Hydrogen Rainbow

Unveiling the Spectrum of Hydrogen Types and their Respective Sustainability Impacts


The quest for sustainable energy solutions has sparked interest in the various hues of hydrogen. Each represents a different production method and corresponding environmental impact. Here, we highlight the different types of hydrogen classified by color, including grey, blue, pink, and green. A nuanced examination of their sustainability impacts reveals the potential of green hydrogen as the most advantageous solution in the ongoing quest for a cleaner and greener energy landscape.

Grey (or gray) Hydrogen:

Primarily derived from steam methane reforming (SMR) using natural gas, grey hydrogen is the conventional method of hydrogen production. Unfortunately, its environmental footprint is significant, with carbon dioxide released as a by-product during the production process. Despite its economic viability, the high carbon intensity of grey hydrogen raises environmental concerns, making it a less favorable option in sustainability contexts.

Blue Hydrogen:

In response to the environmental challenges posed by grey hydrogen, blue hydrogen incorporates carbon capture and storage (CCS) technologies. This process reduces the environmental impact of hydrogen production by capturing and storing carbon emissions. While blue hydrogen is a significant improvement over grey hydrogen, it still faces challenges related to the cost and scalability of CCS technologies. In addition, the percentage of carbon capture can vary depending on the source and the carbon density of the flue gas, requiring careful consideration of its long-term sustainability.

Pink Hydrogen:

Pink hydrogen uses nuclear energy to power the electrolysis process without releasing carbon dioxide. While the technology holds promise for reducing the carbon footprint associated with hydrogen production, challenges such as public perception, nuclear safety, and waste management require careful consideration. Further research and development is essential to assess the scalability, economic viability, and safety aspects of pink hydrogen produced with nuclear energy before we can truly consider this a sustainable way to produce hydrogen.

Green Hydrogen:

The frontrunner in sustainable hydrogen production is green hydrogen, which is derived from electrolysis powered by renewable energy sources such as wind, water, or solar. The electrolysis process cleanly separates hydrogen from water, leaving no carbon footprint and making it a zero-emission fuel. Green hydrogen holds great promise for the decarbonization of industry, transportation and power generation, and aligns seamlessly with global efforts to combat climate change.

Comparative Sustainability Impact:

The analysis of the environmental impacts of grey, blue, pink, and green hydrogen underscores the importance of considering the full life cycle of each production method. Green hydrogen has the most favorable sustainability impact among the types analyzed, due to its zero-emission profile and potential for widespread use. The transition to green hydrogen represents a critical step towards achieving global sustainability goals and advancing the collective goal of a carbon-neutral future.


The diverse spectrum of hydrogen types presents a diverse landscape of opportunities for sustainable energy solutions. While grey, blue and pink hydrogen each offer incremental improvements in environmental impact, we believe it is green hydrogen that emerges as the most advantageous solution. As advances in technology, supportive policies, and global collaboration continue to unfold, the emergence of green hydrogen as a transformative force in the energy transition becomes increasingly clear, propelling us toward a cleaner and more sustainable future.