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Power to the people – the UK’s evolving electricity transmission system
6/4/2022
6 min read
Feature
As the way in which we generate and consume energy changes, the demands on our existing transmission system are changing. Here, Ed Walker MEI, Principal Environmental Consultant, Xodus, considers how the UK network is evolving to meet these demands, and what the transmission network of the future may look like.
Reflected by the UK government’s 10 Point Plan, decarbonisation of our energy system is a cornerstone of the ‘green revolution’, including through the advancement of low carbon technologies for the generation of electricity. And, while generation frequently takes centre-stage, the transmission network forms an equally critical part of our national energy infrastructure.
As older power stations around the UK close and new sources of energy come online, the transmission system requires extensive development to ensure efficiency in connection and delivery of low carbon energy.
By way of illustration, National Grid is continually connecting various energy sources around the UK. One such source is the Nemo Link, a 1 GW interconnector allowing bidirectional transfer of electricity between Belgium and the UK. The high voltage (HV) subsea cables come ashore at Richborough, Kent. However, until recently, the area was lacking the HV transmission network necessary to connect this green energy into the grid.
In December last year, National Grid announced the completion of the new 20 km power line comprising more than 60 new pylons and 43 water crossings. Notably, it is the first major power line in the UK to be constructed since 1961.
This is just one example, and the transmission network is rapidly evolving elsewhere. Looking to the west, Iberdrola (through its subsidiary ScottishPower) and National Grid recently developed the Western Link project which went operational in 2019. This 850 km long primarily subsea cable connects the west coast of Scotland with Quay Bay in Wales, providing more than 2.2 GW of interconnection capacity, facilitating the bi-directional distribution of clean energy.
While certainly a positive investment in the UK energy system, in November 2021 National Grid Electricity Transmission (NGET) and Scottish Power Transmission agreed to pay a sizeable £158mn redress associated with a two-year delay to the project. One of the major factors flagged by Ofgem in this redress was the impact of the delay which made it ‘difficult at times’ for renewable generators in Scotland to export clean energy to England and Wales.
Clearly, then, there is an urgent need for transmission investment, and a pressure on those developing such assets to push forward to reach in-service status swiftly.
As older power stations close and new sources of energy come online, the transmission system requires extensive development to ensure efficiency in connection and delivery of low carbon energy.
Beyond the examples above, a range of other projects around the UK are helping to provide an additional 6 GW of interconnector capacity. Specifically, this relates to a 3 GW link to France (IFA and IFA2), 1 GW to the Netherlands (BritNed), 1 GW to Belgium (the aforementioned Nemo Link), 500 MW to Northern Ireland (Moyle) and a 500 MW link with the Republic of Ireland (East West).
Network of the future
Aside from the operational suite of transmission infrastructure, what’s next? Even longer and more complex links are being developed between the UK and other nationalities, including the X-Links Morocco UK power project. This first-of-a-kind 3.6 GW development will facilitate the transfer of wind and solar energy between North Africa and the UK, supported by a 5 GW battery facility in Morocco.
Within the UK, NGET is preparing to submit applications for two new subsea power cables from Scotland to England; one from East Lothian to Durham (SEGL1), and another from Peterhead to Selby (SEGL2), each providing 2 GW of transmission capacity. Both links will help deliver increased capacity from Scotland’s vast reserves of clean energy down to England.
In January this year, the National Grid Electricity System Operator published the latest ‘Network Options Appraisal’, signalling the start of a wide range of additional transmission improvements, including two potential subsea reinforcements between eastern Scotland and England.
Based on the current trajectory of the transmission system, the network of the future is one which will feature significant infrastructure allowing the transfer of green electricity around the UK. Beyond this, we can also expect to see the emergence of new, novel approaches to transmission, such as multi-purpose interconnectors (MPIs). In considering what the network of the future might resemble, I spoke with Liz Wells of National Grid Ventures (NGV) to gain her insights on the topic – see Box.
Fundamental element
Over recent years, we have witnessed the rapid evolution of our transmission system, both in terms of distribution of power around the UK and also the increasing fleet of interconnectors being used to share clean energy around Europe. The transmission network of the future will build on these operational assets, taking lessons learned to inform transmission improvements, but also to deploy novel technologies.
The UK’s transmission system is a fundamental element of our energy system, underpinning the journey toward solving the energy trilemma. Over the next decade and beyond, I am looking forward to working with others in the Energy Institute’s professional community to support the deployment of the network of the future.
The network of the future
EW: What might the transmission network of the future resemble?
LW: There is a growing recognition of the new and many different sources of energy which we need in order to meet net zero and maintain security of supply. Coal and gas generation, which historically were the backbone of the grid, are being phased out and the locations where we generate our energy are changing, including offshore generation and import.
As we reduce sources of conventional generation and are increasingly relying on a varied mix, our transmission system needs to reflect this and complement it, not compromise it.
EW: How is National Grid Ventures (NGV) involved in this?
LW: NGV has been heavily involved in the Offshore Transmission Network Review (OTNR), headed up by the Department for Business, Energy and Industrial Strategy (BEIS). Within this, there are three key workstreams: ‘Early Opportunities’, ‘Pathway to 2030’ and ‘Enduring Regime’. Multi-purpose interconnectors (MPIs) are part of that solution, and are a tangible means of achieving greater coordination, integrating offshore wind and interconnection.
We know that there is a need to coordinate in industry. There are some real opportunities here to move our clean energy to where it needs to be, while reducing the pressures on coastal communities as well as the marine and terrestrial environments where these projects are developed.
EW: Does NGV have plans for developing projects in the near future?
LW: We are preparing to submit applications for Nautilus and EuroLink, which are MPIs connecting into the Suffolk coast. This will provide around 3.6 GW of new transmission capacity into the UK grid, whilst delivering real coordination. As well as this, we are planning to develop Continental Link, a new HVDC MPI linking the UK and Scandinavia. We already have a range of excellent links with some of our European partners and will be exploring how we can work with them in the future, through coordinated approaches to the transmission of clean energy.
The devil is in the detail, and we are exploring ways in which we can achieve better coordination to enable these projects to be realised. Better coordination can take several forms, but includes consideration of things such as shared construction compounds, shared access routes and coordinated cable corridors – and many other approaches to help achieve full integration.
EW: What in your opinion is the biggest opportunity?
LW: 40 GW by 2030 is a great target, but is this enough? We have an opportunity right now to push toward this and beyond to help tackle the climate emergency. Doing this quickly is one thing, but doing it better is key, and MPIs form part of that improved approach.
EW: And the biggest challenge?
LW: Bringing the complex threads of this all together; there needs to be a step change in policy, regulation and consenting. The current status quo is well established, and stepping away from this in such a wholesale way is going to be difficult.
EW: Is there an opportunity for hydrogen in this new network of the future?
LW: There certainly is, and this is an area which NGV is actively exploring. We are currently working with a range of partners in industry to develop Project Cavendish, a new production facility on the Isle of Grain which could provide up to 700 MW of blue hydrogen and support capture and storage of 1.2mn t/y of CO2 by 2026.
In Yorkshire, we are also promoting Humber Low Carbon Pipelines as part of the East Coast Cluster, a new project involving both carbon capture, utilisation and storage (CCUS) as well as a network of pipelines to transport captured CO2 and hydrogen. Eventually, green hydrogen, as part of these projects, can be realised though renewable energy generation facilitated by a more co-ordinated grid.
Fig 1: Present and future offshore network
Source: National Grid Ventures 2021
