Network Development Roadmap

Our network development transformation plans - as set out in the Network Development Roadmap consultation and subsequent conclusions document - we will build on our Network Options Assessment (NOA) to drive even greater consumer in our network planning through

  • enabling network and non-network solutions across the transmission and distribution systems to compete to meet transmission network needs;
  • assessing the needs of the system over the whole year to a greater extent;
  • carrying out more focused, regional, NOAs which consider how regional voltage issues can be more efficiently managed;
  • investigating the value and feasibility of expanding the NOA approach to system stability in the longer term, which will include challenges such as dynamic voltage, fault levels and inertia; and
  • communicating our transmission system needs and the recommended options for meeting them in a way a wider audience can understand. 
  • Our transformation plans are complex and ambitious and involve a large range of potential stakeholders. We’re therefore working closely with industry, in particular the Electricity Networks Associate (ENA) Open Networks project and taking a learning by doing approach, implementing the changes through a number of pathfinding projects.

Thank you for your input and feedback at this event, a summary of which can be found here along with our immediate response. Further updates in response to this feedback, and our intentions for the future, will be published in our Roadmap Update in the Autumn. 



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. 

Following consideration of the responses received to the RFI for the Mersey region we confirm we will be running a tender for long term reactive requirements. We expect this to be in the Autumn with further details on the timings being communicated over the summer. We are now working towards running a tender for Pennine region in Q1 2020/21.

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. Engagement with the market at this early stage is essential so, on 13 May, we held a stakeholder engagement webinar to discuss how we can set out our requirements and recommendations in such a way that they can be easily interpreted. Webinar slides are available here along with FAQs (5 June update), which will be updated periodically. We intend to launch a market engagement platform such as RFI or Competitive Dialogue to gain further input from the market in Q3 2019/20.  Our aim is to tender for this service in Q1 2020/21.

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. Our intended use for 2019/20 will also be included within the NOA methodology which we will consult on April and May. 

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.


Network Development Roadmap consultation responses

We held the consultation for Network Development Roadmap between 3 May and 15 June 2018.  We are grateful for the feedback you gave and for agreement to publish the responses below.