Reliability of fuel supply tends to be of great concern for authorities having jurisdiction (AHJs). On-site fuel (most often diesel) is typically required for life-safety applications, and
many mission-critical applications like 911 call centers specify it because it is perceivedto be more reliable. Nonetheless, maintenance issues and delivery concerns of diesel
fuel in an emergency, combined with the reliability and cost-effectiveness of natural gas,must be considered in a standby power system. NFPA and NEC offer provisions for theuse of natural gas in standby power applications that had previously been the cleardomain of diesel-fueled systems. There are also many ways to work with the AHJ to clear the way for the use of gaseous fuel in a standby power system.
