1. A method for optimizing the use of electric energy by a facility comprising a plurality of energy assets, the method comprising: (a) modeling, using a computer, the usage of electric energy by the facility, by creating a simulation model of the facility and calculating a customer baseline (“CBL”); (b) storing the model in the computer; (c) determining, using the computer, a plan for controlling the operation of at least one of the facility's energy assets to reduce the electricity provider's overall charge to the facility for electric energy, or to provide a revenue source to the facility, the determining being done on the basis of the model, and variations in the price of electric energy during a day; (d) generating, using the computer, control signals based on the plan from data derived from the computer; and (e) controlling, using the generated control signals, at least one of the facility's energy assets so that operation of the facility conforms to the plan.