National Grid ESO has announced it will soon make changes to allow 300MW of flexible assets to be introduced to the Balancing Mechanism (BM).
This move aims to create greater consumer participation in flexibility, meaning the capacity from small-scale assets like electric vehicle (EV) chargers and electric heating systems can be used to balance the electricity system’s demand.
The firm says it will permit a capped cohort of assets into the BM as part of an aggregated unit, each with an individual capacity of no more than 1MW.
The key change being made by ESO will be relaxing the programme’s requirements for operational metering. Currently, the standard requires metering for assets in the BM to deliver readings every second with an accuracy of +/-1%, which has proven to be an obstacle for many providers.
As part of the company’s Power Responsive trial launch in June 2023, the operational metering standards were relaxed to deliver readings every 10 seconds with a +/-2.5% accuracy.
Then, in December 2023, the metering standards were extended further to include 60-second meter readings with a +/-2.5% accuracy.
The new system gave ESO control room engineers pre-selected lists of units to choose from in order to meet a network requirement. With the aim of reducing the number of manual instructions required from the control room, the company reduced the time taken to instruct balancing mechanism units.
The network provider has also confirmed that it is in the process of commissioning an independent expert study to determine the exact change to be made in order to allow as many flexible assets as possible while remaining secure and cost-effective.
ESO’s flexibility strategy is said to be released later this year (2024) and will aim to provide a clear outline of the opportunities for consumer flexibility across its markets.
To balance or not to balance
As a result of entering into the flexibility demand service space, National Grid ESO has been able to partner with different EV schemes to utilise chargers as access points to the grid. In September 2023, for example, the firm launched a new trial via its Power Responsive programme.
The trial allowed households with smart EV charging capability to adapt their charging habits in response to instructions sent from the ESO, meaning when the grid is strained during peak energy usage periods, the EV drivers are suggested to refrain from charging their vehicles until periods of lessened demand.
The network provider then took the next step by partnering with Octopus Energy to take part in a Vehicle-to-Grid (V2G) trial, also part of the Power Responsive mechanism.
Customers on the company’s ‘Intelligent Octopus’ tariff were able to use their EVs to balance the grid while charging and, when necessary, could send power back to the grid from their vehicles.
However, the ESO’s programme has come under criticism more than once. The first instance followed the firm’s Power Responsive trial launch in June 2023.
The Electricity Storage Network (ESN) wrote an open letter to ESO highlighting an average skip rate of 80% for batteries between November 2022 and May 2023. The letter stated that investment decisions on UK storage projects “depend on efficient dispatch of electricity storage assets in the BM as a crucial segment of the revenue stack”.
Later that year, in September 2023, Ofgem introduced new rules called the Inflexible Offers Licencing Condition (IOLC). to prevent electricity generators from “artificially inflating energy prices and forcing up household bills” and targeted the ESO specifically.
IOLC, which came into force on 26 October 2023, bans the practice of stopping electricity generators from generating in the early afternoon, meaning they would be switched off for the evening peak in demand.