Transmission Impossible: adopting dynamic line ratings in the West

Isabella Meyn ‘23
Hometown: Lake Oswego, OR via Rio de Janeiro, Brazil
Major: Public Policy
Intern, Western Interstate Energy Board

While my project this summer primarily involves the transmission industry, the ultimate goal of the research I’m doing has the interests of the people and lands of the American west at its forefront. Dynamic line rating (DLR) technology is simple in its philosophy: maximize load without compromising safety. The amount of current that can pass through a transmission line--its ampacity--hinges on various factors, including the actual physical specifications of the line. But that current-carrying capacity is deeply influenced by ambient conditions, such as temperature, wind speed, and solar irradiation. The colder, windier, and cloudier, the more electricity a transmission line can transport. A line rating essentially reflects its ampacity and tells a transmission operator how much flow the line can safely handle. As it stands, most transmission owners in the West use static line ratings that don’t take into consideration the impacts of changing weather on ampacity, with some setting one rating per season based on average conditions. Dynamic line ratings calculate a line’s ampacity in real-time, accounting for even the slightest fluctuations in climate, and can thus accurately reflect the current state of the transmission line. 

The implications of DLR use in the West are numerous. Decisions on how much electricity is transported, and invariably how much it’s sold for, are made in part based on line ratings. The more accurately we can capture the actual transmission capacity of a line, the more efficiently and reliably we can transport electricity in the West. Inefficient electricity transmission has disastrous consequences, among them reliability issues--overloading a line can result in wildfires--and congestion from imbalanced demand and supply. While the former poses serious threats to the land in the West, the latter can result in distorted electricity prices for the residents of the West. Dynamic line ratings could help mitigate these contingencies. 

The problem is convincing utilities to implement them in the face of insufficient incentives or regulatory pressure. Understanding how we may go about pushing implementation of DLR in the Western Interconnection allows me to directly be of service to the West. Providing my research findings and conclusions to the Western Interstate Energy Board and energy regulators in the West extends that service past my fellowship and into policy. From writing reports, meeting with mentors frequently, and conducting interviews with transmission experts, I’ve extensively developed my investigative skills this summer. As a public policy major, the knowledge I’ve gained on the ins-and-outs of electricity transmission will be an invaluable tool in my academics.

Read more at the Out West Student Blog »