A method includes a power supply system receiving a first request for a first quantity of power for a first time period from a first unit. The system generates a first quote based on an available power generation capacity, environmental factors and a forecasted level of power consumption. The system transmits the first quote to the first unit. The system receives a second request for a second quantity of power for a second time period. The system generates a second quote based on the same factors as the first quote. The system transmits the second quote to the second unit. The value of the first quote and the value of the second quote are set to discourage demand in a first mode and to encourage demand in a second mode to maximize efficient operating levels of the power generation sources in both the first mode and the second mode.