1. A method of managing energy usage in a building system, comprising: managing energy usage history data of a plurality of energy consumption devices in the building system, the energy usage history data comprising one or more energy usage peaks previously reached by the building system; monitoring current energy usage of the plurality of energy consumption devices in the building system; monitoring a plurality of global variables comprising a building temperature, a building humidity, a building CO 2 level, a weather forecast and a real-time energy price; forecasting whether or not a new energy usage peak is approaching based on the current energy usage and the energy usage history data; and automatically initiating a real-time control of each energy consumption device based on the plurality of global variables in response to a forecast that a new energy usage peak is approaching.