Introduction to Microhydro 15 Apr 2012 Monterey Institute for International Studies Introduction to Microhydro 15 Apr 2012 Monterey Institute for International Studies Chris Greacen

Outline • Micro-hydro system overview • Site assessment – Head – Flow • Civil works • Mechanical • Electrical

Sun, Wind, & Water

Financial analysis pico-hydropower ESMAP, Mattijs, Smits, presentation at Chulalungkorn University

Micro-hydroelectricity: Estimating the energy available Image Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook. height Power = 5 x height x flow Watts metersliters per second

Measuring height drop (head) • Abney level • Site level • Pressure gauge

Abney level (the method we’ll be using today)

Sight level method

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 H1H1

Measuring Flow • Bucket Method • Float Method design 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 Rack Silt 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 Gauge Valve Anchor Block

Penstock diameter Hazen-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 PeltonTurgoCrossflowKaplan Centrifugal pump

Turbine application (April 18, 2003)

Efficiency and Flow Fraction of Maximum Flow Efficiency 50% 0 0% 100% Pelton and Turgo Crossflow Francis Propeller

Generators • Permanent magnet • Wound rotor synchronous • Induction (Asynchronous)

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