1. Monterey Institute for International Studies
Hydro Power
21 Oct 2010
Monterey Institute for International Studies
Chris Greacen

2. Outline Civil works Mechanical Electrical Large Hydro
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

3. Sun, Wind, & Water

4. Micro-hydropower overview
Micro-hydropower harnesses energy from falling water. Typically some water is diverted from a stream using a weir. Water is then transported by a channel or pipes to a powerhouse downstream where the pressurized water spins a turbine, generating electricity.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

5. Sell electricity to PEA – $13,000 per year
Thai Potential:
1000s of projects MW (?)
Micro-hydropower is suitable for both grid-connected and off-grid electricity. This 40 kW installation in Mae Kam Pong village in Chiang Mai province is producing electricity that is providing electricity to the Provincial Electricity Authority (PEA). Eventually revenues from electricity sales will go to the village micro-hydropower cooperative. The project produces about 400,000 baht per year worth of electricity.
Mae Kam Pong, Chiang Mai
DEDE + community
40 kW
$130,000 cost
Sell electricity to PEA – $13,000 per year

6. Huai Krating, Tak Power: 3 kW Head: 35 meter Flow: 20 liters/second
Cost: <$6,000
(turbine - $700 baht)
This is a much smaller installation – a 3 kW installation that uses a centrifugal pump running backwards as a turbine. The installation is at Huai Kra Thing village, Mae Ramat Amphur, in Tak Province. The pump’s motor is run backwards as a generator. This kind of installation requires some custom electronics, but works quite well. An advantage is that repairs to pumps are easy – Thai mechanics are familiar with pumps.
Huai Krating, Tak Province, Thailand
Power: 3 kW
Head: 35 meter
Flow: 20 liters/second
Cost: 200,000 baht

7. Kre Khi village, Tak Province 1 kW for school, clinic, church
Cost: <$3,500
(turbine $250)
Head: 10 meters
Flow: 15 lit/sec
This is an even smaller installation – generating about 1 kW for a school, clinic, and community center in Kre Khi village, Tha Song Yang amphur, Tak Province. It uses a Chinese turgo, which is available for about 10,000 baht ($300). It uses about 15 liters/second of water, and has a head of about 10 meters.

8. Mae Klang Luang, Chaing Mai 200 watts $120 (turbine: $90)
Installed: 2007
Head: 1.7 meters
This tiny installation generates 200 watts, and powers lights in a youth training center in Baan Klang Luang village, Doi Inthanon, Chiang Mai. The turbine, purchased from Vietnam, cost 4,000 baht. It is powered by water falling about 1.7 meters.
3000 baht in Vietnam
2000 baht in Laos
200 watt

9. Micro-hydroelectricity: Estimating the energy available
Power = 5 x height x flow
height
To measure hydropower potential, a rough “rule of thumb” that incorporates generator efficiency is the following.
meters
liters per second
Watts
Image Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

10. Measuring height drop (head)
Site level
Pressure gauge

11. Sight level method

12. 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

13. Measuring Flow • Bucket Method • Float Method
design flow = 50% of dry-season flow

14. Bucket Method

15. Float Method
Flow = area x average stream velocity

16. Civil Works – some golden rules
Think floods, landslides
Think dry-season.
Try to remove sediment
Maximize head, minimize penstock
“wire is cheaper than pipe”
I’m more of an electrical guy, and I don’t consider myself an expert in anything, much less hydropower civil works. I have worked on the civil works parts of about 10 micro-hydros in the Karen hilltribe areas of Thailand. But I have to admit we have been learning by trial and error a lot. We don’t know the ‘right’ way to do things. And we’re experimenting on how to do things and keep costs as low as possible. We cut corners, and then sometimes pay for it later. Sometimes we cut corners and it works out. In the villages I’ve been working in, money is rare and time is less rare. So we figure ‘if it breaks, we can fix it – or – more likely – villagers we work with can fix it.
As a white guy working in this context I try not to go in there and say ‘I’m the expert, we’re gonna do it this way’. So on civil works side of things what we end up building draws VERY heavily on local expertise of the local people. In a real sense, they design it, with myself getting to be part of the discussion.
So, we choose local materials, local knowledge, improvisation, and reparability rather than imported materials, imported knowledge, detailed engineering design, and longevity.
There are some contexts where this is appropriate. There are some where it isn’t. Fortunately, there are a lot of parallels between the ‘off-grid, non-code-compliant universe in the USA, and these hill tribe villages. So based on what I’ll show here you’ll have to make your own choices.
Image source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

17. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Weir submerges intake.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

18. A Sluice allows sediment removal.
Weir
Purpose of weir is to raise water level sufficiently high to submerge inlet
A Sluice allows sediment removal.

19. Example of sluice for sediment removal (plugged with sandbags)
Example of sluice for sediment removal (plugged with sandbags). And also using natural rock features.

20. Locating the Weir & Intake
Head Race
Trash Rack
Silt Basin
Penstock
Locating weir near top of waterfall can maximize head/penstock ratio
The inside of bends accumulate sediment.
The outside of bends are subject to erosion and flood damage.
Place the intake along a straight section.
choose a site with a stable stream bed.
Constant flow stream
Small gradient

21. Intake directly to penstock
If spring run-off sediment is not severe, the penstock may lead directly from the weir.
Screened Intake
Weir
Penstock

22. This intake screen is a woven bamboo basket covered with plastic mesh
This intake screen is a woven bamboo basket covered with plastic mesh. The intake is protected by two rock-filled culvert gabions to divert big logs, etc. that are expected during the rainy season.

23. Good example of side inlet.
Side intake

24. Trash rack: keeps the big stuff out

25. 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

26. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Weir submerges intake.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

27. 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

29. 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.

30. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Weir submerges intake.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

31. 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
Anchor Block

32. 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)

33. Penstock materials Poly vinyl chloride (PVC) Polyethylene (PE)
Aluminium
Steel

34. Anchor and Thrust Blocks

35. Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.
Weir submerges intake.
Source: Inversin, A. R. (1986). Micro-Hydropower Sourcebook.

36. Locating the Powerhouse
Power house must be above flood height.
Locate powerhouse on inside of stream bends.
Use natural features for protection.

37. Micro-hydro technology
Centrifugal
pump
Pelton
Turgo
Crossflow
Kaplan
There are many different types of turbines, and their use depends on the height drop and flow at the site. For small projects, it is also possible to use a centrifugal pump running backwards.
Installed cost is roughly baht 30,000 to 100,000 per kW.

38. Turbine application
(April 18, 2003)

39. Fraction of Maximum Flow
Efficiency and Flow
100%
Pelton and Turgo
Crossflow
Propeller
Efficiency
50%
Francis 0%
0.2
0.4
0.6
0.8
1.0
Fraction of Maximum Flow

40. (break?) Generators Permanent magnet Wound rotor synchronous
Induction (Asynchronous)

41. 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

44. Adjustable permanent magnet generator

46. DC Alternator (automotive)
Readily available.
Easy to service.
Brushes need replacing.
A rheostat controls excitation.

47. (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

49. (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

50. (wound rotor) synchronous generator
small
2,000 watts
Big
50,000,000 watts

51. 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

52. Induction motor/generator

53. Induction Generator Advantages Disadvantages
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

54. Induction generator (mini) grid-tie example
Wires from electrical panel to flow switch 5.5 meters
Single-phase 230 volt power to the resort grid N L
Single-phase 230 vac 50 Hz kWh meter V
Volt-meter (0-500 volt)
Fused cutout, 230 volt
To synchronize, simply start water flowing. Bring it up to speed, then turn on the water supply. 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

55. Induction grid-tie example 1 MW Mae Ya

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

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

58. Mae Wei: ‘pump as turbine’ off-grid induction
To village loads…
School A
Ammeter 15 amp V
Volt-meter (0-500 volt)
Knife switch
Powerhouse A
Ammeter 15 amp
power lines: single phase 230 vac to village. 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

59. Mae Wei – ‘pump as turbine’ off-grid induction

60. Regulation With batteries AC direct Permanent magnet
Trace C-40 type, etc.
Wire to output of Outback
ELC (voltage)
Synchronous
Trace C-40 type
Governor (frequency)
AVR (voltage)
Induction
Capacitors for frequency

61. 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.

