Flexibility baselining in the UK - an assessment of historic methods

Delivery of Distribution System Operator (DSO) Flexibility Services is being explored in the UK. A baseline is needed to determine the flexibility an asset has delivered. Methods for calculating baselines using recent historic data are commonly adopted, but there are few studies examining how these methods perform. This paper analyses the performance of historic methods used in the UK. In many cases, the error in the baseline estimate is typically small, centred around zero without significant bias. However, this is not consistent for each asset type and large errors are possible. No method performs best in all cases, and therefore careful consideration should be given when deciding with method should be applied for different asset types, service types, and event times.