Grey Hydrogen: The Foundation of Today’s Hydrogen Industry
Across global industries, grey hydrogen remains the most widely produced and utilized form of hydrogen. Its role has been firmly established over decades, particularly in industrial applications where hydrogen serves as a critical chemical input rather than a direct energy source.
That said, as climate considerations continue to reshape industrial priorities, relying solely on grey hydrogen is no longer sufficient. Meeting sustainability goals requires a gradual shift toward cleaner alternatives, including renewable hydrogen (green hydrogen).
In this blog, we explore grey hydrogen in detail: how it is produced, where it is applied, and how hydrogen more broadly supports global decarbonization efforts.
How Grey Hydrogen Is Produced
The production of grey hydrogen relies mainly on a process known as Steam Methane Reforming (SMR). This method combines natural gas (methane) with steam under very high temperatures to extract hydrogen. During this reaction, carbon dioxide is generated as a secondary output.
While SMR remains one of the most efficient and cost-effective hydrogen production methods available today, it is also highly carbon-intensive. The CO₂ produced during the process is released directly into the atmosphere, contributing to overall emissions.
In practical terms, grey hydrogen is produced from natural gas through SMR and is associated with high carbon emissions, resulting in a notable environmental impact.
Why Grey Hydrogen Became the Industry Standard
Grey hydrogen emerged as the industry standard largely because it offered consistent performance, large-scale production capability, and widespread access to raw materials. These advantages made it the most practical option for meeting growing industrial demand.
Today, most hydrogen produced worldwide is used in ammonia production for fertilizers, petroleum refining processes that remove sulfur from fuels, chemical manufacturing, electronics production, and aerospace applications.
Refining alone continues to account for a significant share of hydrogen demand, supporting the production of cleaner, low-sulfur fuels.
Hydrogen as an Energy Carrier
Hydrogen is not naturally available in a usable form and must be produced from a primary energy source. In this sense, it functions as an energy carrier rather than a direct energy source. Once produced, hydrogen can be stored, transported, and later converted back into energy or used directly within industrial systems.
This flexibility positions hydrogen as a key enabler of the energy transition. At the same time, it means that hydrogen’s environmental footprint is primarily dependent on the way it is produced.
The Carbon Challenge of Grey Hydrogen
Because grey hydrogen is produced using fossil fuels and generates CO₂ during production, it contributes directly to greenhouse gas emissions. This impact is particularly important in carbon-intensive sectors, which already represent a large share of global emissions.
For this reason, grey hydrogen is generally viewed as an early phase in the transition toward more sustainable hydrogen solutions, rather than a viable long-term option.
Transitioning Away from Grey Hydrogen
Hydrogen has strong potential as a decarbonization tool, but unlocking that potential depends on transforming how it is produced. Moving away from grey hydrogen requires a gradual transition toward lower-carbon and renewable production pathways.
This transition includes integrating carbon capture technologies into existing SMR facilities, substituting fossil-based methane with biomethane to enable low-carbon hydrogen production, and scaling up electrolysis processes powered by renewable electricity.
Together, these approaches support ongoing industrial operations while driving meaningful emissions reductions.
Hydrogen’s Long-Term Role in Decarbonization
At point of use, hydrogen does not emit CO₂. Its overall climate impact is therefore primarily determined during the production phase. While grey hydrogen has underpinned industrial growth for many years, the long-term future of hydrogen lies in low-carbon and renewable alternatives.
Advancing Sustainable Industrial Solutions
As industries move beyond grey hydrogen toward lower-carbon alternatives, sustainability becomes central to how hydrogen solutions are designed and delivered.
Contact Air Liquide Egypt to learn more about our hydrogen solutions.