Notice 2021-5, page 479.

Beginning of Construction for Sections 45 and 48; Extension of Continuity Safe Harbor for Offshore Projects and Federal Land Projects. The notice extends the Continuity Safe Harbor applicable to the production tax credit for renewable energy facilities under section 45 and the investment tax credit for energy property under section 48 for Offshore and Federal

Land Projects. Specifically, the notice provides that if a qualified facility or an energy property construction project is an Offshore or Federal Land Project, the Continuity Safe Harbor is satisfied if a taxpayer places the qualified facility or energy property that is the subject of the project into service by the end of a calendar year that is no more than 10 calendar years after the calendar year during which construction of the project began.