62. Mechanical 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

63. Electronic Governing Types Dump load: Phase angle Binary controller
Pulse Width Modulation
Dump load:
water heating
air heating
lightbulbs (not recommended)

64. Applying Common Property Theory to Village Power Systems
Definition of a common pool resource (Oakerson 1992; Ostrom 1994):
System has limited yields
difficult to exclude individual users from using too much
A nearly universal human trait, it seems, is that when people have access to electricity, they want to get more appliances. First a few light bulbs... But before long many people have televisions, VCD players -- and even worse -- highly consumptive irons, rice cookers and electric water boilers.
The problem is that the village scale system has limited yields, but that it is difficult to exclude individual users from using too much at a given time. This is the classic definition of a common pool resource, and there is a considerable social science literature that addresses community governance of these common property resources -- whether they are grazing lands, fisheries, forests. Surprisingly, no one has ever thought to apply common property insights to village power systems. Apparently village power engineers and practitioners are unaware of common property literature; while common property theorists are unaware of village power systems.
Sources:
Oakerson, R. J. (1992). Analyzing the Commons: A Framework. Making the Commons Work: Theory, Practice and Policy. D. W. Bromley, David Freeny, Margaret A. McKean, Pauline Peters, Jere L. Gilles, Ronald J. Oakerson, C. Ford Runge, James T. Thomson. San Fransisco, ICS Press.
Ostrom, E., R. Gardner, et al. (1994). Rules, games, and common-pool resources. Ann Arbor, University of Michigan Press.

65. Mae Kam Pong Microhydro Unit #2 Voltage and Current (15 minute intervals) 6 Sept to 8 Sept 2001
But these engineering shortcomings are compounded and exacerbated by user behavior. Here is a closer look at the same data. You are looking at 3 days of voltage and current data taken at Mae Kam Pong village east of Chiang Mai. Every day looked pretty much like this. Notice every day there is a small morning peak (POINT) at around 6am which doesn’t cause any problems with voltage, followed by a huge evening peak at 6pm which time the voltage dips to around 150 volts .
High evening time peak consumption is clearly a major contributor to voltage drop. Notice that peak consumption is more than two times typical consumption. In the course of a 24 hour day there is plenty of electricity – just not enough to go around in the evening.

66. Low evening time 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
For common pool resource regimes to be sustainable, one of the insights from the literature is that the rules governing user behavior – such as the tariffs -- have to match with the technical characteristics of the system. Micro-hydro systems in Thailand are a perfect example of a mismatch. In most Thai micro-hydro systems households are metered on standard kWh meters that measure consumption with a dial that spins around and numbers that tell you how many units you have used in a month. But while the microhydro can generate plenty of energy in a 24 hour period, the plant is peak-limited. In fact, power not consumed is "thrown away" at the powerhouse in an electric ballast load that dissipates excess electricity by heating water. Microhydro meters should not be concerned with monthly cumulative consumption – they should be concerned with maximum rate of consumption at any instant.

67. Circuit breakers: a technical fix for a common property problem
kWh meter
Some social scientists might feel uncomfortable, but there is a simple technical fix that can help address the common pool resource problems encountered with village microhdyro. An arrangement used in Nepal and other countries is to throw out the kWh meters and install a mini-circuit breakers in each house and offer electricity on a subscription basis. Small houses might get 1/2 amp and pay 30 baht per month. Bigger ones pay more than twice as much for 1 amp. People can use power whenever they want, but if they consume too much at any one time the breaker trips and they have to turn off some appliances before they can restore power to their house. Though customers pay monthly bills based on the size of their breaker, the "metering arrangement" has no meters. OK
Mini-circuit breaker
Mini-circuit breaker can encourage peak load reduction

