If the Public Utilities Regulatory Authority finds that a public service company, as defined in § 16-1, plans to begin operation of a new electric generating facility having a capacity of one hundred megawatts or more and operation of the facility would increase the company’s revenue requirements by ten per cent or more if all costs associated with construction of the facility were to be included in determining the rates to be charged by the company when the facility becomes commercially operational, the authority shall include such costs as it deems appropriate in accordance with the provisions of this chapter, over a period (A) beginning on the date the facility begins commercial operation, and (B) having a duration of not less than three nor more than ten years, in approximately equal installments, in a manner which will provide optimal short-term and long-term benefits to customers of the company.