Eversource buys generated power and resells it to you. A few years ago Connecticut passed a law that allowed consumers to select their own power generation and pay that rate, instead of being stuck with whatever Eversource picks. The power generation company will tell Eversource that you are buying from them instead and then charge Eversource for the power -- which you see on your bill as the generation charge. It doesn't actually matter where the power comes from. Power generation companies just pump the power into the grid and then power distributors use it and pay them as needed.