Introduction to Hydro Power

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Introduction to Hydro Power

• Matthew Leese
• West Wales Eco Centre

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Introduction

• Hydrological cycle
• What is hydro power?
• Hydro power from the beginning
• Types of waterwheel
• Enter electricity
• Types of turbine
• Head and flow
• Summary

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The hydrological cycle
t

• Courtesy Queen Mary University of London

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What is hydro power?

• Water which is high up has gravitational
  potential energy
• Energy is released when water falls
• Hydro power takes this energy and converts it
  into something more useful

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What is hydro power?

• Power P Q x m x g x H
• P power, Watts
• Q flow rate, cubic metres per second
• m mass of falling water (1,000 kg per cubic
  metre for water)
• g acceleration due to gravity, 9.81 m/s/s
• H head, metres, height through which water falls

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Hydro power from the beginning

• Noria irrigation device over 5,000 years ago in
  the Middle East
• First recorded grain mills about 2,000 years ago
  in Greece, Norway and Middle East
• First waterwheel mentioned in the Domesday Book
  was in the 8th Century
• Some 20,000 working mills in England at its peak

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Types of waterwheel

• Three main types of waterwheel
• Overshot
• Undershot
• Breastshot
• Other types
• Horizontal, Poncelot, Pitchback

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Waterwheel types
Images courtesy http//www.millsofireland.org/M.M
.O.I.Newsletter2nd.edit.html
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Image Courtesy http//www.aberarth.internet-today
.co.uk/cornmill.html
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Enter Electricity

• Electricity was first utilised and stored in
  batteries in the late 1700s, though generation
  was still to be developed
• First hydroelectric plant came into operation in
  1870s
• First electric house Cragside 1878
• High power/torque waterwheels are big and slow
• Electricity generation requires something fast

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Enter Electricity

• Electrical generation needs high speed
  revolution, so are more suited to turbines
• Outputs range from a few Watts to several
  gigawatts per scheme
• Schemes are defined by
• Effective head
• Capacity small, medium, large, pico, micro,
  macro
• Turbine type high-speed waterwheel

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Common types of turbine

• High head gt100m
• Impulse turbines for high pressure
• Medium head 10-100m
• Impulse or reaction
• Low head lt10m
• Reaction turbines for fast flow

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High head

• Pelton and Turgo

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Medium/High head

• Crossflow and Francis

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Low head

• Kaplan, fixed pitch propeller

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Turbine vs head/flow

• Graphic showing turbine vs head and flo

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Hydro power chart

• Green earth energy chart

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Summary

• Hydrological cycle
• What is hydro power?
• Hydro power from the beginning
• Types of waterwheel
• Enter electricity
• Types of turbine
• Head and flow

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Grant

• Low Carbon Buildings Programme
• Small Hydro for householders
• 1,000/kW
• Maximum of 2,500 or 30 of total cost
• Community scheme not supported

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• Rheidol Hydropower Station
• Centred on the valley of the River Rheidol, this
  is the largest conventional hydro-electric
  station in England Wales, with a capacity of 56
  MW. As well as tours of the power station, the
  site includes a visitor centre, fish farm, nature
  trails and scenic drives.
• SE of Aberystwyth, off A44. April 1st-Oct 31st,
  check for times. Groups welcome all year round by
  arrangement. www.powergen.co.uk