DE SB59

Changes the standard for evaluating public utility costs from the "business judgment rule" to the "prudence" standard, requiring utilities to prove that costs and expenses were prudently incurred before including them in rate calculations

Gives the Delaware Public Service Commission authority to deny recovery of imprudently incurred costs, in whole or in part, and to adjust rate base, operating expenses, or fuel costs accordingly

Requires the Commission to consider the "objective reasonableness" of costs based on what the utility knew or reasonably should have known at the time expenses were incurred

Aligns Delaware with 48 other states that already use the prudence standard for utility rate-setting, rather than the more permissive business judgment rule

Takes effect on January 1, 2026