Notice 2019-43 updates and clarifies timeframes when an energy property must be in service, which is the end of a calendar year no more than four years after the calendar year which construction began. Specifically, the notice provides that the Community Safe Harbor may be tolled and extended in certain limited circumstances involving significant national security concerns. The tolling would start if construction has begun, the parties have received government permits or approvals, the DOD provides written notice of significant concerns to national security and modification would be in the best interest, the parties pursue modification of the plan, and it requires new permits or licenses. The tolling goes from the date the DOD provides written notice and lasts until the parties obtain new permits or licenses, find they will not be issued, or the plan will not be pursued. An example of one such concern is the route for a proposed transmission line which runs adjacent to a DOD facility. The DOD states that since the plan raises significant concerns related to national security, a proposed alternative route for the transmission line would be in the best interests of national security objectives.