Is the green hydrogen supply chain sustainable? It would seem not, as revealed by “The illusion of green hydrogen”, based on a research developed by Leonardo Setti (University of Bologna) and Sofia Sandri (Center for Solar Communities) for ReCommon. The critical issues concern various aspects of the supply chain, from production to transport.
To produce 1 kg of hydrogen from electrolysis, about 9 liters of water are needed, therefore, to obtain 1 ton of hydrogen, a good 9 thousand liters must be consumed. To generate the 700,000 tons of hydrogen per year by 2030 envisaged in the Italian strategy, approximately 6.3 million cubic meters of water per year are needed. In other words, an increase in water consumption that would reach approximately 0.6 billion cubic meters in 2050: 0.3% of European fresh water consumption.
Energy is also needed to store, compress and transport hydrogen. Liquid hydrogen needs even more energy, as energy is also needed for the hydrogen ships that we hear about. The evaporation of hydrogen in liquid form is estimated at about 0.4% per day: this means that after 4 months the conveyed energy content would be halved, making the use of hydrogen complex, for example to conserve and transfer energy from one season to another.
Long-distance transport, then, brings with it an important expenditure of energy: to transport hydrogen, a compression power about 3 times greater than that of normal gas pipelines is required, assuming that the transport of 100% hydrogen becomes really feasible.
Finally, there is the physical space necessary to install the renewable energy plants exclusively dedicated to producing hydrogen. To achieve the objective of the Italian strategic plan of an electrolyser power equal to 5 GW, it would be necessary to build 50 electrolysers of 100 MW. To produce that energy, we would need a total area of 550,000 hectares of wind farm or 43,100 hectares of photovoltaic park. 5500 square kilometers is equivalent to the surface of the districts of Modena and Reggio Emilia put together!
