Why Mini or Micro scale Hydro?

Small-scale hydro is one of the most long term cost-effective and reliable energy technologies to be considered for providing clean electricity generation. Hydropower is the nation’s most available, reliable, affordable and sustainable energy source requiring only the power of moving water from rivers and streams.
Weir on the river Camowen, Omagh

Weir on the river Camowen, Omagh

Small scale hydropower systems capture the energy in flowing water and converts it to usable energy. Although the potential for small hydro-electric systems depends on the availablity of suitable water flow, where the resource exists it can provide cheap clean reliable electricity. A well designed small hydropower system can blend with its surroundings and have minimal negative environmental impacts.
 Benefits of small scale hydropower:
  • A high conversion efficiency (70 – 90%), by far the best of all energy technologies.
  • A high capacity factor (typically >50%), compared with <10% for solar and around 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.
  • Hydro produces a continuous supply of electrical energy in comparison to other small-scale renewable technologies. 24 hour generation i.e. works at night.
  • It is a long-lasting and robust technology; systems can readily be engineered to last for 50 years or more.
  • Well-designed schemes are also environmentally benign. Small hydro is in most cases “run-of-river”;  in other words any impoundment is quite small, often an existing weir, and little or no water stored.
  • Small hydro schemes have minimum visual impact on their surrounding environment
  • A climate-friendly energy source with  no direct CO 2 emissions from hydro projects.
Therefore run-of-river installations do not have the same kinds of adverse effect on the local environment as large-scale hydro, which involves a substantial dam and a more fundamental alteration to the downstream flow pattern.

Why micro and small scale hydro?

Why micro and small scale hydro?

Hydropower is a flexible technology, proven, improved and refined over many years, yet its site-specific features make it highly innovatory in application, which makes use of a wide range of available resources – micro, small or large, storage or run-of-river, and  including tidal, canals and even water treatment works. It is still one of the most inexpensive ways to generate power, playing an important role in our electricity system stability.
If you are the owner of an old mill site or a potential hydro site, would like to refurbish or replace a water wheel or a community group interested in developing a hydro project for community use we can help. Just contact us here and we will answer all queries and help you every step of the way with your proposed project.

A look back at 2014 – the power of water!

The blog has been quite of late so now its time to get back into the swing of things.  And what better way than to look back on some of the most memorable posts of 2014.  While looking back through the posts over the past few days it has stuck  me just how busy we were in the last year!

We have had to spend a huge percentage of the year traveling and working in the UK due to the lack of support mechanisms and action on microgeneration here in Ireland. In December ESBCS withdrew their export tariff scheme to new microgeneration customers which now means there is no financial incentive in this country for microgeneration as ESBCS were the only supplier offering such a tariff. Contrast this to the ROCs system in NI and the REFIT scheme in Britain, both these schemes pay for actual generation not just what is exported, there is a smaller top-up payment for export. On the brighter side we got the opportunity to travel through the most scenic countryside to visit and work on beautiful rivers and old mills.

Working in the great outdoors

Working in the great outdoors

Penllergare Valley Woods.

Almost a year ago to the day we visited Penllergare Valley Woods located on the northern fringe of Swansea. It was once a famous gentry estate and home to John Dillwyn Llewelyn, the notable 19-century horticulturalist, philanthropist and pioneering photographer. The development of the hydropower scheme in Penllergare Valley Woods will generate sufficient power to meet the needs of the sites new visitor centre and excess sold to the National Grid, raising an expected £10,000 per year for the trust. The Archimedean Screw with a length of 11m and a capacity of 2880 m3/h is situated next to the waterfall at Penllergare Valley Woods.

Archimedean Screw with ell pass running along side

Archimedean Screw with ell pass running along side

 Osney Lock.

Osney Lock Hydro was the first community-owned hydro scheme to be built on the Thames. There was extraordinary support shown by local people towards the project. The Osney Lock Hydro share offer raised over £500,000 in just four weeks. Without this swift and significant support the project would not have been able to go ahead. Over 40% of the investment came from within a mile of the project and 4 out of 5 investors live in Oxfordshire.  On Tuesday 25th March at midday the dreams of the local residents came to life when a 4.35m-long, four-bladed Archimedean screw was installed at Osney Lock.


Osney lock hydro installation

 Mapledurham Watermill

The watermill is the last working corn and grist watermill on the River Thames and is still producing high-quality stone-ground flour today.  An Archimedean Screw hydro turbine was designed and installed in 2011 to replace the original turbine that had fallen into disrepair.   The 7.27 m Open Compact Archimedean Screw has a capacity of 5,000l/s and a predicted output of 99.95kW. It is estimated that it will save 221 tonnes of CO2 per annum. Over the course of a year, the screw will produce approximately 500,000kWh of renewable electricity which is being bought by Marks and Spencer via the national grid. The electricity generated is sufficient to power one of its stores.

Archimedean Screw

Archimedean Screw

The mill produces stone-ground flour using a waterwheel. Wholemeal and white flour, bran, semolina and Millers Mix, a blended combination bran and semolina, are all produced at the mill.  When the sale of the electricity has covered the cost of the turbine, the profits will go towards renovating the mill and its outbuildings to how it was 200 years ago. The new water wheel is the exact structural copy of the existing water wheel and is made out of oak which was sourced from the Mapledurham Estate.

New water wheel at Mapledurham

 Cragside House

Cragside was the first house in the world to be lit by hydroelectricity. On the 9th April, a century and a half  after the first hydropower installation at Cragside House a new hydropower turbine arrived onsite. A 21st century, 17m long Archimedean Screw rated at 12kW and weighing several tonnes was craned into position at the southern end of Tumbleton lake and  will produce enough energy to re-light the house just like Lord Armstrong did.


