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NOA methodology
Network Options Assessment (NOA)

Latest news and updates

NOA 2021/22 methodology submitted to Ofgem

We have finished our review of the NOA 2021/22 methodology and submitted it to Ofgem on Thursday 29 July. Thank you to those who provided feedback.

NOA 2021/22 methodology consultation now started

We have opened the consultation for our NOA 2021/22 methodology. It will close on Tuesday 22 June 2021.

UoM review of the NOA Process - Economic Aspects

In 2020 the University of Melbourne reviewed the NOA Process as part of an innovation project. Download their report on the economic aspects.

UoM review of the NOA Process - Technical Aspects

In 2020 the University of Melbourne reviewed the NOA Process as part of an innovation project. Download their report on the technical aspects.

Our NOA methodology has been approved

Ofgem have approved this year's NOA methodology and the letter is now available.

What is the NOA methodology?

The NOA Methodology describes how we assess major National Electricity Transmission System (NETS) reinforcements to meet the requirements identified from the outputs of the Future Energy Scenarios (FES) and Electricity Ten Year Statement (ETYS).  

On this page, we explain how the options submitted by stakeholders are assessed in the NOA and how we make the recommendations. 

Read the latest NOA methodology

Supplementary note about storage in NOA

We are looking at how storage can cost effectively help with network constraints. There are a number of complexity challenges associated with storage. This note gives more detail along with our current thinking and possible next steps on how best to assess storage for constraint management.

Storage supplementary note

How do we assess the options in the NOA?

To create an electricity network fit for the future, we assess options that meet the system capability requirements outlined in the ETYS.   

The NOA analysis begins by identifying a future reinforcement need, then assesses all available options to meet this need.

We then recommend and document the option(s) for further development. 

Designer examining a prototype

What is our economic analysis?

Our cost-benefit analysis investigates the economic benefits of different combinations of reinforcement options across four future energy scenarios. We identify the single combination that provides the most value for the consumer.

Our economic analysis is based on a single year least worst regret selection process. The regret of an investment strategy is the net benefit difference between that strategy and the best strategy for that scenario. So, under each scenario, the best strategy will have a regret of zero, and the other strategies will have different levels of regret depending on how they compare to the best strategy. We always choose the strategy with the least regret across all scenarios.

You can find a detailed example in Chapter 2 of the NOA methodology report.

Download report

NOA Committee

Following the cost-benefit analysis and single year least regret analysis, we present the results to the NOA Committee for additional scrutiny. It focuses on marginal options where recommendations are driven by a single scenario or factor, or are considered sensitive in terms of stakeholder engagement. 

The NOA Committee brings expertise from across the ESO, including knowledge on operability challenges, network capability development, commercial operations and insight into future energy landscapes.

You can find the latest meeting minutes as well as the Terms of Reference here.

This year, in collaboration with academics at the University of Melbourne, we developed a new tool called Least Worst Weighted Regret (LWWR). It provides a sensitivity study of varying the probability of each future energy scenario occurring. We used this tool for the first time this year at the NOA Committee, to help improve the robustness of the marginal options presented.

You can find out more by downloading the report on the economic aspects.

Download report

Making new ideas happen

NOA for Interconnector analysis

We use the latest output of the NOA recommendations as the baseline network reinforcement assumptions to assess and provide a view on the optimum level of interconnection to other European markets.

This analysis assesses the potential benefits of interconnection under a range of scenarios. It outlines the socio-economic benefits of interconnection for consumers, generators and interconnector businesses.

You can find our more in Chapter 3 of the NOA methodology. We'd encourage you to share feedback on our interconnector analysis. You can do this by emailing [email protected]

Find out more

Help improve the NOA methodology

You can help us shape next year's methodology during the consultation period which runs between May and June 2021.

Your feedback is important to us, and we urge you to get involved. With your early engagement, we can make sure your views are captured even before the formal consultation process begins.

Email us