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Project Report – Mor Ti Hta Primary School Micro-Hydro Project Report

Chris Greacen and Andrew Pascale

28 February 2007

The Mor Ti Hta village primary school now has 24-hour electricity from a micro-hydropower installation

completed in January/February 2007. The project was funded by the UNDP/GEF Small Grants Program.

Mor Ti Hta village is located in Mae Usu Sub District, Tasongyang District, Tak Province. The village is a

long 4-6 hour drive north and east from Mae Sot, two hours of which is over rough jeep track. The Mor Ti

Hta micro-hydropower provides electricity for lights and TV/VCD player to the Mor Ti Hta Thai/Karen

Primary School using energy from a small waterfall about 1 km from the village’s school. The school

houses 60 children and four teachers, most of whom come from neighboring villages and board at theschool throughout the academic term.

Construction of the project involved considerable contributions from villagers, engineering students fromthe Mae La refugee camp, and a mix of foreign volunteers and students. This report first provides an

account of the project construction process and people, followed by a summary of the technical aspects of 

the project.

Project construction summary: The installation of the Mor Ti Hta micro-hydro took place from the 29th

of January to the 9th of February. The 2kW system is sized to match the resource and to allow for about 10-

fold growth in electricity demand from its current 200 watt load.

This project involved collaboration by diverse groups: residents of Mor Ti Hta village, the Border Green

Energy Team1 (BGET) and associates, Palang Thai , Taipei Overseas Peace Service (TOPS), 7 studentsfrom the Engineering Study Program (ESP) in Mae La refugee camp, 22 students from the Village Studies

 program and Spring Street high school in the USA, The Karen Network for Culture and Environment

(KNCE), and Robert Landau. KNCE’s Watit Hathaipassom and BGET’s technical team selected thevillage based on a variety of factors including the social benefit of the electricity (for the school), the

technical feasibility of the project, the willingness of villagers to contribute labor and local materials for the

 project, and the willingness of villagers to contribute monthly payments to a “sustainability fund” to make

1 BGET is a joint project of the Taipei Overseas Peace Service (TOPS), Palang Thai, Green

Empowerment, the Karen Network for Culture and Environment. www.bget.org. 

Mor Ti Hta Waterfall

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repairs and replace broken parts as needed. Community liaison work, together with project surveys, design

iterations, and equipment procurement took place over a nine-month period starting in early-2006. Later,

these groups installed the system together over a two week period and also took many opportunities to

share cultures, stories, songs, lifestyles, and friendship.

On-site work initiated in mid-January, 2007 as the Mor Ti Hta villagers and teachers from the primary

school prepared for the arrival of large numbers of non-village installation participants. January 29 saw thearrival of BGET staff, BGET associates, and ESP students.

Construction began on January 30th. Three teams were established, each lead by a KNCE Karen foreman.

The first team worked on the weir area (see photo 1) led by Dtay. A second team secured and prepared the

cliff face for the penstock and powerhouse (see photos 2) led by Surat. A third team cleared a path for the

transmission line and dug holes for power poles (see photo 3) led by Yoten. These Karen leaders wereaided by BGET staff and foreign volunteers: Salinee Tavaranan, Andrew Pascale, Arie Jongegan, Angie

Beier, Adrian Armorer, James Pulver, Trevor White, and Blake Sitney.

The first group US students – college students from the Institute for Village Studies -- arrived on January

31st accompanied by Chris Greacen from Palang Thai. Work proceeded with materials being distributed as

needed (see photo 4). Holes were dug, rocks moved, cement poured, jungle cleared, and a firm footing for 

the powerhouse established. Nightly songs and culture were swapped following meals of rice, fish paste,fish can, and mama (ramen noodles). The second group of US students arrived on February 3 and the first

group returned to Bangkok. Subsequently, the penstock (photo 5) and powerhouse were finalized.

Photo 1 – Dam area

Photo 3 – Chris Greacen and the

 power line

Photo 2 – Surat leading

 powerhouse preparation

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The final construction step was the connection of the penstock to the turbine (photo 6). The system was

then commissioned and tested on 6 February (photo 7).

Aside from some leaks and challenges at the penstock / turbine interface, the system worked (see photos 8

and 9)! Over the final few days of the project, February 7 – 9, KNCE/BGET and the ESP students worked

on system cleanup, sustainability training, post project survey, and maintenance education for the villagers.

Photo 5 – Connecting the

 penstock 

Photo 4 – Getting the turbine down

the cliff 

Photo 8 - Lights are on!

