Special Focus: Electrolyzer Technologies

I. MURITALA, American Bureau of Shipping (ABS), Houston, Texas (U.S.) 

Green hydrogen (H₂) is poised to play a critical role in decarbonizing the hard-to-abate sectors of the global economy. Developers are now exploring the integration of electrolyzers with offshore wind farms to produce green H₂ at sea. This approach combines abundant offshore renewable energy with H₂’s versatility, accelerating the energy transition. This article examines the opportunities and challenges of offshore green H₂ and its potential in the future green H₂ economy. 

The concept of a green H₂ economy to decarbonize industries is not new. However, early enthusiasm has waned due to high implementation costs and technical challenges. Despite this, green H₂ remains a compelling solution for reducing emissions in energy-intensive sectors. While demand for H₂ is expected to grow slowly over the next decade, analysts predict significant acceleration after 2035.¹ 

Offshore H₂: A big challenge, a vast opportunity. Renewable energy is key to producing green H₂, moving from gray (produced through methane reforming) or blue (produced through methane reforming with carbon capture and storage) H₂ to fully sustainable solutions. Offshore wind energy offers a unique opportunity to produce green H₂ at scale, contributing meaningfully to global decarbonization goals.

The concept is straightforward: electrolyzers are placed at offshore wind farms, where generated electricity is used to split water into H₂ and oxygen. Different electrolyzer technologies [alkaline, proton exchange membrane (PEM), solid oxide electrolyzers] each have their own varying efficiencies, capital expenditure (CAPEX) and operational characteristics, and they can be directly coupled with floating or fixed-bottom wind turbines. The produced H₂ can then be either transported via pipelines or stored onsite using compressed gas or liquid H₂ technologies and potentially converted into chemical carriers like ammonia for efficient shipping to shore. The choice of technology and system architecture will depend on various factors, including site-specific conditions, energy resource availability and the desired production scale. 

Producing H₂ offshore provides access to abundant renewable energy while avoiding land-use conflicts. It also creates jobs in remote coastal areas and enhances energy security by diversifying energy sources and reducing reliance on fossil fuels. 

Making offshore H₂ work. Producing H₂ offshore offers exciting possibilities, but also presents some significant obstacles that must be overcome to ensure the feasibility and success of these projects, including: 

• Safety considerations: The highly flammable nature of H₂ requires robust safety procedures for storing, transporting and handling H₂ throughout the offshore production process, adding complexity and CAPEX. 

• Specialized infrastructure needs: Offshore H₂ production requires specialized ships, storage facilities and port infrastructure. The unique properties of H₂, particularly its low density, necessitate expensive high-pressure or cryogenic (extremely cold) storage solutions. 

• Challenges in the marine environment: Constructing and maintaining facilities at sea is considerably more expensive than on land. Factors such as corrosion, powerful storms and weather conditions, and the accumulation of marine organisms like biofouling pose constant technical and financial challenges. 

While H₂'s potential as a clean energy vector is immense, it comes with formidable challenges. As previously stated, H₂ is highly flammable, with a low ignition point and broad explosive range that require stringent protocols for storage, handling and transportation. Its low density requires either high-pressure storage or cryogenic liquefaction, which increases the costs and the risk of pressure vessel failures and cryogenic embrittlement. The lack of existing infrastructure or supply chains further contributes to the high CAPEX of any H₂ project, whether onshore or offshore.

Despite these challenges, pioneering companies are pushing ahead with H₂ projects. In Scotland, for example, Hywind Scotland, the world's first commercial floating wind farm, is exploring potential H₂ production add-ons. Meanwhile, the AquaVentus project in Germany seeks to establish a large-scale offshore H₂ production facility powered by dedicated North Sea wind farms, with a targeted production capacity of 10 gigawatts (GW) of green H₂ by 2035.² This huge undertaking is bringing together a diverse range of stakeholders, including energy companies, technology providers, research institutions and government agencies. This collaborative approach is deemed essential to navigate the complexities of creating a robust green H₂ infrastructure in Europe. 

Despite its inherent challenges, H₂ represents a significant opportunity in the transition to cleaner energy systems. As a clean energy carrier, H₂ holds immense potential. It is abundant, and its unique ability to produce only water vapor when utilized in fuel cells and combustion systems makes it a compelling solution to reduce emissions in transport and industrial applications. H₂ acts as a versatile energy storage medium, capable of storing excess renewable energy electrons in molecular form, helping to stabilize power grids reliant on intermittent sources like wind and solar. 

There are economic benefits, as well. According to the Hydrogen Council, a developed H₂ economy could generate as many as 30-MM jobs globally by 2035. Environmentally, offshore H₂ production provides a viable pathway towards reducing greenhouse gas (GHG) emissions and displacing fossil fuels in hard-to-decarbonize industrial processes and transportation sectors.  

Maximizing these opportunities will require continual advancements in electrolysis technology, particularly those that enhance efficiency, durability and scalability, leading to reduced production costs and performance improvements. Similarly, advancements in H₂ storage technologies can enable safe and cost-effective offshore and onshore H₂ storage, which will be vital for integrating offshore production into the wider energy system. 

Robust regulatory support. Beyond technological advancements, robust regulatory support is essential. Governments are increasingly recognizing the importance of H₂ in their energy strategies and are expected to develop more comprehensive regulatory frameworks that foster offshore H₂ facilities development. These frameworks should include: 

• Establishing clear permitting processes 
• Implementing financial incentives and funding mechanisms 
• Developing standardized safety protocols 
• Facilitating integration not just into electricity grids and H₂ distribution networks but also potentially blending H₂ into existing natural gas infrastructure. 

At an international level, the joint development of standardized technologies and the establishment of collaborative research programs across borders will help to reduce costs, streamline the development process and avoid the duplication of effort. This collaboration is also vital for guaranteeing that offshore H₂ production is environmentally responsible, prioritizing the protection of marine ecosystems and local communities. 

Takeaway. Offshore green H₂ represents a transformative opportunity for the global energy transition. While challenges remain—ranging from safety concerns to high CAPEX—collaborative efforts between private industry, governments and research institutions can overcome these barriers. By supporting infrastructure development and certification processes, offshore green H₂ can achieve its potential as a cornerstone of a low-carbon future. H₂T

LITERAUTRE CITED 

¹ PwC, “The green hydrogen economy: Predicting the decarbonization agenda of tomorrow,” online: https://pwc.to/458CVUe. 

² AquaVentus, “The green energy revolution starts in the North Sea,” online: https://aquaventus.org/en/. 

About the author

IBRAHIM K. MURITALA is a distinguished engineer with more than 17 yrs of experience in academia, research and the energy industry, including the oil and gas, maritime and offshore sectors. He serves as the Global H₂ Leader at the ABS Global Sustainability Center in Houston, Texas, where he provides strategic leadership in H₂-related decarbonization initiatives. As a subject matter expert, Dr. Muritala supports the marine and offshore industries in navigating the energy transition, offering technical assessments, feasibility studies and strategic guidance across the H₂ value chain. His research contributions have resulted in internationally recognized publications and patents, reinforcing his thought leadership in sustainable energy solutions. Dr. Muritala’s expertise encompasses chemical process design; renewable energy systems; low-carbon industrial processes; carbon capture, utilization and storage (CCUS); the H₂ economy; and the circular economy. He is committed to driving innovation and shaping the future of sustainable energy through advanced research and industry collaborations.