NOVELTY - The method involves specifying first criteria for an energy management planning system, where the first criteria are indicative of a value stream model for an energy system (100). Second criteria are specified for the energy management planning system, where the second criteria are indicative of an asset cost model for the energy system. Third criteria are specified for the energy management planning system. A processor of the energy management planning system is utilized to determine operation strategy for the energy system based on the first, second and third criteria.    USE - Method for optimizing an energy system for sizing and optimal dispatch of energy assets such as energy storage devices e.g. electrochemical batteries, renewable energy resources e.g. wind turbines, solar panels including photovoltaic (PV) cells, biomass plants, nuclear power plants, natural gas power plants, combined heat and power (CHP) plants, hydroelectric power plants, geothermal power installations, tidal power installations, and wave power installations, and dispatchable energy resources e.g. hydro-power resources, coal power resources, diesel generators, electrical grid connection resources and gas power resources, for managing inter-temporal optimization problem caused by adding the energy assets to the energy system.    ADVANTAGE - The method enables increasing efficiency of storage and utilization of energy from multiple energy sources by utilizing energy storage control systems, reducing costs by transferring delivery of energy from times least expensive to times most expensive, and enhancing energy grid stability including area regulation/control energy, voltage control and reactive power support. The method enables utilizing energy storage devices the ensure energy-savings by reducing requirements for distribution infrastructure and for integrating renewable energy resources into an electrical grid.    DETAILED DESCRIPTION - The value stream model is selected from a group consisting of a peak shaving model, a reduction in-demand charges model, a transmission and distribution deferral model, an area regulation model, a customer load shifting model, a time dependent limits on-sale and purchase model, an optimized utilization of power plants model and an arbitrage model. The asset cost model is a fixed/variable overhead and maintenance costs model and a dynamic performance model. An INDEPENDENT CLAIM is also included for an energy management planning system for an energy system.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of an energy system.    Energy system (100)    Energy system controller (102)    Communications lines (103, 113, 115, 117, 119)    Renewable energy resources (106)    Dispatchable energy resources (108)