AbstractEmergency gas turbine generators manufactured by IHI Power Systems can promptly deliver large amounts of electricity during power outages, thereby playing a vital role in supporting society. When introducing these power generation devices into buildings located in city centers where installation space is constrained, a reduction in size becomes essential. As such, we have outlined a plan to downsize the existing 2 MW engine from NGT3 type to NGT2 type. To accomplish this, it is necessary to increase the output from the NGT2 type 1.6 MW to 2 MW, which entails a redesign of the compressor and turbine. This paper provides a detailed account of our efforts and the resulting outcomes of this undertaking.