Network Development Roadmap

Pathfinding projects

High voltage pathfinding projects

Changes in the energy system over the last decade have resulted in managing system voltages becoming an area of increasing challenge for the Electricity System Operator (ESO). We have seen a continual decrease in both minimum demand and reactive power consumption on distribution networks, resulting in an increasing need to absorb more reactive power on the transmission network. As a first step to developing a regional options assessment process for voltage requirements, these projects focus only on high voltage system issues.

To find the most cost effective solutions to these new challenges, we are going beyond the traditional approaches of looking only at transmission based solutions. We believe greater value for consumers can be achieved by looking also at distribution and market based solutions. 

Through our pathfinding projects we're working with TOs, DNOs and service providers to establish methods to identify the most cost effective approach to addressing these issues. 

Constraint management pathfinding project

The ESO is conducting a pathfinding project with the ambition of providing along-term commercial product to manage network constraints. We are exploring the potential to introduce a product that will provide an opportunity for market participants to deliver a service that reduces constraint costs on the National Electricity Transmission System, such as storage.

Post-fault constraint management commercial solutions

Commercial options that can help mitigate the consequences of unplanned events once they take place (post-fault constraint management services) could help reduce the need for build solutions. The 2018/19 NOA identified that it is possible for such options to provide consumer benefit. Having, explored this further we do not feel there is sufficient benefit in seeking a specific post fault market service in the short term. We will use the learning from developing requirements to continue to consider commercial options as part of the NOA process.

(This work was formerly referred to as 'Commercial solutions in NOA'.)

Stability pathfinding project

We also want to explore the benefits and practicalities of applying a NOA-type approach to the operability aspects of system stability. In this context we are talking about stability of frequency, voltage and the ability of a network user to remain connected to the system during normal operation, during a fault and after a fault. Synchronous generation provides many benefits to system stability that will need to be replaced when this type of generation runs less frequently.

We are exploring how to articulate and quantify the properties synchronous generation gives us, the potential for these to be provided by alternative technologies, and the value of a NOA type process for stability. We published some of our work on the impact of declining short circuit levels in our System Operability Framework (SOF) document, and during 2019 we intend to invite technical and commercial solutions from across the industry to address needs in specific locations.

Probabilistic approach 

The changing nature of the electricity system means that it is increasingly important that we study the system needs across more of the year than our current focus of winter peak. In the future, a probabilistic approach could allow us to pinpoint specific issues down to circuit level so that the most cost-effective, whole system solution, can be identified. We are set out our emerging findings on this in the Electricity Ten Year Statement .

Further to this, we have published the findings from our case study. We’ve developed a probabilistic transmission network planning tool and analysis methodology, and tested it on a part of the south-east coast of England’s transmission network. While we’re still developing this methodology, to allow for a greater assessment of the GB transmission needs, our case study has shown that we can identify more thermal transmission needs. We’re also able to better understand the extent to which future generation mix changes will present new challenges on the network, giving us insight on how we can deal with them. This work presents a step forward from our current planning methodology.

We invite your views and feedback on our probabilistic planning methodology’s development. 

Early Competition Plan

Ofgem has asked the ESO to develop proposals for how early models of competition for onshore transmission (including 'CATO' options) could be introduced - see their request here. On 19 February we published an update on phase 1 of this project, along with supporting appendicies (model development slides and case studies). Phase 1 was developed following stakeholder webinars and workshops. Material from these are below:

• Introductory webinar Slides and a video  - 12 September 
• workshop 1 - 26 September.
• workshop 2 -  22 October 
• workshop 3 - 12 November

Over the next year we intend to have a high level of stakeholder engagement, including the following activities:

• stakeholder workshops in April/May
• a consultation in June/July 
• subsequent engagement on specific issues during the summer/autumn
• final consultation in November/December

On the 3 March we held our Phase 1 Update webinar. To view the webinar please click here.

We have a dedicated distribution list for this project - sign up here. General updates on this project are included in our monthly Network Development Roadmap monthly newsletters.

Other developments

Other projects are also underway looking at more immediate needs and will provide insight for our network development planning. For example, Power Potential assesses the use of distributed resources to address voltage challenges in the South East, and the Phoenix project will assess the potential for hybrid synchronous compensation to provide voltage and system stability. We will feed the learning from these projects into how we develop our network planning tools and processes.