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Hydro Power 21 Oct 2010 Monterey Institute for International Studies. Chris Greacen [email protected] Outline. Microhydro Solar , wind, hydro – brief comparison Hydro system overview Some examples from Thailand and elsewhere Site assessment Head Flow Penstock length

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Hydro Power

21 Oct 2010

Monterey Institute for International Studies

Chris Greacen

[email protected]


Outline
Outline

Microhydro

  • Solar, wind, hydro – brief comparison

  • Hydro system overview

  • Some examples from Thailand and elsewhere

  • Site assessment

    • Head

    • Flow

    • Penstock length

    • Transmission line length

  • Civil works

  • Mechanical

  • Electrical

    Large Hydro

  • The good, the bad, and the ugly…

    Two Lao Hydro stories: NT2 and pico-power



Micro hydropower overview
Micro-hydropower overview

Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.


Thai Potential:

1000s of projects - 700 MW (?)

Mae Kam Pong, Chiang Mai

DEDE + community

40 kW

$130,000 cost

Sell electricity to PEA – $13,000 per year


Huai Krating, Tak

Power: 3 kW

Head: 35 meter

Flow: 20 liters/second

Cost: <$6,000

(turbine - $700 baht)


Kre Khi village, Tak Province

1 kW for school, clinic, church

Cost: <$3,500

(turbine $250)

Head: 10 meters

Flow: 15 lit/sec


Mae Klang Luang, Chaing Mai

200 watts

$120 (turbine: $90)

Installed: 2007

Head: 1.7 meters


Micro hydroelectricity estimating the energy available
Micro-hydroelectricity: Estimating the energy available

Power = 5 x height x flow

height

meters

liters per second

Watts

Image Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.


Measuring height drop head
Measuring height drop (head)

  • Site level

  • Pressure gauge



Hose pressure gauge
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
Measuring Flow

• Bucket Method

• Float Method

design flow = 50% of dry-season flow



Float method
Float Method

Flow = area x average stream velocity


Civil Works – some golden rules

  • Think floods, landslides

  • Think dry-season.

  • Try to remove sediment

  • Maximize head, minimize penstock

    • “wire is cheaper than pipe”

Image source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.


Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.


Weir

A Sluice allows sediment removal.


Locating the weir intake

Silt Basin

Trash Rack

Intake

Head Race

Penstock

Weir

Locating the Weir & Intake


Intake directly to penstock
Intake directly to penstock

If spring run-off sediment is not severe, the penstock may lead directly from the weir.

Screened Intake

Weir

Penstock




Screens
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

Head Race

Penstock

Silt Basin


Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.


Power canal head race
Power Canal (Head Race)

It may be less expensive to run low pressure pipe or a channel to a short penstock.

Head Race

6” Penstock

4” Penstock


Forebay silt basin
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
Penstocks

A vent prevents vacuum collapse of the penstock.

Valves that close slowly prevent water hammer.

Anchor block – prevents penstock from moving

Vent

Valve

Pressure Gauge

Valve

Penstock

Anchor Block


Penstock diameter
Penstock diameter

Hazen-Williams friction loss equation:

headloss friction (meters)

=(10.674*(F/1000)^1.85)/(CoefFlow^1.85*D^4.87)*L

Where:

F = flow (liters/sec)

CoefFlow = 150 for PVC

D = penstock diameter (mm)


Penstock materials
Penstock materials

Poly vinyl chloride (PVC)

Polyethylene (PE)

Aluminium

Steel



Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.


Locating the powerhouse
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
Micro-hydro technology

Centrifugal

pump

Pelton

Turgo

Crossflow

Kaplan


Turbine application
Turbine application

http://www.tycoflowcontrol.com.au/pumping/welcome_to_pumping_and_irrigation/home4/hydro_turbines/turbine_selection (April 18, 2003)


Efficiency and flow
Efficiency and Flow

100%

Pelton and Turgo

Crossflow

Propeller

50%

Efficiency

Francis

0%

0

0.2

0.4

0.6

0.8

1.0

Fraction of Maximum Flow


Break generators
(break?)Generators

  • Permanent magnet

  • Wound rotor synchronous

  • Induction (Asynchronous)


Permanent magnet generator
Permanent Magnet Generator

  • Rotor has permanent magnets

  • Advantages

    • No brushes

    • Efficient

  • Disadvantages

    • Generally limited in size to several kW

  • Some do AC

  • Some do AC and rectify to DC



Dc alternator automotive
DC Alternator (automotive)

  • Readily available.

