New Hampshire
Electric:

New Hampshire customers received the ability to choose their electric provider in 1997, part of an industry reform movement designed to give customers a chance to save money on their electric bills.

New Hampshire utilities sold most of their power plants to open the market to competition, though Public Service of New Hampshire (PSNH) still owns some generation. Utilities still own the transmission and distribution wires, while also providing "backstop" power to customers who do not shop for electricity. With the move to competition, the utilities have separated service into two parts:

Regulated distribution of power, which is still only provided by the utilities, and Supply of the electric commodity, which is open to competition.
Customers can choose to receive their electricity supply from their utility, or an alternate energy provider.  Customers who do not choose an alternate energy provider receive default service from the utility. Utilities buy default service supplies throughout the year on the wholesale market, with PSNH using its own generation for some of the supplies. For most customers, default service rates change every six months.

However, for large business customers at Granite State Electric, default service rates change monthly. To avoid these volatile monthly prices, large businesses can contract for a fixed price with an alternative electric provider.

Customers who choose an alternate energy provider still have their power delivered to them by their utility, and contact their utility for all outage reporting. Customers can choose to receive either a single bill from their utility for their delivery service and energy supply service, or can receive two bills, one from each company.