 The three distribution utilities are Unitil Energy Systems, Inc., Fitchburg Gas and Electric Light Company and Northern Utilities, Inc.The cold weather made more and more people switch to the service of Unitil, which resulted in a gas sale increase, so the company has planned to invest $570 million to expand its distribution infrastructure to serve a larger number of customers.In winter 2014, the company has asked for a price increase to part of its customers in Greater Portland and the Lewiston-Auburn because of the high demand and harsh weather.