Posted: 4 October 2016

Faster and smarter: Enhanced Frequency Response

Enhanced, Frequency, Response, EFR, balancing, grid, services, battery, storage, providers, contracts, capacity, costs, generation, demand, energy, electricity, technology, market, availability, tender

We need to find new and better ways to balance the grid in the most efficient way possible.


Enhanced Frequency Response (EFR) is a new initiative that will help to control system frequency on Britain’s electricity grid faster than ever before. As well as saving an estimated £200 million in costs, its introduction will see battery storage used for the first time at grid scale for balancing services. Leon Walker from National Grid’s Commercial Electricity team explores why EFR is an exciting step forward for our energy system.

To manage energy supply and demand effectively, National Grid must maintain system frequency at 50Hz within very tight parameters. Even relatively small deviations from this figure could potentially affect network stability and our ability to keeping energy flowing to where it’s needed.


Leon Walker, Commercial Electricity Team, National Grid.

While we already have a number of tools in place that help us control frequency, part of our remit as the System Operator is to seek out innovative new technologies that could play a role in the way we balance the grid in future. This is where Enhanced Frequency Response (EFR) comes in.

Existing controls

We currently control system volatility either by using Mandatory Frequency Response, which is an automatic change to active power output when required, or through Commercial Frequency Response services, where contracted providers increase or decrease either their generation or demand as needed in response to frequency variations.

Until now our response has been delivered in under 10 seconds, though it is getting harder to control the system due to the changing energy landscape. The development of a new tranche of technology means that EFR is capable of delivering a sub-second response, so it’s pretty much instantaneous.

The speed of response is critical. Not only does it bring an extra dimension to the way we control frequency, it also means that we can offset the amount of the Frequency Response services that we need to use and therefore reduce overall costs. We estimate that the introduction of EFR will save around £200m over the four years of the EFR programme, which in turn means lower costs to the end consumer.

The route to market for EFR

In September 2015 National Grid called for expressions of interest ahead of a formal tender process, working with the energy industry to identify potential partners who could support the introduction of EFR. This is a new area for all parties and so we set a limit on the capacity we wanted to procure of around 200MW, which should cover a period of four years. The four-year contract gives providers a level of certainty needed to be able to invest in new assets.

The response to this tender was phenomenal, with over 1,200MW of service offers proposed via 64 project submissions. Although there was no barrier in terms of which technology could be offered, it was interesting that a large proportion of the submissions came from the battery storage sector.

Within the tender process we received formal bids from 37 suppliers, and eight were selected to be contracted.

We limited the maximum capacity that could be awarded to a single applicant to 50MW, so that the services were not concentrated with just one or two providers. The eight contracts were awarded to Low Carbon with two schemes (40MW and 10MW), EDF Energy Renewables (49MW), RES (35MW), Element Power (25MW), Vattenfall (22MW), E.ON UK (10MW) and Belectric (10MW), delivering a total capacity of 201MW.

Once each project is operational, the providers will receive availability payments per hour based on increasing or reducing output as and when frequency deviations occur. Now that the contract award has taken place, the assets themselves need to be built – a process that will continue through 2017 and into the first half of 2018.

Power Responsive in action

It’s a really exciting time for many of us who’ve been involved in developing the EFR opportunity. The work goes to the heart of what National Grid is working to achieve through the Power Responsive programme. Power Responsive aims to help Britain maximise the benefit of demand side response (DSR) and thus achieve a secure, sustainable and affordable electricity system.powerresponsivelockup_lbg_cmyk-copy_300x93

We need to find new and better ways to balance the grid in the most efficient way possible. Power Responsive brings together many different stakeholders, all committed to helping Britain use its energy more intelligently.

EFR is a big step in the right direction. By creating a route to market for technologies such as storage we are increasing the potential for greater volumes of DSR to be used. Indeed, the 201MW of capacity equates to around 8% of existing DSR already in place in Great Britain.

We are very much at the start of the journey with EFR, but this is a technology that will play an important role in shaping the way we use energy in the future.


Related links:

Read Charlotte Grant’s blog about the SMART Frequency Control story so far.

James Brand, Managing Director of United Cast Bar, a leading foundry based in Chesterfield, explains why he is a firm fan of Firm Frequency Response (FFR).

Looking ahead to FES 2018
“EFR is capable of delivering a sub-second response, so it’s pretty much instantaneous”

Leon Walker, Commercial Electricity Team, National Grid.