A greenhouse gas footprint and economic assessment of importing renewable H2 from Portugal to the Netherlands, using liquid organic hydrogen carriers

Abstract

This research was conducted to quantify the economic and GHG impact of importing green H2 from Sines, Portugal, to Rotterdam, in the Netherlands. The H2 to be transported was stored within two-way LOHCs – specifically, the toluene-methylcyclohexane (TOL-MCH) and the dibenzyltoluene-perhydro-dibenzyltoluene (DBT-PDBT) systems – and the transportation was assumed to be handled by chemical/oil tankers. H2 has been highly regarded as one of the most important energy carriers of the coming decades (Detz et al., 2019; European Commission, 2018, 2020a), and is projected to have a substantial contribution towards mitigating the inherent intermittence in energy production via RES. This is a crucial step to achieve decarbonization goals of several industries, such as the feedstock industry, process heating, build environment, transportation, etc. (Port of Rotterdam, 2020). This research was further motivated by the bilateral agreement between the Portuguese and Dutch governments to establish a supply chain of green H2 (2020). Moreover, this research complements the study conducted by Carvalho (2021), which optimized the hydrogenation and dehydrogenation processes of the mentioned LOHC systems, for an annual delivery of 50 kt of H2. The necessary data to compute the results was gathered through literature review and interviews with experts from the respective fields. Overall, the results were assessed based on the impact of completing one roundtrip between Sines and Rotterdam, for the years 2030, 2040 and 2050. Following, these values were extrapolated to match the yearly requirements. The findings from this study concluded that transporting DBT-PDBT, while using small tankers – with a capacity of 27,300 DWT – is the most financially viable option. Accordingly, the results attested that transporting H2 stored in DBT from Sines to Rotterdam, would increment the supply chain in 0.30 €/kg-H2 in 2030, increasing to 0.34 €/kg-H2 in 2040, and finally to 0.38 €/kg-H2 in 2050. When added to the costs concerning the production of H2 and the LOHC conversion processes, a total supply chain cost of 4.28 €/kg-H2 can be expected, for 2030. For 2040, this value is slightly lower, at 4.16 €/kg-H2, and for 2050, it is projected to reach roughly 3.17 €/kg-H2. The respective GHG impact was projected to be 2.471 kg-CO2/GJ-H2 (LHV) in 2030 decreasing to 1.309 kg-CO2/GJ-H2 (LHV) in 2040, and 0.461 kg-CO2/GJ-H2 (LHV) in 2050. Comparing with conventional steam methane reforming, the projected LOHC supply chain allows for savings of 96.0% in 2030, increasing to 99.0% in 2050.