Contributions to the internal energy of the BLh ejecta for the simple and detailed thermalization schemes described in Sect. 2.4 (left column), and for selected opacity models from Sect. 2.5 (right column). Top: Average pressure work (blue), nuclear heating (orange), and radiation energy (red) per unit time and per fluid element, mass-weighted over the ejecta. Bottom: Ratio of nuclear heating and radiation energy over pressure work. The horizontal dashed line marks a 30% ratio.