New Hampshire is simply a hard place to make electricity work. If you put power lines above ground, you expose them to trees, of which we have a ton, that blow over onto the power lines. If you put power lines below ground, you get even more problems. For one, not every area even has smooth enough ground to do this, and in the areas that do, you often have to deal with our higher water table which can flood the underground lines and ruin them over time, and when they break it takes like 10x as long to fix. In addition to that, underground power is too expensive and isn't cost effective for most areas, considering this is a rural state.

For both systems, you also have to realize that they're both more likely to be damaged by nature in this part of the country than really anywhere else. Utilities need to keep crews available for issues like this, but keeping too many line workers on hand would cost an insane amount of money just to bring power back a little quicker during a storm. That's why we often get crews coming up from as far south as Florida to work on our power when a storm comes through. It just takes a lot of time and a lot of people to fix the power once it breaks.

The nature that we enjoy so much here in New Hampshire is also the reason our infrastructure is more unreliable. It's not anybody's fault, just simply the environment we live in.

And below is me being pedantic:

It's not necessarily the grid that's the problem, the grid is doing what it's supposed to. It's the local distribution that is the problem, being streetside power lines.