Look at using a Pump as a turbine (PAT). Power control is done by speed control using a VFD.
Less efficient than a Turbine, but much cheaper.
KSB have some good literature for spec'ing a pump for the specified head and flow of your application.
Else contact JOAT, and ask for Neville.
Hi Coen,
Did Revov ever resolve this issue. I'm very interested in their second life batteries, but won't take the plunge if they don't provide good back up.
Thanks.