Electricity Ten Year Statement (ETYS)
The Electricity Ten Year Statement (ETYS) is the ESO’s view of future transmission requirements and the capability of Great Britain’s National Electricity Transmission System (NETS) over the next 10 years.
The ETYS is important in helping us to understand where investment and development is needed to help us achieve our zero-carbon ambition. ETYS 2022’s key messages explain some of the most pressing issues we see on the NETS as we drive towards net zero.
Since the last publication of the ETYS, the world has fundamentally changed. Both the devastating war in Ukraine and the ongoing cost of living crisis has underlined the importance of reaching net zero. A fast transition to net zero will bolster our energy security and reduce our exposure to volatile international fossil fuel prices, by harnessing abundant renewable and low carbon resources. This transition will ultimately minimise the costs for consumers in both the near and future term.
About the ETYS
The ETYS sits at the heart of our network planning process. Using the data from our Future Energy Scenarios (FES), we identify points on the transmission network where more transfer capacity is needed to continue to deliver electricity reliably from where it is generated to where it is needed.
Once we have assessed the network requirements, we invite stakeholders to propose solutions to these requirements. These proposals are assessed through our Network Options Assessment (NOA) process, where the most economic and efficient solutions are given a recommendation to proceed, while others are put on hold or stopped/not started.
Our network planning process is changing as we are transitioning to a new Centralised Strategic Network Plan (CSNP). We are working in collaboration with Ofgem on the Electricity Transmission Network Planning Review (ETNPR) to review our network planning processes to ensure that the network design and investment processes in Great Britain are fit for the future. During this transition there will be some iterations of a transitional CSNP (tCSNP) to continue informing network planning and investment decision whilst we develop the enduring CSNP process.
The enduring CSNP will proactively identify, design, and progress investment in the transmission network onshore, offshore, and across vectors. In addition to economic assessment, the CSNP will also consider environmental and community factors earlier in the planning cycle. To support the development of the CSNP, Ofgem published their decision to allow us to publish the ETYS by 31 January 2023. A transitional CSNP will be published by 31 December 2023.
What’s new in ETYS 2022?
We are continuing to develop our tools to allow us to expand our view of system needs. This year, we have prepared some examples of how year-round thermal system needs could be communicated. These can be found on the Improving ETYS page, and we welcome your feedback on these. Traditionally, the ETYS looks at a single snapshot for the winter peak against which we look to secure the network. Using our in-house year-round thermal probabilistic tool, we can analyse year-round system needs by assessing the network against a range of snapshots across all seasons and subsequently identify a wider range of system needs.
As we continue to work towards integrating voltage system needs into the ETYS publication, we have presented a roadmap to show how this will be integrated into the network planning cycle. Details can be found in Improving ETYS to integrate a wider range of system needs.
Key messages
- Required transfers across Scottish boundaries are expected to almost triple from today to 2030. The coordinated approach of the Holistic Network Design (HND) provides additional transfer capability to these boundaries, especially B6, and will relieve some of the constraints across Scottish boundaries from 2030 by providing new routes for power flows. Offshore wind generation projects considered by the HND and HND Follow-up Exercise (HNDFUE) are factored into the ETYS’s generation background (as per FES 2022).
- Required transfers across North Wales boundaries are expected to quadruple between 2027 and 2032 to a maximum of 11GW in the Leading the Way scenario. Large amounts of generation, including new offshore wind generation is expected to connect in this region.
- In the East Anglia region, growth in low-carbon and renewable generation over the next decade will continue, potentially reaching a total installed capacity of over 13GW by 2030, up from 5.5GW today, across all FES scenarios.
- Interconnector and storage capacity is anticipated to reach a total 9 – 12GW in the South of England by 2030. Network flows in the region will be driven largely by market conditions and the direction of interconnector flow, and large swings in power transfer are possible as these interconnectors move from exporting to importing (or vice-versa). The south coast region will therefore require careful network management.
The ETYS describes the network capability by looking at the maximum secured power transfer between two regions or the power transfer across a boundary.
To operate the network safely, we must make sure that the power flow across the boundary do not exceed the capability of the system between the two regions. To prevent this, we must take actions to constrain generation which can incur significant costs.
The two heatmaps below illustrate the impact of the network reinforcement options recommended in the NOA 2021/22, showing how these options can significantly reduce constraints by increasing the power transfers across boundaries.
It is vital that both onshore and offshore reinforcements are developed in a timely and coordinated manner to maximise the network benefits and ensure that the transmission network can provide power to demand centres in a safe, reliable, and economic manner.
We welcome Ofgem’s decision to accelerate strategic onshore electricity transmission projects through the new Accelerated Strategic Transmission Investment (ASTI) regulatory framework. This recognises the scale and pace required to deliver the Government’s 2030 renewable energy ambitions. Ofgem expect this will have a net benefit to consumers of up to £2.1bn in reduced constraint costs and carbon savings, contingent on timely project delivery. 
Chart uses the NOA 2021/22 recommendations following the Leading the way scenario against FES 2022 flows
The ESO is also proactively developing non-build solutions for regions where a short-term requirement has been identified. For example, the EC5 Constraint Management Intertrip Service (CMIS) is being launched to reduce constraint costs across the EC5 boundary (found in East Anglia) for the 2025 – 2030 period by offering additional network management options during real-time network operation. This follows the success of our Constraint Management Intertrip Service now in operation for the B6 boundary.
The past year has sparked recognition of the importance of a faster transition to net zero and an increasing focus on Great Britain’s, as well as the rest of the world’s, energy security. This highlights the need for the ESO and the wider industry to secure the network against a wider range of conditions.
Currently, the ETYS process focuses on securing the network against a winter-peak scenario for thermal or low-voltage constraints. With the ongoing rise in intermittent and converter-based technology on the transmission system we need to expand our view of system needs to a wider range of requirements including voltage and stability needs across a range of scenarios over the year.
We have continued to develop our year-round thermal analysis tool (Power Uncertainty Year-round Adviser – POUYA) to help us evaluate year-round network flows. The ESO is developing new enduring processes to assist us in identifying and managing system needs relating to voltage and stability. We are also working with our transmission and distribution partners to determine how system needs across the transmission-distribution interface could be communicated.
We will value your feedback on our latest ideas and would like to hear your thoughts on how we can continue to enhance ETYS to communicate a wider range of year-round system needs. Read more in Improving the ETYS to integrate a wider range of system needs.
ETYS 2022
The Electricity Ten Year Statement outlines our view of the National Electricity Transmission System over the next ten to twenty years.
Contribute to our year-round analysis of ETYS
We would like to hear your views on how we can improve the ETYS, and we have set up a short survey to gather feedback.
