http://youtu.be/BJ2sr1iMtTI A large hydro installation using Parker SSD 890 AFE's for the regen inverters. The screws weigh around 40 tonnes each and run 24 hours a day. The hydropower scheme was built by Jackson Civil Engineering and is being managed by the Environment Agency. When both the screws are running they should provide more than half the power for the Queens berkshire residence.