IL HB2372

Defines "underground" or "undergrounding" as routing and constructing electric transmission lines and associated components below ground consistent with sound engineering and utility practices.

Requires public utilities to underground any electric transmission line of 138 kilowatts or greater constructed after the bill's effective date if located within 26,000 feet of an airport in a municipality with population between 70,000-80,000 in or contiguous to a county with over 1,000,000 inhabitants, or if located in 4 or more contiguous municipalities with population density of 1,000 per square mile or more.

Prohibits allocating undergrounding costs solely to the municipality or municipalities where the line is located; instead the Illinois Commerce Commission must allow utilities to recover all reasonable and prudent undergrounding costs from all retail customers throughout their service territory.

Requires utilities to record and defer undergrounding costs as a regulatory asset included in the total rate base and amortized over a period equal to the expected life of the transmission line, with costs collected system-wide from all ratepayers.

Takes effect immediately upon becoming law.