Towards a comprehensive understanding and assessment of Offshore Energy Hubs with a hydrogen focus: An evolutionary perspective

Climate change has necessitated the reduction of CO2 emissions, particularly in hard-to-abate sectors. Offshore Energy Hubs (OEHs), powered by renewable sources, have been proposed as a potential solution for renewable build-out and cross-sectoral integration. This paper presents a comprehensive literature review examining the technical concept and assessment mechanisms of OEHs from multiple perspectives, including chronological, design, and assessment principles. The review reveals a shift in the technical concept and evaluation assessments, evolving from cost-driven to economically driven, with a trend towards harmonized assessments that incorporate both economic and societal values, such as environmental impact. The importance of societal assessments is emphasized, addressing a research gap, where further investigation is needed for a successful implementation of future large-scale OEH projects. The paper highlights the need to develop comprehensive and inclusive evaluation frameworks to ensure the sustainable implementation of OEHs for the ongoing energy transition.


Introduction
The European Commission's 2050 climate neutrality goal requires substantial growth in offshore renewable energy, targeting at least 340 GigaWatt (GW), which is approximately 1,489 TeraWatt hours by 2050, assuming a 50% wind capacity factor.Currently, Europe has roughly 30 GW of offshore renewable energy, including 16 GW within the EU [1].Offshore wind farm capacities have increased dramatically, from 0.45 MW at the 1991 Danish Vindeby Offshore wind farm to future projects exceeding 1 GW, like the UK's 1.8 GW Norfolk Vanguard projects [2].
However, to reach the EU goal of being climate neutral by 2050, the deployment of renewables needs to be faster.This can potentially be large-scale Offshore Energy Hubs (OEHs) accelerating renewable energy deployment, which is not impacted by land use limitations as onshore wind and PV [3].To utilize the benefits of large-scale OEHs, it is important to focus on harmonizing transnational and integrated power trading [4].This means that an offshore energy hub (OEH) can channel the power from multiple offshore wind farms and transmit this to several countries, either via electricity or other energy carriers, such as green hydrogen (H2).Thus, a definition of the OEH can be the following: A central place used for collection and distribution of various offshore produced energy carriers from and to multiple destinations.
As mentioned by Lüth [5], this represents a change from the previous method of building offshore wind farms with a power connection to one onshore assembly point.Figure 1 illustrates a large-scale OEH concept combining H2 and electricity [6,7].(Illustration: based on an illustration from the North Sea Wind Power Hub Consortium [7]) The literature review done for this paper implied that several studies have already investigated the benefits of introducing green H2 for OEHs.In 2016, the North Sea Wind Power Hub consortium was established, investigating the possibilities for North Sea Wind Power Hubs.Several of the reports released from the consortium are within the scope of this paper.
While different studies have explored the advantages of integrating green H2 into OEHs [8][9][10], there is a need for a more comprehensive assessment that considers the societal impact of offshore energy projects.This article is to enhance the understanding of the technical concept development and evolving assessment paradigms of OEHs, as OEHs can be the key to the energy transition.Nevertheless, the methodologies and criteria for their assessment have remained fragmented and economically driven.

Aim of research
The purpose of the article is to create an in-depth understanding of the evolution of OEHs, the design principles, and assessment frameworks to underline the need for a more holistic and comprehensive evaluation framework that incorporates societal values, such as environmental impact.Existing research on the environmental and societal implications of large-scale OEHs is limited, although recent efforts have begun to incorporate Life Cycle Sustainability Assessment (LCSA) elements [11][12][13].However, further work is necessary to develop a more inclusive evaluation model that encompasses sustainability [14].Therefore, this paper aims to investigate the evolution of the technical concept and the value assessment framework of large-scale OEHs.Thus, to set a uniformed description of a societal evaluation framework to enable common ground for future research to enfold the full profitability and sustainability of OEHs when combining H2 production and wind power.The importance of the societal value-driven approach for future large-scale projects is emphasized, thereby contributing to the preparation for largescale renewable build-out and cross-sectoral integration.This paper is organized into three main sections: firstly, exploring the development of the Energy hub technical concept (literature reviewed in section 3.); secondly, examining the evolution of assessments involving green electricity production and other carriers like H2 (literature reviewed in section 4.); and finally, identifying future research directions for developing an OEH evaluation framework that supports data-driven and well-informed decision-making by investors (section 5.).

