Tŷ Mawr Wybrnant run-of-river hydropower demo site
The 16th century historical farmhouse of Tŷ Mawr Wybrnant is a renowned touristic site in Northern Wales managed by National Trust. It was the birthplace of Bishop William Morgan, first translator of the Holy Bible into Welsh.
In an effort to reduce the energy consumption related to lighting and heating of the building a small hydropower installation has been proposed to generate about 4 kW from the water of the nearby Afon Wybrnant stream.
The measured net hydraulic head corresponds to 35 m, and the design flow rate is 25 l/s.
Despite the potential for small-scale hydropower development in Wales being significant, the high upfront investment needed together with the decline in subsidies contribute to making most of it economically nonviable. The novelty of the present approach is to reduce the complexity and cost of the scheme in order to demonstrate its feasibility even down to the "pico" scale (e.g. less than 5 kW of installed power).
In order to do so it was decided to install instead of a "conventional" hydro turbine a Pump As Turbine (PAT) consisting of a regular centrifugal water pump with reversed flow direction as investigated under the Dŵr Uisce project. Being a standard and off-the-shelf available machine, such turbine is 4 to 10 times less expensive than traditional turbines of similar power output besides being easy to install and maintain.
Objectives of the demonstration
The system is expected to generate about 19,000 kWh of clean renewable electricity per year, equivalent to over 8 tons of CO2 avoided per year. The main purpose of the installation is to demonstrate not only the environmental benefits of the scheme (low/null impact on the ecosystem and CO2 savings) but also to prove the economic attractiveness of such small-scale distributed hydro generation.
The construction of the 4 kW generation scheme is due to start in Autumn 2018 and the plant is expected to be online by the end of the year.