Years ago, I worked for a small regional public utility (water) and we had lots of easements obtained over the 100 years of operation. A lot of them were on rural land originally that in the intervening years have become potentially quite valuable due to the location. It was located in the State of Maine and be aware the laws in every state may be different. As they were a public utility, they had eminent domain rights. All they had to do was fill out a form, file it with the registry of deeds and the utility had an easement. Sounds simple but the aggrieved owner had the right to go to court to contest the value they deserved for the taking of the easement and generally the court will allow expansion of contesting the need for the easement to begin with. This can delay things for a very long time, so the utility generally makes a voluntary attempt to buy the easement versus taking it. In many cases, the owners didn't have a great use for the land and rather than have an impacted property with an easement on the land they would sell an entire parcel, much larger than needed for the utility's needs. These parcels would remain on the books "forever" as a public utility is a non profit and there really was no incentive to sell surplus parcels. For the summers I worked for them in the "engineering department" that held the easement records, people were coming in all the time asking about buying unused or surplus land or getting an easement removed. The policy was and had been for as long as any long term employees remember was no. There were some right of ways that had been bought in the 1940s for a future pipeline not yet built 80 years later but they actively checked the right of way on a routine basis and I remember several times where the utility started legal action to have structures moved that were built on the right of way. Be aware that squatter rights (AKA prescriptive rights, or adverse possession) do not apply to government lands like the utility I worked for. But they amy apply to private corporation. Dependent on your states laws you may be able to use squatters rights but be aware you could be facing major legal bills and the rights may not extend to future owners.
Eminent Doman takings are involuntary, and they typically are the just a strip with rights, in most cases they do not own the land underneath only rights to do, build or access something. Rarely will a utility ever release a strip taken by eminent domain as the heirs of the original owner could reappear and try to take control over the easement unless compensated. If it was a voluntary easement, it could be sold but generally the policy is to not do so unless is of benefit to the company. One other thing to consider is that the easement across the lot may be the key to tens if not hundreds of miles of easement so releasing that one strip could make the entire route worthless and some of the rest of the route may have been taken under eminent domain. Far easier to not mess with it.
Note, if the utilities feel that releasing easements are of value to them, they can change policy and make special exceptions. That is what I saw with the utility I worked for and have seen it done with others. Usually, its a potentially high positive publicity project like donating a piece of no longer used land to a public or nonprofit entity usually with retained rights. The utility I worked for had one large central water source but over the years they had acquired several ponds that formerly had been used as reservoirs. These were fenced in wild ponds that may not have had any human presence for 100 years and as the years went by the area around them was developed. In the two cases I was aware of, one set of ponds was donated to the Boys and Girls clubs for a youth camp and the other donated to a municipality as a park. No money got passed. During a recent very controversial project the regional power utility was trying to build a large merchant transmission line in the state. The state had passed legislation from allowing the firm to take land by eminent domain so the utility had to buy land privately. In some cases they paid 10 times the street value. The project was eventually not approved and about 2 years later, the utility with minimal publicity handed some of the land to the original owners for zero cost and some of the land was given to a LLC whose owners are yet to be identified. The ratepayers ended up eating all the cost for buying the land but at least it was released back into private hands.
On rare occasions usually with corporate mergers a new company may elect to abandon unused easements but that is pretty rare. I have a piece of property originally owned by New England Telephone adjacent to mine that is too small to build on. NET was paying taxes on it. NET ended up selling out to a succession of owners and at one point one of the owners transferred it to my local town for zero dollars just to get it off the books. That is your one potential, if it the utility is paying taxes on a right of way, they might elect to transfer it just to get it off the books but that would usually be for multiple properties and not by an individual request.