Methodology
Building on the previously mentioned aim, this paper reviews various OEH concepts and initiatives to understand the development of design and assessment mechanisms, focusing on green electricity and H2 production as potential energy vectors.The literature reviewed is spanning from 2004 to 2022 and primarily in English, encompasses journals, public articles, reports, books, webpages, conference proceedings, and dissertations.The scope is primarily focused on Europe and the North Sea, given the region's prominence in offshore renewable energy development.
For this review, the literature has been segmented into three areas, as illustrated in Figure 2. Furthermore, the literature review has been divided into two sections (section 3. and 4.); Section 3. examines the literature on the technical concept aspects of OEHs, focusing on the development of the definition for energy hubs and the potential for synergy between various renewable energy sources.This section is to provide a foundation for understanding the current state of OEHs, their challenges, and opportunities for improvement.Section 4., on the other hand, delves into the evolution of value assessment frameworks for OEHs, emphasizing the shift from focusing on cost-based evaluations towards a broader perspective on societal value.Other energy carriers, such as ammonia or methanol, could be relevant but are beyond the scope of this paper and may be considered for future work.The conventional feasibility perspective primarily features: x Individual requirements; steered by commercial cost x Lower focus on new technology development and time urgency compared to the other areas x Minor focus on societal value The innovation and commercial perspective is mainly characterized by: x Individual requirements; steered by commercial evaluation and societal cost x Focus on new technology development and time urgency x Recognition of the lack of societal evaluation in academia and industry The societal value perspective is predominantly described by: x Harmonized requirements and development; steered by societal value x High focus on innovative technology development / time urgency to address the climate crisis x Exploration of incorporating societal value in the evaluation These characteristics are based on the reviewed literature.While the literature substantiates the individual characteristics of Offshore Energy Hubs (OEHs) as integrating various energy sources, these traits have typically been examined through separate perspectives.However, in the literature review, the fusion and interaction of different aspects within a framework of creating a societal value assessment of OEH have not been adequately addressed.Therefore, the evolutionary assessment of both the technical concept and value assessment framework from this paper is to emphasize the future importance of considering societal value when designing and assessing OEHs, combining economic evaluations, environmental impact, societal requirements, and technology development.

Technical concept development
This section focuses on the evolution of the technical concept of an Energy Hub from its introduction in 2005, highlighting its development toward accommodating multiple energy carriers from offshore renewable energy sources (RES).The aim of this part of the paper is to determine the technical concept development and how the definition of an Energy Hub has evolved.Table A1 in appendix A provides an overview of the reviewed literature and its categorization into conventional feasibility perspective, innovation and commercial perspective, or societal value perspective.The segmentation is described in section 2.1.

Early phases of OEHs: Conventional feasibility perspective
The technical concept of an Energy Hub was first introduced in 2005 by Geidl et.al., and designed to handle multiple energy forms and exchanges between various carriers [15].Early definitions involved energy inputs such as electricity, natural gas, district heating, and wood chips, with outputs like electricity, heating, and cooling.By 2007, the technical concept expanded to include energy conversion, conditioning, and storage from multiple carriers [16].However, these definitions did not yet consider offshore RES, but arose from this over time.
The literature categorized in the conventional feasibility perspective part of Table A1 (appendix A) emphasizes known technology and infrastructure, focusing on individual requirements for RES and addressing three main areas: Offshore Energy Consumers, Existing Offshore Wind Farms, and Isolated Energy System.

Offshore Energy Consumers.
The literature explores the integration of RES in the Oil and Gas (O&G) sector [17][18][19] and the synergies between O&G and renewable energy [6,[20][21][22][23].It suggests that existing O&G platforms could be repurposed for multiple energy carriers like electricity and H2.However, technical challenges remain, such as the platforms' capacity to support the weight of new technologies and infrastructure.The literature does not specify how to overcome these challenges.

Existing Offshore Wind Farms.
The literature in this category investigates offshore grid investments [16,20,21,[24][25][26] and new RES [27][28][29][30].It posits that existing offshore wind farms could form an energy hub with multiple RES, such as electricity and H2.However, this may require adding technically complex and costly infrastructure.The literature does not determine if multiple wind farms can be combined into a harmonized system, only if individual farms can handle more than just electricity.

Isolated Energy System.
The literature in this category covers multi-carrier energy systems (including H2) [15,16,25,26], 'hybrid energy system' [24], 'electric network design' [31,32] and 'energy planning' [33].It suggests that natural islands could serve as energy hubs, but it remains unclear whether they could function as centralized systems for various energy sources and destinations.

