This use case describes how dynamic rating of transmission lines and transformers can improve SCE’s ability to optimize the power throughput of its transmission assets. Transmission lines are limited in their ability to transmit power by resistive heating. Increasing a line’s loading will increase the conductor temperature, causing the line to sag through thermal expansion. Line sag can result in a violation of California Public Utility Commission clearance requirements, and in some cases it may cause permanent damage to the line. Heat also limits the operation of transformers. To protect these assets and comply with clearance requirements, utilities have historically relied upon static ratings to limit the throughput of these assets. In general, static ratings are designed conservatively to allow the asset to operate under most severe weather conditions (e.g. a hot summer day with no wind). This means that static ratings usually constrain these assets to operate beneath levels at which they can operate safely and reliably. Dynamic ratings take into account real-time weather conditions, in addition to other asset and system conditions, allowing transmission assets to increase power throughput without compromising safety or reliability. The business value of dynamic ratings includes improved system reliability, reduced costs, and increased renewables.