17m long Archimedean Screw insitu

17m long Archimedean Screw insitu


The project consists of two 3.6m diameter Archimedes Screw hydropower  turbines. The turbines were designed to rotate at a speed of 28rpm, which produce a maximum power output of 150kW.  The estimated annual power output is 670,000kWh enough electricity to power over 150 homes and gives an estimated annual CO2 saving of 288 tonnes. A small percentage of the power generated is used to power the owners home and the remainder is sold to the National Grid. The fish pass and hydropower scheme was offically opened in 2009.

Wordless Wednesday ~ the power of water!

 Sowton Weir

Sowton Mill stands on the  River Teign in Devon and has been using hydro power for over 400 years, initially to mill corn and then, from the 1950s, to generate electricity.  In the 1980s a 16kW crossflow turbine was installed which was the U.K.s smallest electricity contributor to the National Grid. To improve the power generation and aid fish migration a decision was made to install the fish-friendly Archimedean Screw hydro turbine. Sowton hydropower scheme was developed by a private client to provide a renewable source of electricity to the property on site with all excess power sold to the National Grid.

95kW Archimedean Screw Hydro turbine

95kW Archimedean Screw Hydro turbine

 Tours and Shows

One of the most exciting memories of 2014 was visiting the IFAT show in Munich and continuing on to visit some Archimedes Screw installations in Munich, Czech Republic and The Netherlands. IFAT 2014 is the world´s leading exhibition of innovation solutions for environmental technology. Climate change, rising raw material prices, an increasing number of mega-cities and advancing industrialization in emerging countries  boost the demand for products and services that address environmental and climate challenges. With growing pressures on European countries to reverse years of environmental damage and to find more integrated pollution control techniques, the potential is limitless.


Frank at IFAT 2014

Frank at IFAT 2014

There are many more projects both here and in the UK at various stages of build which I hope to blog about throughout 2015. The projects mentioned are a taste of what community groups, home owners and businesses have achieved in their desire to harness the power of the river to generate green electricity. On our trips around Ireland with the Mills and Millers of Ireland we met several mill owners and enthusiasts who, like us are promoting the benefits of hydropower and encourage and assist in the preservation of old mills which are part of our Industrial, architectural landscape heritage.

We will continue to fight for microgeneration incentives because after all every person or household in the country that pays an electricity bill also pays a PSO. So  it is a little unfair that the ordinary man in the street who pays the bulk of this PSO does not benefit from it in the form of any incentive that would help him to install his own microgeneration.




Micro-generation export and Refit tariff updates

Micro-generation covers small scale generators where customers can generate their own electricity and export the surplus back to the grid. Microgeneration technologies include small scale wind turbines, hydro turbines and solar photovoltaic systems.

Evance R9000 5kW Wind Turbine

Electric Ireland have extended their micro-generation payment of (9 cent / kWh) by a further year to 31st December 2012. This will be the second successive year that the expiry date has been extended and it reinforces Electric Ireland’s commitment to its support of customers who install a domestic micro-generator.

ESB Networks continue to offer a support package up until 29th February 2012, comprising of a free installation of import / export meter and payment of a support payment of (10 cent / kWh) which applies to the first 3,000kWh exported annually. This payment will last for a period of 5 years and will end on the 5th anniversary of the contract start date.

The ESBN micro-generation payment (10 cent / kWh) and the free installation of import/export meters will not be extended beyond 29th February 2012.  Import/export meters will now be charged at approx €350.00.

Solar pv slates

Budget 2012 and VAT refund for Farmers

The 2012 Budget included an extension of the existing VAT Refund Order for flat-rate farmers to include a refund on the purchase of wind turbines.

The existing VAT refund order, which provides for the refund of VAT paid by un-registered farmers on the construction of farm buildings, fencing, drainage and reclamation of farm land, has been amended to provide that such farmers may claim a refund on wind turbines supplied and installed after  1st January 2012.

Archimedean Screw Hydro Turbine ~ Shane’s Castle

REFIT – Renewable Energy Feed-In Tariff

REFIT stands for ‘Renewable Energy Feed in Tariff’ and is the primary means through which electricity from renewable sources is supported in Ireland.

The REFIT II scheme (onshore wind, small hydro and landfill gas) is open as and from 23rd March 2012 and the REFIT III (biomass technologies) scheme opened in February  2012. Both schemes are for projects built and operational between 1/1/10 and  31/12/15.


Terms and conditions for REFIT II (Onshore wind, hydro and biomass landfill gas) can be found here

The REFIT II scheme is intended to cover small and large scale onshore wind, biomass landfill gas and small hydro (?5MW.) To be eligible for REFIT II, the various requirements that will be set out in the terms and conditions must be fulfilled including proof of planning permission and grid connection -plants must be new plants neither built nor under construction on 1/1/2010.


Terms and conditions for  REFIT III (Biomass Technologies) can be found here

REFIT III is a scheme to cover 310MW of certain biomass related REFIT categories as follows:

> 50MW of AD sub technologies (AD CHP ?500 kW ; AD CHP >500 kW; AD (non CHP) ?500kW ; AD (non CHP) >500kW);

> 100MW of Biomass CHP (non AD) sub technologies (biomass CHP ?1500kW; Biomass CHP >1500kW);

> 160MW of biomass combustion and co-firing.


The REFIT II and REFIT III competitions are separate schemes with separate terms and conditons in respect of each scheme.

New clarifications may issue in due course on the new Terms and Conditions, if deemed necessary.