Eversource doesn’t make any power, they just deliver it. Hence the fee.

What Are Delivery Charges? Electricity delivery charges are the fees that you must pay the utility company for servicing and delivering power to you. The energy grid is managed by a utility company, which is also known as the Transmission and Distribution Utility (TDU) or Transportation Distribution Service Provider (TDSP). This company services and maintains all the equipment that facilitates electricity distribution from the generation source to the commercial or residential customers. Electricity delivery charges are also known as demand charges, pole, and wires charges, or transmission charges, and they are billed by the TDSP. The demand charges are made up of distribution, transmission, and transition charges. These fees are associated with the peak or maximum electricity demand on your electric meter. Put another way, delivery charges are determined by the highest volume of electricity you may require at any given point in time. This differentiates demand charges from what you pay for actual consumption. It’s very helpful to understand the difference between electricity demand and consumption. Demand is measured moment by moment in kilowatts, whereas consumption is about how much electricity you use in a given timespan measured in kilowatt-hours. For example, imagine a situation where the electricity demand in a certain area experiences a sudden surge. The utility company has to respond quickly to meet this peak demand, which will drive up the costs of distribution, transmission, and transition. Included in the total delivery charges, there are also some fixed components such as metering charges.