The diesel engine drives an 8 kW generator, and the additional power loss of the diesel engine must be taken into account.
Additional power lost includes cooling fan power and transmission power lost by the coupling. The fan can be estimated at 1 kW and the transmission loss can be estimated at 5%, or 0.4 kW. The total power loss is 1.4 kW.
The diesel engine must therefore be at least 9.4 kW. For power values listed in the Diesel Engine product series, simply select the closest one. Like 10KW.