Emissions regulations are driving interest in hybrid electric vehicles, where multiple energy sources with several powertrain topology choices introduce a vast design area. This work aims to determine the optimal layout of a hybrid powertrain for a mobile working machine with the sizes of its components based on the given load cycle. The topology choice was implemented for a typical loader recorded cycle. A series hybrid topology with a supercapacitor showed the highest fuel consumption reduction of 2.53% compared to diesel-powered option with minimised costs of the additional electrical components. The overall outcome shows that a switch of the powertrain from a diesel-powered version to a hybridised layout alone will not necessarily bring operational cost benefits because losses in additional components may outweigh any gains in the diesel engine efficiency. To achieve better fuel consumption, additional changes in the layout of components should be considered to enable energy recuperation.
