Difference between revisions of "Hydro Power Basics"

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= <span><span>Micro</span> Hydropower</span>  =
 
  
&nbsp;
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[[Portal:Hydro|► Back to Hydro Portal]]<br/>
  
== How it works  ==
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= Overview =
  
&nbsp;
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A mass of water moving down a height difference contains energy which can be harvested using some waterwheel or turbine. The moving water drives the waterwheel and this rotation either drives machinery directly (e.g. mill, pump, hammer, thresher, ...) or is coupled with a generator which produces electric power.
  
<span>Hydropower is based on simple concepts. Moving water
+
<br/>
turns a turbine, the turbine spins a generator, and electricity is produced.
 
Many other components may be in a system, but it all begins with the energy
 
already within the moving water.</span>  
 
  
<span>Water
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{{#widget:YouTube|id=q8HmRLCgDAI}}<br/>
power is the combination of head and flow. Both must be present to produce
 
electricity. In a&nbsp;typical hydro system water
 
is diverted from a stream into a pipeline, where it is directed downhill and
 
through the turbine (flow). The vertical drop (head) creates pressure at the
 
bottom end of the pipeline. The pressurized water emerging from the end of the
 
pipe creates the force that drives the turbine. More flow or more head produces
 
more electricity. Electrical power output will always be slightly less than
 
water power input due to turbine and system inefficiencies.</span>  
 
  
<span>Head
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= Principle of Hydro Power =
is water pressure, which is created by the difference in elevation between the
 
water intake and the turbine. Head can be expressed as vertical distance (
 
meters). Net head is the pressure available at the turbine when water is
 
flowing, which will always be less than the pressure when the water is turned
 
off (static head), due to the friction between the water and the pipe. Pipeline
 
diameter has an effect on net head.</span>
 
  
<span>Flow
+
Hydro power is probably the first form of automated power production which is not human / animal driven. Moving a grind stone for milling first, developed into the driving of an electrical generator. Next to steam it was for long the main power source for electricity.Its continual availability does not require any power storage (unlike [[Portal:Wind|wind]] / [[Portal:Solar|solar power]]). It is mainly mechanical hardware. This makes it relative easy to understand and repair-/maintainable. In smaller units its environmental impact becomes neglect-able (see: [[Hydro - Environmental Impact Assessment (EIA)|environmental impact assessment]] and [[Micro Hydro Power (MHP) - Pros and Cons|pros and cons of micro hydropower]]).
is water quantity, and is expressed as "volume per time," such as
 
cubic feet per second (cfs), or liters per minute (lpm). Design flow is the
 
maximum flow for which your hydro system is designed. It will likely be less
 
than the maximum flow of your stream (especially during the rainy season), more
 
than your minimum flow, and a compromise between potential electrical output
 
and system cost.</span>
 
  
'''When is hydropower micro?'''
+
<br/>
  
<span>
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= Head & Flow =
</span>
 
  
The definition of micro hydropower varies in different countries and can even include systems with a capacity of a few megawatts. &nbsp;In some cases&nbsp;up to &nbsp;a rated capacity of&nbsp;300 kW is considered as Microhydro &nbsp;because this is about the maximum size for most stand alone hydro systems not connected to the grid, and suitable for "run-of-the-river" installations.&nbsp;
+
<u>In order to create electricity from hydropower, two parameters are critical:</u><br/>
  
But, In general&nbsp;'''Micro hydro'''<span> is a
+
*'''Flow'''; or the minimum amount of water that is constantly available throughout the entire year
term used for hydroelectric power installations that typically '''produce 10 to 100 kW of power '''. They
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*'''Head'''; the difference in height<br/>
are often used in water rich areas as a Remote Area Power Supply (RAPS). </span>  
 
  
&nbsp;
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These specific conditions limit generalising and standartisation of "how to install hydropower plants". Choosing the right location and planning requires some specific knowledge. With knowledge of water flow and height difference the potential power can be estimated. <br />
  
'''<span>Classification</span>''' of Hydropower by size
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== Measuring Head & Flow ==
  
