The Enhanced Reactive Power Service (ERPS) is suitable for generators who can provide reactive power over and above the Grid Code and Obligatory Reactive Power Service (ORPS) requirements. On this page, you can find out about the route to market. 

ERPS provides a route to market for operators of a plant or apparatus that can generate or absorb reactive power but that aren’t required to provide the ORPS. 

ERPS can be provided alongside other balancing services. 

Any site that has plant or apparatus that can absorb or inject reactive power can provide ERPS. This could be from synchronised plant that provides ORPS and would like to provide a level of voltage support that is above the minimum requirements. 

It could also be provided by any other site that has the ability to generate or absorb reactive power. 

Technical Requirements

Where reactive power services are provided by a generator as a condition of their connection to the transmission system, the reactive capability must exceed the minimum technical requirement of ORPS. The ORPS requirements are set out in the Grid Code section CC 6.3.2. 

The service provision will need to be in line with the commercial services agreement awarded in the tender. 

Generators are generally instructed to provide a target megavar (MVAr) level which must be reached within two minutes. 

Instructions for reactive power are normally sent by us to the generator via an Electronic Dispatch Logging (EDL) system. 

Existing Providers


ERPS is procured via tenders. Generators can participate in these tenders, which are held every six months. You can find details of the latest tender round on the Market Information tab. 

Tenders are assessed using the evaluation criteria specified in the CUSC. This evaluation process considers the following: 

  • economics (i.e., the cost of market compared with default price); 
  • the intrinsic capability value of the tendered reactive service, against the alternative of our reactive assets; and 
  • a number of other criteria, such as how competitive the utilisation price was, and what incentive the generator was placing on itself to maintain the reactive capability. 

Tender outcome

  • If the generator is successful following tender assessment in accordance with the evaluation criteria specified in the Connection and Use of System Code (CUSC), then a market agreement is entered into. 
  • If a tender is not successful and the generator is required to provide ORPS then they will continue on default arrangements for the ORPS requirements. 
  • If a tender is not successful and the generator is not required to provide ORPS, then no payments will be made 

Getting paid

If the generator is successful following the tender assessment, then a market agreement is entered into.

The tender allows the generator to request:

  • an available capability price (£/MVar/hr) and/or a synchronised capability price (£/MVar/hr) and/or a utilisation price (£/MVarh); and
  • the choice of term with a minimum period of 12 months or greater,  in six-month increments (12, 18, 24, 30, 36 months, etc).
Document library

Enhanced Reactive Power Service Tender

The reactive market invitation to tender ('the ITT pack') for tender round 52 is now available. The closing date for receipt of tenders is 11 August 2023.