This article is from ECHO Asia Note #3
Rugged northeastern Myanmar is home to the Lahu, Shan, Akha, Palaung and various other ethnic groups. With few paved roads and only a small percentage of the Shan State's population connected to the electrical grid, infrastructure serving the locals is still very limited.
Approximately 10 years ago, traders from neighboring China capitalized on the lack of access to electricity by introducing microhydro generators. Roughly the size of a 20- liter container, the Chinese-made turbines typically generate between 1-3 kilowatts with larger models producing 5 kw or more. While energy within this range is not enough to power larger appliances (e.g., refrigerators, washing machines), a few light bulbs and very small household appliances such as fans, televisions and radios can be operated.
Relatively inexpensive (selling between $70-450 US, depending on electrical capacity), these generators are also fairly simple to install. However, for a generator's turbine to rotate adequately, the main requirement is access to a sufficient volume of water moving at a necessary rate of speed.
According to experts, micro-hydro systems need a combination of head (hydraulic gradient between two or more points) and flow (volume of fluid which passes through a given surface per unit time) somewhere between these extremes: 2 feet (0.6 m) of drop and 500 gallons (1,892.7 l) per minute, or 2 gallons (7.5 l) of water per minute and 500 feet (152.4 m) of drop. Fortunately, the eastern Shan State is rich in sites that meet such criteria.
Local Micro-Hydro Options
Rev. Lazarus Pa, director of the Christian Social Service and Development Department (CSSDD) of the Keng Tung-based Lahu Baptist Convention, also oversees the work of the Rural Integrated Development Program (RIDP). Besides assisting area Lahu hilltribe communities to access clean water, the RIDP team promotes improved agricultural production and extends microcredit opportunities.
Soon after micro-hydro generators were introduced to the region, RIDP's director purchased a 3 kw unit to try out. With the generator proving affordable, easy to install and reliable, Rev. Lazarus became convinced that micro-hydro technology would be an ideal way of providing electricity to offgrid communities.
Since evaluating the first unit, the RIDP team has assisted over 30 communities to install two basic types of Chinese-made micro-hydro generators:
- Pipe-fed units with internal turbines.
- Units containing external turbines mounted onto long shafts (having an appearance similar to an outboard motor).
Regionally, available micro-hydro technology is not limited to simple internal and external turbine models. According to Dr. Thanad Katpradit,managing director of ENGINEO, Ltd., a renewable energy business based in Chiang Mai, Thailand, a more versatile hybrid model that can be powered by either water or an engine is also on the market. However, the simple micro-hydro units are both reliable and more affordable, and remain the generators of choice in the Shan State.
The Installation of Pipe-Fed Units
According to Rev. Lazarus, the pipe-fed units are easiest to install. The main requirement is an adequate supply of falling water which can enter a 3-inch intake pipe at a 45-degree angle (although he says, from experience, angles as low as 20 degrees are still usable).
To enable the internal turbine of a 1 kw micro-hydro unit to operate at an adequate generating speed, Rev. Lazarus' estimation is that a minimum 25 ft. (7.6 m) vertical drop is needed. A 50 ft. (15.2 m) and 75 ft. (22.9 m) drop are required for 2 kw and 3 kw generators, respectively.
The following table offers example specifications related to the drop and volume of water needed to operate certain types of micro-hydro units (ENGINEO, Ltd.):
Water Requirements for Select Pipe-Fed Micro-Hydro Units*
Model Drop Water Volume Intake Pipe Size
(kw) (meters) (l/second) (in.)
0.6 5 5-8 3
1.0 5 5-8 3
1.5 8 10-12 3
2.0 10 15-20 3.5
3.0 15 15-30 3.5
*Water requirements (e.g., drop, volume) may vary among products. Generators should be installed and maintained according to material requirements as stated by the manufacturer.
Therefore, to make use of pipe-fed units with internal turbines, households or communities that are candidates for such technology must be located fairly close to water sources, such as mountain streams or irrigation channels, which can provide adequate drop to generator installation sites.
The External Turbine Unit Option
However, should the local water supply lack the minimum 5-7 m drop, an external turbine unit that can operate with significantly less drop (1.8-3.2 m) may be an option. For example, where lesssteep terrain in the Shan State offers an adequate source of flowing water, part of the stream can be diverted into channels specially made for powering external turbines.
Rev. Lazarus explains that channels providing a necessary flow of water for external turbine units should measure approximately 1 ft. deep by 1 ft. wide (0.3 m x 0.3 m) for 1 kw micro-hydro units. Larger 2 kw units require 2 ft. x 2 ft. (0.6 m x 0.6 m) channels, whereas slightly larger channels are needed for 3 kw generators.
The most important component of such channels is a feature that forces water to ultimately spin in a clockwise vortex which in turn causes the external turbine of a microhydro unit to rotate. To enable the vortex effect, the end of the channel should be rounded and include a minimal 5-6 inch (12.7 cm - 15.2 cm) intake opening through which water can spin into the top of a cement or PVC penstock (a vertical drainage shaft). External turbines are installed in these intakes to take advantage of the vortices.
