The ability to transport hydrogen in bulk will mean clean energy can be taken where it’s needed, as easily as fossil fuels are today. But there is a cost involved in converting the hydrogen into something easy to transport (and un-converting it at the destination). Herib Blanco at IRENA summarises the findings of their paper that looks at those costs: a better understanding will enable us to choose the right pathways today fit for the next 30 years. There are four attractive options. Three will use shipping: ammonia, liquid hydrogen, and liquid organic hydrogen carriers (LOHC). The fourth is compressed hydrogen via pipelines, either newly laid or through upgraded existing gas pipelines. Scale-up saves money, so the minimum scale required is part of the calculation. Blanco concludes that ammonia and pipelines seem to be the best options for starting the global trade in hydrogen. Today, there is no trade in renewable hydrogen so the right decisions need to be made now at the international level.
Hydrogen trade unlocks new possibilities for improving energy security and climate mitigation. It makes renewable energy transport more cost effective over longer distances and in larger quantities (versus electricity as a transport vector). However, hydrogen is a gas under atmospheric conditions, and it needs to be further processed to make it suitable for transport. This can range from compression when transported in pipelines to chemical conversion into other molecules that have a higher energy density and are easier to handle such as ammonia. Therefore, hydrogen transport involves conversion to a suitable form of transport, the transport step itself, and the reconversion back to pure hydrogen (see Figure 1).
The most attractive options for shipping hydrogen are ammonia, liquid hydrogen, and liquid organic hydrogen carriers (LOHC) which are oil derivatives that react reversibly with hydrogen. Furthermore, hydrogen pipelines represent another option for large-scale transport, especially for regions with an existing natural gas network. These pathways are discussed in detail in a recent IRENA report.
What defines the transport cost?
The transport cost of hydrogen is mainly dependent on the size of the project and the transporting distance. The larger a facility the lower the costs until a maximum size is reached beyond which equipment will be numbered up rather than scaled up and cost benefits decrease. Distance is more critical for pipelines since their costs are directly proportional to distance (i.e. more material needed), while for shipping, 70-90% of the total cost is in the terminals (plants and storage).
The largest cost benefit for economies of scale in shipping is achieved with project sizes of 0.4, 0.4 and 0.95 MtH2/yr for LOHC, ammonia and liquid hydrogen respectively. To put these values into perspective, 1 MtH2/yr would be equivalent to a 10 GW electrolyser running for about 60% of the year, or the hydrogen consumption of five commercial ammonia plants.
What technology pathway is preferred?
Figure 2 shows how the technology pathways compare in 2050. Identifying the most attractive pathway by 2050 allows for prioritisation of efforts in the short-term.
Ammonia ships are the most attractive for the widest range of size and distance combinations mainly because of the low transport costs.
The highest energy and cost penalty of this pathway is the reconversion from ammonia to hydrogen (i.e. cracking) which leads to a 13-34% energy loss. This can be avoided however by directly using ammonia for existing applications such as fertilisers or future applications such as bunkering fuel. The cracking step needs further development and demonstration at the scale that would be needed for global trade.
The main challenge for liquid hydrogen is the cryogenic temperatures needed (-253 °C) as it requires expensive equipment for transport, storage, and handling. It also requires 30-36% of the energy contained in the hydrogen for liquefaction. Due to the high capital intensity, liquid hydrogen becomes more attractive as the project size increases which leads to an overlap with the conditions where pipelines are the most cost-effective.
…Liquid Organic Hydrogen Carriers (LOHC)
LOHC can be attractive in a scenario with slower technology progress which leads to higher shipping costs overall and are the most attractive for relatively small projects.
Pipelines are better suited for large flows. The largest common diameter for gas pipelines is about 48 inches (122 cm) which would have a transport capacity of about 13.5 GW at 80 bar. To put this into perspective, the EU target for electrolysis in 2030 was until recently (before REPowerEU) 40 GW.
An advantage for pipelines is that regions with an existing gas infrastructure such as North America, Europe, Eastern China can potentially repurpose them to hydrogen leading to a dual benefit of lower hydrogen transport costs (investment cost for the pipeline can be 65-94% lower than a new one) and avoiding stranded assets. Transport costs for pipelines scale linearly with distance which makes them attractive for short distances up to about 3,000 km, while using repurposed pipelines can make them attractive up to 8,000 km.
About 10% of the global ammonia production is already traded today, there are more than 120 ports with existing infrastructure, and its synthesis is already done at large scale. The project pipeline of renewable ammonia already stands at 15 Mt/yr by 2030 and 71 Mt/yr by 2040. Renewable ammonia could just be mixed in the fossil-based ammonia that is being currently traded as long as a certification scheme is in place to track emissions. What needs further work is the demonstration and scale up of the integrated electrolysis and ammonia synthesis plant.
Hydrogen pipelines can take advantage of the existing natural gas grid as the natural gas demand decreases. This is already happening with a 12-km pipeline in the Netherlands being repurposed to hydrogen and in operation since 2018.
Going from zero to global scale
The job is far from being done. Today, there is no trade of renewable hydrogen and transport costs are high (see Figure 3) mainly because of the scale at which projects would be done are relatively small since they cannot go from zero to global scale overnight.
There are three main levers that allow a drastic cost reduction towards 2050: economies of scale to reduce the specific costs of all the steps in the value chain; innovation to reduce energy consumption; improvement through deployment on aspects like standardisation, global supply chains, equipment manufacturing.
From hydrogen transport to energy transport
Ammonia, liquid hydrogen and LOHC are suitable for hydrogen transport. However, other pathways like methanol, reduced iron/steel, and synthetic fuels have an even lower transport cost and it would make the most sense to transport energy in these forms when those commodities are the intended final use of the hydrogen.
Hydrogen trade will also be largely defined by factors beyond techno-economics including geopolitics, level of policy support, industrial development, current diplomatic relationships, among others. This could potentially lead to industry relocation to places with low-cost renewable electricity.
This work is part of a series of IRENA reports looking at global hydrogen trade. The other two parts look at: supply cost curves for renewable hydrogen; demand, a scenario for 2050, and enabling actions for the coming ten years. These other two reports will be published on May 20th and summarised in articles published here on Energy Post.