112:. The penstock builds up pressure from the water that has traveled downwards. In mountainous areas, access to the route of the penstock may provide considerable challenges. If the water source and turbine are far apart, the construction of the penstock may be the largest part of the costs of construction. At the turbine, a controlling valve is installed to regulate the flow and the speed of the turbine. The turbine converts the flow and pressure of the water to mechanical energy; the water emerging from the turbine returns to the natural watercourse along a tailrace channel. The turbine turns a
145:
head must be considered. Gross head approximates power accessibility through the vertical distance measurement alone whereas net head subtracts pressure lost due to friction in piping from the gross head. "Flow" is the actual quantity of water falling from a site and is usually measured in gallons per minute, cubic feet per second, or liters per second. Low flow/high head installations in steep terrain have significant pipe costs. A long penstock starts with low pressure pipe at the top and progressively higher pressure pipe closer to the turbine in order to reduce pipe costs.
1103:
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299:, the simplicity and low relative cost of micro hydro systems open up new opportunities for some isolated communities in need of electricity. With only a small stream needed, remote areas can access lighting and communications for homes, medical clinics, schools, and other facilities. Microhydro can even run a certain level of machinery supporting small businesses. Regions along the
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101:
diverted from the natural stream, river, or perhaps a waterfall. An intake structure such as a catch box is required to screen out floating debris and fish, using a screen or array of bars to keep out large objects. In temperate climates, this structure must resist ice as well. The intake may have a gate to allow the system to be dewatered for inspection and maintenance.
149:
feet, the theoretical maximum power output is 5.65 kW. The system is prevented from 100% efficiency (from obtaining all 5.65 kW) due to the real world, such as: turbine efficiency, friction in pipe, and conversion from potential to kinetic energy. Turbine efficiency is generally between 50-80%, and pipe friction is accounted for using the
235:, a pressurized self-cleaning crossflow waterwheel, is often preferred for low-head micro hydro systems. Though less efficient, its simpler structure is less expensive than other low-head turbines of the same capacity. Since the water flows in, then out of it, it cleans itself and is less prone to jam with debris.
271: : advanced hydraulic water wheels and hydraulic wheel-part reaction turbine can have hydraulic efficiencies of 67% and 85% respectively. Overshot water wheel maximum efficiency (hydraulic efficiency) is 85%. Undershot water wheels can operate with very low head, but also have efficiencies below 30%.
286:
Microhydro systems are very flexible and can be deployed in a number of different environments. They are dependent on how much water flow the source (creek, river, stream) has and the velocity of the flow of water. Energy can be stored in battery banks at sites that are far from a facility or used in
100:
Construction details of a microhydro plant are site-specific. Sometimes an existing mill-pond or other artificial reservoir is available and can be adapted for power production. In general, microhydro systems are made up of a number of components. The most important include the intake where water is
357:
Microhydro systems are limited mainly by the characteristics of the site. The most direct limitation comes from small sources with the minuscule flow. Likewise, flow can fluctuate seasonally in some areas. Lastly, though perhaps the foremost disadvantage is the distance from the power source to the
182:
always operates at the grid frequency irrespective of its rotation speed; all that is necessary is to ensure that it is driven by the turbine faster than the synchronous speed so that it generates power rather than consuming it. Other types of generator can use a speed control systems for frequency
161:
Typically, an automatic controller operates the turbine inlet valve to maintain constant speed (and frequency) when the load changes on the generator. In a system connected to a grid with multiple sources, the turbine control ensures that power always flows out from the generator to the system. The
148:
The available power, in kilowatts, from such a system can be calculated by the equation P=Q*H/k, where Q is the flow rate in gallons per minute, H is the static head, and k is a constant of 5,310 gal*ft/min*kW. For instance, for a system with a flow of 500 gallons per minute and a static head of 60
144:
is the pressure measurement of water falling in a pipe expressed as a function of the vertical distance the water falls. This change in elevation is usually measured in feet or meters. A drop of at least 2 feet is required or the system may not be feasible. When quantifying head, both gross and net
223:
turbines are used. Very low head installations of only a few meters may use propeller-type turbines in a pit, or water wheels and
Archimedes screws. Small micro hydro installations may successfully use industrial centrifugal pumps, run in reverse as prime movers; while the efficiency may not be as
303:
mountains and in Sri Lanka and China already have similar, active programs. One seemingly unexpected use of such systems in some areas is to keep young community members from moving into more urban regions in order to spur economic growth. Also, as the possibility of financial incentives for less
190:
which produces output at grid frequency. Power electronics now allow the use of permanent magnet alternators that produce wild AC to be stabilised. This approach allows low speed / low head water turbines to be competitive; they can run at the best speed for extraction of energy, and the power
287:
addition to a system that is directly connected so that in times of high demand there is additional reserve energy available. These systems can be designed to minimize community and environmental impact regularly caused by large dams or other mass hydroelectric generation sites.
