The demand for the highest possible overall fuel efficiency is reflected in developments in the propulsion market for oceangoing ships. Today, this market is dominated by highly efficient two?stroke low speed diesel engines which run on low quality fuels and utilise (recover) the exhaust gas heat by means of an exhaust gas boiler/economiser.

The development of high efficiency engines has resulted in reduced specific fuel oil consumption, i.e. increased thermal efficiency of the diesel engine, and thereby lower exhaust gas temperatures. Based on ISO ambient reference conditions (25°C air and 25°C cooling water), and with the present nominal ratings of the MC/MC-C and ME/ME-C/ME-B engines, the exhaust gas temperature after the turbocharger for standard engines without waste heat recovery system, is about 240-270°C, but may be lower for derated engines.