Provision and value of flexibility for reducing financial risks caused by prognosis uncertainties

Due to the European trend of rising penalty costs for causing imbalances, aggregators face higher financial risks when pooling many renewable energy systems in regions with frequent grid congestion. Intra-day deviations from prognosis-based day-ahead schedules can be crucial in case of premature or delayed feed-in reduction. To reduce this risk, the aggregator can contract flexible DER systems as part of their pool to use the flexibility when needed. This defines the flexibility use case risk reduction (UC-RR) considered in this paper. A corresponding flexibility information model (corridor model) is proposed. For a systematic analysis, the occurrence of imbalance risk is related to feed-in management forecast uncertainties due to unexpected early or late grid congestion. Risk-controlled corridor adaptivity is proposed as a strategy for aggregators to prepare the DER schedules within the flexibility constraints communicated via the corridor model, day-ahead. Simulations show that, in the intra-day case of unexpected imbalance events, the immediate response of the DER within the corridor will reduce imbalances and costs, thus showing the validity of the proposed strategy. Consequently, the corridor model is argued to be relevant for standardization in the IEC 61850-7-420 communication protocol.