Does floating offshore wind in the Celtic Sea hold the answer to the UK’s net-zero ambitions? A 2020 ITPEnergised report for the Offshore Renewable Energy Catapult revealed significant potential in the Celtic Sea area, as well as in north Wales and off the coast of Anglesey. Indeed, work by the Catapult and ITPEnergised suggested there is technical capacity around the Welsh coast and southwest of England for up to 50 GW of floating wind and more than 25,000 km2 of sea area potentially suitable for floating offshore wind developments.
This is great news for the industry, local supply chains, and could be a crucial factor in the UK’s ability to meet the Government’s net-zero 2050 target. However, a large volume of concentrated generation capacity in one part of the country presents challenges for the electrical infrastructure.
This issue is the focus of a new ITPEnergised transmission network study for the Welsh Government, which explores the technical barriers, solutions and costs to developing various future offshore wind scenarios off the Welsh coast. A summary of this work, produced by the ORE Catapult and the Welsh Government, was published last week.
So how does the region go about upgrading and reinforcing its infrastructure and how will Wales benefit from getting it right?
The first stage in understanding what upgrades would potentially be required is by undertaking an extensive capacity assessment. In the network transmission study, low, medium and high scenarios for future offshore wind capacity were considered to determine what reinforcements would be required depending on current and future needs, up to 2050.
Offshore wind developments on the west coast have the benefit of learning from experience in North Sea developments; the UK’s east coast is one of the most active areas for offshore wind in the world, with 37 windfarms and nearly 8 GW of capacity. These windfarms have been developed and built over several years and could have benefited from better co-ordination with regards to grid connection.
What is more, when these projects first began, the future success of the offshore wind industry was difficult to predict. Due to regulations, the transmission owners upgrade the grid on an ‘as and when’ basis, as projects are confirmed, rather than taking a more strategic approach.
The challenge is that Ofgem stipulates that any upgrades to the grid need to be made in the most economically efficient way. With this model, there’s a disconnect between what is needed now (so, what is most cost effective) and what might be needed in the future (more expensive in the short term – but makes long-term commercial sense).
Now the industry is more mature, Wales could benefit from lessons learned and a more strategic approach for the region should be investigated.
There are, of course, plenty of tried and tested techniques commonly used in increasing grid capacity, and we believe the National Grid Electricity Networks will need to implement many of these to help prepare the infrastructure for a widespread move to wind power.
For example, the process of reconductoring – a method of upgrading existing transmission lines by replacing the cabling on them with a higher rated substitute – will be important.
Another approach is to add new overhead lines and cables within the GB National Grid. These lines can be added alongside existing ones, or follow a new route, connecting previously unconnected substations.
However, this approach is not without risk. Significant planning and engineering work will be required to design, consent and build the new towers, or underground the cables, and the new infrastructure will have to undergo thorough environmental impact assessments.
Alternatively, the use of interconnectors – high-voltage direct current cables which link two different alternating current grids (typically between electricity markets and countries) – are also likely to play a role in supporting future wind development.
These links allow excess generation in one market to be exported to another and vice versa. The National Grid of Great Britain currently has five main interconnectors, to France, the Netherlands, Belgium, Northern Ireland and the Republic of Ireland (the latter two forming a single market on the island of Ireland), while three more are under construction, to Norway, Denmark and a second to France and a further 18 under development holding agreements with National Grid Electricity System Operator. Further developing interconnection between Wales and other areas of the GB national grid or other markets could be effective at allowing further wind resource to be connected within the region.
As well as the traditional routes to increasing capacity, ITPEnergised’s report discusses the novel approaches that could be proposed when considering grid constraint. It explores how increasing demand could reduce the burden on the grid, the potential role of energy storage and using wind power for the electrification of oil and gas assets.
For example, by targeting demand increase close to generating stations within areas of high boundary flow, network constraints can be reduced, potentially allowing further generation to be added to the system or reducing reinforcements. The generation may be used for new, energy-intensive industries such as data centres; battery energy storage for when generation drops and boundary constraints are lower; or converted into alternative fuels, such as hydrogen, for transmission within the gas network or to be used for local fuel requirements, such as powering ferries.
Data centres produce a large power demand which could be met through renewable energy, either from the grid close to the connection point, or directly through a private wire. By positioning new data centres near to the landfall of offshore renewables, a significant amount of the power production could be diverted from the wider grid, saving on the upgrades required.
Hydrogen production during times of excess wind power is being discussed more often as a solution to the intermittency of offshore wind generation and renewables in general. The principle is that while in normal circumstances, offshore wind generation above the capacity of the grid would have to be curtailed, with a hydrogen electrolysis facility located near landfall (or even offshore), the energy could be stored, mitigating curtailment.
Indeed, there’s precedent there. A report by the Scottish Government recently highlighted that the production of green hydrogen could assist Scotland in meeting its net zero targets while helping to alleviate constraint to the grid.
Both Scotland and Wales have an abundant offshore wind resource potentially greater than the regions’ demand. If used to produce green hydrogen, a greater proportion of this energy could be harnessed and used to reduce emissions in sectors such as heating, transport and industry.
So, there is plenty of work to be done, but also both immediate and long-term benefits to getting it right. We know that today, the improved economics of offshore wind make it highly competitive with other forms of electricity generation, and the cost of floating wind is falling in the same way fixed foundation wind did.
Offshore wind is a ‘low regrets’ option for policy makers, and there is now a significant opportunity for Wales to become a major exporter of this renewable energy and build local supply chains. In addition, there is benefit in diversifying away from the east coast too – most notably to ensure the security and continuity of supply, with the different parts of the country being windy, and therefore generating power, at different times.
There are also many benefits to the local economy: for existing Welsh companies to be involved in offshore wind and for new ones to emerge too. Floating wind can bring significant opportunities to the region, including in the manufacture of floating wind technology and in construction, operating and maintaining the windfarms; Welsh ports can become key O&M hubs, providing ports, logistics, vessels and subsea engineering.
So, there is lots to consider, but we believe that, with the commitment to make necessary upgrades to the grid, the future looks bright for the development of Welsh floating wind.
And the good news is that there is already progress being made. ITPEnergised is supporting Blue Gem Wind’s Erebus project, a 96-MW floating offshore wind demonstration project in the Celtic Sea. Once commissioned, it will be the first of its kind in Wales and Erebus will pave the way for future commercial floating wind in the UK and globally and represents a significant first step towards realising the electricity generating capacity in the Celtic Sea.