Keep in mind a 2 cycle tiny engine puts up 75% or more of the energy as noise and heat. Modern brushless electric motors are 90% or more efficient.
Gas is more dense for sure, but not as much as the energy difference. There are other savings as well, electrics turn on and off so quick, with a trigger that you make 100 cuts during an hour, with gas you leave it on to avoid having to pull start it. With an electric you hit the trigger for each cut. Similar for mowing, you often don't need max torque, but gas often runs at max torque/rpm even when not needed.
Gas is more dense for sure, but not as much as the energy difference. There are other savings as well, electrics turn on and off so quick, with a trigger that you make 100 cuts during an hour, with gas you leave it on to avoid having to pull start it. With an electric you hit the trigger for each cut. Similar for mowing, you often don't need max torque, but gas often runs at max torque/rpm even when not needed.