{| cellpadding="0" border="1"
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<u><span>The first step to judge a sites hydropower potential is to measure/estimate head and flow.</span></u><br/>
 +
 
 +
*<span>Head (the vertical distance between the intake and turbine)</span>
 +
*Flow (how much water comes down the stream)
 +
 
 +
<br/>
 +
 
 +
Head is very often exaggerated as is the flow rate, which varies over the year!
 +
 
 +
Wrong data occurs frequently. Confirmation of existing data is '''highly recommended'''!
 +
 
 +
<span>Head and flow are the two most important facts of a hydro site. This will determine everything about the hydro system - volume of civil constructions, pipeline size, turbine type and power output. </span>Inaccurate measurements result in low efficiency, high cost and scarcity of power.
 +
 
 +
<br/>
 +
 
 +
*For sophisticated methods how to inquire a sites feasibility, please check the [[Micro Hydro Power (MHP) Manuals|Manuals]] section.
 +
*"[[:File:Laymans book - how to develop a small hydro site 128-266.pdf|Layman's book: How to develop a Small Hydro Site]]" may be a good start.
 +
 
 +
<br/>
 +
 
 +
== Methods of Head and Flow Measurement without Sophisticated Tools ==
 +
 
 +
*'''<u><span style="font-weight: bold">E</span>stimation of height</u>''' can be done easiest if there is a steep slope (waterfall) by rope.
 +
 
 +
<br/>
 +
 
 +
<u>Principle of a step by step head measurement:</u><br/>
 +
 
 +
[[File:Head measurement.jpg|thumb|center|600px|Head measurement.jpg]]
 +
 
 +
<br/>
 +
 
 +
By measuring total height step by step, it's crucial to do the bearing strictly horizontally. Ensure that by using a level or a water filled hose. Widely available are hoses and pressure gauges which allow the easiest method of height measurement. As longer the hose as less steps have to be taken to measure the total head.
 +
 
 +
<br/>
 +
 
 +
{| style="width: 500px" cellspacing="1" cellpadding="5" border="0" align="center"
 
|-
 
|-
| valign="top" |  
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| [[File:Height measure by level.jpg|thumb|left|200px|Height measure by level.jpg]]<br/>
<span>Large hydro&nbsp;</span> <br>  
+
| [[File:Head by pressure gauge.jpg|thumb|left|200px|Head by pressure gauge.jpg]]<br/>
 +
| [[File:Height measure by hose.jpg|thumb|left|200px|Height measure by hose.jpg]]<br/>
 +
|}
 +
 
 +
<br/>
 +
 
 +
*<u>'''Estimation of flow'''</u> is very difficult without measurement.
 +
 
 +
<br/>
 +
 
 +
<u>A quick and easy way to measure is the '''floating method''':</u><br/>
 +
 
 +
#<u>First</u>, measure the waters speed at an steady flowing part of the river. Therefore drop some item and stop the time it needs for a certain distance to float.
 +
#<u>Second</u>, do a sketch of the rivers cross section by measuring its depth every 20-50 cm so you come up with a grid showing the rivers profile from side to side. With this data its cross sections area can be calculated easily.
 +
#<u>Finally</u> the flow volume results from (water) speed x (section) area.
 +
 
 +
<br/>
 +
 
 +
[[File:Flow measurement.jpg|thumb|center|600px|Flow measurement.jpg]]
 +
 
 +
<br/>
 +
 
 +
<u>Example:</u><br/>
 +
 
 +
A ball drifts 10 m in 12 s => speed = 10m/12s = <u>0.12 m/s.</u><br/>Cross section => A<sub>1</sub>= 25 cm * 40 cm (0.25 m * 0.4 m) = 0.1 m<sup>2 </sup>; A<sub>1</sub>+A<sub>2</sub>+ ... = A = <u>0.5 m<sup>2</sup></u><br/>Flow volume = 0.12 m/s * 0.5 m<sup>2</sup> = 0.06 m<sup>3</sup>/s => 60 l/s
 +
 