  • Easy to service.

  • Brushes need replacing.

  • A rheostat controls excitation.


Wound rotor synchronous generator
(wound rotor) Synchronous Generator

  • Used in many all stand-alone applications.

  • Single phase up to 10 kW.

  • 3-phase up to >100,000 kW

  • Advantage:

    • Industrial standard

    • Frequency and voltage regulation

  • Disadvantage

    • Wound rotor – not tolerant to overspeed

    • Harder to connect to grid


Wound rotor synchronous generator1
(wound rotor) Synchronous Generator

  • Most large machines use field coils to generate the magnetic field.

  • Rotating magnetic field induces alternating current in stator windings.

Rectifier

Stator Output Winding

Exciter Field Winding

Rotor Field Winding

Exciter Winding

AVR


Wound rotor synchronous generator2
(wound rotor) synchronous generator

small

2,000 watts

Big

50,000,000 watts


Asynchronous induction generator
Asynchronous (Induction) Generator

  • Just an induction motor with negative slip.

  • Used with:

    • grid-tie system (up to 1 MW)

    • Off-grid stand-alone (often in ‘C-2C’ configuration)

    • Can be used with battery based systems



Induction generator
Induction Generator

  • Advantages

    • Simple and robust.

    • Tolerant to overspeed

    • Readily available

    • inexpensive

  • Disadvantages

    • Frequency regulation ‘loose’ in stand-alone applications

    • Requires external excitation

  • When used in off-grid,an electronic load controller (ELC) controls voltage


Induction generator (mini) grid-tie example

Wires from electrical panel to flow switch 5.5 meters

V

Single-phase 230 volt power to the resort grid

N

L

Single-phase 230 vac 50 Hz kWh meter

Volt-meter (0-500 volt)

Fused cutout, 230 volt

A

AC Ammeter (0 to 5 Amp)

X

Indicator lamp

flow switch (open-circuit when no-flow) HFS-25

Outflow pipe

Wires from electrical panel to pump 5.5 meters



Huai krating pump as turbine off grid induction c 2c
Huai Krating:‘pump as turbine’ off-grid induction “C-2C”


Capacitors for external excitation of induction motors theoretical overview of lc oscillators
Capacitors for external excitation of induction motors: theoretical overview of LC oscillators


Mae wei pump as turbine off grid induction

To village loads… theoretical overview of LC oscillators

School

Mae Wei:‘pump as turbine’ off-grid induction

Ammeter 15 amp

A

V

Volt-meter (0-500 volt)

Knife switch

Powerhouse

A

Ammeter 15 amp

power lines: single phase 230 vac to village. 2 @ 25 mm Al

Leonics controller

Ballast load

A

Ammeter 15 amp

V

Volt-meter (0-500 volt)

Capacitor 70 microfarad

Capacitor 140 microfarad

Three phase 230 vac delta


Mae wei pump as turbine off grid induction1
Mae Wei – ‘pump as turbine’ off-grid induction theoretical overview of LC oscillators


Regulation
Regulation theoretical overview of LC oscillators


Regulation synchronous generators typically both voltage and frequency
Regulation – synchronous generators… typically both voltage and frequency

  • Voltage decreases as load current increases.

  • The Automatic Voltage (AVR) regulator increases the field excitation to compensate.

  • Prolonged underspeed can damage an AVR.

  • Still required with a load controller because load power factor can change.


