Computation of strict long-run marginal cost for different HV consumers

•The strict long-run marginal cost is computed using the perturbation approach.•Sensitivity analysis considering an increasing demand increment for each HV consumer.•The main driver of LRMC is the change in operating cost.•LRMC is slightly lower for the off-peak consumer than for the peak-load consumer.•The magnitude of the consumer's load does not differentiate much of the computed LRMC.