Increasing complexity: Innovation and commercial perspective
The literature transitions from the conventional feasibility perspective to the innovation and commercial perspective in Table A1 (appendix A), driven by demand and expectations for OEH development while still maintaining individual systems.It is categorized into three main areas: Offshore wind hub, Offshore hub of electrofuels and Offshore energy hub -small to medium scale OEHs.

Offshore wind hub.
The literature in this segment examines the potential for vast electricity from offshore wind hubs, to connect to an OEH [25].The possibility of utilizing electricity for multiple energy carriers, such as H2, is implied [10,34].However, if the OEH is powered only by wind, electricity supply becomes unpredictable, leading to potentially high infrastructure costs for the OEH.

Offshore hub of electrofuels.
The literature in this category suggests short-term feasibility for building OEHs for specific electrofuels, like H2 [35].For H2 usage, the reviewed literature focuses on applications [36,37] and sector coupling [35,38].The literature primarily explores using the energy for a single electrofuel source, such as H2 or ammonia, and a single off-taker.

3.2.3.
Offshore energy hub -small to medium scale.This category includes OEHs with a total installed wind power capacity of less than 10 GW.The literature is divided into the following (see table A1): 1. Screening of multiple energy hubs options in the North Sea [5,39,40] 2. Combining several energy vectors on artificial islands [5,36,[41][42][43][44] Yue et.al. investigated the availability of current technology for re-electrification, H2 production, and storage, acknowledging the potential of H2 for energy storage and transfer [36].Singlitico et.al. discussed how these OEHs could potentially supply energy to specific communities or regions [44].One main advantage of smaller-capacity OEHs is the potential faster built-out than larger ones.
The literature reviewed highlights an unexplored area of research concerning the societal evaluation of OEHs in both academia and industry.For example, Singlitico et.al. concluded that evaluating environmental and societal impact is crucial for the placement of a Power-to-X facility [44].

Targeting harmonized systems: Societal value perspective
Focusing on the societal value perspective, the literature shifts toward demand-driven harmonized systems and societal development.One key benefit of OEHs is their capacity to channel power from multiple offshore wind farms, supplying power to the OEH and ultimately transmitting energy to several countries.To enable seamless energy transmission, a harmonized approach to transnational and integrated power trading is essential.
In the societal value perspective literature (see Table A1 in Appendix A), integrating offshore wind with other RES can help increase green energy supply, enhance hybrid system flexibility and feasibility, and reduce fossil fuel dependency [5,40,41,43,[45][46][47][48][49][50][51][52][53].The literature references that energy carriers can be stored and transported to different locations for various applications, such as transportation and power generation.For large-scale OEHs (≥ 10GW), it is crucial to have the right planning framework, political support, and readiness of technologies like electrolyzers for large-scale implementation [5,14,26,41,[54][55][56].For example, in a report by Wood Mackenzie, it is emphasised that there is a need for stronger policy to solidify demand across multiple sectors and allow for prototype introduction of H2 production, ensuring future harmonized system integration [56].

Technical Concept Evolution of Energy Hubs: Summary of section 3
This section examined the evolution of the technical concept of an Energy Hub through three perspectives.Through the literature review, the progression from individual requirements to an integrated, harmonized approach becomes evident.Emphasis is given to the increasing significance of technological advancements, political support, and interconnected systems.Various challenges and opportunities were recognised.For instance, the challenges balancing energy supply and demand in an OEH scenario.This is especially pertinent considering the variability of RES and the need for consistent power supply.On the other hand, potential opportunities were also highlighted, as the capacity for largescale renewable energy integration and cross-sectoral decarbonization offered by OEHs.
Such a comprehensive understanding of the technical concept's evolution will be instrumental, gaining insights into how to improve and expand the research of OEHs in the future, thus, providing potential directions in the field.

Development in value assessment framework
As section 3. delves into the specific evolution of the design elements and technical details involved in developing an OEH, this section traces the literature of the evolution of value assessment frameworks of OEHs, including green electricity and H2 production.While both sections are dealing with OEHs, they address different stages of the OEH project lifecycle.Section 3. is more concerned with the technical design phase, whereas section 4. is more focused on the evaluation phase, offering insights into how to assess the performance and impacts of an OEH.The aim of this section is to determine the evolution of evaluating OEHs.The evolution of value assessment frameworks in the literature progressed from focusing on individual assessments driven by cost to techno-economic evaluations that considered both technical and economic aspects of OEHs.Eventually, the focus has shifted towards societal value assessments that combines economic evaluations, environmental impact, societal requirements, and technology development.However, it is clear from the literature review in this section that there is a lack of a developed assessment frameworks, which can holistically evaluate OEH projects, considering all their multi-dimensional impacts.This will be further elaborated in section 5.
The literature in this section is also categorized into the three perspectives: conventional feasibility, innovation and commercial, and societal value.Table B2 (appendix B) presents the categorization.

