Yes, they are within 20% of the Betz' limit. But you must understand that the Betz' law refers to "available power", and the "available power" is higher for a s

Yes, they are within 20% of the Betz' limit. But you must understand that the Betz' law refers to "available power", and the "available power" is higher for a shrouded turbine due to its larger apparent diameter.