How is hydrogen transported?
There are several possible methods for preparing, packaging and transporting renewable hydrogen to get it from its place of production to place of consumption, namely:
– as a gas in cylinders
– as a gas in semi-trailers (tube trailers)
– as a liquid in tanker trucks
– underground pipeline
The choice made depends primarily on the amount of hydrogen being transported and its end use.
Delivery of hydrogen in cylinder frames
A 50-litre cylinder (known as ‘B50’ or ‘L50’) contains 0.75 kg of compressed H2 at 200 bar. They are generally packed in metal frames holding 8 – 28 cylinders. This supply method is favoured when consumption is less than 10 tonnes of H2 a year.
Delivery of gaseous hydrogen by tube trailer
This is the supply method used for filling stations. Upon arrival, the full trailer is connected to the station and refuelling takes place immediately. The truck heads straight back to the production site with another empty trailer, ready to be filled once more. The amount transported depends on the pressure of the hydrogen and type of tank:
– Capacity at 200 bar (steel tank): up to 0.5 t
– Capacity at 300 bar (composite tank): up to 0.8 t
– Capacity at 500 bar (composite tank): up to 1.1 t
Delivery of liquid hydrogen by tanker
In order to deliver hydrogen in a liquid form, it must be chilled to a temperature of -253°C and kept at that temperature in a cryogenic tanker. This type of tanker can hold up to 4 tonnes of liquid hydrogen.
Delivery of hydrogen by pipeline
Gaseous hydrogen passes through a steel pipeline, generally at a pressure of 25 – 60 bar.
The maximum flow rate depends on the pipeline diameter:
150 mm Diameter → 12,000 Nm3/hr i.e. 1 t/hr
250 mm Diameter → 40,000 Nm3/hr i.e. 3.4 t/hr
300 mm Diameter → 80,000 Nm3/hr i.e. 6.8 t/hr
400 mm Diameter → 120,000 Nm3/hr i.e. 10 t/hr
A single 100MW unit producing hydrogen by electrolysis produces 14,000 tonnes of hydrogen a year. Delivery by pipeline or tube trailer is the most appropriate method.