Would have to be something in either the lease for the building or the property deed describing what will happen to this arrangement should one party or the other sell out. Is there a legal way to include the contract in the deed or lease?
"In the event that either party sells out, the contractual agreement between parties shall remain in effect and be binding on the new owner."
Who can end the agreement? Either party just up and snips the wires from the generator??
Who pays the maintenance? And the fuel bill? Is the fuel an on-site tank, or a gas pipeline?