Since the beginning of the development of exoskeletons in the early 1960s there was a constant need for improving their actuators technology. Requirements for high power and torque for the lower body and very high precision for the hand motion, while maintaining the flexibility of biological muscles, are still not fully satisfied. The problem lies not just in the lack of appropriate actuator technology, but also in the inability to meet their energy needs. This paper contributes to this problem, first by describing the most commonly used technologies and then by presenting simulation results for lower limb exoskeleton motion. In addition the energy requirements of the modeled devices and their control possibilities along with their usage in various parts of the exoskeleton construction are analyzed.