Is it possible to convert fuel energy consumption to electricity consumption?

Household electricity generators use liquid fuel to run the engine and generate electricity.

Given a scenario, If a generator uses 2 litre of diesel per hour, is it possible to find out if that same generator was to run on electricity, how much watt the same generator would have used per hour.

for example take this HONDA GX390 engine.

PS: I have no idea on engineering side, just want to find out if it is possible, if yes, how to calculate.

Duh, you don't use electricity to generate electricity. Find somebody who understands what you want to do and follow his advice.

Yes, if you know the efficiency of the unit, or ratio of energy out over energy in, and the energy content of the fuel, then you can calculate the equivalent of the input of electrical energy to an equivalent electric motor driving the same system.