Primarily Cost focused benchmarking: Conventional feasibility perspective
The literature group within conventional feasibility perspective (Table B2, appendix B), primarily focused on the cost evolution of green H2 production from RES and its competitiveness with grey H2 production from fossil fuels [11,12,37,[62][63][64][65].Green H2 costs have decreased by ~30% between 2015 and 2019 [65].However, further cost reductions are necessary for green H2 to become competitive with grey H2, despite the increasing gas prices in 2022 due to the Russian-Ukrainian war [66].

Business case driven approach: Innovation and commercial perspective
The innovation and commercial perspective focused on evaluating OEH competitiveness using techno-economic methods as the assessment framework, which evaluate both the technical and economic aspects of a proposed OEH [8,42].The assessments considered factors like location, types of RES, and infrastructure and often included different H2 production pathways.The most common pathway was the offshore platform with a centrally placed electrolyzer [8,13,20,22,29,42,44,63,72,76,[83][84][85][86][87][88][89][90][91]. Figure 3 illustrates three different H2 concepts: shoreline, platform, in-turbine.Each solution has its pros and cons.For the in-turbine H2 production, illustrated as Offshore H2 WTG in Figure 3, the literature review revealed that one of the benefits is no electrical losses in the grid system, as H2 molecules are sent via an array pipeline connecting to a larger pipeline going to shore.This entails lower power losses, compared to platform or shoreline H2 production [8,23,44,92].The literature reviewed also disclosed that several studies had explored the option of utilizing electricity from offshore wind farms for H2 production at shore [8,9,13,23,29,42,44,72,84,85,87,89,90], which is illustrated as the shoreline H2 plant in Figure 3.A shoreline H2 production has more flexibility, meaning that electricity can be prioritized as the delivery vector at high kWh prices while curtailing H2 production.
Compared to this, an offshore central platform can entail some savings in energy losses when moving from an export cable to a H2 pipeline and may also be able to run flexibly with power and H2 production.
Studies have compared all three concepts to determine the optimal solution, e.g., by calculating the levelized cost of H2 (LCoH) [8,44].Singlitico et.al. concluded that the platform concept had the lowest LCoH, but the technology's immaturity could change this conclusion as it matures [8].
The literature review identified research investigating the optimization of OEH planning and H2 pathways, considering the complexity of the energy system, long-term investments, uncertainties, and expected market mechanisms, which all feed into a framework assessment [29,43,78,93,94].

Holistic focused approach: Societal value perspective
The literature within the categorization of the societal value perspective focused on enhancing the societal value of investments for large-scale OEHs.The literature review revealed an increased focus on environmental impact, sustainability value, stakeholder management, regulatory framework, and harmonized requirements across countries and energy vectors.E.g., the Hydrogen Council identified H2 to be key for the energy transition and that it is not only important to make it economically viable, but also maximize its decarbonization potential and minimize its impact on resources, such as water [12].

Environment value.
The literature addressing environmental value has increased in recent years, covering both the benefits and costs of building OEHs [12,14,20,43,44,49,68,73,74,79,82,89,91,[95][96][97][98][99].Large-scale OEHs can have significant impacts on the environment and local communities.The literature implied that a societal value-driven approach emphasizes evaluating these impacts and incorporating them into the feasibility and sustainability assessments of the project.

Sustainability value.
According to the literature reviewed, the OEHs can provide a range of sustainability values, which benefits the overall society [14,[42][43][44]74,79,86,95,96,99].Examples include job creation, increased RES to reduce dependency on fossil fuels, and decreased CO2 emissions.The North Sea Wind Power Hub consortium stated that, in addition to improving the financial viability of OEH projects by adding new technologies, it is essential to further explore the societal and energy system value of OEHs [95].However, measuring sustainability impact is challenging due to the classification of different indicators in various sustainability dimensions [5,14,99].

Stakeholder Management.
Early stakeholder management is crucial for OEH success, according to the reviewed literature, as these projects involve multiple stakeholders such as government agencies, industry, communities, and environmental groups.As this can lead to complex endeavours, harmonized systems can ensure that the different perspectives and needs of these stakeholders are considered and integrated into the planning and implementation of the project [29,49,87].

