A Guide To UK Mini-Hydro Developments

Overview

This Guide is designed to assist anyone in the UK who is planning to develop a small-scale hydro-electric scheme. It has been prepared by the British Hydropower Association in order to support and encourage new developments in this sector. The term used in this Guide will be “Mini-hydro”, which can apply to sites ranging from a tiny scheme to electrify a single home, to a few hundred kilowatts for selling into the National Grid.

Why mini-hydro ?

Small-scale hydropower is one of the most cost-effective and reliable energy technologies to be considered for providing clean electricity generation.
In particular, the key advantages that small hydro has over wind, wave and solar power are:

• A high efficiency (70 – 90%), by far the best of all energy technologies.
• A high capacity factor (typically >50%), compared with 10% for solar and 30% for wind
• A high level of predictability, varying with annual rainfall patterns
• Slow rate of change; the output power varies only gradually from day to day (not from minute to minute).
• A good correlation with demand i.e. output is maximum in winter
• It is a long-lasting and robust technology; systems can readily be engineered to last for 50 years or more.

It is also environmentally benign. Small hydro is in most cases “run-of-river”; in other words any dam or barrage is quite small, usually just a weir, and little or no water is
stored. Therefore run-of-river installations do not have the same kinds of adverse effect on the local environment as large-scale hydro.