The purpose of this study was to identify contaminants, identify instrumentation needs, assess available instrumentation and identify instruments that should be developed for controlling and monitoring gas streams encountered in the following power plants: Integrated Gasification Combined Cycle, Pressurized Fluidized Bed Combustion, and Gasification Molten Carbonate Fuel Cell. Emphasis was placed on hot gas cleanup system gas stream analysis, and included process control, research and environmental monitoring needs. Commercial process analyzers, typical of those currently used for process control purposes, were reviewed for the purpose of indicating commercial status. No instrument selection guidelines were found which were capable of replacing user interaction with the process analyzer vendors. This study leads to the following conclusions: available process analyzers for coal-derived gas cleanup applications satisfy current power system process control and regulatory requirements, but they are troublesome to maintain; commercial gas conditioning systems and in situ analyzers continue to be unavailable for hot gas cleanup applications; many research-oriented gas stream characterization and toxicity assessment needs can not be met by commercially available process analyzers; and greater emphasis should be placed on instrumentation and control system planning for future power plant applications. Analyzers for specific compounds are not recommended other than those needed for current process control purposes. Instead, some generally useful on-line laser-based and inductively coupled plasma methods are recommended for further development because of their potential for use in present hot gas cleanup research and future optimization, component protection and regulation compliance activities. 48 refs., 21 figs., 26 tabs.