High-Capacity Grid Act

This bill requires public utilities to use the most efficient and high-capacity power line conductors available when building new transmission lines or making major upgrades to existing lines under federal jurisdiction. It creates a legal presumption that costs for these "best-available" conductors will be approved in rate cases, while costs for less efficient conductors will likely be denied. The rule applies only to projects overseen by the Federal Energy Regulatory Commission (FERC). FERC must issue specific rules within 180 days to define what qualifies as a "best-available" conductor based on capacity, efficiency, and thermal performance.