Jul-2023

LOHC: H2 delivery pathway for emerging hydrogen market

Hydrogen is set to play a pivotal role in future energy landscapes, and several countries around the world have already laid out detailed hydrogen roadmaps and targets.

Sebastien Lecarpentier, Arnaud Cotte and Stephanie Decoodt
Axens

Article Summary

The challenges to achieve hydrogen's potential are immense, and a concerted effort is needed for the necessary technological and infrastructure development. The transportation and storage of Hydrogen pose logistical and safety challenges, and choosing the right technology depends on a wide array of parameters.

This article makes a case for using Liquid Organic Hydrogen Carriers (LOHC) such as toluene/MCH (methyl-cyclohexane).

The DOE H₂@Scale Demand Analysis report mentions that in addition to growing existing markets such as petroleum refining and ammonia production, hydrogen helps the development of new markets such as metals refining, synthetic fuel and chemical production, biofuels, fuel cells, transportation sector, industrial processes, and injection into natural gas pipelines (DOE, 2020). According to the IEA’s Net Zero by 2050 Roadmap, the size of the H₂ economy could be as large as 500 MTA (see Figure 1), including about 200 MTA of blue H₂ (IEA, 2021).

Hydrogen requires a range of supporting infrastructure for production, storage, and distribution at a scale large enough for the hydrogen economy to play a key role in the energy transition. Technology for hydrogen distribution is currently available commercially, and several companies deliver bulk hydrogen today. However, future hydrogen demand will require regional expansion of this infrastructure and the development of new technologies, such as chemical carriers, to transport hydrogen at high density and high throughput.

Therefore, the feasibility of transporting H₂ is an important element of the emerging H₂ economy. The choice of hydrogen transportation technology depends on a wide array of parameters, and this article makes a case for using liquid organic hydrogen carriers (LOHC) such as toluene/MCH (methyl-cyclohexane).

Transport: a key element of the hydrogen economy
The most favourable renewable energy production locations are often found in remote, renewable-rich locations, whereas demand will likely be highest in heavily industrialised and densely populated areas. As shown by the IEA (see Figure 2), H₂ production cost, which depends on the cost of green electricity used in the electrolysers, can be reduced by a factor of almost three in countries such as Chile or Australia where renewable energy such as solar and wind is abundant compared to Europe or Japan.

To reconcile supply and demand for green and affordable hydrogen, there is a need for viable, large-scale clean hydrogen transportation solutions. Four hydrogen transportation technologies have the highest potential: pipelines that transport gaseous hydrogen and the three hydrogen transportation vectors ammonia, liquefied hydrogen, and LOHC carriers. On a regional scale, repurposing the natural gas distribution networks over land may be an option. This repurposing to hydrogen may require significant investment, but there is growing confidence, especially in the EU, that this could be done successfully. However, in regions where new pipelines are needed for hydrogen transport, especially over long distances such as in North America from the Gulf Coast to West Coast states, and certainly for oceanic transport, hydrogen carriers could be more competitive.

LOHC: a safe and scalable transportation solution
LOHC are a unique way to deliver and store hydrogen by hydrogenating a chemical compound at the site of production and then dehydrogenating it at the demand centres.

The transport of hydrogen in LOHC systems has numerous advantages over other carriers such as ammonia and liquid H2, as shown in Table 1:
•    Safety: equivalent to petroleum products or sustainable fuels
•    Handling convenience: liquid at ambient conditions, which is more economical as there is no need for expensive refrigeration systems
•    Lossless transport and storage: there is no material loss through boil-off compared to liquid hydrogen, and LOHC is chemically stable.

More importantly, LOHC systems enable the use of existing infrastructure for fuel, including storage facilities, without the added complexity or need to mitigate operational/safety risks. Additionally, the use of existing infrastructure potentially decreases CO₂ emissions as it negates the production effort for new infrastructure.
LOHC: a cost-competitive solution

Various entities have evaluated several LOHC carriers compared to liquid and gaseous H₂ and ammonia. The section below highlights two such reports: Roland Berger for the EU and the US DOE for North America.

Roland Berger assesses three hydrogen carrier technologies – liquefied hydrogen, ammonia, and LOHC – and analyses their costs and feasibility, with a focus on Europe (Roland Berger, 2021). This includes a comprehensive model comparing the cost of ownership of the technologies based on four hydrogen transportation routes that will likely emerge in the future. Choice is dependent on defined use cases, transportation modes, distances, and potential partner synergies. This report concludes that all the technologies still require development work, with ultimate success depending on cost-cutting potential, speed of market uptake, and ease of use. Per this report, for large-scale harbour-to-harbour and mid-scale multimodal transportation, LOHC is cheaper than other carriers and almost comparable to ammonia for small-scale transportation. The transportation could be either inland trucks or intercontinental hydrogen trade using tankers.

The US DOE report (Argonne National Laboratory, 2019) compares ammonia and LOHC (specifically toluene/MCH). Hydrogen carrier pathways assume large production plants (hydrogenation) for economy of scale, located in the US Gulf Coast area with a low natural gas price outlook and diverse sources. The reference pathway is hydrogen production by steam methane reforming with comparative production, transmission, and decomposition costs at different demands. The transport assumes by train to storage terminals in California with local transmission by truck at the end. The MCH pathway includes a transmission leg for return of toluene to the production plant. Per this report, NH₃ and MCH are comparable for long-range transport.