Blue Hydrogen versus Green Hydrogen: What’s the Difference?
23 November 2022
Hydrogen is a chemical element and fuel that produces only water and can be produced by a wide range of resources like nuclear power, natural gas, renewable power, and biomass. The energy industry sees hydrogen as a valuable form of energy that could one day play a vital role in the energy transition and reaching the international goal of net zero. Here lies the big question: what’s the difference between blue and green hydrogen?
Blue hydrogen is created when steam at high temperatures produces hydrogen from natural gas. The primary process through which this happens is called steam methane reforming. According to the U.S. Office of Energy Efficiency & Renewable Energy, this steam reforming process creates hydrogen, carbon monoxide, and carbon dioxide by-product. Other impurities, along with the carbon dioxide, are then removed, producing the final product – blue hydrogen. Because of the carbon dioxide by-product, a carbon capture and storage system are used to store the carbon.
Carbon capture and storage, or CCS, is a relatively simple process that traps carbon dioxide. The carbon dioxide is separated from other gases, then transported through pipelines and ships to a storage site. These storage sites are typically injection sites deep in the ground where the carbon dioxide can be safely and permanently stored.
The main highlight of green hydrogen production is that it’s produced with zero harmful greenhouse gas emissions. This type of hydrogen is created when the electrolysis part of the production process is sourced from renewable resources. Electrolysis only requires a large amount of water and electricity. Green hydrogen currently makes up a small percentage of the overall amount of hydrogen due to its high cost. According to the International Energy Agency, the cost of green hydrogen production is estimated between $3 to $7.50 per kilo – a significant price increase compared to the production cost of blue hydrogen. A large part of this cost comes from the steep cost of electrolyzers, one of the main components of green hydrogen production.
Green hydrogen has many uses – mainly for heat production or supplied to fuel cells to form electricity. According to the Commonwealth Scientific and Industrial Research Organization, hydrogen could be applied to fuel-cell hydrogen vehicles. These container ships are powered by liquid ammonia, green steel refineries, and hydrogen-powered turbines.
When looking forward to the future of net zero emissions, hydrogen is a promising power source. Energy systems across the globe are constantly evolving, so companies globally are constantly evaluating hydrogen’s role in their projects and searching for practical opportunities to introduce it.