Washington, D.C. — Increased transmission capacity is critical to improving grid reliability. Incremental interregional transmission enables higher generation diversity and access in the face of uncertainties like fuel or generation loss, transmission outages, and extreme weather events.
Such benefits were powerfully evident during Winter Storm Uri. While MISO and SPP experienced a “handful of short duration” outages, ERCOT’s capacity outages averaged 34,000 MW for two consecutive days. More than 4.5 million people lost power, some for up to four days, while temperatures were below freezing. ERCOT has just two DC transmission tie lines to the Eastern Interconnection and imported only 800 MW of power throughout the week. MISO’s imports, meanwhile, peaked at 13,000 MW.
ACEG recommends steps FERC should take to improve interregional transmission capacity and planning. ACEG also encourages action at the state commission level, particularly those in states that cross or border more than one region.