This is interesting. It’s an alternator driven by exhaust gas instead of a mechanical drive system. The TIGERS Turbo generator Integrated Gas Energy Recovery System alternator can be spun up to 80,000rpm and generate as much as 6kW. By eliminating the mechanical drive and parasitic losses, they immediately gain efficiency. In cars and especially trucks, this can be a substantial benefit though I don’t know that this is directly applicable to motorcycles.
These types of systems always require careful thinking, basic laws of thermodynamics still apply so when you gain efficiency by reducing mechanical losses one place, the losses from the exhaust driven generator must be added back in. Figuring out the net benefit is beyond my calculating powers so we’ll have to read the article and go from there. Neat idea, though.