Waterwheels ~ Ancient Wheels of Power

Travelling throughout the country both here in Ireland and in the UK I see mills dotted around the countryside that are just derelict structures on a river bank and some that are working mills with water wheels generating electricity. The waterwheel is an ancient device that uses flowing or falling water to create power by means of a set of paddles or buckets mounted around a wheel. A waterwheel consists of a large wooden or metal wheel, with a number of paddles or buckets  arranged on the outside rim forming the driving surface. Most commonly, the wheel is mounted vertically on a horizontal axle.

Derelict Mill and Waterwheel

Derelict Mill and Waterwheel

Prior uses of water wheels include milling flour in gristmills and grinding wood into pulp for paper making, but other uses include hammering wrought iron, machining, ore crushing and pounding fibre for use in the manufacture of cloth.

Bretts Sion Mills

Working Waterwheel

On occasion the old water wheel is still insitu and can be refurbished but in many cases the wheel has been removed and sadly sold for scrap metal value or taken apart to be kept as keepsakes or used as garden ornaments.

Derelict Mill and Wa

Derelict Mill and Waterwheel

If a mill has a vacant wheel pit it is possible to construct a water wheel which is aesthetically pleasing and brings the character back to the old mill.

Waterwheel Components

Waterwheel Components

 

Completed laser cut waterwheel

Completed laser cut waterwheel

The installed laser cut waterwheel

The installed laser cut waterwheel

Advantages of waterwheels

Waterwheels are widely regarded as being rather inefficient compared with turbines. This is not necessarily the case as studies have shown that waterwheel efficiency can be in excess of 80% for Overshot waterwheels and 75% for Breast-shot waterwheels [Muller 2004]. This in combination with highly respectable part-flow performance and lack of fine intake screening requirements can often result in very worthwhile overall energy capture so are still a viable proposition for producing electricity for domestic purposes. They are simple to control and aesthetically pleasing. Although they run relatively slowly and require a high ratio gearbox to drive a generator, for low powers – say below 5kW – and heads below 3m, they are worth considering.

Water wheels are also safe for the passage of fish.

  • Output reduction due to screen blockages is avoided since fine intake screens are not required.
  • Part-flow performance of waterwheels can be very good without requiring complex control systems.
  • Often minimal building work is required, particularly at former watermills if there is a vacant wheel pit.
  • Waterwheels have obvious aesthetic benefits over turbines and provide an excellent attraction at sites where visitors are encouraged.

If you are the owner of an old mill or indeed a mill site and would like to find out more please contact us here for further information and we will endeavour to point you in the right direction.

All photographs are copyright of Eco Evolution

Eco Evolution Pioneers Fish-Friendly Hydro Generation

Ferns company sees green opportunity

The two 150kW turbines at the Landustrie factoryA FERNS-BASED company has become the first company in the country to commercialise a range of hydro-turbines to produce electricity from water flow.

Eco Evolution has been appointed the main agents in Ireland for Mann Power Consulting Ltd., who are leading specialists in the area.

Mann Power is the sole UK authorised dealer for the Rehart range of Archimedean screw hydro turbines that are manufactured in Germany.

Rehart are leaders in the field of mechanical engineering in Germany with a 25-year history of excellence. This sustainable technology will allow Irish home and business owners to produce energy in a more eco-friendly way.

“We are absolutely delighted to be working with Mann Power and we are looking forward to a very exciting future together,” says Frank Gethings, managing director of Eco Evolution.

“While water has been used for energy generation for centuries, Archimedean screw hydro turbines are relatively new to the market, a 21st century application of an ancient technology,” explains Mr. Gethings.

Archimedean screws were traditionally used as water pumps to lift water from one level to another.

Archimedean screw hydro turbines work in reverse, water from a river or stream flows down the screw causing it to rotate, the screw is coupled to a generator via a gearbox and hence power is generated.

The Archimedean screw is suited to low head sites and can cater for heads of between one metre and ten metres in height and can take flow rates ranging from 100 litres per second to 10,000 litres per second. For larger flows two or more screws can be used.

“They have many advantages over the more traditional types of hydro turbines; the most important of these probably being the fact that they are fish friendly, also leaves and debris simply pass through the turbine with no fine screening required.

They are also highly efficient across a large flow variation, with a hydraulic efficiency of 87 per cent and a ‘water to wire’ efficiency of 77 per cent. They are suitable for small domestic applications from 1kW up to larger commercial applications of 350kW.”

Eco Evolution specialises in consultancy and design, supply and installation of renewable energy technologies, not only hydro electricity generation but also Wind Turbines, Solar Thermal, Solar Photovoltaic, Heat Pumps and Heat Recovery Ventilation.

