Why Storage and Transport Are Hydrogen's Most Difficult Problems
The green hydrogen market's development creates a commercial challenge the industry is now confronting directly: produced hydrogen must be stored and transported from locations where cheap renewable electricity makes electrolysis economical to locations where industrial hydrogen demand exists. The physical properties of hydrogen make this a technically and economically demanding problem that has no fully satisfactory solution at the scale the green hydrogen transition requires. Hydrogen is the lightest element, with an energy density per unit volume that is extremely low at atmospheric pressure — requiring either high-pressure compression, cryogenic liquefaction to -253 degrees Celsius, or chemical conversion to a carrier molecule such as ammonia or liquid organic hydrogen carriers to achieve the energy density required for practical storage and transport. Each approach imposes energy penalties and capital costs that add substantially to the delivered cost of hydrogen and must be incorporated into the economic assessment of green hydrogen supply chains whose viability is already marginal in many applications at current production costs.
The storage and transport challenge is not merely a cost issue — it is a fundamental infrastructure development challenge whose resolution requires investment in facilities, vessels, pipelines, and handling infrastructure that does not currently exist at the scale a commercial green hydrogen economy requires. The natural gas infrastructure delivering pipeline gas from production fields to consumers was built over a century and represents trillions of dollars of accumulated capital investment. The equivalent hydrogen infrastructure does not exist, and its development requires resolution of technical standards, regulatory frameworks, safety protocols, and commercial arrangements still being developed. The hydrogen storage and transport market is consequently both essential for the broader clean energy transition and subject to the chicken-and-egg dynamic that characterises infrastructure development: supply chains will not invest in hydrogen production at scale without confidence in transport infrastructure availability, and transport infrastructure will not be built without confidence in the hydrogen supply that will utilise it.
Compressed and Liquid Hydrogen: The Near-Term Infrastructure
The most commercially mature hydrogen storage and transport modalities are compressed gaseous hydrogen — stored in high-pressure cylinders or tube trailers at 200 to 700 bar — and liquid hydrogen, produced by cooling hydrogen to cryogenic temperatures and stored in vacuum-insulated vessels or cryogenic tanks. Compressed hydrogen is the standard modality for mobility applications — fuel cell vehicle hydrogen refuelling stations dispense compressed hydrogen at 700 bar, and the tube trailer fleet distributing hydrogen from industrial production sites to refuelling stations and smaller industrial customers is the backbone of existing hydrogen distribution infrastructure. The capital cost of compression equipment and the energy cost of compression — consuming approximately 15 percent of the stored energy content at 700 bar — are well-understood characteristics of compressed hydrogen infrastructure.
Liquid hydrogen offers substantially higher energy density than compressed gas — a litre of liquid hydrogen contains approximately twice the energy of a litre of 700-bar compressed hydrogen — but requires cryogenic storage and handling infrastructure whose capital cost and operational complexity are substantially higher, and the liquefaction process itself consumes approximately 30 percent of the hydrogen's energy content, creating an efficiency penalty that must be offset by the transport volume economies that liquefaction enables over long distances. The liquid hydrogen infrastructure being developed for long-distance hydrogen shipping — from Australia, Chile, and the Middle East to Japan, South Korea, and Europe — requires liquefaction plants, cryogenic storage tanks at export terminals, specialised liquid hydrogen carriers, and regasification or reconversion infrastructure at import terminals whose combined capital cost represents one of the largest infrastructure investment categories in the hydrogen supply chain.
Ammonia and LOHC: The Chemical Carrier Routes
Ammonia — the compound of nitrogen and hydrogen produced by the Haber-Bosch process — is the most commercially developed chemical hydrogen carrier, offering the advantage of existing global trade infrastructure including ammonia storage tanks, tanker vessels, and port terminals developed for the fertiliser trade and adaptable for hydrogen transport with relatively modest additional investment. Green ammonia — produced from green hydrogen rather than fossil-fuel-derived hydrogen — can be reconverted to hydrogen at the import destination through thermal decomposition (cracking), or used directly as a fuel or feedstock without reconversion where ammonia itself is the desired product. The dual-use flexibility of green ammonia — as a hydrogen carrier for reconversion and as a zero-carbon fuel for shipping, power generation, and industrial processes — is a commercial advantage over liquid hydrogen and liquid organic hydrogen carriers that are produced specifically for hydrogen transport.
Liquid organic hydrogen carriers — organic molecules including methylcyclohexane, dibenzyltoluene, and a range of purpose-designed LOHC molecules that can reversibly absorb and release hydrogen through catalytic hydrogenation and dehydrogenation reactions — offer the advantage of ambient temperature and pressure storage and transport in standard liquid chemical infrastructure, eliminating the cryogenic requirements of liquid hydrogen and the toxicity and volatility management requirements of ammonia. The energy efficiency of LOHC systems — consuming energy in both the hydrogenation step at the hydrogen source and the dehydrogenation step at the delivery destination — is lower than that of liquid hydrogen or ammonia, creating a delivered cost penalty that must be offset by the infrastructure cost savings and handling simplicity that ambient-condition liquid transport provides. The commercial development of LOHC infrastructure is targeting niche applications where the ambient storage and transport advantage justifies the energy efficiency penalty, while liquid hydrogen and ammonia address the larger-volume, longer-distance transport requirements of intercontinental hydrogen trade.
Pipeline Infrastructure and the Grid of the Future
The development of dedicated hydrogen pipeline infrastructure — or the repurposing of existing natural gas pipelines for hydrogen transport — is the long-term solution that would provide the lowest marginal transport cost for large-volume hydrogen flows between production regions and consumption centres. The European Hydrogen Backbone initiative — a consortium of European gas infrastructure operators proposing a network of dedicated hydrogen pipelines connecting hydrogen production in North Africa, the North Sea, and Southern Europe with industrial hydrogen consumption in Germany, the Netherlands, Belgium, and other major industrial markets — represents the most ambitious hydrogen pipeline planning effort globally, proposing approximately 28,000 kilometres of hydrogen pipeline infrastructure developed by 2040 through the combination of repurposed natural gas pipelines and new-build hydrogen-dedicated pipelines. The technical challenge of hydrogen pipeline transport — hydrogen causes embrittlement of conventional steel pipeline materials and requires specific engineering standards and material specifications still being finalised — is manageable but requires regulatory clarity, commercial framework, and hydrogen demand commitments from industrial customers that are still developing at the pace that major infrastructure investment requires to justify project sanctioning decisions.