What is Micro Hydro Power?

Introduction to Micro-Hydro

Micro hydro refers to hydro power systems with a power rating of 100kW or less. A 100kW system will produce 100 standard units of electricity in one hour. Micro hydro systems differ from large hydro power since the flows of water required are much smaller.

Micro hydro systems have been popular in some less-developed countries for a number of years enabling rural communities to enjoy the benefits of electrification in areas with hydro power potential but without a grid network. New technology, less stringent regulation of grid-connected micro hydro generators and standardised turbine designs are now encouraging more widespread interest in micro hydro in the UK.

What are the Benefits?

  • The considerable benefits of micro hydro power include the following:
  • ‘Fuel-free’ source of power
  • Different to large hydro since environmental impacts of installation are negligible.
  • Renewable energy source therefore helping to reduce greenhouse gas emissions and having a net positive impact on the environment.
  • Constant generation over long periods unlike wind and solar power
  • Good correlation with demand (more hydro energy is available in winter when heating loads are high)
  • Long lifetime of systems, typically 25 years or more Low maintenance requirements and running costs
  • Reasonable payback for grid -connected systems, often 10 years or less

Where can it be installed?

There are three main types of sites which are particularly worthy of consideration for development:

  • Historic Water Mills Water was once used extensively as a source of motive power in the British Isles. Some estimates put the number of old mill sites in the UK as high as 20,000. Government targets for renewable energy and the development of modern, small-scale turbine units now make re-activation of many of these old sites for electricity generation economically worthwhile. A major advantage of these sites is that it is often possible to reuse some of the existing civil structures such as the weir and the leat, thereby reducing the cost of the installation.
  • Hilly Areas with Spring-Fed Streams In addition to historic sites, considerable potential exists in many hilly areas of Britain for micro hydro power. Turbines are available which can utilise quite small spring fed streams for power generation if the fall is sufficient. These sites can often be developed at reasonable cost since civil structures associated with large flows of water, such as weirs , are not required.
  • Weirs. The UK’s rivers have between them 1,000’s of weirs not linked to mill facility, and many of these could be relatively converted to power generation using Hydro Generation’s low cost modular turbine system.

Please visit our other Hydro web pages for further information on estimating your potential, feasibility studies, abstraction licensing, system design and installation. maintenance.

Keywords:Micro Hydro Power search results from Nov 11 to Dec 10, 2010.
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Introduction to Water Turbines
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Output Voltage(v):220(VC),Output Power(w):100,150,250-350
We guarantee a long stable period of the spare-parts supplying.
Station Site and Installtion
Solar Energy
A ‘made to measure’ service?
Some sites have historical connections with hydropower, or another reputable hydro company may have already completed some feasibility work.  For sites like this all of the stages above might not be required, so we can tailor our feasibility services to meet your needs and ensure that work isn’t duplicated.
Modular turbine systems
Worldwide there are literally hundreds of thousands of micro-hydropower sites (up to 100 kW) that could be developed to supply environmentally friendly renewable energy. Two factors limit how many of these sites are developed; cost and local technical knowledge.At present micro-hydropower systems are basically scaled-down versions of large-scale systems, and are bespoke designed for a specific site. The turbines themselves are fabricated in steel at great expense in materials and skilled labour time. This makes the current technology prohibitively expensive for many potential sites.

Our water turbine is based around a polymer moulded rotor and stator unit. The complex geometrical shapes typical of any turbine are ideal for polymer moulding. We can produce a finished turbine rotor or stator relatively quickly, using low-cost materials. The turbine itself is a ‘back-to-back reaction turbine’. The water enters at the centre of the rotor and is discharged in equal quantities from the two ends. This means that there is zero net axial thrust on the rotor which minimises bearing wear. The flexible but tough material used for the rotor and stator also absorb the energy of waterborne particles (they effectively ‘bounce off’), minimising erosion. The whole design is ‘modular’ which reduces the amount of site-specific design work that has to done, and the level of local expertise required.The other system components are similarly innovative, including a fibreglass volute casing and a modular chassis system. The whole system is weatherproof so there is no need for an expensive turbine house. The overriding factors that have driven the design are low cost, ease of installation and minimal, simple, maintenance requirements. We can manufacture four rotor sizes; 200, 300, 400 and 600 mm. The power outputs for the operating range of heads and flows are shown below:

Rotor diameter
200 mm
300 mm
400 mm
600 mm
Power output (kW)
@ flow rate (l/s)

Power output (kW)
@ flow rate (l/s)
Power output (kW)
@ flow rate (l/s)
Power output (kW)
@ flow rate (l/s)
Power output (kW)
@ flow rate (l/s)

Power output (kW)
@ flow rate (l/s)

We are working on mating our water turbines to a permanent magnet synchronous generator with power electronic power conditioning. This will enable the turbine to operate as a variable speed machine, optimising efficiency over a wider flow and head range and allowing local power conditioning, such as varying the amount of reactive power generated. This flexibility will make integrating the system in local electricity distribution networks more straightforward, especially in developing countries. The water turbine can also be operated as a standalone system with resistive dump load to dissipate excess energy.

Installation and Commissioning

Hydro Generation can project manage all stages of construction of a micro hydro installation to make sure that all building work is carried out to specification. Our own engineers can install and commission the hydropower mechanical and electrical hardware.We can also condense the various manufacturer’s instructions into a simpler single document, complete with a structured easy-to-follow maintenance schedule.

Detailed System Design

Hydro Generation can provide a complete service for all aspects of hydro system design. We either have the necessary skills in-house or have links to suitably experienced engineers. System design can be broken down into mechanical / civil and electrical spheres.
Mechanical / civil design

This broadly covers:
1. Intake system, including trash racks, fish screens and fish bypasses.
2. Penstock.
3. Turbine / transmission / generator specification and installation plans.
4. Turbine house.
5. Water control structures (overflows, sluices, gates etc.).
6. Structural weir design (we sub-contract this to structural engineers).
Electrical design
1. Standalone or grid-connected designs.
2. For grid systems, liaison with local distribution company to specify type of connection.
3. System design and specification to G59/1 or G83.We can also obtain quotes for clients and carry out an analysis of the often confusing array of offers made by potential suppliers, and make recommendations.