The Oklahoma State Legislature hereby determines that expenditures of funds for the purposes of the conservation of electricity or natural gas by public agencies is in the public interest. In furtherance of this public interest, municipally owned utilities or public trusts thereof or the Grand River Dam Authority may expend, with governing board approval, funds to assist consumers in the establishment of energy conservation activities if there is a defined and measurable conservation of energy. The expenditures may be made subsequent to achievement of measures outlined in an energy audit or an engineering audit of the consumer's operations.