As to your paragraph about the possible but illogical situation, wouldn't you expect that the power co. obtained similar easements on all the surrounding properties that might be affected?
To me the intriguing thing is the 40-year duration of the easement. Maybe there's case law to the effect that after that amount of time, any buyer of the affected property should know what he's buying, including the flicker, etc.
But as to the tax result, maybe I'm just connecting OP's facts with deducting a conservation easement, the latter requiring that the easement be perpetual. Maybe that's where the rental notion comes in. Anyone feel like looking up the legislative or rgulatory discussion as to why the consrvation easement has to be perpetual?
(5) Exclusively for conservation purposesFor purposes of this subsection—
(A) Conservation purpose must be protected
A contribution shall not be treated as exclusively for conservation purposes unless the conservation purpose is protected in perpetuity.
(2) Qualified real property interestFor purposes of this subsection, the term “qualified real property interest” means any of the following interests in real property:
(A) the entire interest of the donor other than a qualified mineral interest,
(B) a remainder interest, and
(C) a restriction (granted in perpetuity) on the use which may be made of the real property.
Or why this provision exists.
(3) Denial of deduction in case of certain contributions of partial interests in property
(A) In general
In the case of a contribution (not made by a transfer in trust) of an interest in property which consists of less than the taxpayer’s entire interest in such property, a deduction shall be allowed under this section only to the extent that the value of the interest contributed would be allowable as a deduction under this section if such interest had been transferred in trust. For purposes of this subparagraph, a contribution by a taxpayer of the right to use property shall be treated as a contribution of less than the taxpayer’s entire interest in such property.