Small hydro, which includes so-called mini- and micro-hydro projects on small rivers and creeks, is most often defined as dams with a capacity up to 10 megawatts, though some countries define it as including dams of up to 25 or 30 megawatts. (The world’s biggest dam, the Three Gorges Dam in China, has a 22,500-megawatt capacity). Although designs differ and sometimes rivers do get diverted, small hydro dams are often built as “run-of-river” projects, meaning the flow of the river turns some turbines in the dam to produce electricity without the need to create a reservoir behind those turbines. This can provide cheap, off-grid power, allowing rural areas access to electricity.
So far, about 75 gigawatts of small hydro have been installed worldwide, the bulk of it in China (37 gigawatts), Europe (about 17 gigawatts), and North America (about 8 gigawatts). So how much small hydro potential remains? According to one assessment from the United Nations Industrial Development Organization (UNIDO), the total remaining global potential is just under 100 gigawatts of projects of 10 megawatts or less. That’s equal to 100 nuclear reactors or big coal power plants.
A glance at the specifics of small hydro’s potential sharpens the focus on developing countries even further. East Africa has only 208 megawatts of installed small hydro, with another 6,000 megawatts (6 gigawatts) that could be added; Kenya alone, with less than 2,000 megawatts of installed electricity from any source, could add 3,000 megawatts of small hydropower, according to UNIDO. Southeast Asia also has 6,000 megawatts of untapped potential. (The U.S. and Canada have tapped more than 85 percent of their small hydro potential already, with about another 1,000 megawatts that could still be developed, UNIDO says.)
Indian Scenario
It has been estimated that there are more than 1.5 lakh potential water mill sites in the Himalayan regions of India. With the R&D efforts, new and improved designs of water mills have been developed for mechanical as well as electricity generation of 3-5 kW. These designs were tested at AHEC, IIT Roorkee and have been replicated by 6-7 small scale manufacturers. Two Watermill Development centers, One in Uttrakhand and another in northeast, are proposed to be developed in coordination with reputed local NGO’s engaged in training and development of Watermills capacity building programme etc., the AHEC,IIT Roorkee and concern SNAs may also be involved as a technical partner for the center. The Center will also act as monitoring cell of the Watermill and Micro Hydro Project system.
To encourage and accelerate the development of water mills and micro hydel projects in the remote & hilly areas, a scheme for providing Central Financial Assistance (CFA) during 2014-2015 and the remaining period of the 12th Five year Plan for development/upgradation of watermills and setting up of micro hydel projects upto 100 kw capacity to State Government Departments/State Nodal Agencies/Local Bodies/Co-operatives/NGOs/Tea Garden & Individual entrepreneurs