Frank Gethings is originally from Ferns and studied Electronic Engineering at Dublin City University from 1985 to 1989.

After working as an engineer for 17 years, he was made redundant in 2006, giving him the opportunity to set up his own business.

“I had an interest in renewable energy since my early school days and it seemed like it was an industry with a bright future, it was also well suited to my experience and engineering background.”

After two years of intensive research, training and cherrypicking products, Eco Evolution started trading in September 2008. The company is codirected by Frank and his wife, Mary.

“At the moment we have a few exciting prospects in the pipe line.

Our products are mainly top end of the market, they were chosen because our research showed that they were the best quality and best performing products on the market, but they are not necessarily the most expensive.

“We are fully committed to providing energysaving solutions to Irish customers by offering the very latest and most technologically advanced renewable energy products on the market today.”

Articles:  Wexford Echo  , Enniscorthy Echo ,  Gorey Echo

Top Myths About Wind Energy

Many people make many claims about wind turbines and the effects that they allegedly have. We’ve collated our favourites and given the answers.

Windfarm near Kilmuckridge, Co. Wexford.

Windfarm near Kilmuckridge, Co. Wexford.

  1. Myth: Tens of thousands of wind turbines will be cluttering the British countryside Fact: Government legislation requires that by 2010, 10% of electricity supply must come from renewable sources. Wind power is currently the most cost effective renewable energy technology in a position to help do that. Around 3,500 additional modern wind turbines are all that would be needed to deliver 8% of the UK’s electricity by 2010, roughly 2,000 onshore and 1,500 offshore.
  2. Myth: Wind farms won’t help climate change Fact: Wind power is a clean, renewable source of energy which produces no greenhouse gas emissions or waste products. The UK currently emits 560 million tonnes of carbon dioxide (CO2), the key greenhouse gas culprit, every year and the Government target is to cut this by 60% by 20501. Power stations are the largest contributor to carbon emissions, producing 170 million tonnes of CO2 each year2. We need to switch to forms of energy that do not produce CO2. Just one modern wind turbine will save over 4,000 tonnes of CO2 emissions annually3.
  3. Myth: Building a wind farm takes more energy than it ever makes Fact: The average wind farm will pay back the energy used in its manufacture within 3-5 months of operation4. This compares favourably with coal or nuclear power stations, which take about six months. A modern wind turbine is designed to operate for more than 20 years and at the end of its working life, the area can be restored at low financial and environmental costs. Wind energy is a form of development which is essentially reversible – in contrast to fossil fuel or nuclear power stations.
  4. Myth: Wind farms are inefficient and only work 30% of the time Fact: A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs depending on the wind speed. Over the course of a year, it will typically generate about 30% of the theoretical maximum output. This is known as its load factor. The load factor of conventional power stations is on average 50%5 . A modern wind turbine will generate enough to meet the electricity demands of more than a thousand homes over the course of a year.
  5. Myth: Wind energy needs back-up to work Fact: All forms of power generation require back up and no energy technology can be relied upon 100%. The UK’s transmission system already operates with enough back-up to manage the instantaneous loss of a large power station. Variations in the output from wind farms are barely noticeable over and above the normal fluctuation in supply and demand, seen when the nation’s workforce goes home, or if lightning brings down a high-voltage transmission line. Therefore, at present there is no need for additional back-up because of wind energy. Even for wind power to provide 10% of our nation’s electricity needs, only a small amount of additional conventional back-up would be required, in the region of 300-500 megawatts (MW). This would add only 0.2 pence per kilowatt hour to the generation cost of wind energy and would not in any way threaten the security of our grid6. In fact, this is unlikely to become a significant issue until wind generates over 20% of total electricity supply.
  6. Myth: Installing wind farms will never shut down power stations Fact: The simple fact is that power plants in the UK are being shut down, either through European legislation on emissions or sheer old age. We need to act now to find replacement power sources: wind is an abundant resource, indigenous to the UK and therefore has a vital role to play in the new energy portfolio.
  7. Myth: Wind power is expensive Fact: The cost of generating electricity from wind has fallen dramatically over the past few years. Between 1990 and 2002, world wind energy capacity doubled every three years and with every doubling prices fell by 15%7. Wind energy is competitive with new coal and new nuclear capacity, even before any environmental costs of fossil fuel and nuclear generation8 are taken into account. The average cost of generating electricity from onshore wind is now around 3-4p per kilowatt hour, competitive with new coal (2.5-4.5p) and cheaper than new nuclear (4-7p)9. As gas prices increase and wind power costs fall – both of which are very likely – wind becomes even more competitive, so much so that some time after 2010 wind should challenge gas as the lowest cost power source. Furthermore, the wind is a free and widely available fuel source, therefore once the wind farm is in place, there are no fuel or waste related costs.
