Energy in hydraulic circuits is transported through the work done by incompressible oil rather than through changes in potential energy. Although oil is nearly incompressible, it can still experience pressure changes without altering its density. The internal energy changes of liquids due to pressure increases are minimal and do not contribute significantly to energy transport. Energy is effectively transferred from the source, such as a motor, to the load only when there is movement at the contact surface. Therefore, movement is essential for energy transport in hydraulic systems.
