Floating wind and green hydrogen - fostering future Scottish-French research and development collaboration: report

Context and technical outlook

Many in the energy industry now foresee a vital role for hydrogen in facilitating the energy transition which will be required to deliver upon global climate change mitigation and net zero targets. As an energy vector (a way of storing, transmitting or consuming energy), hydrogen offers a means of decarbonising sectors where it is 'difficult to meaningfully reduce emissions’ ^[5], due to technical challenges which may limit the utility of other solutions.

In particular, it is expected that there will be a role for hydrogen in providing fuel for heavy duty and long-range road, rail, marine and perhaps even air transport. In addition, hydrogen may also be a suitable means of providing heat and chemical inputs in industrial processes such as the production of ammonia, steel or concrete.

One of the merits associated with using hydrogen in both transport and industrial sectors is the opportunity to provide the required energy inputs without releasing any greenhouse gas emissions at the point of use. In the longer term, hydrogen is also considered to be a credible energy storage solution with application in the storage of renewably-produced power over daily, weekly or even seasonal timescales ^[5].

Synergies and links exist between the offshore wind and hydrogen sectors, in that cost reductions in the power produced by offshore wind farms can lead to the realisation of significant reductions in the costs of producing hydrogen via electrolysis ^[6]. Perhaps more importantly when considering floating wind to hydrogen projects, hydrogen is expected to offer an efficient method of large scale, long-distance energy transmission. This means it is well placed to help integrate ever-increasing shares of power produced by offshore wind generators where the most abundant sources are often long distances from significant demand centres.

Any future energy system dominated by renewable generation, including wind power, would likely rely on large scale upgrades in electricity transmission and distribution infrastructure to manage the flow of the power produced. This is especially true of offshore wind, and even more so of floating wind, which is expected to be deployed in ever deeper waters, further away from shore.

Floating wind turbines are expected to provide higher capacity factor^[2] power generation than that gained from existing offshore wind farms due to the ability to access stronger, more reliable winds far out to sea. However, locating floating wind farms further from shore also increases the cost and logistical challenges associated with transmitting the power produced back to shore, and on to locations of power demand.

Hydrogen is expected to play a role in addressing this challenge, either by reducing the transport and handling costs directly – from a technical perspective gas can often be more conveniently transported than electricity ^[7]. Hydrogen may also provide opportunities for producers of renewable power to access additional, high value markets for the energy that they produce, for example in providing renewably-produced fuel for hard-to-decarbonise sectors like aviation and shipping.

Many of the innovation activities described subsequently in this report are seeking to develop solutions to facilitate exactly the scenario described here. Some outstanding technical challenges will need to be addressed to pave the way for widespread deployment of the technologies and systems described.

The world’s first floating wind farm was deployed in Scottish waters in 2017 by Equinor, who developed the Hywind Scotland project. The Hywind demonstration project saw the deployment of five six megawatt (MW) floating wind turbines in waters east of Peterhead, in the north east of Scotland ^[8]. Since then, a 24 MW project has also been deployed off the coast of Portugal, within the WindFloat Atlantic project ^[9]. The Kincardine floating wind farm, which will be the world’s largest at 50 MW, is also currently under construction in Scottish waters and due for commissioning in 2021 ^[10].

Europe is also arguably leading the world in developing renewable hydrogen research and demonstration projects, with electrolysis capacity in the pipeline for the continent having scaled from 0.1 gigawatt (GW) in 2016 to ambitions for around 10 GW announced by mid-2020 ^[11].

Cross-cutting technical challenges

Across both sectors, these initial research, development and demonstration projects have contributed to identifying and proposing solutions to several outstanding technical challenges which are itemised below.