 +
<br/>
 +
 
 +
*<u>To estimate a sites '''potential cost''' its necessary to know additionally:</u><br/><ul style="margin-left: 40px;">
 +
</ul>
 +
<li>Pipeline (penstock) length</li>
 +
<li>Electrical transmission line length (from turbine to consumer). As smaller the sites power output as higher the power lines cost share</li>
 +
<li>Number of potential customers</li>
 +
 
 +
[[Hydro Power Basics#toc|►Go to Top]]
 +
 
 +
<br/>
 +
 
 +
== Units and Power Estimations ==
 +
 
 +
Power: watts [W] or Kilowatts [kW] 1 kW = 1000W<br/>Flow: 1 m³/s = 1000 l/s<br/>Gross heat: height difference the water "falls down"<br/>Net head: a little smaller than gross head. Gross head deducted by energy loss due to friction in penstock
 +
 
 +
<br/>
 +
 
 +
<u>'''Potential power ('''electric)'''''' is calculated as follows:</u><br/>Power [W] = Net head [m] x Flow [ l/s] x 9.81 [m/s²] (est. gravity constant) x 0.5 (turbine/generator efficiency)<br/>Potential power is <u>estimated</u> as follows:<br/>Power output [W] = height [m] * flow [l/s] * 5
 +
 
 +
<br/>
 +
 
 +
<u>'''More accurate estimations''' take into consideration:</u>
 +
 
 +
*exact net head (intake to powerhouse)
 +
*exact flow (constant during the year?)
 +
*combined efficiency of turbine and generator (depends on quality, est. 60% = 0.6)
 +
 
 +
<br/>
 +
 
 +
'''Example:'''<br/>A 6 m high waterfall has 300 liter/sec => potential power est.&nbsp;: 6 m * 300 l/s * 5 = 9000 W = 9 kW
 +
 
 +
[[Hydro Power Basics#toc|►Go to Top]]
 +
 
 +
<br/>
 +
 
 +
= Classification of Hydro Power =
 +
 
 +
== By Size ==
 +
 
 +
Hydropower installations can be classified by size of power output, although the power output is only an approximate diversion between different classes. There is no international consensus for setting the size threshold between small and large hydropower.
  
| valign="top" |
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For the [http://www.unido.org/ United Nations Industrial Development Organization (UNIDO)] and the [http://www.esha.be/ European Small Hydropower Association (ESHA)] and the [http://cbip.org/iash/iash.html International Association for Small Hydro (IASH)] a capacity of up to '''10''' '''MW''' total is becoming the generally accepted norm for '''small hydropower plants (SHP)'''. In China, it can refer to capacities of up to 25 MW, in India up to 15 MW and in Sweden small means up to 1.5 MW, in Canada 'small' can refer to upper limit capacities of between 20 and 25 MW, and in the United States 'small' can mean 30 MW.<br/>
<span>More than 100 MW and usually feeding into a large
 
</span>electricity grid <br>  
 
  
 +
The German Federal Ministry for Environment, Nature Conservation and Nuclear Safety mentioned that a SHP is <1 MW, everything above is a large hydro electric plant and usually comes along with a large dam. The [http://www.icold-cigb.org/ International Commission on Large Dams (ICOLD)] defines a large dam as a dam with a height of 15 m or more from the foundation. If dams are between 5-15 m high and have a reservoir volume of more than 3 million m<sup>3</sup>, they are also classified as large dams. Using this definition, there are over 45 000 large dams around the world.<br/>
 +
 +
<br/>
 +
 +
<u>Small hydro can be further subdivided into mini, micro and pico:</u>
 +
 +
{| class="FCK__ShowTableBorders" style="width: 100%" cellspacing="1" cellpadding="1" border="1"
 +
|-
 +
|
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*'''Mini (MH)'''<br/>
 +
 +
| style="width: 70px" | < 1 MW
 +
| style="width: 155px" | grid connected
 +
| special know how required
 
|-
 
|-
| valign="top" |  
+
|  
<span>Medium-hydro
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*'''Micro'''
</span><br>
 
  
| valign="top" |  
+
| style="width: 70px" | < 100 kW
15 - 100 MW - usually feeding a grid
+
| style="width: 155px" | partially grid con.<br/>
 +
| professional know how required
 +
|-
 +
|
 +
*'''Pico (PH)'''
  
