"Is it an easement? or is it a lease?"

Could be both.  They may want to rent a portion of the land for placement of equipment needed for the project.  Then they may want a temporary easement over or under the land to run wires.  With $100,000 involved the wording of the agreement is important.  Your client should want to make it look as much like an easement as possible.  Or he may want to be a conservative taxpayer and try to negotiate $4,000 a year so he doesn't get pushed into a higher bracket.  Of course if he sells the land, he loses the future payments.