Photo 6 – Penstock to turbineconnection with gate valve

Photo 9 – Light in Assembly Hall

hydropower system

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Technical Summary:

The micro-hydrpower project comprises four main parts: First, a small weir made of rock, mortar, and sand

 bags located immediately before a waterfall raises the water level in the stream sufficiently high to

submerge a 3-inch diameter pipe (Photo 1); Second, 52 meters of 3-inch diameter pipe brings the water 

downhill (Photo 5) dropping an elevation of 32 meters. The pressurized water enters a two kilowatt “turgo”type generator (Photo 6). The forth component of the project is a set of aluminum wires that transmits the

electricity about one kilometer to the school (Photo 3). 

Electrically, the system at Mor Ti Hta is simple: 230 volt (nominal) electricity is generated at the micro-

hydro turbine/generator unit and transmitted directly to loads (Figure 1).

An important characteristic of the system is that it has no Electronic Load Controller (ELC). In the last

system (Huai Kra Thing, built in 2006) we used an ELC. In Huai Kra Thing, the ELC maintains voltage at230 vac by diverting any excess electricity to a ballast load. This works well, but a problem is that ELCs of 

appropriate size for this project are not available in Thailand. Importing necessary equipment from Nepal is

costly and time-consuming. The cost of the ELC is several times the cost of the micro-hydro turbine. The

Mor Ti Hta system tries to emphasize locally available parts as much as possible.

The downside of not having a load controller is that voltage varies depending on the load and on the

amount of water flowing through the pipe. If load decreases but water flow remains the same, then the

turbine will speed up, generating higher voltage. If voltage is too high, it can damage lights and other appliances.

To keep voltage stable, we need to keep both loads and water flow more or less constant. Keeping water 

flow constant is easy: we adjust the water valve so that sufficient water is flowing to power up the loads

and maintain proper voltage.

Controlling loads is easy too: we have installed very few switches in the system, so most of the lights are

on all the time. This may seem strange and wasteful, but it reflects the nature of a micro-hydropower 

 project with no storage: “use it or lose it”. Whatever electricity is generated has to be consumed right then.

Some lights (at the dorms) are switched simply because it is unpleasant to sleep in a lit room. As long asthese switched loads are small compared with the total load, the voltage variations induced by switching on

and off lights are manageable.

If their is a long school break, the operator has been trained to turn off the micro-hydro by turning off the

water supply.

Even with these provisions, there is some voltage variation. Fortunately, the main electrical load at Mor Ti

Hta is mostly lighting load, and tube-fluorescent lights are particularly robust to variations in voltage if 

accompanied by variations in frequency. The reason has to do with the way that tube fluorescent lighting

 ballasts are made: they have a big coil of wire (an inductor). Inductors have the electrical characteristic that

their electrical impedance (resistance, if you will) is proportional to frequency. The higher the frequency,

the higher the resistance.

Our micro-hydro generator is a permanent magnet generator, and a characteristic of permanent magnet

generators is that voltage is proportional to frequency. Thus, high voltage at the generator is accompanied

 by high frequency – which is exactly the conditions that are safe for tube fluorescents.

Other loads (TV, VCD, satellite dish) don’t share this happy electrical characteristic. Exposed to highvoltage (whether or not accompanied by high frequency) can destroy their circuits. To protect these

sensitive electronics, we made use of the schools’ existing battery and inverter to provide a separate,

electrically isolated alternating current source (Figure 1). We provided a battery charger that uses the

micro-hydropower to charge the school’s battery.

With each incremental growth of the school loads (more lights, refrigerator, etc), the operator will have to

open the water valve a little bit more to provide more mechanical power to overcome the additional

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electrical drag of the new load. Right now, the electrical load is only about 200 watts, which is far less than

the 2,000 watt rated capacity of the generator. There is plenty of room to grow.

In the event of an emergency, operators have been trained to open a fused cut-out switch located both at theschool and at the power house. Opening this switch will disconnect the mirco-hydropower generator from

the entire load, shutting off all electricity. This cut out switch provides a safety mechanism in the case that

there is a short circuit, an electrical fire, or other dangerous condition. But this switch should not be used

routinely as the loss of load will cause the turbine to spin roughly double its typical speed, possibly leading

to premature bearing failure.

Initial status:The system is running, but we’ve had some challenges with substantial leakage in the penstock/turbine

connection which will require a new custom-designed hardware fitting (designed and implemented as of 

3/6/07). We are also making adjustments on the electrical side – adding power factor correction capacitorsto compensate for the low power factor of the fluorescent light ballasts (not implemented yet).

Figure 1: Electrical schematic

Mor Ti Hta School and Loads