Blue hydrogen can qualify as a clean fuel under existing taxonomies but this will depend heavily on reducing CO₂ and methane emissions in the natural gas supply chain, risk management firm DNV says in a paper published this week.

“The results of our analysis show that blue hydrogen can be delivered with a lower [greenhouse gas] footprint than the thresholds in the taxonomy as defined by the EU and World Business Council for Sustainable Development and be classified as low carbon,” DNV says.

This will also require low process-related emissions from hydrogen production and carbon capture.

“Our data show that this can be delivered with current natural gas supply in some regions, but not all,” DNV says. “Methane emissions due to leakage and venting needs to be well managed for blue hydrogen to contribute to decarbonisation of the energy system as stated in the national and corporate strategies.”

“Methane emissions due to leakage and venting needs to be well managed” DNV

The content of hydrogen strategies and regional variations in methane emissions from natural gas production are two key factors to consider when investing in blue hydrogen production.

DNV cites IEA data showing fugitive and vented methane emissions in 2018 were the highest in Russia and North America and lowest in Europe and Latin America, with the Middle East and Asia Pacific ranking in the middle. But methane emission intensity, based on IEA data for 2020, is highest in Africa, the Middle East and Europe, with North America ranked lowest and Asia Pacific and Latin America in the middle.

ATR versus SMR

The highest overall CO₂ capture rates are achievable with autothermal reforming (ATR) of natural gas combined with syngas high pressure CO₂ capture, delivering capture rates of about 94-94.5pc of emissions.

The highest capture rate using steam methane reforming technology (SMR)—which is commercially more advanced—is 91.2pc, according to DNV’s analysis.

ATR technology has lower energy requirements that SMR as the heat used in the reformer is supplied by the process itself, eliminating the need for a furnace. But a shortcoming of ATR is the need for oxygen rather than air combustion, as an oxygen production plant requires significant investment.

In August this year a paper by two US academics claimed blue hydrogen has no role in a low carbon future. The paper said total CO₂ equivalent emissions for blue hydrogen are only 9-12pc less than for unabated grey hydrogen because of an increased use of natural gas to power carbon capture.

Others have since disputed the paper’s findings.

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Author: Stuart Penson