Osbaston Hydropower Turbine and fish pass ~ Revisited!

On one of our recent visits to Wales we visited the Osbaston hydropower project on the river Monnow. 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.

Osbaston Hydropower and fish pass ~ Revisited!

Osbaston hydropower and fishpass opened in 2009

An earlier hydroelectric power station had been on the site from 1896 and provided Monmouth with electricity, using the weir and water channels of the forge, until 1953, shortly after the nationalisation of the power grid in 1947. Landowner Ronald Kear unearthed the foundations of a 110 year old hydropower station whilst working on his property and this prompted him to consider the prospect of building a new power station as a source of renewable energy.

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The two 75kW Archimedean Screw hydropower turbines

Alongside the hydropower scheme is the Osbaston fish pass, built in 2008 by the Environment Agency Wales so that salmon could avoid the weir and spawn upstream. The following year migratory salmon were found 20 miles (32 km) above the fish pass. The fish pass allows river-spawning fish, such as salmon, to access an extra 125 miles of river – something which they had not been able to do since Osbaston Weir was put in place in the 18th century.


The Larinier style fishpass

The new fish pass also provided an opportunity to significantly improve the ecological quality of the water. Additional work completed by the Agency helped reduce the build up of sediment and provide freedom of movement for other species of fish, upstream and downstream. Environment Agency Wales is working to bring all rivers in Wales up to a ‘good’ standard by 2027 as required by the Water Framework Directive, a major environmental initiative to make Wales’ natural waters even better.


Looking up the fish pass

The fish counter has recorded several species of fish using the pass, including salmon which have not been observed in the Monnow upstream of Osbaston Weir in living memory. Not only is this positive in terms of biodiversity, but the establishment of a river as a salmon fishery can also bring major benefits to local communities through a growth in the leisure industry supported by angling.

Leat supplying the hydropower turbines with public footpath alongside

Leat supplying the hydropower turbines with public footpath alongside

Once again we see the Ancient power of Archimedes being used for hydropower generation because if it’s fish-friendly credentials. The Archimedean Screw turbine provides a fish-friendly alternative to conventional turbines, ideally suited to low-head (1m-10m) sites, and sites with fish protection issues. Extensive fish passage tests have conclusively demonstrated that the large water chambers and slow rotation of the Archimedean Screw allow fish of all sizes, and debris, safe passage through the turbine. As a result, the Environment Agency has agreed that no screening is required.

Sluice gate at Osbaston hydropower scheme

Sluice gate at Osbaston hydropower scheme

 If you are the owner of an old mill site or a potential hydro site or are a community group interested in developing a hydro project for community use please contact us.




Hydropower generates electricity at off-grid farm

A family living in a remote part of the North York Moors are proving that hydropower really works.

The National Trust owned farm is situated seven miles from the nearest town, surrounded by moorland, has no neighbours, no mains gas, no mains water and no mains electricity. The farmhouse was originally built in 1707 and when the family moved in in 1995 there was no central heating, electric kettle, toaster, fridge, washing machine – in fact there was no electrical mod cons of any description. Bottled gas was used for the cooker and a diesel generator operated  in the evenings only.

The generator was expensive to run because of the cost of diesel (approx £5,000 per year),  spare parts for the generator because it was running for so many hours every day, maintenance, filters etc .

Adding the clear panes before covering the hydropower turbine

The family contacted the electricity board about installing an electricity supply but because their farm was so remote and they were surrounded by moors the cables would have to go underground and this was just too expensive and would also have had an adverse affect on the landscape.

The stream running pass the farmhouse made hydro power seem the obvious choice for power generation but the shallow gradient of the stream initially caused problems because at the time they couldn’t find a suitable turbine for the low head site.


Photo Credit: Mannpower Consulting Ltd

They then heard about the Archimedean Screw hydropower turbine which operates at low heads heads from 1m – 10m.  Mann Power Consulting Ltd brought the Archimedean Screw turbine into the UK for the first time, and has been at the forefront of supplying this equipment for hydro generation projects since 2004.  After visiting an Archimedean Screw  hydropower project  the family decided that this was indeed a viable option for them to eventually generate electricity.

The North York Moors National Park Authority had also just started a sustainable development fund and the families’ landlord, the National Trust, were keen to tap into that. In 2007 Mannpower Consulting Ltd were  engaged to design and install the Archimedean Screw.

Photo Credit: Mannpower Consulting Ltd

After carrying out a feasibility study it was decided that the best option for the site was an enclosed compact Archimedean Screw hydro turbine as it would not adversely affect property downstream or wildlife. Each Archimedean Screw hydropower turbine is manufactured to be site specific. The enclosed compact allowed the turbine to be positioned underground, minimising its impact on the environment.

Three clear panels enable the screw to be monitored and also allow the workings to be visible to the public. This also allows it to be used to educate the public about hydropower and alternative energy sources.

