Intelligent software functions for energy management form a crucial element for aircraft electrical and thermal systems. In the electrical system, these are currently electrical load or power management functions that can cut and reconnect loads based on fixed priorities. The main aim of these functions is to prevent overload in failure mode of electrical generators, for example if one generator fails and another one has to take over its loads. For more-electric or all-electric aircraft, these functions should also cut loads during normal operation, since the electrical systems will not be sized to simultaneously provide maximum power to all loads. Additionally, energy management functions shall deal with multiple, parallel sources and should split power off-take in a way to reach maximum system efficiency.This paper provides an object-oriented tool and a method that enable a more intuitive development of an energy management function using economic models. They can deal with different criteria like efficiency and priorities while keeping computational effort low. For each load and each generator, a cost-over-power function is provided. A set of rules limit the characteristics of these functions. This enables a reliable and easy setup of the management function. This approach enables dynamic time-shifting of loads like galleys or environmental control systems (ECS) without defining fixed timetables in advance.