1.0 Mini-hydro: a step-by-step guide

This Guide is designed to assist anyone in the UK who is planning to develop a small-scale hydro-electric scheme.

� The technology involved

Where to go for help and sources of funding

This guide can also be downloaded as a single PDF file, 955 kilobytes and 31 pages in length.

Each section of the Guide is listed in the menu titles across the page. You can either follow the Guide through from page to page, or pick out the topics of interest from the drop-down menus. Each page can be printed out on A4 by selecting the printer-friendly icon in the corner of each page.

Getting started with your own project

Begin by reading this Guide from start to finish, then note the topics that apply to your own site. Gather information about the water supply, the land, and the nearest electricity connection, because these facts shape every later decision.

When you are ready to take the next step, visit the about page to learn more about the people behind the Guide, or the FAQ page for answers to common questions about small-scale hydro.

The principal steps in developing a project

Development usually begins with a site survey, which records the head, flow and access to the water. The next stage is a feasibility study that estimates output, cost and the likely environmental impact, and that tests whether the scheme is worth taking further.

After feasibility, the developer prepares the detailed design, seeks the permissions the site requires, and arranges a connection to the network. Construction and commissioning follow, and the scheme is then operated and maintained over its working life.

The purpose of each component

A typical scheme has an intake that screens debris from the water, a channel or penstock that carries the flow, a turbine that extracts energy, and a generator with control equipment. Each part has a clear job, and a weakness in one part limits the output of the whole scheme.

Control equipment keeps the generator matched to the flow, protects the turbine, and connects the output to the local electricity network or to a single building. Understanding these roles helps a developer ask the right questions of suppliers and designers.

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:

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.

Contact

For questions about the Guide, use the contact page.

Purpose

Who prepared this Guide

It has been prepared by the British Hydro 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.

Sources of help and funding

Anyone planning a small scheme can seek advice from the British Hydro Association and from specialist consultants who design and install hydro equipment. Early conversations with these bodies help a developer understand what the project will involve before committing money.

Funding for renewable energy projects can come from several sources, and the available schemes change over time. Developers should check current options before they start, and they can find general support through the services described on this website.

The basic concept of generating power from water
The purpose of different components of a scheme
The principle steps in developing a project

A mini-hydro scheme takes water from a river or stream, directs it through a channel or pipe, and passes it through a turbine. The fall of the water, known as head, and the volume of flow together set how much power the site can produce. Greater head or greater flow gives greater output.

The turbine turns a generator, which converts that motion into electricity. Because run-of-river sites usually store little water, the output follows the natural flow of the river through the seasons, so a careful study of flow records is an early and essential step.