Hydrogen Production

Hydrogen is an energy carrier that can store and deliver usable energy, and a crucial feedstock for various industrial sectors.

While its combustion produces no greenhouse gases, the production of hydrogen can have varying degrees of associated greenhouse gas emissions. 

• Electrolytic hydrogen should only be produced from additional renewable electricity, linked to when and where it is being generated.

• The amount of greenhouse gasses emitted to produce hydrogen, regardless of technology or feedstock, must be central to assessing the climate impact of hydrogen. 

Currently, the vast majority of hydrogen produced worldwide is “grey” hydrogen, produced using fossil gas and generating large amounts of greenhouse gas emissions. Renewable hydrogen, or “green” hydrogen, has the potential for very low associated carbon emissions but requires large amounts of renewable electricity to be produced. This renewable electricity demand must be met with additional renewable capacity, and must be produced and consumed simultaneously, and in the same areas. If not, “green” hydrogen production cannibalises existing renewable electricity needed to decarbonise the power grid and support the phase-out of coal and gas through direct electrification. It therefore shifts emissions to a different place in the wider system instead of reducing them. 

“Blue” hydrogen is produced through the same process as grey hydrogen (i.e., by reforming natural gas), but it is paired with carbon capture and storage (CCS) and has the potential to be low-carbon. Whether this potential is realised depends on the amount of upstream methane emissions resulting from natural gas extraction and transportation, as well as the share of CO₂ emissions resulting from hydrogen production that cannot be captured and permanently stored. To be considered low-carbon, these emission sources, as well as other potential points of emissions along the entire value chain, must be kept to an absolute minimum, strictly monitored, and regulated. 

Substituting “grey” hydrogen and unabated fossil fuels with low-emission hydrogen has great potential for reducing emissions if done right. However, the production of low-emission hydrogen must be paired with renewable energy sources and careful management of greenhouse gas emissions throughout the entire value chain. 

Figure 1: Producing Hydrogen from Electricity

Hydrogen Use

Hydrogen is a potential substitute for hydrocarbons like fossil gas or coal in various applications. However, its production requires significant amounts of energy as well as infrastructure that currently does not exist.

Indiscriminate use of hydrogen, such as blending it with fossil gas for combustion, is unsustainable. Instead, hydrogen should be used wisely, with a particular focus on sectors with no other decarbonisation options.

For now, hydrogen will remain a scarce resource, and direct electrification should be prioritised wherever possible to reduce carbon emissions.

In short:

• Hydrogen should be considered judiciously in targeted applications where more efficient alternatives like electrification are not feasible. 

• Blending hydrogen into the existing gas grid should be minimised as it does not provide significant emissions reductions and unnecessarily locks in the use of fossil gas. 

Hydrogen supply is limited, and it should primarily be used to decarbonise harder-to-abate sectors, where a cheaper or more efficient alternative does not exist. Moreover, direct use of electricity is more energy-efficient and preferable even if additional renewables and electrolyser capacity were to be built up at an unprecedented speed.  

Targeted and prioritised use of hydrogen is essential to ensure the most efficient decarbonisation pathway possible for our energy systems. Clean hydrogen is needed first in those sectors where unabated fossil-based hydrogen is currently used as feedstock, like fertilisers. Additionally, where other solutions are not available, hydrogen will be needed to replace fossil fuels in shipping, long-haul aviation, and as a means to store energy over long periods of time. 

However, the transport of hydrogen poses significant challenges due to its specific characteristics such as the smaller size of the molecule, its lighter weight, and its higher flammability compared to other gases. Hydrogen infrastructure must also bear a higher burden due to these characteristics and the fact that the energy content of the molecules is lower than that of fossil gas. As a result, hydrogen cannot entirely replace fossil fuels as the existing infrastructure is inadequate, and much larger volumes would be required than for fossil gas. A dedicated hydrogen distribution network should therefore be established, primarily serving industrial clusters with harder-to-abate industries, and not allowing for the transport of hydrogen blended with natural gas. 

Prioritising targeted use of hydrogen is crucial to ensure the efficient decarbonisation of harder-to-abate sectors where alternatives are not available. The challenges of hydrogen production, transport, and infrastructure also require not only a dedicated hydrogen network, but also to limit the blending of hydrogen with fossil gas, and to primarily serve industrial clusters with harder-to-abate industries.