The Archimedean Screw hydropower turbine blending into the landscape

Rated at 1.0kW and a capacity of 100 l/s and an estimated annual output of 3,500kWh the hydro turbine is predicted to save in excess of 1 tonne of Carbon Dioxide (CO2) annually. An underground cable connects the generator to the control panel in the farmhouse via the batteries and inverter located in the store near the farmhouse. The family can now operate appliances for their home especially a fridge freezer and lights at night – necessities they couldn’t have while using a diesel generator.

Extra batteries were added to the storage so that they can, if fully charged, power the farm for almost a week in the event of no water flow. The family have also installed a solar pv panel to boost their electricity and also a solar thermal panel to supply their hot water needs.

Green energy has made a huge difference to the lives of this family. Is this something you would consider doing?




Mapledurham Watermill ~ the last working cornmill on the Thames.

Over the last couple of weeks Frank has been in the UK commissioning various hydropower schemes around the country. During this time he also carried out some maintenance work on the Archimedean Screw Hydro Turbine which was recently installed  at the award winning Mapledurham watermill to generate clean green elcetricity which is being sold to the national grid. The watermill is the last working corn and grist watermill on the River Thames and is still producing high-quality stone-ground flour today.


Mapledurham Watermill with working waterwheel and Archimedean Screw

A mill was already situated at Mapledurham at the time of the Domesday Survey. The central section of the current mill building dates back to the 15th century. Originally the mill had a single water wheel, on the river side of the building. The mill was increased in size in the 1670s, and a leat was constructed to drive a second water wheel on the village side. It is this second wheel which is still in use today. At its busiest it employed five people, and the miller was prosperous enough to rent the finest house in the village street.

Mapledurham Watermill - last working watermill

In 1690 the mill was leased to James Web for the sum of £60 per year. Around 1700 he expanded the mill again, to allow him to install the equipment to produce the refined flour that was becoming popular. His son Daniel Webb took over from him in 1726 at a rent of £100. Thomas Atrum took over the mill at a rent of £150 p.a. in 1747, which was raised to £205 in 1776. In 1777 a barn was added on the mill island, and a wharf built to allow the mill to supply flour to the London market by barge. However by 1784 Thomas Atrum was bankrupt.

Mapledurham watermill

Mapledurham WatermillThe mill continued to flourish, and as late as 1823 plans were drawn up to rebuild the mill in classical style. The advent of cheap imported flour from North America damaged the mill’s prosperity, but it remained in use until just after the Second World War. It was restored and brought back into use in 1980.


Original Waterwheel at Mapledurham watermill built in 1670

Built in 1670 the waterwheel at Mapledurham watermill still grinds flour today

Over the years some of the paddles of the existing original wheel were beginning to show their age so these paddles were replaced so as to extend the life of the waterwheel and to allow it to continue to grind the flour. A new waterwheel is currently under construction and it is hoped that it will be installed during the Summer. The main reason for replacing the wheel is the appearance of a number of splits in the wheels framework and also many of the joints are showing signs of decay and movement. The wheel will be as exact structural copy of the existing one and will be made out of oak which has been sourced from the Mapledurham Estate.

The new oak waterwheel in construction ~ Photo Credit: www.mapledurhamwatermill.co.uk

The new oak waterwheel in construction ~ Photo Credit: www.mapledurhamwatermill.co.uk

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. The Mapledurham estate also produces milk for Marks and Spencer. 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.

Mapledurham Watermill

Parts of the original machinery from the watermill

On our return visit to the watermill this week we were delighted and surprised to see that the new wheel had been installed.

The mill is located in the grounds of Mapledurham House, and like the house is open to visitors on weekends and bank holiday afternoons from April to September. The water mill is normally working on opening days, and visitors can visit both main floors of the mill, and see  its operation.

The watermill is perhaps best known for its starring role in the 1976 film, The Eagle Has Landed, where the mill leat is the scene of the dramatic rescue of a local girl by a German paratrooper that results in the unmasking and ultimate failure of the raid. It is also the backdrop in the image on the cover of Black Sabbath (album), by the band of the same name.

 If you’re interested in getting an existing water wheel refurbished or own the site of an old mill that has the possibility of reinstating a water wheel and would like more information please contact us here.



Archimedes arrives at Osney Lock!

Osney Lock Hydro is the first community-owned hydro scheme to be built on the Thames.

Constructing a community-owned hydro scheme at Osney Lock has been a dream for local residents for over thirteen years. It started in 2001 with a survey of  Osney Island residents that revealed a shared concern about climate change and a desire to harness the power of the river that ran around the island to generate green electricity. A small island next to Osney Lock was identified as the best site for the hydro scheme. The island is owned by the Environment Agency so they were approached about the possibility of leasing the site. It was discovered that work was to begin on the weir in 2013 so the pressure was on for the residents to draw up plans for the Archimedean Screw and secure planning permission and then most importantly secure funding for the project.

Construction work prior to installation

Construction work prior to installation

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.

