[Allch Chcar]

Christ, You're forgetting wind speed when you use the formula. The given amount of energy you can obtain from a windturbine is based on the amount of force applied. The commonly sold wind turbines generate more like 1500 watts from 8 foot blades at 30mph wind speed.

The advantage to an electric supercharger is the lack of a turbine in the exhaust. A fan in the intake could function as a restriction for cruise which improves fuel economy and yet adds hp under boost.

The BMW exhaust heat device that helped to power accessories only improved FE 5%.

@micondie, the net energy loss is very small. The act of temporarily increasing the hp allowing for a smaller displacement effectively means more energy is saved overall in a DD. While a Naturally aspirated engine does get better energy efficiency from a larger displacement than a turboed smaller engine the cruise fuel economy is worse due to less efficient application. A bigger N/A ICE would have less load than a smaller turbomotor off boost and be less economical.

The Electric Supercharger would NOT generate any additional electricity. The battery system can handle 350 amp discharges but only for 30 seconds pulses. Battery systems use such amperage for the starter and engaging the starter too long can burn up your starter or discharge your battery. A controller would be necessary to limit boost events and keep the battery from being discharged too low and keep the supercharger from overheating. More than likely they size the supercharger for pulse events(30 seconds) which effectively increases the motors output by 10x the continuous rating. If ran for too long the motor or the battery will overheat.

The Honda Insight Gen1 and Honda Civic Hybrid use a 15kw continuous motor. The 12 volt motor in the electric supercharger pulses 5kw but probably has a continuous rating of 420 watts or so, which is much too small for powering anything very far.

Anything else depends on more details. You can't compare a electric supercharger to an electric drive motor merely on a energy basis. An electric supercharger is designed to increase the max output of an ICE and can be much smaller and cheaper than the motor in a hybrid-electric vehicle.