Introduction to Microhydro
15 Apr 2012Monterey Institute for International Studies
Introduction to Microhydro
15 Apr 2012Monterey Institute for International Studies
Chris [email protected]
Outline
• Micro-hydro system overview• Site assessment
– Head– Flow
• Civil works• Mechanical• Electrical
Sun, Wind, & Water
Financial analysis pico-hydropower
Pico-hydro (Laos)
Pico-hydro (Vietnam)
Community pico-hydro
Solar home system
Diesel/petrol
gensets
0
50
100
150
200
250
300
350
US
Dol
lar p
er h
h/ye
ar
ESMAP, 2005
4Mattijs, Smits, presentation at Chulalungkorn University
Micro-hydroelectricity: Estimating the energy available
Image Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
heightPower = 5 x height x flow
Watts meters liters per second
Measuring height drop (head)
• Abney level• Site level• Pressure gauge
Abney level (the method we’ll be using today)
Sigh
t lev
el m
etho
d
Hose & Pressure Gauge• Accurate and simple method.• Bubbles in hose cause errors.• Gauge must have suitable scale and be calibrated.• Use hose a measuring tape for penstock length.• Feet head = PSI x 2.31
H1
Measuring Flow
• Bucket Method• Float Methoddesign flow = 50% of dry-season flow
Bucket Method(probably the method we’ll be using today)
Float Method
Flow = area x average stream velocity
Image source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Civil Works – some golden rules
• Think floods, landslides
• Think dry-season.• Try to remove
sediment• Maximize head,
minimize penstock– “wire is cheaper than
pipe”
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Weir
A Sluice allows sediment removal.
Locating the Weir & Intake
Weir
Intake
Head Race
Trash RackSilt Basin
Penstock
Side intake
Screens• Screen mesh-size should be half the nozzle diameter.• A self-cleaning screen design is best.• The screen area must be relatively large.
Screen
PenstockHead Race
Silt Basin
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Power Canal (Head Race)
• It may be less expensive to run low pressure pipe or a channel to a short penstock.
4” Penstock
6” Penstock
Head Race
Forebay (Silt basin)• Located before penstock• Large cross-sectional area, volume Water velocity reduced
sediment (heavier than water but easily entrained in flow) has opportunity to drop out.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Penstocks• A vent prevents vacuum collapse of the penstock.• Valves that close slowly prevent water hammer.• Anchor block – prevents penstock from moving
Penstock
Valve
Vent
Pressure GaugeValve
Anchor Block
Penstock diameterHazen-Williams friction loss equation:
• C = roughness coefficient
Penstock materials
• Poly vinyl chloride (PVC)• Polyethylene (PE)• Aluminium• Steel
Anchor and Thrust Blocks
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Locating the Powerhouse• Power house must be above flood height.• Locate powerhouse on inside of stream bends.• Use natural features for protection.
Micro-hydro technology
Pelton Turgo Crossflow Kaplan Centrifugal pump
Turbine application
http://www.tycoflowcontrol.com.au/pumping/welcome_to_pumping_and_irrigation/home4/hydro_turbines/turbine_selection (April 18, 2003)
Efficiency and Flow
0.2 0.80.60.4 1.0Fraction of Maximum Flow
Effi
cien
cy
50%
00%
100%Pelton and Turgo
Crossflow
Francis
Propeller
Generators
• Permanent magnet• Wound rotor synchronous• Induction (Asynchronous)
Thank you
For more information, please contact [email protected]
This presentation available at:www.palangthai.org/docs