A few cross-cutting technical and logistical challenges are evident in both sectors. These challenges and innovation needs largely apply globally, though there are localised dynamics influencing the degree to which they may impede the development of floating wind and hydrogen in Scotland and in France. These relate primarily to supply chain readiness and the relative availability or state of development of the infrastructure required for large scale developments and deployments of the technologies required. In floating wind these challenges primarily relate to the availability of suitably equipped ports to enable the transport of components (such as cranes to move wind turbine blades and cabling) and systems (relating both to the equipment needed to move integrated, bulky equipment such as floating support platforms, but also the working practices required to do so safely). The absence of suitably developed port infrastructure and vessels may also make it more difficult to access wind farms for maintenance. A further key challenge is in understanding how to conduct maintenance on floating wind turbines once they are deployed far out at sea. Both aspects rely on expertise and capabilities which are as underdeveloped as the industry is nascent. This challenge also applies to the hydrogen sector, where a skills shortage is observed internationally in the wider supply chain, constraining the full value chain from product development, through manufacture and deployment, and into maintenance. This is an obstacle to ensuring that equipment can be looked after appropriately once deployed. In considering floating wind to hydrogen integration, potentially offshore, this manifests particularly in questions around the degree to which supply chains are equipped and/or trained to maintain integrated floating wind and hydrogen assets at sea. There may be significant opportunities for existing offshore engineering specialists to refocus their efforts in applying skills, capabilities and services developed for the oil and gas sectors for floating wind and hydrogen projects offshore. Like other northern European countries with established oil and gas supply chains, there is good scope for Scottish and French organisations to explore these opportunities.

Both sectors also experience challenges with regard to conforming to extensive and varying health, safety and environmental standards, particularly in the marine environment, and developing systems and practices to ensure safe and responsible ways of working. Linked to environmental standards is the challenge of consenting offshore energy projects of all varieties, as a result of understandably stringent marine environment protection requirements and planning processes. The effects of waste products (predominantly heat, saline water and oxygen) must be further studied and the associated survey and monitoring requirements understood.

Addressing these cross-cutting challenges will require novel systems and procedures, as well as investment in infrastructure and training. Across the world, innovation projects seeking to develop these new systems are underway, and some relevant projects being carried out in Scotland and in France are described in subsequent sections of this report.

Floating wind challenges

In floating wind specifically, there is a challenge in providing efficient and cost-effective mooring and anchoring solutions to ensure the platforms remain in position ^[9]. There are different designs for the floating platform to support the wind turbine; these different designs each have different implications for their fabrication, installation and maintenance.

Hydrogen integration challenges

As noted already, power transmission challenges for floating wind developers are a potential enabler for future hydrogen markets. However, the circumstances which give rise to this opportunity also create inherent challenges. If hydrogen is to be produced in the vicinity of floating wind farms to reduce reliance on electricity transmission infrastructure, then solutions will need to be developed for transporting that hydrogen back to shore safely and at scale.

More important, perhaps, is the fact that in order to produce hydrogen offshore via electrolysis there are some outstanding research questions in terms of guaranteeing affordable fresh water availability. Fresh, purified water is currently required for electrolysis, as contaminants (including dissolved salts in seawater) can take part in undesirable chemical reactions within the systems, leading to damage to components. The use of seawater in specially designed saline electrolysers may help to resolve this, however further innovation is required to develop such systems. In this instance there are mooring, anchoring and stabilisation challenges for electrolyser developers to contend with; it is so far unclear whether an electrolysis platform moving with the motion of waves could feasibly operate and to what extent motion will affect electrolyser performance and longevity. This issue is further complicated by the range of electrolysis technologies available and being developed.

Beyond the transport of the hydrogen produced, some form of storage will be required and, as yet, no fully optimised hydrogen storage system has been developed or optimised for the marine environment onboard a floating wind turbine.

Further additional challenges emerge when attempting to integrate floating wind and hydrogen production and handling systems. The first and most obvious challenge relates to how devices should be connected electrically and the design of the required onboard microgrid. Furthermore, the presence of elevated oxygen levels and the potential for hydrogen building up in the vicinity of the turbine (due to venting) must be fully investigated. Methods of protecting electrical and mechanical systems operating in these environments must be understood, and protection systems will need to be developed where necessary.

Having made hydrogen offshore, and assuming that a suitable storage and transport system or procedure has been developed, there is also a question of identifying the most appropriate markets and applications for hydrogen. This will be a very important element for any would-be developer of integrated floating wind and hydrogen projects.

Proposing solutions to these challenges is beyond the scope of this report, but the following sections seek to elaborate on the policy and innovation contexts underpinning efforts to move these sectors forward in both Scotland and France.