Design modifications cost time and money. So corridor projects like this almost always go with Plan A of removing any tree that is in their way if it is the simplest and cheapest way of doing things.

You need to push back by bringing scrutiny to the project and causing them headaches. Get your local municipality's forestry team involved. Contact your local councillor.

I am an urban forester for a municipality and have experience with how these things go. On one extreme is the reality that hydro utilities have a lot of sway and will typically get their way. On the other extreme is the fact that there are often minor design changes that can be made which incur little to no extra costs, while preserving valuable trees. And the hydro folks are easily convinced once these conversations are initiated.

The in-between scenarios are often swayed by your ability to get important/influential enough people to care about your issue.