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.

Short term operating reserve (STOR)

At certain times of the day we may need access to sources of extra power to help manage actual demand on the system being greater than forecast or unforeseen generation unavailability.

12th April 2019 - The Invitation to Tender has been launched for TR38. Providers who have participated in previous STOR Tender Rounds via Ariba should shortly receive an automatically generated email to enable access to Tender Round 38 event using their existing Ariba account.

20th December 2018 - Following the publication of the STOR Outline Change proposals we are now publishing the Detailed Change Proposal.  Alongside the DCP we are publishing the Standard Contract Terms (issue #11)

We have published documents on the new PAS project that we are developing to provide a new dispatch system for Non-BM STOR. These can be found under the Technical Requirements tab under the PAS Documents heading.

Where it is economic to do so, we will procure sources of extra power ahead of time through the STOR service. Providers of the service help to meet the reserve requirement either by providing additional generation or demand reduction.

The requirement for STOR varies depending on time of year, week and day.

Providing STOR

Both Balancing Mechanism (BM) and non-BM participants with a connection to either the electricity transmission or distribution network are able to provide STOR.

The service is open to any technology with the ability to increase generation or reduce demand by at least 3 MW.

Current STOR providers are located throughout Britain, although providers closer to high demand areas, including south east England and Wales, are more desirable.

Service dispatch

There are particular times of the day when the STOR service is more likely to be required. These are known as ‘availability windows’.

Providers are required to be available to operate at their contracted volume during these windows.

Availability windows

Typically, the service is used over two pre-defined windows:

  • morning window; and
  • evening peak window.

STOR may be required outside of these times.

STOR dispatch

BM providers will be dispatched through the Balancing Mechanism, while non-BM participants will be instructed and metered through STOR Dispatch (SRD PC). 

The installation of STOR dispatch is undertaken by external parties and takes six months to complete.