Small Hydro Power

For a small hydro system to work, all you need to do is simply harness the energy of continual running water with a turbine, and convert this energy into either DC or AC electricity. Small hydro power systems are classified as mini, small, and micro depending on the capacity of the plant. There are already many villages in India and Nepal that have access to small hydro electricity.
Record shows that small hydro power was introduced in India in 1897 during the time of British colonization. Various cases have been reported which say the small hydro power installed during the early 1900s are still in good condition and functioning properly. Only after Independence did India start working extensively on Small Hydro Power under Five-Year plans. With the effort made by MNES (Ministry of Non-conventional Energy Sources) during the period of the Eighth Five-Year plan, Small hydro was upgraded and additional funds allocated for improvement and expansion. The total installed capacity of small hydro projects in India is 144.28 mw while another 241.87 mw is under construction.
In India, the Hilly Hydro Project funded by United Nations Development Programme–Global Environment Facility have shown considerable amount of interest in the sector in 13 Himalayan states. Many demonstration project on the use of small hydro power for lighting, heating, cooking, irrigation, and small industry have been carried out in the 13 states to check deforestation trends. Various social and technical aspects namely, geography, people, end-use, head, flow, and total power generated have been considered. With the lending operations funded primarily by the World Bank and the Global Environment Facility, the Asia Alternative Energy Program (ASTAE) has assisted with the design of mini-hydro components. 15 small hydro schemes representing 68 MW of capacity are under operation in India.
Nepal being a country of rural and isolated committees, the suitability of micro-hydro systems is distinctly visible. The government of Nepal has great plans to increase the mega Hydro Power generation, and has shown almost the same amount of interest in developing small hydro power, but the policy toward small hydro is not very clear yet. Basically, there are foreign-aided projects that support the development of the power sector in Nepal, including the development of mini- and small hydro resources. Recently, some initiatives have been taken by facilitating Kathmandu University with programs for small hydro power research. In India, Alternative Hydro Energy Centre, set up by ministry of Non-conventional Energy Resources in the year 1982, at the University of Roorkie, Roorkie, has been working for the cooperation in small hydro power research and technology transfer, project design, development and consultancy services.
Both in India and Nepal, small hydro power plants has been considered for rural electrification. This has helped to reduce dependence on fuel wood, generate small enterprises and uplift the rural economy. Nepal is second only to Brazil in terms of hydro power. Nepal has numerous rivers, so there is further prospect of small hydro power in Nepal. The availability of water beyond 4000 meters of height has made permanent settlement possible. At such great heights, one of the most economical means to make electricity available is through the use of small hydro plants.
Small hydro has proved to be very advantageous in both India and Nepal. Micro-hydro has been very helpful in saving trees in the rural parts of both the countries. In addition, small hydro has been instrumental in enhancing economic development and living standards especially in remote areas with limited or no electricity both in India and Nepal. Ghandruk Power Plant in small village Ghandruk in the Annapurna region of Nepal, provides electricity to all houses for lighting purposes. Lodges (usualy meant for foreign tourists) and households have electricity for cooking. Since it is cost-effective, time-saving, and labor-saving, lodge-keepers are very positive about it and are ready to maintain it for ever. They have been able to make good profit out of it. There has been an increase in the local incomes in the Annapurna region. Employment opportunities to people were created when village electrification committee was established to oversee the project. Also when Forest Management Committee regulated some laws regarding the protection of forests, local people benefitted with better employment opportunities. Economic structure has changed and is way too different from many of the rural communities of Nepal. Revenue generated from the households and lodges is used for the village development. It has enhanced the interest of local manufacturers in manufacturing devices out of locally available materials.
Micro-Hydro systems are preferable from an environmental point of view as seasonal river flow patterns downstream are not affected and there is no flooding of valleys upstream of the system. Because of the fact that the motion of the river operates the machine, a complex mechanical governor system is not required, which reduces costs and maintenance requirements. The systems can be build locally at low cost, and the simplicity gives rise to better long term reliability. Dry season, and the lack of storage of excess power generated can be hazardous though.
The future of small hydro power both in India and Nepal is bright. India can provide consultancy services in number of areas of small hydro power like planning, investigation and hydro resource survey, engineering designs for construction works, techno-economic analysis of small hydro power, to name a few. With more private sector participation, the chances of improvement are very high. Even without it, it is likely that there will be a shift in the prority to small hydro projects considering the environmental consequences of large hydro projects, the fragile geology and active seismicity of the region, and the high costs associated with the large hydro projects.

(source:http://web.grinnell.edu/courses/ant/S00/ANT154-01/magar/Hydro.html)