The role of green hydrogen in decarbonizing refineries
Today, refineries are the largest consumers of hydrogen.
While a low-carbon future requires a gradual phase-out of fossil fuels, modern societies still rely heavily on petroleum.
In this context, decarbonizing refineries is both urgent and essential.
Among the strategies to cut emissions in this traditionally carbon-intensive sector, green hydrogen for refineries stands out for its ability to replace fossil-based hydrogen in key refining processes, such as hydrocracking and desulfurization.
This transition reduces emissions without compromising product quality or production capacity.
Hydrogen plays an indispensable role in modern refineries, primarily in hydroprocessing operations that break down and purify hydrocarbons. Two of the most hydrogen-intensive processes — hydrocracking and hydrodesulfurization — are essential for producing cleaner fuels.
In particular:
• Hydrocracking converts heavy petroleum fractions into higher-value products such as gasoline, jet fuel, and diesel. This is achieved by injecting hydrogen at high pressure and temperature in the presence of catalysts.
• Desulfurization (hydrodesulfurization) removes sulfur compounds from fuels to meet environmental regulations and cut sulfur dioxide emissions during combustion. In this process, hydrogen reacts with sulfur to form hydrogen sulfide, which can then be separated from the fuel.
Currently, the hydrogen used in these processes is predominantly "gray hydrogen", produced via steam methane reforming (SMR) of natural gas — a process that emits significant quantities of carbon dioxide. This undermines the environmental benefits of downstream desulfurization and hydrocracking.
Green hydrogen, produced via water electrolysis powered by renewable energy, is carbon-free.
By replacing grey hydrogen with green hydrogen in refining operations, it is possible to virtually eliminate emissions from hydrogen production. This shift not only lowers the carbon footprint of refined fuels but also helps refineries comply with emerging standards and regulations for low-carbon fuels.
The integration of green hydrogen into refineries is technically feasible, as the processes already rely on large volumes of hydrogen. The primary challenge remains economic: green hydrogen is currently more expensive than its fossil-derived counterparts.
However, the cost is expected to fall significantly as electrolysis technologies mature, and renewable electricity becomes more abundant and affordable.
Some refineries in Europe and the Middle East are already piloting green hydrogen projects, blending it into existing hydrogen networks or building dedicated electrolyzers for desulfurization units.
These early adopters are proving not only the technical viability but also the strategic advantage of future-proof operations in a decarbonizing world.
Green hydrogen is a practical and powerful lever for refinery decarbonization. By replacing gray hydrogen in hydrocracking and desulfurization, refineries can drastically reduce their carbon footprints while continuing to produce essential fuels.
This represents a decisive step in aligning industrial operations with environmental, regulatory, and climate goals.