The NOA High Voltage Pathfinder looks for the most cost-effective ways to address high voltage system issues created by the need to absorb more reactive power on the transmission network.

This need is the result of a drop in both minimum demand and power consumption on distribution networks. 

Our first step is to develop a regional options assessment process for high voltage system issues. Then we’ll look at distribution and market-based solutions as well as the more traditional transmission-based solutions. 

What we’re trying to achieve

Seeking services from new providers

We’re looking for new providers to help us address high voltage system issues.

We’ll invite providers to submit proposals that address specific system needs via a competitive tender process. This is a collaborative process between ESO and the relevant network owners to allow us to assess the feasibility and commercial value of received proposals.  

Contracts will be awarded where the tender identifies commercially competitive solutions that meet the technical requirements.

You can see an indicative process and associated timings for this process below. Please note however the timings and process for each tender will vary depending on the scale of the requirement.

Supporting the transition to a carbon-free network

The increase in renewable energy generation is changing patterns of reactive power consumption. Plus, generation is increasingly remote from demand centres. 

Services that help control the voltage support our transition to renewable energy, and ultimately a zero-carbon network.

Our high-level approach to the NOA Voltage Pathfinder

Step 1

We’ll study voltage requirements across the National Electricity Transmission System (NETS) and identify specific needs. Then we’ll communicate these needs to the industry to inform potential service providers.

Step 2

We’ll engage with commercial providers and the relevant network operators to carry out any necessary technical studies.

Step 3

We’ll carry out a commercial assessment before awarding contracts to successful solutions providers.

Pennines Conclusion

NOA Pennines High Voltage Pathfinder results in multi-million-pound consumer savings to deliver engineering solutions needed for tomorrow’s greener grid. 

We have today, 7 February 2022, announced the results of the NOA Pennines High Voltage Pathfinder. As part of introducing greater competition onto the network, National Grid ESO’s second voltage pathfinder compares market-based solutions against transmission owner solutions.   

Dogger Bank Offshore Wind Farm Project 3 Projco Ltd’s converter station from its offshore wind farm and National Grid Electricity Transmission (NGET) will provide 700 MVAr reactive power capability in the Pennines regions between 2024 and 2034 following a competitive tender process.

Please see our results letter and results table for further information.

What was the requirement?

This High Voltage Pathfinder identified two areas where reactive power solutions would be needed in the years ahead. In the North East, the 200 MVAr requirement was driven by the closure of Hartlepool power station, while in West Yorkshire regions, the 500 MVAr requirement was driven by closure of power stations and changes to the electricity network.

How did we arrive at the outcome?

To deliver greatest value for the consumer and building upon the lessons learned from the first high voltage pathfinder in the Mersey region, we have compared commercial providers of reactive power to counterfactual solutions by NGET. 

National Grid ESO ran a two-stage pathfinder event with the support of the TO and DNOs (Northern Powergrid and Electricity North West). The first stage consisted of technical submissions where parties received feasibility assessments of their solutions to support their bids. Following commercial submissions, National Grid ESO conducted the economic assessment as outlined in our commercial assessment methodology.

What is the impact?

The successful solutions are worth £22.5m with estimated multi-million-pound savings for the end consumer. 

Julian Leslie, Head of Networks at National Grid ESO said: “These services take us another step closer to 100% zero carbon operation, showcasing Britain’s innovation in engineering and driving competition within the system, ultimately saving consumers millions of pounds.

“Reactive power capability is vital for managing voltage and being able to operate a zero-carbon system of the future so we’re excited to see that a wind farm’s onshore transmission asset will deliver reactive power for the first time in Britain.”


The below dates were key milestones in the tender process:

  • 26 March 2021: The technical tender phase 1 starts and lasts seven weeks.
  • 14 May 2021: Providers submit technical proposals.
  • 31 May 2021: The TO/DNO feasibility assessment starts, lasting three months.
  • 4 October 2021: The commercial tender phase 2 starts, lasting six weeks, that will include commercial and Q&A webinars.
  • 15 November 2021: Commercial submissions including programme capability review and contract declaration form received.
  • 17 January 2022: Pathfinder participants notified of outcome
  • 7 February 2022: Industry publication of results
  • 1 April 2024: Contract start date.

Please contact us at [email protected] for further queries.

Documentation can be found on the Transmission Constraint Management page page.


During the tender, we held technical and commercial webinars. Recordings are available below.

Technical webinar recording

Technical webinar slides

Commercial Q&A Webinar

Commercial webinar Q&A

Commercial webinar presentation

Mersey Conclusion

The NOA High Voltage Pathfinder – Mersey was looking for long term voltage support in the Mersey region.

Latest updates

This Pathfinder project has come to an end and lessons learned have been published. Here’s a look at how we got there.

Step 1: Publish findings (complete)

Findings from our work form part of a case study with the ENA, which looks at utilising distribution solutions.

Step 2: Launch RFI (complete)

Our first RFI for the Mersey region, and Slides and Q&A from our 1 May 2020 Q&A webinar (Q&A updated 22 May 2020).

Step 3: Launch tender (complete)

We launched a tender for long-term voltage support in Mersey, alongside a tender for near-term support. 

Step 4: Publish results (complete)

Results from the tender have been published and can be seen below.

Step 5: Publish lessons learned (complete)

We published lessons learned from the end to end process on 11 December 2020. We use these to inform future tender processes. They can also be found below.

Documents and materials

ST Mersey 20-21

ST Mersey 21-22

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