Low Energy House

Low Energy House - Small Scale Hydro Power

Small scale hydro power systems generate electricity from running water and can produce enough electricity for lighting and electrical appliances in an average home

Small Scale Hydro Power - Electricity Generation

Small Scale HydroMost hydro electricity is produced in hilly and mountainous areas or in river valleys. The amount of electricity that can be produced is determined by how much water is available and how fast it flows. Small scale hydro power systems use running water to turn a small turbine which generates electricity. The faster the water flows the more water power there is and consequently the more electricity is generated. The amount of electricity a system actually generates depends on how efficiently it converts the power of the moving water into electrical power.

How Small Scale Hydro Power Works

In simple terms, water is diverted from a watercourse into a channel or weir. The small scale hydro turbine is located on the channel and the water passing through the turbine causes electricity to be generated. Once through the turbine, the water is returned to the watercourse.

Small Scale Hydro Power - System Sizing

Energy available in a body of water depends on the head of water and the rate of flow. A small turbine on a hill stream with a flow of 15 litres per second and a head of 15m will generate about 1kw of power.

Small Scale Hydro Power - Installation

The site must have access to a fairly fast flowing water course and have the right to build near it. Small scale hydro power requires the source to be relatively close to the site where the electricity is to be used or close to a suitable National Grid connection. Underground cables or overhead lines that transmit electricity to its point of use must be of sufficient size to minimise voltage drop.

It is possible for households with a mains connection located near a suitable water source to install a small scale hydro power system. In the case of an off-grid small scale hydro system, electricity can be supplied to battery storage. In such cases allowances should be made for seasonal variations in water flow which will affect the amount of electricity delivered by the system. Alternatively, they can be connected to the National Grid supply and sell any excess electricity to the Grid using the Government Feed in Tariffs scheme.

The Benefits of Small Scale Hydro Power

Installing a small scale hydro system can be expensive but in many cases, particularly on isolated sites, it can be cheaper than the cost of obtaining a connection to the National Grid. After the initial investment in a small scale hydro installation, electricity bills should be much reduced or even eliminated altogether.

Abstraction Licence for Small Scale Hydro Power

It is necessary to obtain an Abstraction Licence from the Environment Agency (in Scotland the Scottish Environment Protection Agency).

Small Scale Hydro Power - Planning Permission

Small scale hydro power requires consultation with neighbours and planning permission. Environmental issues will be the main influencing factors; principally, noise, visual impact and access to the site. When considering a small scale hydro power installation it is important to make early contact with the local planning authority, the Environment Agency and other statutory bodies.

Small Scale Hydro Power - Professional Advice

It is important to take advice at the outset from an experienced hydro consultant. It will be necessary to make an early assessment of the site and the water source. There are many experienced suppliers and consultants in the UK who will have the specialist equipment required and will be able to give essential advice on a small scale hydro project.

Small Scale Hydro Electric Power - Levels of the Feed in Tariffs in 2010

Tariff levels vary depending on the scale of the installation.

Technology      Scale   Tariff level (p/kWh)      Tariff  (Years)
Hydro Electric 0 to 15 kW        19.9p       20

Power generated will be used by the property thereby reducing electricity bills. If more power is generated, the surplus will be exported to the National Grid and the electricity supplier will be paid for the excess.  

If the power generating potential is greater than that necessary to generate electrical power for a single dwelling then benefits can be achieved by communities grouping together to increase buying power.

Small scale hydropower is a mature, proven technology and one of the oldest method of harnessing renewable energy