Please note: We are no longer actively procuring this service. The information provided on this page is for existing providers of BM start up services. 

The BM start up service gives us on-the-day access to additional generation. Balancing Mechanism (BM) participants who expect to be unavailable within BM timescales of 89 minutes. 

This service is made up of two elements: 

  • BM start up 
  • Hot standby 

BM start up is the process of bringing the generating unit to a state where it is capable of synchronising with the system within BM timescales. 

Hot standby holds the generating unit in this state of readiness. The unit will then either remain in hot standby until the end of its capability, or be instructed to run via an offer in the BM. 

BM start up instructions are issued via the Electronic Dispatch Logging (EDL) system. The instruction will specify a hot standby target time. This is the time at which the unit must be ready to synchronise within BM timescales of 89 minutes. If we wish to terminate the start-up instruction prior to the hot standby target time, the instruction to cease will also be issued via EDL. 

Technical Requirements

BM start up providers must: 

  • Have the ability to prepare the generating unit towards a state of readiness, in order to enable synchronisation in response to an instruction within BM timescales of 89 minutes. Typically this may involve warming the unit in order to facilitate a quick synchronisation time. 
  • Be capable of terminating the start up process at any time, prior to reaching hot standby. 

Once in hot standby, providers must be able to maintain the unit in a state of readiness for an agreed period, to allow synchronisation to the system within 89 minutes. 

New Providers

The BM start up service is procured through generic contract terms but is a bilateral agreement between us and the generator containing the specific service parameters and service costs. 

A commitment to deliver the BM start up service is made via a bilateral agreement between us and a generator.

This agreement outlines the service parameters and costs. Each bilateral agreement is based on generic contract terms, which can be found below.

We contract for the BM start up service throughout the year.

BM start up providers are able to submit changes to their prices up to a maximum of once a week. Changes must be submitted by 12:00 on a Thursday to take effect from 00:00 on the following Sunday.

These prices are then assessed at both day-ahead timescales and closer to real time in order to determine which providers to instruct. In addition to economic considerations, the technical capabilities of the unit, such as the time taken to synchronise and minimum run time, are also considered by the Control Room when assessing which units to dispatch.

Existing Providers

 Getting paid 

There are two forms of payment for the BM start up service: 

  • BM start up payment (£/hour) – providers may submit up to three payment rates depending on the different lead times of a start-up instruction. These payments are designed to cover the costs associated with getting a unit ready for dispatch. 
  • Hot standby payment (£/h) – these payments are designed to cover the cost of sustaining a generating unit in a state of readiness. 

Providers are able to submit their own prices for both BM start up and hot standby. These prices can be updated up to a maximum of once a week. Submitted prices inform the economic assessment to determine which providers are dispatched. 


The number of instructions per provider is largely dependent on economics, with more economically efficient units being utilised ahead of more costly options. 

Other factors that may also be considered when instructing BM start up are system constraints and the unit’s technical capabilities, such as the time taken to synchronise and minimum run time. 

There were 336 instructions issued for BM start up in 2016. Find out more information about the units that were instructed to run on the System Operator Notification and Reporting (SONAR) system. 

Document library

Market information on the utilisation of BM start up contracts is available through SONAR (System Operator Notification and Reporting System). 

SONAR is a web based bulletin board for the provision of near to real time data on information and actions taken outside the BM with respect to system operation. 

Woman looking at phone with glowlines

Further enquiries

Get in touch with the right team within Balancing Services, who are on hand to answer any questions you may have.