 +
| style="width: 70px" | < 10 kW
 +
| style="width: 155px" | island grids
 +
| small series units produced locally; professional equipment available
 
|-
 
|-
| valign="top" |  
+
|  
<span>Small-hydro
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*'''Family (FH)'''
</span><br>
+
 
 +
| style="width: 70px" | < ~1 kW
 +
| style="width: 155px" | single households/clusters
 +
| often locally handmade solutions; professional equipment available
 +
|}
  
| valign="top" |
+
<br/>
1 - 15 MW - usually feeding into a grid
 
  
 +
There is no binding definition how mini hydro power output is to be classified. Rules for communication avoiding misunderstandings: Generally the terms can be used "downwards compatible". Pico- is also Mini- but not visa versa. Specific terms (Pico, Family) should be used only if they are required to indicate specifics. The spectrum needs higher diversification as smaller it becomes as there are certain differences in technique, usage, applicability and the grade of of ability to replicate them.<br/>
 +
 +
<br/>
 +
 +
<u>'''Comments:'''</u><br/>
 +
 +
*all installations require "special" knowhow
 +
*there are "over the counter" pico turbines available for "self installation"
 +
*<span>Micro hydro is perhaps the most mature of the modern small-scale energy supply technologies used in developing countries. There are thought to be tens of thousands of plant in the “micro” range operating successfully in China</span>[[#ftn1|[1]]]<span>, Nepal, Sri Lanka, Pakistan, Vietnam and Peru.</span>
 +
*Historically the term hydropower developed from naming very small units towards nowadays huge dams. Then there where new terms created to separate different clusters. All of them are hydropower. What is considered "mini or "micro" may be defined once and forever ... or not. If there are different opinions on this topic you're welcome to open a discussion group on this.
 +
 +
<br/>
 +
 +
<u>Comments on the Debate “small” versus “large” Hydro Power:</u><br/>
 +
 +
Classification according to size has led to concepts such as ‘small hydro’ and ‘large hydro’, based on installed capacity measured in MW as the defining criterion. Defining hydropower by size is somewhat arbitrary, as there are no clear relationships between installed capacity and general properties of hydro power or its impacts. Hydro power comes in manifold project types (see Classification [[Hydro Power Basics#By Facility Type.5B3.5D|By Facility Type]]) and is a highly site-specific technology, where each project is a tailor-made outcome for a particular location within a given river basin to meet specific needs for energy and water management services.
 +
 +
<br/>
 +
 +
'''Large hydropower developments''' involve large dams and huge water storage reservoirs. They are typically grid connected supplying large grids. Preference for large hydro is on the decline due to the high investment costs, long payback periods and huge environmental impacts (losses of arable land, forced migration, diseases and damage to biodiversity). Many [[Micro Hydro Power (MHP) - Pros and Cons|social and environmental impacts]] are related to the impoundment and existence of a reservoir, and therefore are greater for 'large hydro' plants with reservoir.
 +
 +
<br/>
 +
 +
'''Small hydropower stations '''are typically run-of-the-river. They combine the advantages of hydropower with those of decentralised power generation, without the disadvantages of large scale installations. [[Socio-economic and Environmental Impacts of MHP|Advantages]] include: low distribution costs, no/low environmental costs as with large hydro, low maintenance and local implementation and management. Power generated with small hydro station can be used for agro-processing, local lighting, water pumps and small businesses<ref name="Energy Technology">GTZ (2007): Eastern Africa Resource Base: GTZ Online Regional Energy Resource Base: Regional and Country Specific Energy Resource Database: I - Energy Technology</ref>.
 +
 +
<br/>
 +
 +
The constructions and integration into local environments of '''Small Hydro Power (SHP)''' schemes typically takes less time and effort compared to large hydropower plants. For this reason, the deployment of SHPs is increasing in many parts of the world, especially in remote areas where other energy sources are not viable or are not economically attractive.
 +
 +
<br/>
 +
 +
However, larger facilities will tend to have lower costs on a USD/kW basis due to economies of scale, even if that tendency will only hold on average. Moreover, one large-scale hydropower project of 2,000 MW located in a remote area of one river basin might have fewer negative impacts than the cumulative impacts of four hundred 5 MW hydropower projects in many river basins (see also [[Socio-economic and Environmental Impacts of MHP#Negative Environmental Impacts|Negative Environmental Impacts]]
 +
 +
<br/>
 +
 +
{| style="width: 100%" cellspacing="1" cellpadding="5" border="1"
 
