apparently they make enough power to power a small town or something to that effect.
there ya go
Each submarine is equipped with three Garden Island-Hedemora HV V18b/15Ub (VB210) 18-cylinder diesel engines, which are each connected to a 1,400 kW, 440-volt DC Jeumont Schneider generator.[56][121] The combined electrical generation capability of each submarine is 4.2 megawatts.[130] The Hedemora diesels were chosen because of modular construction, which made servicing easier; they could be installed three across in the available space, while other contenders required at least two banks of two; and they ran with turbochargers driven by the exhaust gas.[88] Fifteen diesel fuel tanks are located throughout the submarine: they must be used in specific sequences to preserve the submarine's trim.[131]
1.21 gigawats V18 apparnetly maybe i heard wrong. No pics though, cameras not allowed here
but theres this from public collection
http://en.wikipedia.org/wiki/File:Mark_48_...edo_testing.jpg