Osney Lock hydro installation

Lifting the 4.35m Archimedean Screw into place

osney lock hydro installation

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 – the final construction phase of the Osney Lock Hydro scheme. The screw was designed by Mann Power Consulting Limited in the UK and manufactured in the Netherlands by Landustrie. Once operational, the 49kW variable speed Archimedean Screw turbine  will harness the power of the river to generate approximately 179,000kWh of green electricity per year.  When the scheme is completed it will generate enough electricity equivalent to that used to power around 60 houses. It will also generate an income of over £2 million over the lifespan of the project for the community to use for further environmental projects in the community.

Osney lock hydro installation

The four bladed Archimedean Screw being guided into position ~ Photo Credit: Andrew Watson

Over the coming weeks the power house will be constructed and then the gearbox and generator added. Once the Archimedean Screw is commissioned it will generate clean green elcetricity for the Osney Lock community – a long awaited dream that came to life 🙂

Update: Gear box and generator connected.

Gearbox and generator connected

Gearbox and generator connected

A labour of love ~ restoring Howsham Mill back to its Gothic Georgian glory!

Howsham  Mill is a Grade II listed building, built in 1755 and attributed to the architect, John Carr of York.  It was both a folly and a working grist mill on the Howsham Hall estate.  The mill was powered by a breastshot waterwheel connected by a gear wheel to millstones, that ground the grain into flour. Grinding ceased in 1947 and by the 1960s the mill had fallen into serious decay.

Over grown and lost to the world the derelict mill lay hidden in the trees on a small island in the River Derwent, in North Yorkshire until one day in 2003 it was discovered by Mo McLeod and Dave Mann who fell in love with the ruin and bought it in 2004. They had plans to renovate it and turn it into their home but they soon discovered that sadly this was not to be as they were turned down no matter what road they took.

Howsham Mill in 2003

Howsham Mill in 2003 ~ Photo Credit – Renewable Heritage Trust

Undeterred by all the set backs they decided to change tactic and formed the Renewable Heritage Trust with the help of the local residents with the aim of restoring the mill as an environmental study centre promoting renewable energy and local history and wildlife. It will also be available for use as a community venue for local people.

Photo Credit - Renewable Heritage Trust

Photo Credit – Renewable Heritage Trust

The first phase of the restoration was completed in 2007 and involved installing the new waterwheel and  an Archimedean screw as well as rebuilding the walls and roof of the granary to the north of the main building, allowing the installation of a kitchen and toilets as well as housing the control equipment for the hydro generation. Fund raising and grant funding enabled the installation of a new waterwheel and  the Archimedean screw to generate electricity and help fund the project in the long term. Much of the hard work of restoring the mill was done by enthusiastic volunteers, with families joining in for work days, and regular groups of trainee soldiers and school parties  helping out at the mill.

Archimedean Screw hydropower at Howsham Mill

Archimedean Screw hydropower at Howsham Mill

Both the waterwheel and the Archimedean Screw generate electricity from the fall of water over the weir. The reinstatement of the waterwheel will again harness the power of the river, but rather than driving millstones, this time will generate electricity. Both the water wheel and the Archimedean Screw are grid connected and excess electricity generated is sold to the National grid.

A view of the water wheel taken from inside Howsham Mill

A view of the water wheel taken from inside Howsham Mill

In June 2012 work began on restoring the main part of the building. Today, a decade on, Howsham Mill has been returned to its former glory as it was when it was abandoned in 1947.

Howsham Mill restored to its former glory

Howsham Mill restored to its former glory

Howsham Mill

Howsham Mill

The magnificent restored ceiling in Howsham Mill

The magnificent restored ceiling in Howsham Mill

Howsham Mill - copyright Eco Evolution)

The magnificent Gothic windows and stone work at Howsham Mill

The aim of the Renewable Heritage Trust is to make the building totally self-sustaining for the 21st century using revenue from power sales to fund future restoration and conservation work at the site.

The mill has underfloor heating beneath the flag stones which is a wet system with a sealed network of pipes connecting to a coil in the hot water tank, which is heated partly by the solar thermal panel installed on the roof of the mill and topped up by an immersion heater run from their own electricity.  A wood-burning stove connected to a flue liner has been installed in the original fireplace and will burn logs from the island.

Solar Thermal panels supplement the underfloor heating in the mill

Solar Thermal panels supplement the underfloor heating in the mill

The final stage of the restoration was the placing of the statue of Diana the huntress created by wire-mesh sculptor Nikki Taylor which replaces the original lead sculpture of the Roman goddess, most of which was taken for scrap.

Sculpture of the goddess Diana - Photo Credit www.yorkpress.co.uk

Sculpture of the goddess Diana – Photo Credit www.yorkpress.co.uk

Howsham Mill is located in a Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC). The small wooded island has a wealth of native trees including ash, sycamore, oak, wych elm and hawthorn trees.  Above and below the weir are beds of water crowfoot, teeming with invertebrates eaten by fish and birds. Otters were re-introduced to the river in the mid-1980s and can occasionally be spotted from the island.

The weir on the River Derwent

The weir on the River Derwent

A rich diversity of plant and animal life

A rich diversity of plant and animal life


Photographs unless otherwise credited are copyright of Eco Evolution