Green and Blue Hydrogen, a Brief Comparison

Hydrogen is emerging as a key energy carrier in the global transition to net-zero emissions. Today, most hydrogen is produced from fossil fuels, but low-carbon pathways — notably green and blue hydrogen — are increasingly studied and deployed in industrial applications such as refining, chemical production and steel decarbonization. These technologies are influenced by evolving policy incentives and climate targets aimed at reducing CO₂ emissions from industrial processes (Nakimera et al. 2025)

On one hand, green hydrogen is produced by the electrolysis of water, that splits water into hydrogen and oxygen. When powered exclusively by renewable electricity, like wind or solar, it is not generating CO₂ emissions during the process (Hafner et al. 2020). On the other hand, blue hydrogen is produced from natural gas through steam methane reforming, that uses high‑temperature steam to extract hydrogen from natural gas, or similar reforming processes. Carbon capture, utilisation and storage (CCUS — technology that traps CO₂ from industrial processes and either stores it underground or uses it in other products) is then applied to reduce the emissions from this production. We do need to remember that this method still relies on fossil fuels and requires highly effective capture systems to minimise overall emissions (Abushaikha et al. 2023).

Green hydrogen’s primary benefit is its near-zero carbon footprint when renewables are used, enabling deep decarbonization in sectors where direct electrification is difficult, such as heavy industry and long-distance transport. It also enhances energy security by leveraging abundant renewable resources. Blue hydrogen can act as a transitional technology by providing lower-carbon hydrogen infrastructure using existing natural gas systems. However, its sustainability depends on high capture rates and minimising methane leakage, and it cannot fully eliminate lifecycle emissions.

In general terms, current production costs for green hydrogen remain higher than for blue hydrogen due to the costs of electrolysers and renewable electricity. Scientific reviews indicate costs ranging widely but generally higher for green hydrogen under current technology and market conditions. Blue hydrogen can be cheaper where natural gas prices are low and CCUS is effective (Nakimera et al. 2025).

While blue hydrogen may support early market development, research suggests that rapid cost declines in electrolysers and stronger carbon pricing mechanisms may increasingly favour green hydrogen over the long term (Beck et al. 2025). Sustainable energy frameworks emphasise investments in renewable capacity and electrolyser scale-up to obtain truly low-carbon hydrogen at competitive cost.

For the energy transition to be deep and durable, green hydrogen must take a leading role. Its near‑zero emissions and compatibility with renewable energy make it a practical foundation for industrial decarbonization. Initiatives like PHOTOSINT — using sunlight, wastewater and CO₂ to create renewable fuels — highlight how scientific progress is turning green hydrogen from a promising idea into a cornerstone of tomorrow’s energy landscape.

References:

1. ARTICLE  - The role of green and blue hydrogen in the energy transition – A technological and geopolitical perspective (2020). Michael Noussan, Pier Paolo Raimondi, Rossana Scita and Manfred Hafner.
2. ARTICLE  - Blue hydrogen production from natural gas reservoirs (2023). Osama Massarweh, Maha Al-khuzaei, Manal Al-Shafi, Yusuf Bicer, Ahmad S.Abushaikha.
3. ARTICLE  - Green hydrogen role in sustainable energy transformations (2025). Sameer Algburi, Hassan Munther, Omer Al-Dulaimi, Hassan Falah Fakhruldeen, I.B. Sapaev, Karrar Fadhil Khalaf Al Seedi, Doaa H. Khalaf, Feryal Ibrahim Jabbar, Qusay Hassan, Ali Khudhair and Grace Nakimera.
4. ARTICLE  - Dynamics of price-based competition between blue and green hydrogen with net zero emissions targets (2025). Reza Fazeli, Thomas Longden, Fiona J. Beck.