An electric power generation system (20) is disclosed, which includes a back-up electronic power generator (22) driven by a four-cycle internal combustion engine (30). The engine (30) includes a plurality of reciprocating cylinder (C1-C6) each rotatable coupled to a crankshaft (34), which drives the electric power generator(22). The engine (30) also includes a compressor (72) along an intake pathway (50) to deliver pressurized air to the cylinders (C1-C6) and a turbine (78) along an exhaust pathway (60) to power the compressor (72) when driven by exhaust discharged from the cylinders (C1-C6). The engine (30) is prepared to accept a generator load by increasing boost pressure provided by the compressor (72). This increase is accomplished by skip-firing the cylinders (C1-C6) in a selected pattern, retarding ignition timing for the cylinders (C1-C6), or a combination of these techniques. A unique skip-fuelling control pattern is also disclosed.