Octopus Energy has revealed around 1.5 million of its customers participated in the Electricity System Operator’s Demand Flexibility Service (DFS) over the last winter. This was more than double the 700,000 customers which took part the previous winter when the service was introduced as one of several contingency measures to ensure the security of electricity supplies. Speaking to Utility Week, Kieron Stopforth, head of flexibility at Octopus, gives his views on the service and how it can be improved.