Electrical control systems have been developed and are very feasible for harsh climates or when handling toxic fluids in the flowline.
One Company location in Wyoming, faced with an extremely high level of H2S, has successfully used electric pressure switches, hand switches, and solenoid valves on every wellhead in the entire field for years. They also included H2S detectors as one of the shutdown sensors.
When annunciation or indication of the shutdown sensor is important, electric shutdown systems would be more flexible, easier to implement, and more cost effective than pneumatic systems.
Electric systems are far easier to interface with a Supervisory Control And Data Acquisition (SCADA) system for remote monitoring and control.