be a versatile tool to exploit fully the potential of renewable energy sources. Using a holistic approach within a techno-economic optimisation, this study aims at analysing quantitatively the effect of different possible energy pathways employing hydrogen, taking the Italian energy system as a case study, assuming a progressive growth in both renewable power generation capacity and electric mobility in private transport. Results confirm the beneficial impact of hydrogen and identify three hydrogen-based pathways in the optimised energy scenarios: production of synthetic natural gas to partially replace natural gas in the grid and both direct hydrogen consumption and production of synthetic liquid fuel in the heavy transport sector. Direct hydrogen injection in the gas grid plays a negligible role instead. At most, CO 2 emissions can be reduced by 49 % within the investigated scenarios, with an increase in annual costs of 8 %. • Different green-hydrogen pathways are applied to the Italian energy system. • A techno-economic optimisation is performed to assess the best trade-off scenarios. • H2 plays a better role in powering FCEV than in generating synthetic fuels. • Synthetic fuels, EVs and FCEVs reduce CO2 emissions by up to 49% compared to 2017. • Synthetic fuel production is more effective than direct H2 injection in the gas grid.