What: An equity stake in an operating single Archimedes Screw
Where: on the River Teign near Chudleigh, designed and built by Hydrosense.
Why we love it: Already generating electricity and ready for investment. Increases in migratory fish population in the upper Teign as a result of new fish pass installed with the project.
Total installed capacity: 100 kW Average annual generation: 368,000 kWh CO2 equivalent per year: 165 tonnes
Customer equivalent per year: 112 families’ typical use
Est. annual income to TRESOC (30% stake): £13,800
Total Cost: £200,000 to buy a 30% stake in the project
Status: Commissioned in October 2013


Sowton Weir

We have signed an agreement to invest £200,000 in the recently constructed 100 kW hydro power plant at Sowton Weir on the River Teign. Like the Hatchlands Farm solar roof, income will begin to accrue as soon as the purchase is made, with an internal rate of return to TRESOC of around 7% per annum. As with our estimates for Totnes Weir we have calculated returns over a 30 year-period rather than the full period of the lease to exercise some caution in our estimates. Effective optimization at the site has led to better than expected returns from the project. The generation meter readings have been matched to flow data to show that the system is producing slightly more electricity than predicted. Although exact numbers are hard to predict, there may be an increase in fish populations of 10 to 30% over the next 3 to 5 years.

The Archimedes at Sowton Mill has improved the fisheries ecology of the River Teign by allowing more juvenile salmon and sea trout to reach the sea. The improved fish pass at the weir means more adult salmon and sea trout can reach spawning grounds on the upper Teign. An automatic fish counter has been installed that records fish numbers and species using the fish pass. This is one of only 4 fish counters in the South West and provides valuable information for the Environment Agency and the Teign Fishing Association.”

Pete Kibel, Fishtek Consulting Ltd.