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“Blue” or “green” is a misnomer: development of a hydrogen sector needs bulk “clean” hydrogen


As part of the ongoing research of Delta-ee’s Gas Heating Service ( on “Hydrogen for Heat”, I recently attended the H2FC SUPERGEN Conference, a meeting of both academia and industry stakeholders primarily from the UK that operate across the fuel cell and wider hydrogen sector. Although there were many interesting sessions, the take-home message from this conference that challenged my thoughts and those of Delta-ee was the move in thinking from blue or green to blue then green.

Bulk supply of “clean” hydrogen is key to establishing a hydrogen sector

Hydrogen can play an important role in the decarbonisation of several sectors including industry, heat and transport sectors through harnessing existing technologies such as gas turbines, fuel cell vehicles and hydrogen boilers. However, without bulk supply of competitively priced “clean” hydrogen or the required infrastructure to distribute it, the hydrogen sector will struggle to develop or play any major role in achieving decarbonisation goals.

Clean hydrogen is labelled either blue or green depending on the process used to produce it; green H2 is produced by electrolysis of water using renewable electricity, while blue H2 is natural gas derived and relies on the coupling of steam methane reforming (SMR) and carbon capture and storage (CCS).

Green H2 cannot currently produce scale or price to compete

While green H2 represents a means to decouple hydrogen and natural gas, it cannot yet be produced at sufficient scale for widespread use. The largest current power-to-gas project uses ten 1 MW PEM electrolysers to produce 1,300 tonnes H2 per year for a refinery in Wesseling, Germany (REFYNE). This is tiny compared to the output of a typical SMR plant operating today which can produce more than 100,000 tonnes H2 per year.

By not benefitting from economies of scale, the higher capex still associated with electrolysers (per MW of fuel cell) and the current high price of electricity mean green hydrogen currently costs approximately €10 / kg H2 compared to €2 / kg H2 via SMR: far too expensive to use for heating homes or powering industry. Despite this, one application where green H2 can currently find a market in supplying transport fuel; this was explored by Delta-ee in a recent project (

Bulk production of blue H2 is proven and can be delivered now

Blue H2 has been successfully produced in bulk quantities by Air Products at the Port Arthur Refinery (Texas, USA) and by Shell’s Quest CCS project (Alberta, Canada). These plants produce well in excess of 200,000 tonnes of blue H2 a year (containing enough energy to heat 350,000 homes) for petroleum refining. The economies of scale associated with these plants mean that the cost of blue H2 is estimated to be far lower than green, approximately €3 / kg H2. These projects have shown that with appropriate financial incentives, (provided by enhanced oil recovery at Port Arthur and backing by both regional and national governments at the Quest project) clean hydrogen can be produced in bulk and at a competitive price.

A government funded industrial hydrogen hub is essential for a low regret hydrogen roll-out in the UK

The industrial sector is perhaps the most challenging sector to decarbonise; only two options are viable to reduce CO2 emissions from the industrial sector as a whole: clean hydrogen or CCS. The establishment of a government backed large-scale blue H2 plant in a heavily industrialised area (such as Merseyside, Teeside, Grangemouth or Humberside) could demonstrate the use of low carbon hydrogen as a fuel or feedstock for a range of carbon intensive industrial users, but also provide the necessary scale and infrastructure required to provide competitively priced, low carbon hydrogen to the heat and transport sectors.

The UK government has recognised the need for such a large-scale production of clean hydrogen though the Hydrogen Supply project funded by the Department for Business, Energy and Industrial Strategy. This £20m fund aims to “identify and test approaches to supplying bulk low carbon hydrogen; either to the gas grid, industry, power, transport, or import terminals.”

Blue H2 is essential for scale and deployment, but green H2 is needed to meet climate goals

Blue H2 is therefore key in the short term to establish large scale clean hydrogen production and demonstrate the decarbonisation of several sectors. However blue H2 is not a perfect solution. While current methods of hydrogen production (SMR) produce 300g CO2 / kWh H2, and blue H2 carries a carbon footprint of 75-150g CO2 / kWh H2, green H2 produces only 23g CO2 / kWh H2; green H2 is therefore essential to meet climate change targets for 2050. Moreover, the competitiveness of green H2 will only increase with the increasing availability of low-cost renewable electricity toward 2050 and the consequent increase in scale that will be enabled by further technological development of electrolysers.

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