The Balancing Mechanism – the flexibility market used by National Grid Electricity System Operator (ESO) to correct imbalances between supply and demand - saw a large influx of smaller participants over 2020, both in terms of the number and capacity of active units, analysis from Cornwall Insight has revealed. The greatest growth came from aggregated units, which more than doubled in number from 20 to 45 as their combined active capacity rose by more than 87 per cent to around 1.7GW.