ERS-H

Can the ERS-H decouple the rod connecting the turbine to the compressor? For example when the driver lifts off the throttle, the ERS-H could decouple the turbine from the compressor while at the same time harnessing the energy that's spinning the turbine while preventing the compressor from unnecessarily compressing unneeded air. And if that is the case wouldn't that circumvent the need of a wastegate?