Any power or powers exercised or capable of exercise by a city with respect to its electric utility system, or any project, or by a municipal power agency, may be exercised jointly with any other public agency having such power or powers. In furtherance of joint exercise of powers, a city or municipal power agency may enter into an agreement with one or more public agencies for joint or cooperative action pursuant to this section, including the creation of a separate entity to carry out the purpose of the agreement. Appropriate action, by resolution or otherwise pursuant to law of the governing bodies of the cities, municipal power agencies, or other public agencies involved in authorizing or approving the agreement, shall be necessary before any agreement may become effective. Any agreement shall specify its duration, the precise organization, composition, and nature of any separate legal or administrative entity created, together with the powers delegated, its purpose or purposes, the manner of financing the joint or cooperative undertaking, the permissible method or methods to be employed in accomplishing the termination of the agreement and for disposing of property upon termination, and any other matters deemed necessary or appropriate. In addition, the agreement may provide for the joint or cooperative undertaking through the use of a separate legal entity already in existence. No agreement pursuant to this section shall relieve any city or municipal power agency of any obligation or responsibility imposed upon it by law except to the extent of actual and timely performance of the agreement by another party to the agreement or by a legal or administrative entity created by the agreement, which performance may be offered in satisfaction of the obligation or responsibility. Agreements pursuant to this section shall not be subject to any of the provisions, limitations, or restrictions contained in chapter 54-40.