|-
 
|-
| valign="top" |  
+
| style="background-color: rgb(153, 153, 153)" |  
<span>Mini-hydro
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'''General concepts like ‘small’ or ‘large hydro’ are not technically or scientifically rigorous indicators of impacts, economics or characteristics. Hydropower projects cover a continuum in scale, and it may be more useful to evaluate a hydropower project on its sustainability or economic performance, thus setting out more realistic indicators'''<ref>IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation, Chapter 5 Hydropower (2011). Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref>.<br/>
</span><br>  
+
 
 +
|}
 +
 
 +
[[Hydro Power Basics#toc|►Go to Top]]
 +
 
 +
<br/>
 +
 
 +
== By Facility Type ==
 +
 
 +
<u>Hydropower plants can be classified in three categories according to operation and type of flow:</u><ref name="http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.">http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref>
 +
 
 +
#'''Run-of-river (RoR), '''<br/>Small and micro hydropower utilizes water that runs of a river and avoids big environmental impacts.
 +
#'''Storage (reservoir)'''
 +
#'''Pumped storage hydro power plants (HPPs)''' work as energy buffer and do not produce net energy.
 +
#'''In-stream Hydropower Schemes '''use a rivers natural elevation drop without to dam a river.
  
| valign="top" |
+
<br/>'''<u>'Run-of-River Hydropower' Plant (RoR)</u>'''<ref name="http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.">http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref>
<span>Above 100 kW, but below 1 MW; either stand alone
 
</span>schemes or more often feeding into the grid <br>  
 
  
 +
{| style="width: 100%" cellspacing="1" cellpadding="1" align="left"
 
|-
 
|-
| valign="top" |  
+
| style="width: 248px" | [[File:Run-of-River Hydropower Plant.JPG|thumb|left|x199px|Run-of-River Hydropower Plant]]<br/>
'''Micro-hydro'''
+
| style="width: 407px" |
 +
*RoR plant produce energy from the available flow and the natural elevation drop of a river<br/>
 +
*It is suitable for rivers that have at least a minimum flow all year round.<br/>
 +
*The water to powers th turbine is diverted and channeled into a penstock and then returned to the river
 +
*RoR plants usually have no or only small storage, allowing for some adaptations to the demand profile.
 +
*As bigger the storage capacity is as higher the environmental impacts are
 +
*Power generation is dictated by local river flow conditions and thus depends on precipitation and runoff and may have substantial daily, monthly or seasonal variations
  
| valign="top" |
+
|}
'''<span>From 5kW up</span>''' to 100 kW; usually provided power for a small community or rural industry in<br>remote areas away from the grid. <br>
 
