In classic Battletech there are few types of power plants. In MW:LL we use following three:
This is the most common fusion engine found all over the Inner Sphere. It is considered the standard of military grade equipment from the space faring ships down to the light scouting vehicles and tools.
Extra Light Engine
And technological leap lost to the fog of war. The XL engines are lighter, more expensive and prone to more easy undergo critical destruction than the STD counterparts. Other than that, they share the same power rating as the other engine types.
Internal Combustion Engine
On the periphery and in the dire times elsewhere, the ICE engines find their use in not only utility vehicles and mechs, but also in some main battle tanks and even some rare battle mechs.