Nothing in this act shall be taken to prohibit any public utility from itself profiting, to the extent permitted by the commission, from any economies, efficiencies or improvements which it may make, and from distributing by way of dividends or otherwise disposing of the profits to which it may be so entitled, and the commission is authorized to make or permit such arrangement or arrangements with any public utility as it may deem wise for the purpose of encouraging economies, efficiencies, or improvements and securing to the public utility making the same such portion, if any, of the profits thereof, as the commission may determine.