Deliverable 10.1: Stakeholder perspectives on the SWEETHY electrolyser system

Objective: What is the objective?

This work presents stakeholder insights from the early phase of the SWEETHY project. It examines factors beyond technical innovation that influence seawater electrolysis (SWE), including environmental impacts, circular resource strategies, industrial symbiosis, economic aspects, health and safety, and public perception. Using a mixed-methods approach with questionnaires and expert interviews, it identifies key challenges and opportunities. The analysis addresses technical and operational issues, stakeholder views on sustainability, and implications for biodiversity. These findings inform strategies for deploying the SWEETHY electrolyser system within a broader hydrogen transition.

Our research had three overarching aims:

1. Examine the main technical and operational challenges associated with the SWEETHY protype.
2. Investigate stakeholder perceptions of the environmental, economic, and social sustainability of seawater electrolysis, including the relevance of industrial symbiosis in aligning the SWEETHY concept with existing infrastructure and processes.
3. Assess the risks and opportunities that experts associate with the long-term implementation of the SWEETHY system, particularly in relation to biodiversity and local communities.

Research: What has been researched? And how has this been done?

The SWEETHY project seeks to advance AEMWE technology by improving energy efficiency, reducing costs, enhancing material durability, utilizing by-products, integrating renewable power, and minimizing environmental impacts. While technical progress is essential for scaling SWE, success also depends on broader factors such as environmental impact, circular use of by-products, market incentives, infrastructure development, employment, health and safety, and public acceptance. To capture these dimensions, we mapped technical, environmental, economic, and social factors through expert input on the SWEETHY electrolyser concept. These insights reveal key themes and lessons for raising technology readiness and preparing for future deployment, helping anticipate challenges and opportunities beyond the prototype stage and informing strategies for scaling SWE within the hydrogen transition.

As part of the SWEETHY project’s stakeholder perspectives task, a structured questionnaire and a semi-structured interview guide were developed and distributed to consortium members. These instruments were intended not as independent research activities, but as supporting tools to provide input for other key tasks within the sustainability work packages. This work adopts a systems perspective, considering not only the technical prototype but also how the SWEETHY concept could interact with broader environmental, economic, and social systems when scaled up and implemented. Although the technical activities in this project focus on material development and electrolyser configuration at TRL 2–4, this work addresses those aspects while also exploring broader questions related to future deployment.

Together, these interactions ensure that the sustainability work packages remain closely aligned and actively engage with the technical development activities within the project, reflecting the interdisciplinary approach required for successful real-world implementation.

Result: What was the result?

From the interview findings and questionnaire results, the following items were revealed:

Technical:

• Both questionnaire respondents and interview participants highlighted corrosion as the most significant technical challenge for seawater electrolysis systems. This issue can severely degrade components, requiring careful material selection, protective strategies, and pretreatment processes. They also noted trade-offs in system design, including performance, durability, and selectivity, which cannot all be optimized simultaneously. Corrosion concerns extend beyond the electrolyser to balance-of-plant components, even when purified water is used. Additionally, participants stressed the need for highly selective membranes and catalysts to manage seawater’s complex ionic composition and reduce fouling.
• Participants raised concerns about system durability and cost-performance trade-offs. They questioned whether the lifetime of seawater-fed electrolysers would justify the added cost of water purification systems, suggesting that purification could be economically and energetically viable if it extends system lifespan. They also highlighted the need to analyse pressurization, energy efficiency, and integration, noting that challenges extend beyond the electrolyser to the broader technical ecosystem.
• Despite these challenges, participants expressed optimism about rapid progress in AEM technologies, predicting that membrane performance will improve over time, building on knowledge from PEM systems.

