We are a separate company

On 1 April the Electricity System Operator became a legally separate company within the National Grid Group. Find out more about what this change means.

Network Development Roadmap

The Network Options Assessment (NOA) - our process for developing an efficient, coordinated and economic system of electricity transmission - has already saved several millions of pounds for consumers and we’re continuing to drive even greater value through transforming our network planning tools.

Our transformation plans, as set out in the Network Development Roadmap, will drive even greater consumer value 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.

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. 

Findings of our phase 1 study are available on the ENA website. As part of phase 2 of the project, we have now launched the first of our RFIs seeking input from potential providers. A further RFI for the Pennine region will be published in Q1 2019/20

We previously indicated we would also tender for long term voltage support in South Wales. However, recent analysis no longer indicates a need in this area and so we will not be seeking this service at this time. The need for voltage support in different regions will be reviewed and communicated annually.

Constraint management pathfinding project

The ESO is conducting a pathfinding project with the ambition of providing a commercial product based around future constraints on the network. 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. Engagement with the market at this early stage is essential so we are holding a webinar in May to discuss our initial findings and future plans. This is likely to be of interest to service providers who can provide a long duration product (one example may be storage providers).

Post-fault constraint management commercial solutions

For NOA 2019/20 we are, for the first time, requesting information on commercial options that could help mitigate the consequences of unplanned events once they take place. The 2018/19 NOA identified that it is possible for such options to provide consumer benefit in the near future. In the next few weeks we will be coming to the market to request information for potential providers of post-fault constraint management services.

(This work was formerly referred to as 'Commercial solutions in NOA'. We have renamed it for clarity.)

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.