No. Integrel generates a lot of power at low engine revs. This optimises engine fuel consumption, which keeps the fuel bills down and ensures that the engine is properly loaded even at low revs. Your main engine becomes an optimally loaded, fuel efficient, stand-alone generator. 

Without Integrel (or a stand alone generator), most cruisers have to run the main engine at anchor to charge the batteries from a conventional alternator; this does not load the engine optimally, is an expensive way of producing power and is not good for the engine due to the light load.