Energy consumption is becoming a major subject when designing, developing and running programs. Most developers code and run their applications in an energy oblivious manner, mostly because of a lack of energy-related knowledge about their system. This problem also exists in the realm of executable domain-specific modeling languages, where end-users create models conforming to a given meta-model and execute them with little knowledge about their operational semantic and related energy consumption. In this work, we propose a domain-specific language for decorating meta-models of executable languages with platform-specific energy estimation formulas. We also extend the GEMOC execution engine to dynamically perform energy estimations on any executable model conforming to the decorated meta-model. The energy estimation model defined can then be easily adapted to other models and platforms, without requiring any measurement tooling or knowledge from the end-user.