Power stations all have requirements for gas detection. All will have multi-channel portable instruments for confined spaces, and most will also have a fleet of personal monitors for numerous gases. Typically a coal or fossil fuel-fired station will monitor for Flammables, CO, CO2, H2S, SO2, O2, and NH3.
Nuclear stations will have the same requirements. They have a greater need for CO2 monitoring. In all cases these instruments are typically the responsibility of the station chemist.
The requirement for fixed systems is less, and usually restricted to small systems for oxygen or toxic gas monitoring. Typically SI-100IM or SI-100 IS.