River/tidal energy: The Anchor Stone Project

The story of our Anchor Stone Channel research project demonstrates that making progress with Community Energy is as much about relationships as projects.

Back in March 2013, TRESOC was hopeful that the channel of water passing through the Anchor Stone Channel, near the National Trust’s Greenway property would be suitable for producing renewable energy at a small scale (kilowatts rather than megawatts).

It had been observed that the water is around 20 meters deep just there, much deeper than at other parts of the river, and the strength of the tidal flow had carved out the channel at this point.  The Anchor Stone is a pinch point, where large bodies of water from above Dittisham are forced through a narrow channel, by virtue of the topography… the perfect circumstances for a research project.

In the summer of 2013, TRESOC collaborated with Plymouth University’s School of Marine Science & Engineering to create a project for Masters student, Francesca Ford, to assess the potential for producing electricity there.  Using the Plymouth University boat, Falcon Spirit, which came around the coast from Plymouth, a sonar measuring device was positioned on the river bed, just south of the Anchor Stone.  Francesca analysed the data and wrote up the project as part of her Master’s degree.  The strength and volume of flows in and out each day were measured for one month, to cover a full lunar cycle.

As part of our community engagement efforts, we hosted a meeting in June 2013 in Dittisham where interested members of the community could attend to hear more about the project, and take a trip out on a boat to view the site.  About 40 people came along to discuss what this might mean for the community, with many people in favour, in principle, of the idea.  For a write up of this day with photos, by one of our supporters, visit The Occam’s Typewriter Irregulars blog:

The results of Francesca Ford’s research were shared at an event hosted by TRESOC, in the Civic Hall in Totnes on 4th December 2013.  Unfortunately, Francesca determined that the average speed of the current at this particular location is not of sufficient speed to power an existing renewable energy device.  Although the speed of the current is quite high at times, the average speed – including tides and periods of slack water – shows that there is insufficient volume of water and speed of flow to warrant the installation of a device.It is likely that at a future date, the technology develop such that the energy in low flow rates will be harnessed, opening up possibilities for Community Energy groups located along lots of rivers.  This might take up to seven years, but the industry is moving in this direction, making ever more sensitive devices.

Just as importantly, our relationship with Plymouth University led to the entire MRE Masters cohort being involved in collaborative research, culminating in a presentation given at the same event (poster below): Investment Opportunities in Marine Renewable Energy in Devon and Cornwall.  Their research highlights 4 possible areas that appear promising.

We look forward to hearing again from Plymouth University with more concrete proposals. Together we can make things happen.

Alix Riley, TRESOC