Mechanical governing
Mechanical voltage Governing

  • As load varies, mechanical control keeps frequency constant by varying water flow

    • Advantage:

      • Saves water

    • Disadvantage:

      • Electro-mechanical moving parts

      • Slower reacting

      • More expensive

Deflector


Electronic governing
Electronic voltage Governing

  • Types

    • Phase angle

    • Binary controller

    • Pulse Width Modulation

  • Dump load:

    • water heating

    • air heating

    • lightbulbs (not recommended)


Applying common property theory to village power systems
Applying Common Property Theory to Village Power Systems voltage

Definition of a common pool resource (Oakerson 1992; Ostrom 1994):

  • System has limited yields

  • difficult to exclude individual users from using too much


Mae kam pong microhydro unit 2 voltage and current 15 minute intervals 6 sept to 8 sept 2001
Mae Kam Pong Microhydro Unit #2 Voltage and voltage Current (15 minute intervals) 6 Sept to 8 Sept 2001


Low evening time voltage symptom of a common property problem
Low evening time voltage: voltage symptom of a common property problem

  • Rules governing user behavior should match with the technical characteristics of the system

  • kWh Meters are a mismatch for microhdyro

  • Should be concerned with kW, not kWh

  • Low voltages… kWh meter is a culprit


Circuit breakers a technical fix for a common property problem
Circuit breakers: a technical fix for a common property problem

X

kWh meter

OK

Mini-circuitbreaker

Mini-circuit breaker can encourage peak load reduction


Hourly load curve, by year from 1985 to 2000. Graph based on an appliance usage survey of 35 families in Mae Kam Pong village, April and June 2001.



Large hydro for the years 1985 – 2001.


Large hydro t he good
Large hydro: for the years 1985 – 2001.the good…

  • Seasonal energy storage

  • Fast ramp-up rates

    • Great at load following

    • Stabilizes grid

    • Supports deployment of intermittent renewables (wind, etc.)

  • Low carbon (usually)

  • Can be inexpensive

  • Domestic resource – helps diversify against fossil fuel (natural gas) price volatility

Gordon Dam, Southwest National Park, Tasmania, Australia

Image Source: Noodle Snacks, Wikipedia


Large hydro t he bad ugly
Large hydro: for the years 1985 – 2001.the bad & ugly…

  • Environmental issues

    • Kills fish

      • Too Low dissolved O2 (turbine outlet) or too high (spilling over dam), reservoir predation, fish passage blocked

    • Submerge land & fragment habitat

    • Methane (especially in tropical areas)

    • Low suspended solids => downstream scouring

  • Displaces people (40-80 million so far)

  • Energy security -- Low output in dry years

Image Source: California Hydropower Reform Coalition


Large hydro t he bad ugly1
Large hydro: for the years 1985 – 2001.the bad & ugly…

  • Energy security

    • Low output in dry years

    • Climate change 

      • Hotter (less snowpack)

      • More annual precipitation variability

Net Electricity Generation - Uganda

Load Shedding


Chinese dams on mekong river
Chinese for the years 1985 – 2001.Damson Mekong River

Manwan Dam on the Lancang River, Yunnan Province, China


Myanmar
Myanmar for the years 1985 – 2001.

Source: Myanmar Country Report on Progress of Power Development Plans and Transmission Interconnection Projects, Nov 2008. Downloaded from http://www.adb.org/Documents/Events/Mekong/Proceedings/FG7-RPTCC7-Annex3.4-Myanmar-Presentation.pdf


Greater mekong subregion gms transmission grid
Greater Mekong for the years 1985 – 2001.Subregion (GMS) Transmission Grid

  • promoted by ADB since the early 1990s under the Greater Mekong SubregionProgramme

  • When resistance is tough in Thailand, GMS grid allows cross-border exports of environmental & social problem

  • Socializes transmission costs.


