Data storage is cheap and most power lines aren't going anywhere - they are thin enough that one could approximate them as points where the towers are and line segments between the points; for multiple parallel lines, use the middle and set a width value. Add in a GPS receiver and one could have an avoidance system for the electrical wires; also guy wires and radio/tv/water towers as well.
It's not typical that the locations of these wires or towers changes rapidly, but I would expect a subscription service could pay for keeping the map updated. This would work whether the lines were energized or not, lighted or not.
There appear to be about 700k miles of main transmission line, estimate roughly 10 towers per mile, that's 7 million points/line segments. say 24 bytes for lat, long, alt, and 4 for width - that's 200 MBytes and covers within a couple of meters for the entire continental US. Make that 10 times that for secondary lines and guy wires, et al, and it's 2 GBytes.
A 128GByte USB stick is $14, so there's room for other features/higher definition at that price.
Other sources say only 200K miles main but 5.5M miles secondary, which is lower than my estimate. So it's doable by a wide margin.