Regulatory framework.
Connected to above, the literature review implied that incentives from regulators can play an important role in the economic profitability of large-scale OEHs.These incentives can help to reduce the cost of building and operating the infrastructure, as mentioned in section 3.1.thereby, making an OEH more economically viable [29,56,87,94].However, in the literature reviewed, it was also noted that there is an absence of a clear regulatory framework, potentially delaying OEH acceptance [14,29,44,56,[73][74][75]77,87,94,[100][101][102].Parra, et.al. did already in 2019 state that policymakers and technology developers should work together to build smart strategies for cost reduction, standardization, new market structures and regulatory frameworks, enabling H2 technologies to deliver low-carbon applications and products [77].

Harmonized requirements.
The final subject of the literature review within section 4.3.was centred around the need for harmonized requirements across countries and energy vectors for crosscountry energy trade and utilization of energy for various purposes, such as electricity and H2 [29,48,49,56,76,[94][95][96]103,104].The literature reviewed implied that to ensure a consistent approach to OEH development and operation, harmonized requirements across countries and RES are necessary.
The literature identified that current infrastructure and market frameworks have not been designed to facilitate the coordinated energy system required for large-scale OEHs or enable optimized investment decisions [26,29,43,48,49,53,56,76,82,94,95,100,103].Decisions and clarity on these topics are urgent due to the long lead times of large-scale offshore projects.

Multi-dimensional OEHs Assessments: Summary of section 4
Section 4. investigates the transformation of OEHs' value assessment frameworks, tracing the shift from cost-centric evaluations to methodologies that address societal implications more comprehensively.Initially, the assessment frameworks predominantly centred around cost-effectiveness and financial viability, overlooking the broader impacts of OEHs.However, as the field evolved, this method was gradually replaced by a more comprehensive multi-dimensional approach.This new paradigm considers a wide array of factors beyond simple cost calculations, like the potential for technological innovation, environmental consequences, and socio-economic implications.For example, the inclusion of environmental impact analyses emphasises OEHs' role in mitigating climate change.Additionally, social aspects like public engagement and job creation gained focus in the assessments.
This section endorses this multi-dimensional approach for future OEH assessments, emphasizing its role in well-informed decision-making.Understanding these complicated frameworks aids in identifying research gaps and future refinement opportunities.