  
 +
<br/><br/><br/><br/><br/>
 +
 +
<br/><br/><br/><br/><br/><br/><br/>
 +
 +
<u>'''Hydropower Plant with Reservoir'''</u><ref name="http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.">http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref>
 +
 +
{| style="width: 100%" cellspacing="1" cellpadding="1"
 
|-
 
|-
| valign="top" |  
+
| style="width: 222px" | [[File:Hydropower Plant with Reservoir.JPG|thumb|left|x159px|Hydropower Plant with reservoir]]
<span>Pico-hydro
+
| style="width: 433px" |
</span><br>  
+
*Hydropower projects with a reservoir (storage hydropower) store water behind a dam for times when river flow is low<br/>
 +
*<span style="line-height: 1.5em">Therefore power generation is more stable and less variable than for RoR plants</span>
 +
*The generating stations are located at the dam toe or further downstream, connected to the reservoir through tunnels or pipelines
 +
*Type and design of reservoirs are decided by the landscape and in many parts of the world are inundated river valleys where the reservoir is an artificial lake
 +
*Reservoir hydropower plants can have major environmental and social impacts due to the&nbsp;[[Using Hydro Power Plants for Flood Prevention|flooding of land for the reservoir]]<br/>
 +
 
 +
|}
  
| valign="top" |
+
<u>'''Pump Storage Hydropower Plant'''</u><ref name="http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.">http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref>
From a few hundred watts up to 5kW
 
  
 +
{| style="width: 100%" cellspacing="1" cellpadding="1" border="0"
 
|-
 
|-
| valign="top" |  
+
| [[File:Pump Storage Project.JPG|thumb|left|x188px|Pump Storage Project.JPG]]
&nbsp;
+
|  
 +
*Pumped storage plants are not energy sources, instead they are storage devices
 +
*Water is pumped from a lower reservoir into an upper reservoir, usually during off-peak hours, while flow is reversed to generate electricity during the daily peak load period or at other times of need
 +
*Although the losses of the pumping process make such a plant a net energy consumer, the plant provides large-scale energy storage system benefits
 +
*Pumped storage is the largest capacity form of grid energy storage now readily available worldwide
 +
 
 +
|}
  
| valign="top" |  
+
<u>'''In-stream Hydropower Scheme'''</u><ref name="http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.">http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref>
&nbsp;  
+
 
 +
{| style="width: 100%" cellspacing="1" cellpadding="1" border="0"
 +
|-
 +
| style="width: 206px" |
 +
[[File:In-stream Hydropower Scheme.PNG|thumb|left|x134px|n-storgare hydropower scheme]]non typical installation of an in-stream HPP
 +
 
 +
| style="width: 547px" |
 +
*Basically in-stream Hydropower functions like a RoR scheme, but the turbine is mostly built within the dam in the riverbed. Usually the river flow is not diverted.
 +
*To optimize existing&nbsp; weirs, barrages, canals or falls, small turbines or hydrokinetic turbines can be installed
 +
*At rivers close to the sea the technologies may operate bi-directional (tidal)
  
 
|}
 
|}
  
&nbsp;
+
► Text and Figures of this chapter are originally mainly taken from the Chapter 5 of the [http://srren.ipcc-wg3.de/report IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation (2011)].
  
<span>Micro
+
[[Hydro Power Basics#toc|►Go to Top]]
hydro is perhaps the most mature of the modern small-scale decentralized energy
 
supply technologies used in developing countries.&nbsp;There are thought to be tens of thousands of
 
plant in the “micro” range operating successfully in China</span>[[#_ftn1|<span><span><span><span>[1]</span></span></span></span>]]<span>, and significant numbers are operated in wide ranging countries such as
 
Nepal,
 
Sri Lanka,
 
Pakistan,
 
Vietnam
 
and Peru.&nbsp;This experience shows that in certain
 
circumstances micro hydro can be profitable in financial terms, while at
 
others, even unprofitable plant can exhibit such strong positive impacts on the
 
lives of poor people.&nbsp;</span>
 
  
<br>  
+
<br/>
  
<br>
+
= Facts on Hydro Power =
  
== '''<span>Components of a Micro</span> Hydro system'''  ==
+
== Existing Generation<ref name="http://www.hydropower-dams.com/world-atlas-industry-guide.php?c_id=159">http://www.hydropower-dams.com/world-atlas-industry-guide.php?c_id=159</ref><ref name="http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.">http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.</ref> ==
  
<!--[if gte vml 1]>
+
In 2010, in 161 countries hydropower is installed making up a worldwide installed hydro electric capacity of 926 GW which provide one-fifth of the world's electricity supply. Out of these 161 countries five countries make up more than the half of the world's hydropower production: China (~200 GW), Canada (74.4 GW), Brasil (84 GW), the USA (78.2 GW) and Russia (49.7 GW).
  
