Although typically, electricity customers are charged based merely on the total number of kilowatt-hours they consume, some utilities have payment plans designed to encourage customers to shift their energy use to off-peak times. Suppose that a utility charges most customers a flat 7.9 cents/kWh under their standard plan, but under a special time-of-use plan, it charges 3 cents/kWh for off-peak times (between 10 p. m. and 11 a. m. on weekdays) and 16 cents/kWh at other times. If a customer always consumes electricity at the same rate, which plan should he or she sign up for? (Text Problem Number 12)

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?