68. Is growing appliance use an issue. Well, you tell me
Is growing appliance use an issue? Well, you tell me. This graph shows the results of interviews with 35 households concerning the appliances they use, when they use them, and how long they’ve had them. I conducted the surveys in the same village as the datalogging you saw earlier. On the vertical axis is power consumption measured in watts. On one horizontal axis is time of day from 5 o’clock in the morning until 11 at night. On the other horizontal axis is the year. The graph shows striking growth in energy use over the years. Look first at 1985 – there was clearly an evening peak, but it was well under 2000 watts. But year by year this peak grew, more than tripling in 15 years. The data nicely mirrors the datalogged data I showed earlier with a small but distinct peak in the morning and a huge peak in the evening.
In the next graph I will trace only the ridgeline of the growing evening peak – but break it down by appliance.
Hourly load curve, by year from 1985 to Graph based on an appliance usage survey of 35 families in Mae Kam Pong village, April and June 2001.

69. The rapid growth in peak consumption is largely due to growth in non-lighting loads. In the households surveyed electricity was increasingly used for entertainment and electric cooking.
Appliances such as rice cookers and water boilers that use electricity to produce heat have a particularly large impact on aggregate consumption. Even though rice cookers and water boilers are owned by a minority of households together they account for over 30 percent of total peak evening consumption in the sample. If these families would use LPG or return to using firewood as they traditionally did then the system would, needless to say, perform a lot better.
Contribution to evening maximum peak demand by appliance, for the years 1985 – 2001.

71. Large hydro

72. Large hydro: 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

73. Large hydro: 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

74. Large hydro: 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

76. Chinese Dams on Mekong River
Changes to water flows in the Mekong – particularly during dry season
Blockage of sediment transportation (around 50% of Mekong’s sediment load originates in China)
Blockage of fish migration
Release of poor quality and cold water
Manwan Dam on the Lancang River, Yunnan Province, China

78. Myanmar
Source: Myanmar Country Report on Progress of Power Development Plans and Transmission Interconnection Projects, Nov Downloaded from

79. Greater Mekong Subregion (GMS) Transmission Grid
promoted by ADB since the early 1990s under the Greater Mekong Subregion Programme
When resistance is tough in Thailand, GMS grid allows cross-border exports of environmental & social problem
Socializes transmission costs.

80. Nam Theun 2
Two decades in the making…
Sponsors: Electricité de France, EGCO, Ital-Thai, Government of Laos
Cost = US$1.45 billion
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

81. Nam Theun 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

82. A contrast in support...Nam Theun 2 versus pico-hydro in Laos
Vs.

83. Pico-hydropower use (installation)
Flat
Mountainous
Influences
Seasonality
Type of Installation
Mattijs, Smits, presentation at Chulalungkorn University

84. Pico-hydropower use (river)
Mattijs, Smits, presentation at Chulalungkorn University

85. Pico-hydropower use (river) (2)
Mattijs, Smits, presentation at Chulalungkorn University

86. Pico-hydropower use (river) (3)
Mattijs, Smits, presentation at Chulalungkorn University

87. Pico-hydropower problems
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

88. Financial analysis pico-hydropower (3)
ESMAP, 2005
Mattijs, Smits, presentation at Chulalungkorn University

89. Conclusions technography (1)
Important technology for rural electrification (estimated 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

90. Conclusions technography (2)
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

91. Political ecology: actors
Government (Ministries, institutes)
Multilateral organizations (World Bank, ADB, ...)
International NGOs
Private sector
Mattijs, Smits, presentation at Chulalungkorn University

92. Narratives about pico-hydro
Common narrative: “We do not support pico-hydropower,
because ...
Risks
Seasonal limitations
No increased productivity
Mattijs, Smits, presentation at Chulalungkorn University

93. Interpreting actors’ narratives on pico-hydropower (1)
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

94. Interpreting actors’ narratives on pico-hydropower (2)
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

95. Thank you … and please bring tools for Saturday hands-on PV workshop blender (!) wrenches pliers screw drivers leatherman
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