Person checking phone while charging their Electric Vehicle

ESO to make change allowing up to 300MW of flexible assets into the Balancing Mechanism

As part of our ongoing commitment to remove barriers to participation for distributed flexibility, the ESO will soon be admitting up to 300MW of aggregated assets into the Balancing Mechanism (BM)

This will allow for greater consumer participation in flexibility, allowing capacity from small scale assets, such as EV chargers and electric heating systems, to be used to balance the electricity system in real time by our control room. 

To enable this development, we will be allowing this capped cohort of assets - each with an individual capacity of less than 1MW - into the BM as part of an aggregated unit with relaxed requirements for operational metering.

Opening up to flexible assets of this kind is vital in achieving our ambition of 100% zero carbon operation of the electricity network by 2035 and delivering the clean, green energy system of the future. 


Currently, the standard requires metering for assets in the BM to deliver readings every second with an accuracy of +/- 1%, which is a barrier to entry for many assets and providers. 

In a Power Responsive trial launched last June year we relaxed operational metering standards to allow small scale aggregated assets into the BM at a standard of 10-second readings and +/-2.5% accuracy. In December, we further evolved this small-scale trial to allow for a more relaxed metering standard, of +/-2.5% and 60-second metering reads.

Today’s announcement builds on this work, allowing a greater range of participation from different types of assets. In addition, we are also giving assurance that the 300MW we are opening up will be available to participants on an enduring basis meaning that industry can have confidence and plan ahead to participate in this opportunity. 

This decision will further expand access to this important and growing market while still maintaining the security of the system. 

These changes will be implemented with immediate effect. Providers who are interested in entering into this initiative are encouraged to reach out to the Power Responsive team at [email protected].

We are also in the process of commissioning an independent expert study to determine the exact change we should make to operational metering requirements for these kinds of assets to participate in the BM over the long term, while maintaining system security in a cost-effective manner for Great Britain. We will make further announcements to stakeholders on the scope and timeline of this study in due course.  


As set out in our Future Energy Scenarios, the energy market of the future must harness the vast potential of demand side flexibility to integrate renewables and ensure security of supply at least cost for all.  Market changes must facilitate flexible tariffs, support innovation and reduce barriers to participation for new market entrants from the industrial and commercial sector or in the form of aggregated residential demand.

Our flexibility market strategy, coming later this year, will highlight the opportunities for consumer flexibility across our markets and explore the potential for any further reforms that might be needed.