It is hereby declared to be in the public interest that public utilities be regulated as hereinafter provided in order to provide the retail consumers of natural gas and electric service in this state with adequate and reliable services at reasonable rates, consistent with the financial and economic requirements of public utilities and their need to construct facilities to provide such services or to otherwise obtain energy supplies, to avoid unnecessary duplication of facilities which increase the cost of service to the consumer and to minimize disputes between public utilities which may result in inconvenience or diminish efficiency in service to the consumers. Because municipal utilities are presently effectively regulated by the residents of the municipalities which own and operate them, and cooperative electric associations are presently effectively regulated and controlled by the membership under the provisions of chapter 308A, it is deemed unnecessary to subject such utilities to regulation under this chapter except as specifically provided herein.