A forward-looking method and system is provided for determining an economically optimal energy dispatching schema to meet the combined demands of heating, cooling and electrical by an energy plant and a facilities plant. The optimal energy dispatching schema is determined for each of a plurality of incremental time segments defined in a forward-looking time period by optimizing these loads. The schema can be used for real time energy dispatching by the energy plant, in an existing energy plant optimization, and/or a new energy plant planning and design over the forward looking time period or any other forward-looking time period.