He's not trying to make boost -- so his energy requirement can be much lower as he won't be generating extra entropy compressing air
And as he's not trying to generate any pressure, he doesn't need as big a compressor that you'll find in your typical 4 cylinder.
Combinations like that are why others have been successful with reclaiming exhaust energy and putting it back to the crank -- at non high rpm loads.
then comes the next problem.... what are you going to do when you aren't producing sufficient cfm of exhaust to spool your turbo? thats right, its still connected to the crank, robbing power from it....
That's a problem that can be easily designed around and plenty of simple mechanisms exist for situations just like this
While we only have a slight idea of what he wants to do - it's been proven that a compressor to mechanical output is a viable way to recover energy.
Time is the best teacher. Unfortunately it kills all its students.
Bike Miles (Begin Aug. 20 - '07): ~433.2 miles