As we transition to a greener world, hydrogen will play a role in reducing carbon emissions. This will mainly be through injection into the distribution grid for blending with natural gas but there will also be 100% hydrogen and ammonia transportation systems (ammonia offers a route to transport hydrogen in a liquid phase).

The design of hydrogen pipeline facilities presents a unique challenge due to the high wavespeed of the fluid (the speed in which pressure waves travel through the fluid). The wavespeed of natural gas is typically around 450m/s but it can be as high as 1,400 m/s in hydrogen, depending upon the pipeline pressure. Pressure changes in hydrogen pipelines therefore rapidly pass through the system and consequently it can be very difficult maintaining a packed pipeline, if there is a reduction in supply pressure. A hydrogen pipeline will depressurise must faster than a natural gas, oil or water pipeline and it can take much longer to re-pack the pipeline following a supply pressure drop. Any pressure control stations therefore need to have very tight control bands to avoid passing high pressures into lower rated pipework although the challenge with designing and installing responsive pressure control equipment is to then avoid introducing controller instabilities. Hydraulic Analysis have experience with the design, modelling and commissioning of hydrogen pipelines.

The chart below shows how the fluid wavespeed in natural gas increases with increased hydrogen content. It can be seen that there is little impact on fluid wavespeed with blending at low percentages but the effects become far more pronounced when the hydrogen percentages increase above 40%.

Our hydrogen experience includes the sizing of storage facilities to ensure hydrogen demand can be met during periods of low production.

Hydrogen Distribution System Case Study