Effort would be better invested in removing the accessory train than shifting its power source.
A turbo-driven accessory belt is going to be a pain to design and build. I don't mean to be a naysayer, but that time will see bigger returns by losing the alternator, A/C, water pump, and oil pump and going electric.
If you want to drive something with the turbo, send the energy back into the engine. You'll need a slip clutch, sprag clutch, and reduction gears. It has been done since WWII to great effect. Improving the efficiency at the top of the chain will yield more results than improving efficiency somewhere along the middle.
It feels like this forum is starting to cycle. I remember talking about these ideas months ago, and reading them half a year ago on GS. There needs to be a booklet or something...
- LostCause