A few years ago NH deregulated their electricity suppliers. Several companies have sprung up in the last two years that will sell you the electric killawatt charge of your bill at a discount to the local distributor PSNH. They are doing this by buying electricity on the market from natural gas power plants that can produce it cheaper than PSNH’s coal, wood biomass,etc. plants. They originally started selling to commercial users. About a year ago they started advertising to homeowners(like me). I signed a contract for two years with a company called Resident Power.
It saves me about $15-20/ month from what I was paying PSNH.
Low Natural Gas prices gave some options including a plan that tied the electrical generation charge to the spot price of Natural Gas in the area.
During some peak consumption times, spot prices of Gas and Energy spiked. Fly by night companies that did not own generation but was buying power on a futures exchange and then couldn't cover the spike of price and high demand folded leaving customers without a contract and paying spot prices or exceeding high prices due to the timing of entering the market for a new contract.
caveat emptor
Know who you are doing business with and read the whole contract. Even then, some companies depend on bankruptcy protection as their risk management plan.