When FERC issues a preliminary permit, it specifically acknowledges that the permit "confers no authority on the permittee to undertake construction of the proposed project or any part thereof, or to occupy or use lands or other property of the United States or of any other entity or individual." For more on preliminary permits, please see our Hydro Guide [1].
For the Metro Project (P-12484) in Ohio, a dispute arose over whether the project proponent should be permitted to conduct studies on county park lands, managed by Summit County's Metro Parks. When Metro Parks refused, the Metro Hydroelectric Company took them to court. The Company argued that the federal permit leads to federal legal jurisdiction.
The federal Sixth Circuit Court of Appeals ruled that a FERC preliminary permit does not give the permit holder the right to trespass onto property that it does not own in order to perform feasibility studies. If there's a property right dispute during the study phase of a FERC (original) licensing, the place to hear that dispute is in state court. The mere existence of a FERC proceeding doesn't make the issue ripe for a federal court.
See attached May 25th decision.