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3.4 Hydrogen Supply Chains

Site: Hamburg Open Online University
Course: Green Hydrogen
Book: 3.4 Hydrogen Supply Chains
Printed by: Gast
Date: Saturday, 23 November 2024, 10:33 AM

Description

After you have learned about the different technologies for storing and transporting hydrogen in the previous two sections, you will learn in this last part of the chapter what future supply chains for green hydrogen could look like. The term hydrogen supply chain describes the entirety of all process steps and the technologies applied between the production of the initial raw materials (e.g. renewable electricity) and the end use of the hydrogen or the derivative.

Table of contents

1. Supply chains

The general components of green hydrogen supply chains are shown in the figure below. The production of hydrogen via electrolysis is the central element of all supply chains. Renewable electricity and treated water are needed for the electrolytic production of green hydrogen. Usually, the hydrogen cannot be consumed directly at the place of its production. Therefore, the next step in the supply chain is conditioning for storage or transport (see 3.2 Hydrogen Storage). The type of this conditioning depends on the form in which the hydrogen is to be transported and stored. If ammonia, methanol or a synthetic fuel is produced, additional feedstock substance (carbon dioxide or nitrogen) is needed in addition to electrical energy and water. If LOHCs are used for the storage and transport of hydrogen, a respective carrier liquid is needed.

 
General overview of the components of hydrogen supply chains
General overview of the components of hydrogen supply chains by Fabian Carels and Lisa Karies (CC BY-SA)

At present, it is still uncertain which technologies and carrier media will become established in future supply chains for green hydrogen. It is conceivable that not only one path will emerge, but that different supply chains will be realised depending on the respective boundary conditions. In principle, the distance between the place of production and consumption as well as the form in which the energy is demanded by the end consumer will probably determine the composition of the respective supply chain. Thus, scientific analyses show that in many cases it is advantageous, both in terms of total supply costs and energy efficiency, to transport the hydrogen in the form in which it has to be supplied to the customer at the end. 

To illustrate this, three supply chains for providing different consumers with green hydrogen or its derivatives are presented in the following. Since, as already mentioned, there are currently no supraregional supply chains for green hydrogen, the examples presented here only illustrate possible future scenarios that are realistic from today's perspective. 




 

2. Example 1: Storage and transport of compresses hydrogen

Hydrogen supply chain Example 1: Storage and transport of compressed hydrogen in Spain
Hydrogen supply chain Example 1: Storage and transport of compressed hydrogen by Fabian Carels and Lisa Karies (CC BY-SA)

The production of crude steel is nowadays a process that emits very large amounts of greenhouse gases. Hydrogen-based steel making is potentially climate-neutral and is currently being developed (for more information, see Chapter 4). If entire steel mills are converted to green steel production in the future, they will need very large quantities of gaseous hydrogen. For the supply of hydrogen to very large individual consumers, such as steelworks in this example, transport via pipelines is usually the best option. Compared to other transport options, such as delivery by truck, pipelines allow very large quantities of hydrogen to be supplied continuously with relatively little effort. In the future, it will probably also be possible to connect large-scale underground hydrogen storage facilities to hydrogen pipelines in order to compensate seasonal fluctuations in the availability of renewable energies.

As explained in Chapter 3.1, Germany will probably not be able to cover its hydrogen demand completely by itself. Importing by pipeline from sun-rich regions in Southern Europe and North Africa is a possible alternative. In order to make such an import possible, a transnational network of hydrogen pipelines must be established. Numerous operators of natural gas pipelines from various European countries have joined forces for this purpose and want to set up the so-called European Hydrogen Backbone (for further information click here) by 2040, which is to enable the transport of hydrogen from North Africa or Southern Europe via Spain or Italy to Sweden. 



 

3. Example 2: Transport of liquid hydrogen via ship

Hydrogen supply chain - Example 2: Transport of liquid hydrogen via ship
Hydrogen supply chain - Example 2: Transport of liquid hydrogen via ship by Fabian Carels and Lisa Karies (CC BY-SA)

Aviation is another sector in which hydrogen may be used in the future to replace fossil fuels and minimise greenhouse gas emissions. Unlike for steel production, however, hydrogen for aircraft refuelling will most likely not be demanded in gaseous form but as liquid hydrogen (you will also find more information on the use of hydrogen in aviation in chapter 4). One possible option to provide liquid hydrogen for aviation can be the import via liquid hydrogen tankers. Since very few airports have their own port, the liquid hydrogen has to be transported to the airport by truck after the ship arrives.

Since the boil-off losses that occur during the storage of liquid hydrogen (as described in Chapter 3.2) increase with the duration of transport, liquid hydrogen-based supply chains are less suitable for very long transport distances. For the assumed supply of liquid hydrogen to an airport in Northern Germany, Tunisia is chosen as an export country becuase it is relatively close to Central Europe. Large-scale seasonal hydrogen storage is not used in this example for two reasons. Due to its geographical location, the seasonal fluctuations in the availability of renewable energies in Tunisia are significantly lower than in most parts of Europe. In addition, the boil-off losses already mentioned would be high if liquid hydrogen were to be stored for long periods of time. 



 

4. Example 3: Transport of green methanol

Hydrogen supply chain - Example 3: Transport of green methanol
Hydrogen supply chain - Example 3: Transport of green methanol by Fabian Carels and Lisa Karies (CC BY-SA)

Many chemical processes require hydrocarbons or alcohols as feedstocks. Today, these chemical compounds are usually produced on the basis of fossil raw materials such as natural gas or crude oil. Methanol produced on the basis of green hydrogen can be used in future as a raw material for climate-neutral processes in chemical industry.

Due to its good transport properties, green methanol may also be imported from very distant regions in the future. Since methanol, unlike liquid hydrogen, can be transported by ship almost without losses, the transport costs barely contribute to the overall costs, irrespective of the distance to be covered. For the supply chain illustrated here, Patagonia was chosen as an exemplary export region, where green hydrogen and its derivatives can potentially be produced at low cost due to very favourable wind conditions.

In the schematic representation of the supply chain, the supply of carbon dioxide for methanol synthesis was neglected for reasons of clarity. However, the availability of green carbon dioxide may be an important criterion for the selection of sites for the production of green methanol in the future. It is conceivable, for example, that regions that have a large biomass potential - and thus at the same time a high availability of green carbon dioxide - have decisive location advantages with regard to the production of green methanol compared to regions without such a biomass potential.



 

5. Expert lecture

 

Lucas Sens; Institute of Environmental Technology and Energy Economics,  Hamburg University of Technology
Hydrogen supply chains – Options and their assessment  
Future Supply Chains for Green Hydrogen: From Production to End Use by Lucas Sens (CC BY-SA)