Industrial symbiosis:

• The questionnaire revealed limited knowledge on the concept of industrial symbiosis. As a result of this finding, a workshop was held on Nov 21^st to introduce the SWEETHY consortium to the concept, provide examples, and brainstorm potential symbiotic pathways for the system.
• However, some questionnaire respondents highlighted potential synergies with other sectors, including desalination plants, agriculture, and construction, as well as opportunities to utilise by-products for battery applications and oxygen for fish farming to support water oxygenation.
• Conditions considered most critical for enabling the use of SWE byproducts included economic incentives or market demand, and the availability of infrastructure for transport and storage. This suggests that respondents view technical feasibility, economic viability, and logistical capacity as key enablers for industrial uptake.
• Barriers suggested were economic feasibility, uncertainty about benefits or outcomes, and the lack of infrastructure.

Economic:

• Material selection was identified as critical for economic feasibility. It was stated that cost risks could arise if specialised or expensive components become necessary, significantly increasing CAPEX. While non-noble materials like nickel and iron offer stability, reliance on scarce elements such as iridium or cobalt introduces price volatility and sourcing challenges. This highlights the need to balance technical performance with material availability and market stability.
• The importance of investing in high-quality materials for BoP components was also mentioned, as durable materials, such as robust steel, could reduce long-term maintenance costs and be more cost-effective than cheaper alternatives that require frequent replacement. However, it was also noted that uncertainty in assessing economic implications due to the limited number of operational systems and ongoing technology development.

Environmental:

• Participants noted potential environmental concerns such as marine ecosystem disruption, brine discharge, and saline impacts. While these are not expected to affect the current prototype, it was highlighted that such issues become significant for large-scale implementation, where the source and quality of seawater would require careful consideration.
• Participants suggested that biodiversity impacts depend heavily on project location and planning and warned against the scientific tendency to focus narrowly on technical tasks without considering downstream environmental implications. Thus, integrating lifecycle thinking early in development to anticipate impacts at scale is important.
• Given the uncertainty surrounding large-scale deployment of SWEETHY and similar projects, several environmental impacts remain difficult to predict. The need for proactive monitoring and robust regulatory frameworks to identify and manage potential risks as the technology evolves, was highlighted.

Social:

• Transparency and open dialogue are critical for the successful adoption of electrolysis and hydrogen technologies. To address public knowledge gaps and improve awareness and acceptance, stakeholders recommended more proactive communication strategies. These include promoting projects more openly and using popular science platforms, social media, and news outlets to make the technologies more visible and relatable to local communities. Questionnaire respondents also noted that environmental concerns are closely linked to social acceptance and community engagement. Issues such as visual impacts, water access, and ecological risks were often framed in terms of how local communities perceive industrial development in coastal areas. This suggests that beyond technical feasibility, the success of SWE projects depends on integrating environmental and social considerations into local contexts.
• Local political context and regulatory conditions strongly influence social acceptance of hydrogen projects. It was mentioned that public support depends on how the technology is introduced and whether it is perceived as safe, beneficial, and aligned with local values. Engagement strategies should be tailored to regional attitudes and regulatory frameworks, which vary from strict protections in sensitive areas to more flexible rules elsewhere.
• Participants suggested that hydrogen projects can bring tangible local benefits beyond environmental impact like job opportunities and training programs, resource sharing, and reusing existing infrastructure to enhance feasibility of hydrogen integration.
• Potential health and safety risks (protype and at scale): corrosive hydroxide solutions, potential exposure to electrical currents, production of flammable gases. All regarded as mild to medium risk, but risks mitigated through training and proper PPE.

What will it be used for: What will the results be used for?

Analysed findings from both the questionnaire and the interviews contribute to internal project learning, especially the eLCA, sLCA, and TEA in WP 11, as well as support decision making across the technical WPs. Moreover, they offer input for industry and policy actors to support the development of sustainable pathways within the broader hydrogen transition.

Impact: What is the Impact?
By connecting sustainability considerations across all work packages, this work strengthens interdisciplinary collaboration and ensures that real-world implementation integrates technical development with economic, social, and environmental dimensions. As this is an emerging field, it also creates an opportunity to learn from experts about what should be considered as the project evolves and scales up in real-world contexts. Taken together, these insights provide valuable guidance for shaping future activities and ensuring that sustainability remains embedded throughout the development process.

The public summary of deliverable 10.1  is available on our results page here.