Managing Flexibility Whilst Decarbonising the GB Electricity System

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Integrating wind into the grid


The amount of intermittent generation connected to the grid is expected to increase significantly over the next couple of decades. This, alongside significant changes to the generation portfolio, is likely to have significant impact on the role and operation of all generation plant. There is likely to be an increased demand for ancillary services such as reserve, response and inertia whilst traditional providers retire from the market place. The project examined the entire market for ancillary services including the need to maintain firm capacity to provide security.

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The project undertook some modelling and analysis of the GB electricity system in the light of the carbon targets set by the Committee on Climate Change. Firstly a brief examination was made of the German and Irish markets with the hope of learning from their advanced penetration of variable renewables. Secondly a new model, BERIC, was written to simultaneously balance the need for energy, reserve, inertia and firm capacity on the system and its findings compared with simpler stacking against the load duration curve. The intention was to assess the need for flexibility on the system but some broader conclusions also emerged:


A system with weather dependent renewables needs companion low carbon technologies to provide firm capacity. This firm capacity could be supplied by a number of technologies such as nuclear, biomass or fossil CCS.

Policy makers and system operators need to value services that ensure grid stability so new providers feel a market pull. Currently some necessary services are provided free or as a mandatory service. However traditional providers (fossil plant) are disappearing at the same time that demand is growing. New providers can’t develop in the absence of a market signal.

A holistic approach to system cost would better recognise the importance of firm low carbon technologies and the cost of balancing the system. The value to the system of a technology is dependent on the existing generation mix and the services which that technology can provide. This means that a technology cannot be characterised by a single number such as levelised cost of energy.


A much deeper examination of the issues raised here is needed but must employ a whole systems approach.

New zero carbon firm capacity is essential to decarbonisation but leading technologies such as nuclear and CCS require long lead times so meeting 2030 targets requires action today.

DECC and National Grid should consider how new providers of ancillary services can be given the financial comfort needed to underpin their development and deployment before traditional providers disappear.

This work supports some key recommendations from the European Commission’s Smart Grid Task Force, in particular:

  • Equal access to electricity markets for all providers
  • Contractual simplicity and transparency
  • Standardised measurement of flexibility
  • Incentives to grid operators to enable flexibility for meeting 2030 targets rather than focussing on short-term optimisation
  • Improved price signals for providers of flexibility

Follow-up activities

A workshop was held in November to test these initial conclusions. Further work and modifications to the modelling will take place in response to that. Talks have also been given to the 14th Annual APGTF Workshop, the Gas to Power UK Forum 2014 and the IChemE workshop at the Grantham Institute for Climate Change.

Working Group

Project Chair:

Peter Emery – Drax

Steering Group:

  • Phil Lawton – National Grid
  • Nick Bevan – DECC
  • Nick Eraut – ETI
  • Ed Sherman – BIS
  • Alexandra Malone – SSE

Steering group advisor

  • Dame Sue Ion – RAEng

Further Information

Please contact Andy Boston or Helen Thomas from the ERP Analysis Team.

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