How to Harness the Power of a Waterfall

In some parts of the world having electricity is still only a dream. People in countries like Bangladesh are suffering through major energy crises. Bangladeshi people in small towns and rural villages live with a limited supply of electric power, and some have none at all. The need for renewable, home-based sources of energy is urgent. In the rural hills of Bangladesh, a micro-hydroelectric power station could be installed across a stream, spring, or waterfall to generate electricity for local villagers, and help to alleviate the country's energy crisis. Several such projects are under development in Bangladesh. In a study published in the Journal of Applied Sciences, engineers from Malaysia evaluated streams and waterfalls in the Khagrachari Hill District of Bangladesh for their potential as micro-hydroelectric power generators. Due to its location near three small villages, and relative accessibility, the Sapcharai Waterfall was chosen for closer study.

Micro-hydroelectric plants are small hydroelectric energy systems, with the ability to generate between one kilowatt and one megawatt of power. Head and flow determine the amount of electricity that can be generated by the waterfall. Head defines the distance water drops, from the highest level, to the turbine or water wheel, to generate electric power. Flow is a measurement of how much water moves through the system. A higher head requires less water flow for the same amount of electricity. Data on rainfall, waterfall flow rate, and power generation potential was collected for a period covering the dry season throughout the entire monsoon season of Bangladesh. The waterfall head was measured from the primary to the secondary reservoir, and from the secondary, or main reservoir, to the tertiary reservoir. Flow rate was measured using a bucket and a stopwatch. Power generation capacity is nearly proportional to the flow rate, and will vary throughout the year, increasing during the rainy season, and declining in drier months.

The study included a limited evaluation on the effect of a micro-hydroelectric generator on the ecosystem. The waterfall habitat includes small fish, prawns, and other microorganisms. The authors determined that leaking oil or other lubricants from mechanical parts could endanger aquatic life, as well as the supply of drinking water for local villagers. However, preventive measures during construction, and proper maintenance will minimize the potential impact.

The new power generator is expected to have a positive impact on the local community, making daily life more manageable, and improving the local economy. New electric water pumps will ease the challenge of getting water to hilltop villages. The authors suggest that the new power station may bring more tourist dollars to the area as well. The waterfall is already an attraction for adventurous tourists, and a micro-hydroelectric power station may boost interest in the waterfall.

The authors concluded that the Sapchari waterfall has excellent potential for micro-hydroelectric power generation. Both head distance and a flow rate are adequate for use even in the drier season. The area is fairly accessible using local transportation, and effects on the ecosystem are expected to be minimal. The beauty of the area, and curiosity over the power station may also bring the boon of tourism to the local economy. In rural Bangladesh, where electricity is hard to come by, a local waterfall has the potential to provide both a clean, renewable source of power, and, for local villagers, an opportunity to transform their way of life forever.

Reference

Wazed, M., Shamsuddin, A.

A Feasibility Study of Micro-Hydroelectric Power Generation at Sapchari Waterfall, Khagrachari, Bangladesh

Journal of Applied Sciences, http://www.scialert.net/jindex.php?issn=1812-5654

http://www.scialert.net/pdfs/jas/2009/372-376.pdf