Stability Network Services

Seeking services from a range of providers and technologies

Stability service providers are vital to meeting system needs. We are looking for new and existing solutions to help us address stability issues on the electricity system.

We will invite potential providers, and where relevant, network owners, to submit proposals that can help resolve specific system needs. The needs set out will inform interested parties of the service that NESO is seeking to procure, and will be open to all forms of technologies that are eligible to participate based on communicated tender rules and requirements.

Following technical and economic assessment we will recommend solutions to move forward either via commercial contracts or regulated arrangements.

Supporting the transition to a carbon-free network

The decline in synchronous generation is leading to a decline in system stability. 

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

NOA Stability Pathfinder - Phase 3 updates

Phase 3 is focused on increasing inertia and short circuit level in England and Wales. Inertia is the mass of the system used to control frequency, while short circuit level is the amount of current that flows on the system during a fault.

As traditional coal and gas plants are phased out from Britain’s energy system, the transmission system inertia and short circuit levels are falling. Renewable generators like wind and solar connect to the grid in a different way, which doesn't provide the network the same stabilising properties. So, we need to find new providers to help support the system.

On 23 November 2022, ESO published the results of the Stability Phase 3 tender. The successful companies are now working on delivering solutions in line with their contracts. For more information, please see the results table below, or read our news article detailing how the contracts will deliver over £14 billion in savings. 

Phase 3 news

Pathfinder steps

Step 1 – Identify stability needs across Great Britain – January 2021 to September 2021 (Complete)

The System Operability Framework highlighted the operability risks expected due to the decline in transmission connected synchronous generation over the next decade.

Step 2 – Launch Pre-Tender Information, Launch Expression of Interest (EOI) Period – September 2021 to December 2021 (Complete)

ESO published draft documents for pre-tender consultation; including draft technical specification, draft contract terms, and a connection approach document. This allowed market participants to provide feedback prior to the tender launch. As a result of consultation feedback, tender documents and requirements were revised between the pre-tender consultation and the launch of the tender.

This stage triggered the opening of the window of time for market participants to express their interest in participating in the Stability Phase 3 tender event.

Step 3 – Launch Tender – December 2021 to June 2022 (Complete)

Market participants who expressed their interest of participating in the Stability Phase 3 tender during the EOI Period were invited to the Stability Phase 3 tender stage, where ESO assessed technical and commercial submissions alongside any solutions submitted by Network Operators.

Key tender dates include:

• Commercial webinar: 11 January 2022 (available to registered tender participants only)
• Technical webinar: 25 January 2022 (available to registered tender participants only)
• Final deadline for expressions of interest: 31 January 2022
• Tender submission deadline 6 June 2022 9:00am

As a result of continuous market engagement during the tender, ESO iterated the tender requirements based on feedback from the market. Market participants should ensure the most recent versions of tender documentation are referred to.

The tender window has now closed and submissions have been received. The ESO has started the tender assessment stage, which will be followed by the sanction and contract award stages later this year. The outcome of the tender will be released publicly after contract award.

Step 4 – Contract Award – November 2022 (Complete)

Market participants whose tenders are successful will be notified by NGESO, awarded contracts and can begin work developing their solutions.  

Documents and materials

Phase 2 is focused on increasing Short Circuit Level in Scotland. Short Circuit Level is the amount of current that flows on the system during a fault.

As traditional coal and gas plants are phased out from Britain’s energy system, the transmission system short circuit levels are falling. Renewable generators like wind and solar connect to the grid in a different way, which doesn’t give us the same stabilising properties. So we need to find new providers to help support the system.

6 April 2022 - We are pleased to announce the result of the Stability Pathfinder Phase 2 tender has been published. This can be found under the Tender Outcome heading in the Documents section below. Further information on the tender outcome can be found here.

If you have any queries relating to the tender outcome, please contact [email protected] 

Latest updates

The feasibility study stage has now concluded and the connections review work is ongoing. An updated timeline for the Phase 2 process has been published here.

Step 1: Identify stability needs across Great Britain (complete)

The System Operability Framework (SOF) highlighted the operability risks expected due to the decline in transmission connected synchronous generation over the next decade.

Step 2: Launch RFI (complete)

We launched a Request for Information (RFI) for Phase 2 in June 2020, seeking feedback on the process we’d proposed and any impacts of Covid-19.

Step 3: Launch EOI (complete)

The Expression of Interest (EOI) was an opportunity for any interested commercial and network owners to submit their solutions. The EOI window for Phase 2 closed in January 2021 and submissions have been reviewed. A summary of submissions can be found here.

Step 4: Launch feasibility study (complete)

Solutions which passed the EOI stage were subject to a feasibility study to ensure they meet the technical specifications. This included the submission of desktop-based power system simulations and manufacturer datasheets or specifications. A feasibility study summary can be found here.

Step 5: Launch connections review (complete)

Solutions without connection offers or agreements undertook the connections review process. This provided them indicative costs and timescales for new connections. The connections review scope document explains the scope of the work and associated limitations.

Step 6: Launch tender (complete)

Providers whose solutions have passed the feasibility study were invited to participate in the commercial assessment stage, where we assessed commercial solutions alongside those submitted by network owners.

Providers whose tenders were accepted were awarded contracts and can begin work on developing their solutions.

The results of the Phase 2 can be found under the Tender Outcome heading below.

Documents and materials

Phase 1 was looking for the most cost effective way to increase inertia (stored energy) across Great Britain.

Following a Request for Information (RFI) issued in July 2019, we’ve identified a number of providers who could deliver stability solutions quickly. As a result, we kicked off an accelerated tender process to procure inertia services across Great Britain.

Latest updates

Phase 1 of the NOA Stability Pathfinder concluded in January 2020 and 12 contracts were awarded to five providers. Here’s how we got there.

Step 1: Identified stability needs across Great Britain

The System Operability Framework (SOF) highlighted the operability risks expected due to the decline in transmission connected synchronous generation over the next decade.

Step 2: Launched RFI

We launched our RFI for stability in July 2019  and identified interest from the industry in providing a service.

Step 3: Launched tender

We invited providers to tender for GB-wide inertia solutions for delivery from April 2020.

Step 4: Published results

We have published the tender results for Phase 1.

Documents and materials