A G7 meeting of environment and climate ministers has agreed to cooperate on developing a “rule-based, transparent global market and supply chains based on reliable international standards and certification schemes” for low-carbon hydrogen.

The G7 notes in a communique that the group of countries will prioritise reducing the cost gap between low-carbon hydrogen and current fossil fuel-based production, while also adhering to safety, environmental and social standards “in particular with regard to water use conflict”.

12–13kg of CO₂e/kg – Global hydrogen production emissions intensity

The IEA recently released a report feeding into the G7 meeting, Towards hydrogen definitions based on their emissions intensity, collating current data on emissions intensities of different production methods and calling for a harmonised approach to calculating lifecycle emissions. It notes that, while a number of countries have already released certification systems and regulations with “significant similarities”, these standards can also vary depending on lifecycle emissions intensity limits and requirements around production methods.

“This variability in criteria, scope and methodologies increases regulatory and certification barriers faced by project developers, who need to undertake ad hoc certification processes for each country where they want to access the domestic market, increasing transaction costs,” the report notes, adding that “this is likely to limit trade to that covered by bilateral agreements”.

Emissions intensity

The IEA calculates that the average emissions intensity of global hydrogen production is 12–13kg of CO₂e/kg of hydrogen.

Based on current policies across governments, the IEA estimates that emissions intensity could fall to 11–13kg of CO₂e/kg of hydrogen by 2030 and 10–11kg of CO₂/kg of hydrogen by 2050 owing to reduction in upstream and midstream natural gas feedstock emissions and limited deployment of low-emission hydrogen technologies. However, the agency calculates that under its ‘net zero’ scenario, wherein countries ramp up climate action, emissions intensity could fall to 6–7 kg of CO₂/kg of hydrogen by 2030 and 0.8–0.9kg of CO₂e/kg of hydrogen by 2050.

The emissions intensity of hydrogen produced via unabated natural gas ranges from 10–14kg of CO₂e/kg of hydrogen, while production from coal gasification—which accounts for a fifth of global hydrogen—has an emissions intensity of 22–26kg of CO₂e/kg of hydrogen.

The report notes that retrofitting gas-based hydrogen production with current CCS technology with a capture rate of 60pc would bring emissions intensity down to 5–8kg of CO₂e/kg of hydrogen, with further reduction to 0.8–6kg of CO₂e/kg hydrogen if using CCS technology capable of capturing more than 90pc of emissions. Similarly, retrofitting CCS with a 93pc capture rate to coal gasification units would reduce emissions intensity to 2.6–6.3kg of CO₂e/kg of hydrogen.

The IEA cautions that producing hydrogen via electrolysis using power from the grid during peak hours could result in emissions intensity of 24–32kg of CO₂e/kg of hydrogen if additional demand is covered by gas-fired power plants and 50–57kg of CO₂e/kg of hydrogen if covered by coal-fired power. As such, the agency notes that many standards and certification systems include additionality requirements, as well as provisions for temporal and geographic correlation, in an effort to avoid increasing fossil-based electricity generation while maintaining grid stability.

While hydrogen produced directly from renewables is estimated to have a carbon intensity of zero, the IEA notes that this could change depending on whether upstream emissions from manufacturing the renewables assets are taken into account.

For example, solar panel manufacturing is estimated to have an emissions intensity of 18–50g of CO₂e/kWh, resulting in 0.9–2.5kg of CO₂e/kg of hydrogen production powered by those modules. “In the case of onshore wind, embedded emissions of 8–16g of CO₂e/kWh would translate into an emissions intensity of 0.4–0.8kg of CO₂e/kg [of hydrogen],” the report adds.

The report calculates that hydrogen production from bioenergy could have a negative emissions intensity if coupled with CCS able to capture 95pc of emissions.

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Author: Polly Martin