210:
can be used in micro hydro installations, selection depending on the head of water, the volume of flow, and such factors as availability of local maintenance and transport of equipment to the site. For hilly regions where a waterfall of 50 meters or more may be available, a
311:
Micro-hydro installations can also provide multiple uses. For instance, micro-hydro projects in rural Asia have incorporated agro-processing facilities such as rice mills – alongside standard electrification – into the project design.
277: : part of the river flow at a weir or natural water fall is diverted into a round basin with a central bottom exit that creates a vortex. A simple rotor (and connected generator) is moved by the kinetic energy. Efficiencies of 83% down to 64% at 1/3 part flow.
349:" system meaning that water diverted from the stream or river is redirected back into the same watercourse. Adding to the potential economic benefits of microhydro is efficiency, reliability, and cost effectiveness.
59:
is offered. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without the purchase of fuel. Micro hydro systems complement
265: : Is a high flow, low head, propeller-type turbine. An alternative to the traditional kaplan turbine is a large diameter, slow turning, permanent magnet, sloped open flow VLH turbine with efficiencies of 90%.
174:
may be automatically connected to the generator to dissipate energy not required by the load; while this wastes energy, it may be required if it's not possible to control the water flow through the turbine.
139:
of electricity. This can be enough to power a home or small business facility. This production range is calculated in terms of "head" and "flow". The higher each of these are, the more power available.
227:
In low-head installations, maintenance and mechanism costs can be relatively high. A low-head system moves larger amounts of water, and is more likely to encounter surface debris. For this reason a
120:; this might be directly connected to the power system of a single building in very small installations, or may be connected to a community distribution system for several homes or buildings.
809:
104:
The intake is then brought through a canal and then forebay. The forebay is used for sediment holding. At the bottom of the system the water is tunneled through a pipeline (
64:
because in many areas water flow, and thus available hydro power, is highest in the winter when solar energy is at a minimum. Micro hydro is frequently accomplished with a
1067:
333:
Microhydro power is generated through a process that utilizes the natural flow of water. This power is most commonly converted into electricity. With no direct
55:. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks, particularly where
841:
186:
With the availability of modern power electronics it is often easier to operate the generator at an arbitrary frequency and feed its output through an
337:
resulting from this conversion process, there are little to no harmful effects on the environment, if planned well, thus supplying power from a
994:
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pool, at the top of a waterfall, with several hundred feet of pipe leading to a small generator housing. In low head sites, generally
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site in need of energy. This distributional issue as well as the others are key when considering using a micro-hydro system.
737:
150:
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711:
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794:
Quaranta and Muller (2017). "Sagebien and
Zuppinger water wheels for very low head hydropower applications".
608:
555:
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375:
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253:
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187:
61:
966:
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Quaranta and
Revelli (2015). "Output power and power losses estimation for an overshot water wheel".
696:. Final Technical Report, The US Department of Energy, August 1998, The Department of Energy's (DOE)
113:
81:
198:), a few kilowatts or smaller, may generate direct current and charge batteries for peak use times.
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969:(project financed by the European Commission, involves Italy, Croatia, Norway, Greece and Austria)
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high as a purpose-built runner, the relatively low cost makes the projects economically feasible.
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The cost of a micro hydro plant can be between 1,000 and 5000 U.S. dollars per kW installed
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256:: the Gorlov helical turbine free stream or constrained flow with or without a dam,
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use an
Archimedes' screw which is another debris-tolerant design. Efficiency 85%.
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SMART - Strategies to promote small scale hydro electricity production in Europe
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Microhydro systems are typically set up in areas capable of producing up to 100
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Usually, microhydro installations do not have a dam and reservoir, like large
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processes grows, the future of microhydro systems may become more appealing.
170:. In some systems, if the useful load on the generator is not high enough, a
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662:"Module 3e: Comparison of Pipe Flow Equations and Head Losses in Fittings"
51:
using the natural flow of water. Installations below 5 kW are called
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frequency is controlled by the electronics instead of the generator.
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have, relying on a minimal flow of water to be available year-round.
1009:
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1004:
631:"Preparing Your Land for Hydroelectric Power - Renewable Energy"
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72:, low flow water supply. The installation is often just a small
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242:(Reverse Archimedes' screw): two low-head schemes in England,
73:
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698:
Information Bridge: DOE Scientific and
Technical Information
27:
Hydroelectric power generation of 5 to 100 kW of electricity
931:
929:
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885:. The Ashden Awards for Sustainable Energy. Archived from
47:
that typically produces from 5 kW to 100 kW of
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RENEWABLE ENERGY TECHNOLOGIES: COST ANALYSIS <:SERIES
1000:
Example of a new
Scottish Highland micro hydro system
694:
Development of the helical reaction hydraulic turbine
609:"Determining a Potential Microhydropower Site's Flow"
550:
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1068:List of conventional hydroelectric power stations
877:
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671:. University of Alabama College of Engineering
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8:
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166:generated needs to match the local standard
858:. Research Institute for Sustainable Energy
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498:"Micro Hydro in the fight against poverty"
108:) to the powerhouse building containing a
504:. TVE/ITDG. November 2004. Archived from
215:can be used. For low head installations,
31:
991:, Idaho National Engineering Laboratory
744:. MJ2 Technologies. n.d. Archived from
460:
840:: CS1 maint: archived copy as title (
833:
979:European Small Hydropower Association
660:Pitt, Robert; Clark, Shirley (n.d.).
