A slew drive is essential for solar tracking systems, enabling panels to follow the sun for maximum energy capture. There are several types of slew drives: worm gear, helical gear, and hydraulic. Worm gear drives offer high torque and self-locking capabilities, ideal for single-axis trackers but are less efficient. Helical gear drives are more efficient and quieter, suitable for dual-axis trackers, though they may need additional braking.