Combe Gill Hydro in Borrowdale

Coming down off Rosthwaite Fell we spotted the tell-tale signs of another hydro project. This is it: https://www.nationaltrust.org.uk/borrowdale-and-derwent-water/projects/combe-gill-hydro-power-project-diary and https://consult.environment-agency.gov.uk/psc/the-national-trust-29470-28031/supporting_documents/29470%20Design%20and%20Access%20Statement.pdf It will supply 200 homes. Suppose they paid £500 a year in electricity bills. That would raise £100000 a year. I can't find how much it cost to install. Given that some of the bill goes to maintain the National Grid and other such, and also that it is costing £6 million to repair the Keswick to Threlkeld cycle track, I suspect it will take some decades to pay back this project. I was interested to see that they are using a Coanda plate for the stream intake. I have posted before about the Coanda Effect http://wigtonphysics.blogspot.com/2016/10/coanda-effect-and-toilet-at-watchtree.html but you can read about the application to hydro plants at https://www.powerspout.com/products/diy-coanda-intake-screen