The electrothermal energetic plasma source (ETEPS) is a new concept in which the ablative mechanism is forced inside of the capillary which has energetic liner, i.e. a chemical propellant. The generation of the electrothermal plasma results from Joule heating and radiant heat transport to the liner. The discharge initiates erosive burn of the propellant and the mixed plasma-propellant gasification produces high enthalpy energetic flow. In the ablation-dominated capillary discharge the eroded materials from the solid propellant liner are mixed inside the source before flowing out as a result of the large pressure gradient. The energetic electrothermal source may also be used in a regime where no ablation occurs, where the plasma is generated from the injection of energetic gasses or liquids into the confined capillary. The ablation-free source generates the plasma from the dissociation of the gaseous/liquid components, which in turn releases the chemical energy of these propellants and mixing the energy with the electrical energy of the plasma. This concept is different from electrothermal chemical sources; it generates the propellant or energetic flow without requiring a combustion chamber. It also provides mixing at the ionic level not available in current configurations of electrothermal chemical launchers, igniters, or thrusters. The electrothermal plasma code ETFLOW-EN was developed to computationally simulate the plasma generation and flow in energetic ET capillary discharges to predict the behavior of the energetic source with the use of lined solid propellants. Operation with liquid/gaseous energetic forms in a non-ablative capillary is also a character of this concept and is part of the ETFLOW code. Results of using different forms of energetic materials in solid, liquid and gaseous mixtures have shown the applicability of ETEPS to produce high enthalpy energetic plasma flows with sufficient parameters suitable for ETC launch applications.