The Federal Energy Regulatory Commission yesterday (June 27) began a move to improve the efficiency of the existing U.S. national electric transmission system, along with its earlier efforts to push grid expansion.
The commission approved an unusual “advanced notice of proposed rulemaking” seeking advice on how to use state-of-the-art weather forecasting to improve the operation of the various high-voltage transmission lines that characterize the grid. The aim is to reduce outages and increase grid capacity dynamically, as opposed to static line ratings.
In a fact sheet, FERC notes, “Transmission line ratings represent the maximum transfer capability of each transmission line and can change based on weather conditions.” Cool weather can increase transfer capability and hot weather can degrade it. FERC notes, “Solar conditions, including solar heating and cloud cover, and wind conditions, including wind speed and direction, affect transfer capability by heating or cooling transmission lines. Increased cloud cover and increased wind speeds across transmission lines can cool the lines and increase their transfer capability while still maintaining safe and reliable grid operations.”
The “advanced” NOPR is a bit of a departure from the commission’s usual practice of issuing a proposed notice before starting a rulemaking. The commission is seeking public comment so that it will be on firmer ground when it considers a conventional NOPR. According to a staff briefing, the commission is particularly interested in issues of how to implement dynamic line rating in transmission systems not governed by existing wholesale competitive electric markets, RTOs and ISOs.
The advanced notice is also evolutionary. In December 2021, FERC issued Order 881, requiring transmission line ratings to reflect ambient (static) air temperatures to improve operations. In February 2022, FERC published a “Notice of Inquiry” on dynamic line ratings. Comments on the advanced notice are due 90 days after the publication in the Federal Register and reply comments at 120 days.
The advanced notice outlines a “framework” of potential requirements for dynamic line ratings:
- “Solar conditions: Transmission providers would be required to reflect more detailed solar heating forecasts in all transmission lines’ ratings.
- “Wind conditions: Transmission providers would review their own transmission congestion patterns to identify any highly congested transmission lines located in windy areas.
- “Transmission providers would be required to reflect forecasts of wind speed and direction in their lines’ ratings.
- “The ANOPR also seeks comments on new methods to measure congestion for transmission line and related data reporting requirements.”
“Its a no-brainer if you can get more capacity out of existing lines.” — FERC Commissioner Mark Christie
FERC Chairman Willie Phillips, noting the earlier work to boost new transmission lines in Order 1920, said, “Today, we are looking to wring efficiencies out of the grid so we can make the best and most efficient use of what we already have.” Commissioner Mark Christie commented, “Its a no-brainer if you can get more capacity out of existing lines.”
Commissioner Allison Clements said that not moving to dynamic line rating would constitute “leaving significant benefits and savings on the table,” adding that there is a “need for good thoughtful comment.” It was Clements’ final, somewhat tearful, FERC meeting, as her 2020 appointment expires June 30.
It also marked the first meeting for Commissioner David Rosner, the first of three commissioners the Senate approved earlier in June, bring FERC back to a full complement of five commissioners. A FERC staffer on detail to the Senate Energy and Natural Resources Committee when nominated to a vacant FERC seat, Rosner was sworn in on June 17. He took no official actions at Thursday’s meeting. The other new commissioners, Judy Chang and Lindsey See, have yet to be sworn in.
–Kennedy Maize