Discussion and conclusion
The literature review in this paper underscores the significance of technology development and scaling up supply chains for OEHs to satisfy the growing demand for green energy, which includes H2 production.In recent years, the technical concept of OEHs has moved to cover the ability to aggregate energy from various offshore wind farms, delivering energy either via electricity or H2, and ultimately distributing that energy to multiple nations (see section 3. for more details).
Furthermore, research of the value assessment framework has shifted its focus towards the societal feasibility of OEHs, the timeline for the implementation of green H2 applications, and the optimal placement of H2 production when using LCoH as the calculation method [8].The latter is particularly challenging due to uncertainties surrounding infrastructure development and costs (see section 4. for more details).Consequently, future efforts should be directed towards assessing the reducing costs, including enhancing system efficiency and durability, and investigating serviceability aspects.
As indicated by Lüth [5], then more and more journal articles and reports are mentioning the need to assess OEHs in a more holistic view, considering a wide range of factors, such as environment, society, economic, and emerging technologies.Furthermore, regulatory bodies such as the European Union and the International Renewable Energy Agency (IRENA) have increasingly emphasized the necessity for harmonized regulations, standards, and guidelines for the development and operation of OEHs [65].E.g., the EU taxonomy aims to deliver a system to ensure investments in environmentally sustainable wind development [105], as well as non-price criteria are being included in tenders to help identify and reward the added value that wind energy brings [96].Adding to this, the literature review revealed that industry, agencies, and regulators are getting more and more involved in the assessments and discussion of the societal evaluations of RES and the need of build-out of several energy carriers, which enhance the possibility of the future projects to become bankable [106].
To address the growing need for a comprehensive and inclusive approach, below is a proposed future evaluation framework for OEHs that encompasses several key aspects: environmental impact, societal requirements, economic evaluation, and technology development.This can serve as the foundation for further research, ensuring that OEHs contribute effectively to sustainable energy transitions within the broader context, such as the European energy landscape.An assessment framework can help policymakers and stakeholders make more informed decisions regarding the development and operation of OEHs, ultimately leading to more sustainable and efficient energy systems.
The factors can among others, cover the following: Environmental impact: x Reduction of CO2 x Water and energy use, as well as waste generation x Decommissioned and recyclability of materials Societal requirements: x Stakeholder management for social acceptance and public engagement x Job creation and labour conditions x Societal justice, as ensuring that there is not a disproportionate impact of the project Economic evaluation: x Cost considering economy of scale and benchmark against fossil fuel x Value of harmonized systems allowing cross-border trading and utilization of several RES x Risk assessment via, e.g., long-term multiperiod planning Technology development: x Innovative technology development for large-scale harmonized roll out x Incorporation of learnings from small-scale test facilities to de-risk the use of emerging technologies for large-scale OEHs x Technical feasibility of an OEH's structure However, there are still significant challenges that need to be addressed.Uncertainties in green electricity and H2 production technologies, coupled with the lack of quantification of the societal value, make it difficult to quantify the benefits of large-scale OEHs.As a result, developing an assessment framework and devising measures to promote the integration of green H2 into energy systems are crucial steps in overcoming these challenges.Without this, it may lead to indecision and a lack of consensus among stakeholders, resulting in delays in the deployment of H2 production technologies and the overall progress of energy transition.Thus, this fragmentation could slow down the development of breakthrough technologies and limit the overall impact of research in advancing the H2 economy.The future of large-scale OEHs will be shaped by a myriad of factors, including advancements in technology, changes in energy demand, and the establishment of harmonized systems for cross-border trading and utilization of various RES, as also implied by this literature review.
Moreover, for future research it is essential to develop quantifiable measures for social acceptance, public engagement, and the decommissioning process to ensure that OEHs are developed and operated in a sustainable and responsible manner.In this regard, future research should focus on integrating societal evaluation into the assessment of OEHs, as well as investigating potential risks associated with the planning and implementation of large-scale OEH projects.E.g., as energy systems continue to evolve, they become more complex and interconnected, often involving a mix of different renewable energy sources, storage technologies, and transmission networks.An assessment framework for OEHs would help streamline decision-making processes by providing a consistent and transparent methodology to assess the performance and potential benefits of various OEH configurations.According to the literature review, the North Sea Wind Power Hub has initiative the aims to integrate multiple factors to supply power to several European countries [40,57,94,107,108].By addressing the concerns, the proposed future assessment framework can not only help to guide the development of OEHs but also contribute to a more sustainable and integrated energy transition on a larger scale.
In summary, a future assessment framework for OEHs would provide a systematic approach in assessing the performance, benefits, and risks associated with OEH projects, facilitating the development and deployment while addressing stakeholder concerns and aligning with policy objectives.Such a framework would ultimately contribute to the successful integration of OEHs in the wider energy transition and help meet the ambitious renewable energy and climate targets set by the European Union and other jurisdictions.

Figure 1 :
Figure 1: Illustration of OEHs acting as central places for various renewable energy sources (RES) and distributing the energy via electricity cables (yellow dotted line) and / or H2 pipelines (blue solid line) to multiple destinations.(Illustration: based on an illustration from the North Sea Wind Power Hub Consortium [7])

Figure 2 .
Figure 2. Development of design and assessment mechanisms for OEHs powered by RES 2.1.Description of the segmentation Figure 2 demonstrates the segmentation of the literature into three areas, characterized as follows:The conventional feasibility perspective primarily features:x Individual requirements; steered by commercial cost x Lower focus on new technology development and time urgency compared to the other areas x Minor focus on societal value The innovation and commercial perspective is mainly characterized by:x Individual requirements; steered by commercial evaluation and societal cost x Focus on new technology development and time urgency x Recognition of the lack of societal evaluation in academia and industry The societal value perspective is predominantly described by:x Harmonized requirements and development; steered by societal value x High focus on innovative technology development / time urgency to address the climate crisis x Exploration of incorporating societal value in the evaluation These characteristics are based on the reviewed literature.While the literature substantiates the individual characteristics of Offshore Energy Hubs (OEHs) as integrating various energy sources, these traits have typically been examined through separate perspectives.However, in the literature review, the fusion and interaction of different aspects within a framework of creating a societal value assessment of OEH have not been adequately addressed.Therefore, the evolutionary assessment of both the technical concept and value assessment framework from this paper is to emphasize the future importance of considering societal value when designing and assessing OEHs, combining economic evaluations, environmental impact, societal requirements, and technology development.

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