The Different Colours of Hydrogen
Otto Simon • July 28, 2023
You may have heard of ‘blue hydrogen’, ‘green hydrogen’, possibly even ‘pink hydrogen’ and thought—wait a minute, isn’t hydrogen a colourless gas?
Yes, hydrogen is an invisible gas, it burns with a near invisible flame, and despite the colourful names, there’s no visible difference between the different types of hydrogen. The ‘colours’ of hydrogen are used within the energy industry to differentiate between hydrogen production methods.
Currently, there’s no universal naming convention, so the colour definitions vary by region or industry, but here’s our guide to the most commonly used hydrogen colour code:
Green Hydrogen
- Green hydrogen is produced with no harmful greenhouse gas emissions. It’s made by using ‘clean’ electricity from renewable energy sources (e.g. solar, wind, etc.) to electrolyse water. Electrolysers use electricity to split water into its components of hydrogen and oxygen, emitting zero-carbon dioxide in the process, making it a ‘zero-carbon’ process.
- Currently, this makes up a small portion of overall hydrogen production due to the high cost of production, but many emerging hydrogen projects are looking for ways to increase green hydrogen production and usage. By 2050, as part of the UK’s drive towards Net Zero, it is hoped that all hydrogen produced within the UK will be ‘green’.
- Hydrogen produced via solar power is sometimes referred to as yellow hydrogen.
Blue Hydrogen
- Blue hydrogen is produced mainly from natural gas (and some other fossil fuels) via steam reforming. This process produces a carbon dioxide by-product which is captured, stored or utilised via CCUS technology.
- Blue hydrogen is considered a ‘low carbon’ option as CCUS technology is not yet 100% efficient.
- Otto Simon expects blue hydrogen production in the UK to increase over the next decade, as a more environmentally friendly alternative to grey hydrogen.
Grey Hydrogen
- Grey hydrogen is blue hydrogen without the CCUS step.
- Currently, the majority of hydrogen is produced this way but many of the emerging hydrogen projects across the UK are looking for ways to turn grey hydrogen production into blue.
Black or Brown Hydrogen
- Hydrogen produced from coal (black) or lignite (brown) via gasification processes is a highly polluting and environmentally damaging process that produces carbon dioxide, carbon monoxide by-products which are generally lost to the atmosphere.
- Confusingly, black or brown hydrogen is sometimes used interchangeably for hydrogen produced via any fossil fuel or biomass.
Pink Hydrogen
- Pink (sometimes red or purple) hydrogen is generated through electrolysis powered by nuclear energy.
Turquoise Hydrogen
- A potentially interesting route for hydrogen production which involves methane pyrolysis to produce hydrogen and solid carbon.
- Turquoise hydrogen may prove valuable in the future as a low-emission hydrogen, providing the thermal process can be powered by renewable energy and the solid carbon can be permanently stored, however, this process has yet to be proven at scale.
White Hydrogen
- White hydrogen refers to the naturally-occurring hydrogen found in underground deposits. This is of academic interest only and there are no industrial strategies to exploit this hydrogen at present.
Otto Simon is currently working with companies in the industry to develop methods of green hydrogen production, deploy electrolyser technology, and improve methods of CCUS.
A member of the North West Hydrogen Alliance, Otto Simon is working at the forefront of technical innovation for the Hydrogen market. Our team has considerable experience with hydrogen as a fuel and is providing technical engineering support and practical hands-on engineering expertise.
Contact us for more information or to see if we can help with your hydrogen project.
Back to Blog
Show More
Recent Blog Posts
The air in the office is buzzing with more than just morning coffee today – it's electric with the excitement of new beginnings! We're thrilled to officially announce that the refurbishment of our newly consolidated United House office building has kicked off! This marks a significant milestone for us as we bring together our team under one roof. By sharing one building we can reduce overheads, invest in new facilities and maintain our valued location right here in Cheadle, Manchester. This amalgamation isn't just about combining physical spaces; it's about weaving together our collective talents, fostering closer team working, and building an even more vibrant and unified company culture. So, let the transformation begin! We're incredibly excited about this new chapter and look forward to sharing the journey with all of you. Stay tuned for more updates as our new, united office takes shape!
Presenting at Energy Storage & Hydrogen Solutions Last month, our Head of Consultancy, Clare Dunkerley, was invited to speak at an event in Cyprus, hosted by Ideopsis and the British High Commission Nicosia. The Energy Storage & Solutions Conference brought together leading experts, policymakers, and industry players, with the aim of to fostering dialogue, sharing expertise, and catalysing action towards a more sustainable, resilient, and low-carbon future. The conference attracted some esteemed speakers, including introductory addresses from the Deputy High Commissioner, Adam Sandbrook and the Minister of Energy, Commerce and Industry, George Papanastasiou. The programme was split into 2 sessions with the first highlighting the future of energy storage, moderated by Dr Alexandros Charalambides from the Cyprus University of Technology. Staveros Stavrinos, the Executive Director of the Transmission System Operator Cyprus, explained the issues the Cyprus Energy Transmission System faced, concentrating on curtailment of renewable solar power. Michael Toumbas, of EV power Ltd, shared innovative thinking around an AI enabled electric vehicle local grid power sharing mechanism. There were also great presentations from smart grid expert Dr Andreas Procopiou and the Cyprus Energy Regulatory Authority. The second session concentrated on hydrogen solutions. Dr Andreas Poullikkas delivered on future energy systems while Charles Purkiss updated us on the latest developments at ITM Power. Jeremy Bowman, from Hypermotive Ltd, discussed hydrogen technology for transport and Philippa Oldham shared some work from the Advanced Propulsion Centre. An interesting Q&A session was chaired by Dr Nestor Fylaktos of the Cyprus Institute. Clare presented ‘A Safe Hydrogen Future’, addressing the importance of public perception and the imperative for no major incidents. Clare shared her experience from working on hydrogen projects and provided an insight in how to use the current UK regulatory framework in conjunction with industry codes and standards to demonstrate that risks in hydrogen projects were acceptable to all concerned. It was a fascinating conference providing a fantastic insight to the current and future energy situation in Cyprus, with plenty of time for networking and discussing hydrogen solutions and projects with all the attendees. Our thanks go to Ideopsis and the British High Commission in Nicosia for the invitation and opportunity to participate in the discussions.
Taking Safety Seriously at Otto Simon We’re proud to celebrate the achievement of our Head of Construction and Commissioning, Hugh Doble, who has recently earned his NEBOSH Certificate in Health and Safety Management for Construction. Hugh has been instrumental in the successful delivery of multiple EPC and EPCm contracts across various sectors nationwide. Our continued commitment to excellence and safety underscores the core values we uphold at Otto Simon — ensuring the wellbeing of our people and partners on every project. Congratulations Hugh! To learn more about how Otto Simon can support your Construction and Commissioning needs, get in touch with us at eng@ottosimon.co.uk .