Introduction to Microhydro

15 Apr 2012Monterey Institute for International Studies

Introduction to Microhydro

15 Apr 2012Monterey Institute for International Studies

Chris Greacenchris@palangthai.org

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 chris@palangthai.org

This presentation available at:www.palangthai.org/docs