  8. Myth: The UK should invest in other renewable energy technologies and energy efficiency instead of wind power Fact: Wind energy’s role in combating climate change is not a matter of either/or. The UK will need a mix of new and existing renewable energy technologies and energy efficiency measures, and as quickly as possible. Significant amounts of investment have been allocated for wave and tidal energy development, and these technologies, along with solar and biomass energy, will have an important role in the UK’s future energy mix. However, wind energy is the most cost effective renewable energy technology available to generate clean electricity and help combat climate change right now. Furthermore, developing a strong wind industry will facilitate other renewable technologies which have not reached commercialisation yet, accumulating valuable experience in dealing with issues such as grid connection, supply chain and finance.
  9. Myth: Wind farms should all be put out at sea Fact: We will need a mix of both onshore and offshore wind energy to meet the UK’s challenging targets on climate change. At present, onshore wind is more economical than development offshore. However, more offshore wind farms are now under construction, with the first of the large-scale projects operational at the end of 2003, and prices will fall as the industry gains more experience. Furthermore, offshore wind farms take longer to develop, as the sea is inherently a more hostile environment. To expect offshore to be the only form of wind generation allowed would therefore be to condemn us to missing our renewable energy targets and commitment to tackle climate change.
  10. Myth: Wind farms are ugly and unpopular Fact: Beauty is in the eye of the beholder, and whether you think a wind turbine is attractive or not will always be your personal opinion. However, studies regularly show that most people find turbines an interesting feature of the landscape10. On average 80% of the public support wind energy, less than 10% are against it, with the remainder undecided. Surveys conducted since the early 1990’s across the country near existing wind farms have consistently found that most people are in favour of wind energy , with support increasing among those living closer to the wind farms.
  11. Myth: Wind farms negatively affect tourism Fact: There is no evidence to suggest this. The UK’s first commercial wind farm at Delabole received 350,000 visitors in its first ten years of operation, while 10,000 visitors a year come to take the turbine tour at the EcoTech Centre in Swaffham, Norfolk. A MORI poll in Scotland showed that 80% of tourists would be interested in visiting a wind farm. Wind farm developers are often asked to provide visitor centres, viewing platforms and rights of way to their sites.
  12. Myth: Wind farms harm property prices Fact: There is currently no evidence in the UK showing that wind farms impact house prices. However, there is evidence following a comprehensive study by the Scottish Executive that those living nearest to wind farms are their strongest advocates12.
  13. Myth: Wind farms kill birds Fact: The RSPB stated in its 2004 information leaflet Wind farms and birds13, that “in the UK, we have not so far witnessed any major adverse effects on birds associated with wind farms“. Wind farms are always subject to an Environmental Impact Assessment and BWEA members follow the industry’s Best Practice Guidelines and work closely with organisations such as English Nature and the RSPB to ensure that wind farm design and layout does not interfere with sensitive species or wildlife designated sites. Moreover, a recent report published in the journal Nature confirmed that the greatest threat to bird populations in the UK is climate change14.
  14. Myth: Wind farms are dangerous to humans Fact: Wind energy is a benign technology with no associated emissions, harmful pollutants or waste products. In over 25 years and with more than 68,000 machines installed around the world15, no member of the public has ever been harmed by the normal operation of wind turbines. In response to recent unscientific accusations that wind turbines emit infrasound and cause associated health problems, Dr Geoff Leventhall, Consultant in Noise Vibration and Acoustics and author of the Defra Report on Low Frequency Noise and its Effects16, says: “I can state quite categorically that there is no significant infrasound from current designs of wind turbines. To say that there is an infrasound problem is one of the hares which objectors to wind farms like to run. There will not be any effects from infrasound from the turbines.”
  15. Myth: Wind farms are noisy Fact: The evolution of wind farm technology over the past decade has rendered mechanical noise from turbines almost undetectable with the main sound being the aerodynamic swoosh of the blades passing the tower. There are strict guidelines on wind turbines and noise emissions to ensure the protection of residential amenity. These are contained in the scientifically informed ETSU Working Group guidelines 199617 and must be followed by wind farm developers, as referenced in national planning policy for renewables18. The best advice for any doubter is to go and hear for yourself!

SOURCE:  http://www.bwea.com/energy/myths.html