You're burning 1kg of gasoline with 46MJ/kg energy at 20% efficiency gives you 9.2MJ of work done. Do you need to replace 46MJ energy embodied in gasoline with

You're burning 1kg of gasoline with 46MJ/kg energy at 20% efficiency gives you 9.2MJ of work done. Do you need to replace 46MJ energy embodied in gasoline with 46MJ worth of electricity? No. Electric engine has 95% efficiency so you need 9.68 MJ of energy.