Innovative Steam Technologies Inc. (IST) manufactures once-through steam generators (OTSGs) to recover the heat from the gas turbine exhaust stream. IST has two primary product lines. The first is Compact OTSGs for combined cycle and combined heat and power applications; the second is with gas turbine steam (GTI) applications. The earliest unit has been in operation since 1985 and IST has accumulated over 2.5 million hours of operation experience with its fleet of over 107 OTSGs installed in 13 countries and 5 continents.

IST's Once Through technology has earned a reputation as the simple way to help owners and operators generate more money with their plant.

OTSGs avoid the complications of boil out and chemical cleaning; they eliminate the operational headaches related to the control of blow-down systems and steam drum levels. Further, OTSGs provide significant additional cost reduction since there is no heat loss and maintenance of the bypass stacks with diverter valves, often required in traditional drum type steam generator systems.