The height of the penstock is a critical component for the function of external turbine units. Depending on the electrical output of generators, drop should range between 6-10 ft. (1.8 m - 3.1 m). Additionally, to intensify the vortex effect, the diameter of the water outlet at the bottom should be twice the diameter of the top intake with water exiting from the side of the penstock rather than being dumped vertically. User manuals for the micro-hydro generators also recommend that the outlet at the bottom of each penstock be fully submerged in the water course into which it empties.
Community-Based Generator Installation and Maintenance
Through RIDP's ongoing work, one to three generators (1.5, 2 or 3.5 kw units) are installed in each focus community. Rev. Lazarus states that although 5 kw generators are available, they are more expensive, require more water and are more difficult to install.
According to the capacity of each community, the residents contribute a percentage of the overall cost of the generators. And after initial training, community members are fully responsible for the installation of the equipment and the construction of necessary infrastructure such as water channels. However, the RIDP team provides follow up and offers trouble shooting assistance as needed.
Because two ball bearings within the generators are often of inferior quality, Rev. Lazarus recommends that the components be changed out for higher quality bearings within six months of initial use. However, little additional maintenance is required except to protect the inner works of the generators from rainwater, sand and corrosives such as salt.
Additionally, leaves and other debris can collect in the channels which feed water to the external turbine units, causing water intakes to clog and turbines to stall. Therefore, channels and drainage shafts should be checked regularly and foreign materials removed as needed.
Electricity in Eden
Rev. Jabo, pastor of the Baptist church in the RIDP focus community of Eden on the outskirts of Keng Tung, reports that among 140 households there are currently 20 micro-hydro generators in service, including both pipe-fed and external turbine units. The first village micro-hydro unit was purchased from a Chinese trader six years ago. Today, dozens of electrical lines crisscross the village, connecting homes to an array of generators that line a tumbling stream beyond the village.
The church pastor explains that each 1 kw generator serves five households, providing enough power to operate a few light bulbs, a radio and perhaps a TV.
It should be noted, however, that basic micro-hydro generators are not equipped with voltage regulators needed to maintain a steady electrical supply for the efficient operation of household appliances. To avoid electrical load problems for appliances being powered by micro-hydro, ENGINEO's Dr. Thanad recommends the use of an automatic voltage regulator (AVR) or stabilizer.
Despite the limited amount of electricity that each household receives, Rev. Jabo says that the benefits from micro-hydro units are significant. For example, because children have more time to study after sunset, school performance improves. The availability of electricity also makes it possible for women to spend more time on handicrafts in the evening, which in turn improves household income generation. And on a community level, local micro-hydro power allows church members to conduct choir practice and other church-related activities after dark.
The Regional Spread of Micro-Hydro
Rev. Lazarus observes that access to the Chinese-made micro-hydro generators is not limited to the Shan State. He has received reports that the technology has spread to other mountainous regions of Myanmar, including the distant Kachin, Chin and Kayah States.
And RIDP is not alone in promoting alternative energy in the region. Inside neighboring Thailand, Palang Thai , a non-profit organization, and the affiliated Border Green Energy Team (BGET) promote alternative energy options including the installation and sustainable operation of micro-hydro systems.
Related to such micro-hydro installation, Palang Thai/BGET has filmed the process in various locations with related videos posted on YouTube. The following links include micro-hydro work at Mae Wei , a 200-watt system at Mae Klang Luang, another 500-watt system at Mae Klang Luang, and the Kre Ki hydropower project.
In the Myanmar border town of Tachilek, as well as Keng Tung, the Chinesemade micro-hydro units are readily available in hardware stores. However, in Thailand, where most of the population is already connected to the national power grid, such units are somewhat difficult to locate. And due to import taxes, the cost of units is approximately twice those in Myanmar.
Meanwhile, the spread of micro-hydro power in the eastern Shan State is obvious from the number of light bulbs seen glowing in houses along remote stretches of the road between the Thai border and Keng Tung. Impressively, all this is made possible by the availability of affordable appropriate technology, natural resources and innovative people.
Guanxi Rongxian Luo Jiang Industrial Development Area (Chinese language micro-hydro product manual), People's Republic of China.
ENGINEO, Ltd., Micro hydro turbine. http://www.engineo.co.th/hydro%20turbine.files/hydro.htm
Hren Stephan and Rebecca. Excerpt from "The Carbon-Free Home: 36 Remodeling Projects to Help Kick the Fossil-Fuel Habit, "The Chelsea Green Newsletter," May 2009, Issue 1. http://www.chelseagreen.com/content/microhydro-power-in-your-backyardhow-to-assess-your-site/
Thanad Katpradit, e-mail message, June 6, 2009.
Yong Zir Hydro-Electric Equipment Dian Ji Tzu, (Chinese language micro-hydro product brochure), Kunming, People's Republic of China.
Wikipedia contributors, "Hydraulic head," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Hydraulic_head&oldid=318228316 (accessed October 19, 2009).
Wikipedia contributors, "Volumetric flow rate," Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php? title=Volumetric_flow_rate&oldid=318556938 (accessed October 19, 2009).
Thanks to Sarah Rutherford and Ayixianmu Maihesuti for helping to translate portions of the Chinese micro-hydro generator manuals