Green hydrogen produced from the electrolysis of water powered by clean electricity is a critical component of the future sustainable energy economy. Indeed, it figures into all eight of the EU’s goal-scenarios for achieving climate neutrality by 2050. One of the greatest obstacles to the proliferation of hydrogen as an energy source are the substantial costs associated with the delivery infrastructure.
An assessment by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) in Golden, Colorado cited the high capital investment required for pipeline construction as making gaseous pipeline transport in particular “the most expensive delivery method” compared to other options like liquefaction and gas tube trailer delivery.
The reason gaseous pipeline delivery has recently returned to the limelight is because, for the last several years, researchers have reduced to practice the idea of using existing natural gas pipeline infrastructure to additionally transport hydrogen streams known as “hydrogen blending.”
The idea is not at all new: plenty of technical studies and cost analyses of hydrogen blending have been carried out by countries like the United States and Germany as early as 2010, where the key challenges of the approach have been clearly delineated.
These mainly include the effects of increased hydrogen concentrations on the infrastructure itself posed by the embrittlement of the steel pipes, which support the delivery network as well as power plant machinery and household appliances on the user-end. The graphic below summarizes the complications with introducing hydrogen at various locations along the transport chain.
More recently, studies designed to address precisely these challenges have been put to work. The U.S.’s HyBlend project led by NREL, which started in 2019, aims to experimentally evaluate the effects of hydrogen on pipeline materials and subsequently make publicly-available solution models for adapting infrastructure to be used by the industry.
The U.K.’s HyDeploy project, which started in 2019, focuses on studying possible user-end difficulties by injecting hydrogen into publicly used gas networks and monitoring feedback from users.
Just last month, HyDeploy successfully completed its phase 1 trial, where a 20% hydrogen blend was injected into the private gas network of Keele University in Staffordshire. Customers in the area were able to use existing appliances without having to make any changes, allowing hydrogen to seamlessly power their home utilities.
Widespread adoption of hydrogen blending has the potential to directly displace fossil fuels in pipelines, create a steady demand for hydrogen in mainstream usage, and give new hydrogen ventures an opportunity to scale up without having to commit to a dedicated infrastructure.
Additionally, hydrogen blending may even be able to draw support from fossil fuel giants like ExxonMobil and BP, which have both already demonstrated significant interest in embracing hydrogen. Because of the plethora of existing infrastructure, hydrogen blending may be the easiest way for these companies to redirect the ever-mounting pressure on them to decarbonize.
Hydrogen blending introduces an interesting dilemma, however. At present most hydrogen is made through reforming methane, which produces CO2. The end goal is of course to transport cleanly-produced hydrogen, which would offset emissions from natural gas while still retaining both its production and its infrastructure. If widespread clean hydrogen blending is implemented but is capped at a certain concentration of hydrogen because of technical constraints—such as hydrogen embrittlement—do we run the risk of actually further entrenching the use of natural gas by making the streams just clean enough to be palatable?
Guided by the results of studies like HyDeploy and HyBlend, considerations like these will need to be carefully weighed by both industry proponents and policymakers in order to determine the role which hydrogen blending will play in paving the way to a clean energy landscape.