Nam theun 2

Received support from World Bank, Asian Development Bank, European Investment Bank, COFACE, Agence Française de Développement and others in 2005

Supposed to be a “poverty-reduction” project and help raise the bar for other dams in Laos

Nam Theun 2

  • Two decades in the making…

  • Sponsors: Electricité de France, EGCO, Ital-Thai, Government of Laos

  • Cost = US$1.45 billion


Nam theun 2 1000 mw
Nam European Investment Bank, COFACE, Agence Française de Développement and others in 2005Theun 2 (1000 MW)

  • 95% of electricity goes to Thailand

  • 6,200 people in Laos resettled

  • Endangered species, elephant habitat to be flooded

  • Opened floodgates to Chinese, Vietnamese, Russian, Thai investment with reduced social & environmental safeguards



Pico hydropower use installation
Pico-hydropower use (installation) Laos

  • Flat

  • Mountainous

  • Influences

  • Seasonality

  • Type of Installation

Mattijs, Smits, presentation at Chulalungkorn University


Pico hydropower use river
Pico-hydropower use (river) Laos

Mattijs, Smits, presentation at Chulalungkorn University


Pico hydropower use river 2
Pico-hydropower use (river) (2) Laos

Mattijs, Smits, presentation at Chulalungkorn University


Pico hydropower use river 3
Pico-hydropower use (river) (3) Laos

Mattijs, Smits, presentation at Chulalungkorn University


Pico hydropower problems
Pico-hydropower problems Laos

  • Hardware

    • Lower output than indicated

    • Low efficiency

    • Winding failure

    • Bearing failure

  • Voltage fluctuations

    • No regulation

    • Burning out of light bulbs

    • Broken devices

  • Cables

    • Breaking

    • Bare cables

Mattijs, Smits, presentation at Chulalungkorn University


Financial analysis pico hydropower 3
Financial analysis pico-hydropower (3) Laos

ESMAP, 2005

Mattijs, Smits, presentation at Chulalungkorn University


Conclusions technography 1
Conclusions technography (1) Laos

  • Important technology for rural electrification (estimated 60.000 units throughout Laos)

  • Diversity in uses and geographical contexts

  • Cheapest source of electricity available(compared to e.g. solar and diesel generators)

  • Poor people are willing and able to pay for electricity

  • Dissemination by word of mouth

Mattijs, Smits, presentation at Chulalungkorn University


Conclusions technography 2
Conclusions technography (2) Laos

  • Whole supply chain oriented toward lowest costs  little awareness about quality differences

  • Unsustainable practices (regulation problems, breaking devices, etc)

  • No support from government or other organizations

    •  Why?

Mattijs, Smits, presentation at Chulalungkorn University


Political ecology actors
Political ecology: actors Laos

  • Government (Ministries, institutes)

  • Multilateral organizations (World Bank, ADB, ...)

  • International NGOs

  • Private sector

Mattijs, Smits, presentation at Chulalungkorn University


Narratives about pico hydro
Narratives about pico-hydro Laos

  • Common narrative:“We do not support pico-hydropower,

  • because ...

    • Risks

    • Seasonal limitations

    • No increased productivity

Mattijs, Smits, presentation at Chulalungkorn University


Interpreting actors narratives on pico hydropower 1
Interpreting actors’ narratives on pico-hydropower (1) Laos

  • Government

    • Maximizing foreign investment and export revenues

    • Preference centralized supply of electricity

    • Control over remote rural areas: grid extension

  • Multilateral organizations

    • Following line of government

    • Main focus on grid extension

    • Using ‘universally applicable’ solutions

Mattijs, Smits, presentation at Chulalungkorn University


Interpreting actors narratives on pico hydropower 2
Interpreting actors’ narratives on pico-hydropower (2) Laos

  • International NGOs

    • Not many activities on renewable energy

    • Electricity usually not considered one of the most important basic needs

  • Private sector

    • Very little private sector activity (outside pico-hydropower and batteries)

    • Hardly viable: rock-bottom electricity price

Mattijs, Smits, presentation at Chulalungkorn University


Thank you Laos… and please bring tools for Saturday hands-on PV workshopblender (!)wrenchespliersscrew driversleatherman

For more information, please contact [email protected]

This presentation available at:

www.palangthai.org/docs


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