>>... robotic systems and combat lasers
Off topic, but one of the reasons for the new powerplant in the Abrams-X is the electric power needed to drive lasers. They've been a SF staple since the 50s, but they're actually a thing now, at least for anti-missile defense. The Navy has some as modern ship designs (turbine /electric in particular) can produce the massive amount of electricity needed. I'd guess the hybrid power plant in the X is as much about that as about fuel economy or being able to run silent.