Looking for more information about the 9 August power cut?

See our interim technical report and other ESO resources.

Network Options Assessment (NOA)

The NOA has an important role in developing an efficient, coordinated, and economic system of electricity transmission.

NOA highlights

  • Learn about options that transmission owners have provided to meet capability requirements on Britain's electricity transmission network.
  • Read about options the system operator recommends to the transmission owners to further develop for this investment year.
  • Discover options that meet Ofgem's criteria for onshore competition.
  • Interconnection analysis.

What NOA does

  • Recommends which options and when the TOs should invest in them, so their transmission networks can manage risk in an uncertain world.
  • Recommends whether TOs should delay or continue current projects to make sure they are completed at a time that will deliver the most benefit.
  • Can indicate the optimum level of interconnection to other European electricity grids to maximise socio-economic welfare, based on market-driven analysis.
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NOA 2018/19

NOA's purpose is to make recommendations to transmission owners across Britain as to which projects to proceed with to meet the future network requirements as defined in the Electricity Ten Year Statement (ETYS).

Download the NOA

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NOA Methodology 2019/20

We have amended our NOA methodology following our consultation on the document and submitted it to Ofgem. It now includes the ESO process High Voltage Management section. Like the draft during the consultation, you can either download the full document on the link below or the individual sections on the links to the side.

Download the NOA methodology

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Network Development Roadmap

Thank you for your input to our Network Development Roadmap consultation that closed on 15 June.  We’ve used your feedback and have published our conclusions in the Network Development Roadmap – confirming the direction document. It confirms the direction of travel for the Electricity System Operator’s network planning activities over the next three years.  You can find the Roadmap consultation and the Confirming the direction documents our Network Development Roadmap page. This page also contains updates on progress and will contain information on how to get involved.

Network Development Roadmap

NOA documents

NOA Committee

We held NOA Committee meetings in December and January to scrutinise the NOA results.  The minutes of the December meeting and previous meetings are available to view. The minutes for May’s meeting will be available after the next meeting in October.

Long-term market and network constraint modelling

Since 2016, we have used BID3 to model European wholesale electricity markets and the GB balancing mechanism. BID3 replaced our previous market modelling tool, ELSI in order to allow us to perform our enhanced SO role in the following ways:

  • More sophisticated and accurate modelling of European wholesale electricity markets, and the related market dispatch, including interconnector operations
  • More sophisticated and accurate modelling of balancing mechanism and related market re-dispatch.

BID3 is retailed by Pöyry Management Consulting (www.poyry.co.uk), who have enhanced BID3 to include a Balancing Mechanism re-dispatch for Great Britain, thus allowing users to model the impact of GB transmission networks and calculate constraint costs, which we do for the purpose of Cost-Benefit Analysis in the NOA.

Transition report

A report that explains why we needed to move from ELSI to a new model, why we chose BID3, what we will use the model for and how we ensured the model is the most economic and efficient solution for current and future work.

In order to improve transparency, the SO is pleased to provide an updated version of our former optimisation model ELSI. This is populated with updated scenario data. As such the user can gain valuable insight into the rationale behind investment decisions made by the SO in the data used for SO analysis. For reference, a user guide is also provided here.

Please send any comments or questions on the release of this model to [email protected].

Independent reviewer report 

BID3 has been extensively benchmarked against ELSI. Two independent reviewers (Professor Keith Bell, University of Strathclyde and Dr Iain Staffell, Imperial College London) were appointed to review our development work, BID3 configuration and benchmarking.

Backcasting report

We have also performed a backcasting exercise on the GB balancing mechanism to assure our stakeholders that BID3 can accurately depict GB balancing costs for our long term constraint forecasting. A report on this exercise can be found below which includes detailed analysis of how accurately BID3 can replicate 2015 balancing mechanism costs.

SO Process for Input into TO Led SWW Needs Case Submissions