Waves, weirs and waterwheels – unleashing the power of water

How can we use and manage water in a more sustainable way? CAT volunteer and MSc student Ed Macdonald has been exploring the issues and delving into the detail of hydro power.

Born in the year of the water dragon, perhaps my interest in watercourses is to be expected. As a kid in a nearby natural sandpit I was enchanted by flow of the stream, able to bypass attempts to dam it with clay. Fast forward 20 years, I found a refreshing challenge in designing water treatment facilities for schools in the Kenyan highlands with an NGO, which led me to CAT’s Graduate School of the Environment for further training. 

An introductory workshop on the MSc course opened up the discourse on water security and led to a broad range of solutions being explored by the group – many of them focusing on ‘ecosystem services’ within watersheds such as wetlands. As luck would have it, we volunteers were soon set to work shovelling ‘humanure’, slashing reeds and coppicing willow from the CAT reed bed system. Working up from sewer to source, I wished to develop a systemic understanding of the ways in which watercourses have been and can be utilised more sustainably. It seemed apt, then, to take a module on hydroelectricity.

20161217_122735Beginning an intensive week of classes, we learned that water wheels have a long history of use (to fill aqueducts since the 6th and mill corn since the 2nd century BC) and that turbines were developed to significant capacity throughout the industrial revolution, electrifying villages and towns, particularly in hilly areas.

In the decades prior to CAT’s foundation, hundreds of Welsh micro hydro setups had been decommissioned in the wake of national grid connection. In the present century, increasing appreciation of the value of renewable energy correlates with a growth in numbers of hydro schemes. Although many of the most productive sites were developed during the recent scramble for the government’s feed in tariff, thanks to continuing refinements in turbine design and ever smarter grid networks, viable schemes remain to be attempted by entrepreneurs with an eye for sustainable investment.

20161216_104335The course was relentlessly informative and consistently stimulating. Seasoned hydro engineers laid theoretical groundwork for younger professionals (some of them CAT graduates) to detail specialist topics. We were equipped with the basic physics and design tools as well as the legislative, economic and ecological considerations for planning small/micro/nano hydro schemes in the UK and abroad.

Whilst large scale hydro, along with its negative environmental, geological and social impacts, was given cursory attention, there was extensive coverage of sea power, which is a rapidly expanding sector in the UK thanks to the gulf stream and high tidal flux. Micro hydro, though, takes centre-stage for provision of viable, sustainable, reliable power at the grassroots of rural communities. Although the case studies were decidedly UK-centric, their applications are clearly universal. One student had travelled from New Zealand and others were returning to south-eastern Africa (the continent with the greatest untapped potential for micro hydro). Several other students had come with projects in mind, and teaching staff fielded a steady stream of practical questions. After long hours in the classroom, discussion flowed on over a well-earned drink in the bar.

The theory laid down in class came into focus during practical and calculative sessions. We surveyed the site using ‘dumpy’ levels, long staffs and metre wheels to determine the distance from weir to turbine (the head) and the penstock (the pipe length) which, alongside flow, are the key determinants of power generation.

When I visit my godfather’s community hydro scheme in the Brecon Beacons, I hope to appreciate the system design within the context of the community group that initiated and maintain the project. Having now read up and envisioned scenarios of water security and clean power in developing regions for the MSc Sustainability and Adaptation coursework, I wonder if it’s too good to be true – could micro hydro schemes be used to simultaneously buffer watersheds, feed cisterns, irrigate crops and reduce flooding?

CAT’s turbines have been a role model for countless hydropower projects over the years. This course functioned as a springboard for informed engagement with this key renewable technology, which is needed now more than ever.

Edward Macdonald is a volunteer in the gardens at CAT and lives on site whilst studying the MSc in Sustainability and Adaptation. Before arriving he had worked on various small scale green community projects in the UK, Latin America and East Africa. He has an MA in Philosophy, speaks Spanish and Portuguese, is a keen drummer and lifelong Yoga practitioner. His future ambitions involve working with communities to facilitate the transition towards sustainable technology, healthy lifestyle, social empowerment, gender equality, celebration of cultural diversity and respectful relationship with nature.

Check out other CAT short courses in renewable energy or read about our new MSc Sustainability in Energy Provision and Demand Management.