What primarily drives the operation of an air compressor?

Air compressors primarily operate through an electric motor. This motor converts electrical energy into mechanical energy, which drives the compressor mechanisms, compressing air for various applications in both industrial and commercial settings. Electric motors are prevalent because they provide reliable and consistent power, making them suitable for continuous operation and effective in meeting the demands of different tasks.

While gas engines can be used in portable air compressors, especially in situations where electrical outlets are not accessible, the widespread use of electric motors in stationary compressors makes this option the standard in many facilities. Hydraulic systems are typically not utilized for air compression directly, but rather for other types of machinery. Windmills could theoretically drive a compressor, but they are not a conventional method in modern air compression technologies. Therefore, the electric motor's prevalent use in standard air compressor operations makes it the correct answer.