Not sure if you're Eversource but I would think it's fairly standard, but YMMV:

https://www.eversource.com/content/nh/residential/account-billing/manage-bill/about-your-bill/understanding-my-bill/understanding-supply-and-delivery-charges

TL;DR and oversimplified:

1. The cost to bring it from the source / supply to your local system
2. The cost of maintaining your local supply system
3. Government fees (etc.)