Hydrogen according to the Global Hydrogen Review 2023

Hydrogen is attracting global attention as a key low-carbon energy carrier of the future for decarbonising transport, power generation, heating and energy-intensive industries such as chemicals and steel. Most of the data in this article comes from this comprehensive report.

Emissions intensity

Direct emissions from producing hydrogen from natural gas are around 9 kg of CO2 equivalent per kg of hydrogen (kg CO2-eq/kg H2). Further emissions also arise from the production, processing and transport of natural gas, in the form of methane emissions from venting or leaks, or as CO2 emissions from burning methane at gas fields or associated with the energy used in natural gas production and transport. These additional emissions amount to 2.4 kg CO2-eq/kg H2, bringing total emissions from natural gas to 10-13 kg CO2-eq/kg H2.

To achieve cost parity between hydrogen from natural gas and renewables, a carbon price of USD 230–550/t CO2 would currently be required. The EU ETS price has ranged between EUR 20 - 100/t CO2 over the past five years. Although it reached a peak of more than EUR 100/t CO2 in 2023, it does not yet offer sufficient stability or predictability to finance long-term hydrogen projects and contracts.

Electrolyser prices

They range from USD 1,700/kW to USD 2,000/kW (for alkaline and PEM electrolysers, respectively). Alkaline electrolysers manufactured in China are much cheaper than those made in Europe or North America, at around USD 750-1,300/kW.

Shipping hydrogen

There are currently no commercially available tankers for transporting liquefied hydrogen. The Suiso Frontier, with a capacity of 1 250 m3 (~75 tonnes [t] LH2), was the only demonstration project to ship LH2 from Australia to Japan in 2022. A valve failure in the hydrogen gas combustion unit caused a fire while the ship was docked in Australia. Lessons from this incident will be incorporated into the design of a new hydrogen combustion unit for a larger 20 000 m3 tanker (~1 200 t LH2). Given the critical issue of hydrogen boil-off, Shell signed a memorandum of understanding with Alfa Laval in December 2022 to develop a gas combustion unit for excess hydrogen. Several companies are developing liquefied hydrogen tankers expected to enter service by 2030, with hydrogen cargo capacity of up to 160 000 m3 (-9 600 t LH2). Transporting hydrogen in tankers powered by fuel oil results in a high carbon footprint. For example, transporting ammonia or LOHC (e.g. methanol) over 15 000 km results in emissions of 1.2 kg CO2-eq/kg H2 or 3.9 kg CO2-eq/kg H2.

Hydrogen pipeline transport

Using, for example, electricity with an emissions factor of 540 g CO2-eq/kWh (the global average emissions factor for natural gas-fired electricity generation) to compress hydrogen over 5 000 km in a 48-inch pipeline operating at 100% of its design capacity would result in emissions of 1 kg CO2-eq/kg H2. Alternatively, compressors can be powered by hydrogen from the pipeline. Transporting compressed hydrogen by pipeline may be the most cost-competitive option, adding only about USD 0.4–0.5/kg H2 over 3 000 km.

Hydrogen storage

Global underground natural gas storage capacity is approximately 490 billion m3, equivalent to around 12% of annual gas demand. Around 90% of existing capacity is in porous storage facilities, particularly depleted gas fields. Depending on geological availability, non-porous storage facilities such as salt caverns or hard-rock cavern storage are preferable, although they are more expensive. Porous storage facilities are more widely available, but the technology has not yet been demonstrated for storing pure hydrogen. Moreover, because hydrogen has a low density, storing the same amount of energy as hydrogen requires three to four times the volume compared with natural gas at the same pressure. Austria is now testing the world’s first pure hydrogen storage facility in an underground porous reservoir (~3 GWh of hydrogen). “In our pioneering demonstration facility, we will bring 4.2 million kWh (4.2 GWh) of summer electricity into winter in the form of hydrogen, thereby ensuring renewable energy supplies.” See here.

Hydrogen and its impact on the climate

Since hydrogen is an indirect greenhouse gas, it is also important to better understand and account for potential leaks along the hydrogen supply chain, including storage, loading/unloading and transport. Hydrogen is not a direct greenhouse gas, but it interacts with other compounds in the atmosphere, affecting the concentrations of greenhouse gases such as methane, tropospheric ozone and stratospheric water vapour. The latest scientific estimates suggest that hydrogen could have a GWP of 11.6 ± 2.8 kg CO2-eq/kg H2 over a 100-year time horizon. Hydrogen has a short atmospheric lifetime, and estimates suggest that its global warming potential over a 20-year horizon would be more than three times its 100-year impact. Due to the small size of hydrogen molecules, their high diffusivity and low viscosity, leaks can occur throughout the supply chain, with transport and storage posing greater risks.

According to the IPHE methodology and the global assumption for renewable electricity regardless of its use, renewable electricity from wind, solar PV, hydropower and geothermal energy has zero emissions, and direct emissions—i.e. emissions associated with the manufacture of solar photovoltaic systems or wind turbines—are not taken into account. As a result, even electrolysers using these forms of renewable electricity are considered to have zero emissions.

Conclusion

To avoid ending on a pessimistic note, the report describes a hydrogen production project by NEOM Green Hydrogen in Saudi Arabia, with an interesting price of USD 3 - 4/kg of hydrogen, but that would be a topic for another article.