A hydrogen economy: Why blue plus green is the right sum
18 Nov 20 by Engerati
I recommend Sir David Attenborough’s recent work ‘A Life on Our Planet’. This sobering book cries out for urgent and substantive actions. That last word is intentionally plural. There is no single lifestyle change, energy source or technology that will alone solve the existential threat we face. We must deploy all available solutions rapidly.
We have socialised and legislated Net Zero in 2050. However the 30-year gap can desensitise us to the ticking clock. The brutal truth is that every year the UK emits another 350 million tonnes of CO2, worse if other greenhouse gases are counted. The Committee on Climate Change says that we are not on track to meet our intermediate carbon budgets, let alone Net Zero in 2050.
We have made great progress in decarbonising electricity generation. However, the UK gas networks transport roughly three times as much energy as the electricity network. Add on liquid fuels currently used for transport and we must do much more, and quickly.
Low carbon hydrogen is widely accepted as the key energy vector required alongside low carbon electricity. Not one or the other, but both.
We need to rapidly deploy hydrogen as a resilient distributed utility to displace natural gas and other fossil fuels for industry, space heating, dispatchable power and transport. This requires a joined-up system of hydrogen production, distribution networks, bulk storage and fuel switching by consumers.
There are several ways to produce low carbon hydrogen, of which the most readily available are:
- “Blue” hydrogen – produced by stripping the carbon from natural gas to produce hydrogen and CO2 which is captured and permanently stored (CCS).
- “Green” hydrogen – produced by splitting water with intermittent renewable electricity into hydrogen and oxygen.
Neither is perfect, but the climate crisis means we need to progress both as rapidly as possible.
- Blue hydrogen production using auto thermal reforming technology with CO2 capture rates of 97% can be delivered cost effectively at scale now, rapidly unlocking substantial carbon savings. It does mean there are some residual emissions, as well as those associated with natural gas extraction. The HyNet North West project plans to create the UK’s first low carbon industrial cluster, including distributing 30TWh per year of hydrogen by 2030, the energy equivalent of roughly 45% of the natural gas currently delivered in the same region. Emissions reduction will start as soon as 2025.
- Green hydrogen does not require fossil fuel and the production process emits no CO2. However, it requires low utilisation assets for electricity generation and electrolysis, because the wind doesn’t consistently blow all the time – UK offshore wind generation achieves 50% load factor at best. The scale of electrolysers available today is also relatively small. Green hydrogen production assets are therefore capital intensive and incur a substantial environmental footprint to manufacture and build.
Neither technology being perfect is not a reason to dismiss either. Blue hydrogen must be deployed urgently because its scale and cost of production, expected below £50/MWh, enables implementation of an affordable support regime, will enable the connected infrastructure of distribution and storage to be developed quickly, and allow fuel switching to start. Green hydrogen production scale and cost will improve, connecting into the network infrastructure created by blue hydrogen as projects are delivered.
It’s not one or the other, but both that we need. Arguing which is better means delay which we cannot afford.
Blue + green is the right sum.
By John Egan, North West regional lead at Progressive Energy, and North West Hydrogen Alliance member
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