From where do you think the scissor lifts get the energy to move up and down? It is different in different types of lifts. In lifts that are operated electrically it is the power supply that helps the lift in doing its duty of taking the work force to specific heights. One demerit with this type is if there is power shortage the lifts might not work hindering the job ultimately making it unfit for emergency situations. The ones that operate on a liquid medium like hydraulic oil or diesel are those that can serve all types of situation provided their tanks are filled to the brim. And here there is absolutely no electric power and everything happens with just the liquid in the lift. So this type of lift proves to be a very efficient and feasible option for use in any type of situation. To learn more about these lifts visit the www.saxonlifts.com website.