Small hydro is the devel opment of hydroelectric power. The definition of a small hydro project varies, but a generating capacity of 1 to 20 megawatts (MW) is common. In contrast, the three Gorges Dam is 22,500 megawatts or the vast multiple projects of the Tennessee Valley Authority. In India, hydro projects up to 25 MW station capacities have been categorized as Small Hydro Power (SHP) projects. Small hydro projects may be built in isolated areas that would be a national economic grid, or where a national grid does not exist.

The use of the term “small hydro” varies widely around the world, the maximum limit is usually between 10 and 30 MW. While the US National Hydropower Association specifies a minimum limit of 5 MW. The “small hydro” description can be stretched up to 50 MW in the United States, Canada and China. Small hydro can be further subdivided into mini hydro, usually defined as 100 to 1,000 kilowatts (kW), and micro hydro which is 5 to 100 kW. Micro hydro is usually the application of hydroelectric power sized for smaller communities, single families or small enterprise. The smallest facilities are pico hydro, below 5 kW.Since small hydro projects usually have a correspondingly small civil construction and small or no reservoir,

According to REN21, during 2008 small hydro installations grew by 28% over year 2005 to raise the total world small hydro capacity to 85 gigawatts (GW). Over 70% of this was in China (with 65 GW), followed by Japan (3.5 GW), the United States (3 GW) and India (2 GW). Global growth is expected to be 2.8% worldwide until mid-2020 when capacity will be about 150 gigawatts. China plans to electrify a further 10,000 villages between 2005 and 2010 under their China Village Electrification Program, including further investments in small hydro and photovoltaics. By 2010, China had 45,000 small hydro facilities, especially in rural areas, producing 160 twh annually. Over 50% of the world’s potential small hydro power was found in Asia; however, the report noted, ” In the mountains and rain forests of British Columbia, Canada there are many suitable sites for hydro development. However environmental concerns towards large tanks after the 1980s halted new dam construction. The solution to coping with the market, which has built 100 run of the river projects under 50MW. Power production without reservoirs varies dramatically, but does not allow the production of conventional products. In 2014 these independent producers generated 18,000 GWh from 4,500 MW of capacity. In the mountains and rain forests of British Columbia, Canada there are many suitable sites for hydro development. However environmental concerns towards large tanks after the 1980s halted new dam construction. The solution to coping with the market, which has built 100 run of the river projects under 50MW. Power production without reservoirs varies dramatically, but does not allow the production of conventional products. In 2014 these independent producers generated 18,000 GWh from 4,500 MW of capacity. The solution to coping with the market, which has built 100 run of the river projects under 50MW. Power production without reservoirs varies dramatically, but does not allow the production of conventional products. In 2014 these independent producers generated 18,000 GWh from 4,500 MW of capacity. The solution to coping with the market, which has built 100 run of the river projects under 50MW. Power production without reservoirs varies dramatically, but does not allow the production of conventional products. In 2014 these independent producers generated 18,000 GWh from 4,500 MW of capacity.

Hydroelectric power is the generation of electric power from the movement of water. A hydroelectric facility requires a dependable flow of water and a reasonable height for the water to fall, called the head. In a typical installation, water is fed from a reservoir through a pipe into a turbine. The water flowing through the turbine causes an electrical generator to rotate, converting the motion into electrical energy. Small hydro can be developed by constructing new facilities or through re-development of existing ones whose primary purpose is flood control, or irrigation. Old hydro sites can be re-developed, sometimes with substantial investment in the facility such as penstock pipe and turbines, or just re-using the water rights associated with an abandoned site.

Many companies offer a range of 200 kW to 10 MW. These “water to wire” packages simplify the planning and development of the site since one looks after the most of the equipment supply. Because these costs are minimized and expanded, the cost of such packages is reduced. While synchronous generators can be used for small and medium sized plants, they can be used to reduce the cost of production. Small “run of the river” projects do not have a reservoir, only a weir to form a headpond for diversion of inlet water turbine. Unused water can be used to save time and money, but it can not be enough. A preferred scenario is to have an inlet in an existing lake. Countries like India and China have policies in favor of small hydro, and the regulatory process allows for building dams and reservoirs. In North America and Europe the regulatory process is too long and expensive to consider a dam and a reservoir for a small project. Small hydro projects generally have more rapid environmental and licensing procedures, and the construction of the equipment is standardized and simplified, and the civil works construction is also reduced, the projects may be developed very rapidly. The smaller size of the equipment makes it easier to transport the goods. One measure of low environmental impact with lakes and reservoirs depends on the balance between water flow and power production. Reducing water diversions helps the river’s ecosystem, but reduces the system’s return on investment (ROI). The hydro system design must strike a balance to maintain both the health of the stream and the economics.

Africa * Zengamina, 700 kW plant in Kalene Hill, Mwinilunga District in northwestern Zambia. 2008Asia