476:International Renewable Energy Agency
7:
345:manner. Microhydro is considered a "
275:Gravitation water vortex power plant
937:"Micro Hydro Power - Pros and Cons"
25:
1093:Run-of-the-river hydroelectricity
995:Ashden Awards hydro power winners
939:. Alternative Energy News Network
1101:
975:, Dorado Vista ranch application
396:
382:
368:
36:Micro hydro in northwest Vietnam
1073:Pumped-storage hydroelectricity
531:"How a Microhydro System Works"
291:Potential for rural development
259:Francis and propeller turbines.
1005:Home built micro hydro project
449:Gravitation water vortex power
1:
583:"Micro Hydroelectric Systems"
131:Head and flow characteristics
116:, which is then connected to
781:10.1016/j.renene.2015.05.018
585:. Oregon DOE. Archived from
324:Advantages and disadvantages
1208:
984:Micro Hydro Association UK
962:Portal on microhydro power
194:Very small installations (
1099:
556:"Microhydropower Systems"
96:Typical microhydro setup.
1182:Power station technology
157:Regulation and operation
973:Micro Hydro information
478:. June 2012. p. 11
376:Renewable energy portal
151:Hazen–Williams equation
1192:Distributed generation
1177:Appropriate technology
1136:Gorlov helical turbine
97:
62:solar PV power systems
37:
989:Hydropower Prospector
95:
35:
414:up to 10,000 kW
125:hydroelectric plants
822:on 26 December 2017
635:motherearthnews.com
589:on 29 November 2010
180:induction generator
164:alternating current
45:hydroelectric power
1151:Cross-flow turbine
889:on 1 November 2010
796:Hydraulic Research
748:on 16 January 2017
738:"Hydrovision 2015"
434:Sustainable energy
98:
82:Archimedes' screws
38:
1164:
1163:
909:"Microhydropower"
639:Mother Earth News
297:rural development
233:Ossberger turbine
206:Several types of
168:utility frequency
162:frequency of the
16:(Redirected from
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1187:Hydroelectricity
1112:Hydroelectricity
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641:. February 1986
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420:up to 5 kW
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295:In relation to
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1141:Pelton wheel
1082:
941:. Retrieved
916:. Retrieved
903:
891:. Retrieved
887:the original
860:. Retrieved
856:"Microhydro"
850:
824:. Retrieved
817:the original
804:
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750:. Retrieved
746:the original
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716:the original
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591:. Retrieved
587:the original
560:. Retrieved
535:. Retrieved
510:. Retrieved
506:the original
501:
492:
480:. Retrieved
463:
444:Vortex power
439:Water wheels
404:Water portal
356:
347:run-of-river
332:
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294:
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244:Settle Hydro
231:also called
226:
213:Pelton wheel
205:
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103:
99:
88:Construction
78:water wheels
66:pelton wheel
57:net metering
40:
39:
29:
1156:Water wheel
1083:Micro hydro
1078:Small hydro
943:24 November
918:20 November
893:20 November
826:25 December
775:: 979–987.
690:Gorlov A.M.
615:28 November
562:28 November
537:28 November
424:Hydro power
412:Small hydro
343:sustainable
269:Water wheel
248:Torrs Hydro
49:electricity
41:Micro hydro
18:Micro-hydro
1171:Categories
1088:Pico hydro
1056:generation
1046:Hydropower
914:. U.S. DOE
862:9 December
752:14 January
675:14 January
669:eng.ua.edu
645:14 January
611:. U.S. DOE
593:1 December
558:. U.S. DOE
533:. U.S. DOE
512:14 January
482:14 January
474:(Report).
455:References
418:Pico hydro
329:Advantages
196:pico hydro
183:matching.
84:are used.
53:pico hydro
1114:equipment
339:renewable
335:emissions
172:load bank
137:kilowatts
114:generator
68:for high
836:cite web
362:See also
188:inverter
106:penstock
722:29 June
502:tve.org
217:Francis
110:turbine
254:Gorlov
74:dammed
912:(PDF)
820:(PDF)
813:(PDF)
665:(PDF)
472:(PDF)
301:Andes
945:2010
920:2010
895:2010
864:2010
842:link
828:2017
754:2017
724:2009
677:2017
647:2017
617:2010
595:2010
564:2010
539:2010
514:2017
484:2017
316:Cost
246:and
80:and
70:head
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