Dynamic Line Rating and Residual Congestion: Implications for Storage Sizing and Availability

Dynamic Line Rating (DLR) can recover transfer capacity on wind dominated corridors because high wind generation often coincides with stronger conductor cooling. This paper examines a 380 kV Schleswig-Holstein export corridor and compares five operating cases: a static baseline, conservative DLR, two DLR paired battery energy storage system (BESS) configurations sized to the 95th and 99.5th percentile of residual overload, and a standalone BESS without DLR. A full year deterministic simulation using IEEE 738-2012 thermal modelling and ERA5 weather data shows that conservative DLR alone reduces annual curtailment by 95.8%, from 87,177 to 3,689 MWh, with payback below one year. Adding a small DLR paired BESS at the 95th percentile sizing point (21 MW/70 MWh) increases the total curtailment reduction to 97.7%, while the 99.5th percentile variant (22 MW/72 MWh) yields almost no further benefit. A standalone BESS sized to the same percentile rule (173 MW/254 MWh) achieves only 26.2% reduction because its rated discharge window is too short for the multi hour and multi day winter congestion that dominates this corridor. DLR therefore does more than lift the transfer limit. It also changes the shape of the remaining congestion, which sharply reduces the storage size needed for residual relief.