Rated with prime power output of 39 kVA, the G40WDO mobile generator is equipped with a Doosan D24 diesel engine rated at 49 horsepower. Consequently, the new G40 is exempt from permitting fees or surcharges assessed on diesel-powered equipment of 50 horsepower or greater in some states, such as the California Portable Equipment Registration Program and Texas Emissions Reduction Plan.

The G40 also offers many of the same features as the higher-prime output G50, including high-performance alternators for challenging motor-starting applications and precision voltage stability for sensitive applications, including special events.