 +
Often hydropower is the main or even only source for electricity production in developing countries.<br/>Any other conventional energy source requires steady fuel. Such, like coal, gas or oil has to be purchased.
  
 +
<br/>
  
 +
{| style="width: 100%;  height: 534px" cellspacing="1" cellpadding="1" border="1" align="center"
 +
|-
 +
! style="width: 147px;  text-align: left;  background-color: rgb(204, 204, 204)" scope="row" | Country<ref name="http://www.hydropower-dams.com/world-atlas-industry-guide.php?c_id=159">http://www.hydropower-dams.com/world-atlas-industry-guide.php?c_id=159</ref>
 +
! style="width: 147px;  text-align: left;  background-color: rgb(204, 204, 204)" | Installed Hydropower Capacity in MW
 +
! style="width: 147px;  text-align: left;  background-color: rgb(204, 204, 204)" | &nbsp;% of total electricity generation
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Burundi
 +
| style="width: 237px;  text-align: center" | 50.5
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Bhutan
 +
| style="width: 237px;  text-align: center" | 1488
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Congo, Dem. Rep.
 +
| style="width: 237px;  text-align: center" | 2442
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Lesotho
 +
| style="width: 237px;  text-align: center" | 76
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Namibia
 +
| style="width: 237px;  text-align: center" | 249
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Paraguay
 +
| style="width: 237px;  text-align: center" | 68000
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Mozambique
 +
| style="width: 237px;  text-align: center" | 2179
 +
| style="width: 230px;  text-align: center" | 100
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Zambia
 +
| style="width: 237px;  text-align: center" | 1812
 +
| style="width: 230px;  text-align: center" | >99
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Norway
 +
| style="width: 237px;  text-align: center" | 29636
 +
| style="width: 230px;  text-align: center" | 99
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Albania
 +
| style="width: 237px;  text-align: center" | 1450
 +
| style="width: 230px;  text-align: center" | 98
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Lao PDR
 +
| style="width: 237px;  text-align: center" | 2000
 +
| style="width: 230px;  text-align: center" | 98
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Tajikistan
 +
| style="width: 237px;  text-align: center" | 5200
 +
| style="width: 230px;  text-align: center" | 96
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Ethiopia
 +
| style="width: 237px;  text-align: center" | 784
 +
| style="width: 230px;  text-align: center" | >95
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Malawi
 +
| style="width: 237px;  text-align: center" | 290
 +
| style="width: 230px;  text-align: center" | 95
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Cameroon
 +
| style="width: 237px;  text-align: center" | 720
 +
| style="width: 230px;  text-align: center" | 94
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Nepal
 +
| style="width: 237px;  text-align: center" | 660
 +
| style="width: 230px;  text-align: center" | 92
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Kyrgyz Republic
 +
| style="width: 237px;  text-align: center" | 2910
 +
| style="width: 230px;  text-align: center" | 91
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Congo, Rep.
 +
| style="width: 237px;  text-align: center" | 119
 +
| style="width: 230px;  text-align: center" | >90
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Georgia
 +
| style="width: 237px;  text-align: center" | 2850
 +
| style="width: 230px;  text-align: center" | 86
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Brazil
 +
| style="width: 237px;  text-align: center" | 84000
 +
| style="width: 230px;  text-align: center" | 84
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Swaziland
 +
| style="width: 237px;  text-align: center" | 42
 +
| style="width: 230px;  text-align: center" | 82
 +
|-
 +
! style="width: 147px;  text-align: left" scope="row" | Central afric. Rep.
 +
| style="width: 237px;  text-align: center" | 24.6
 +
| style="width: 230px;  text-align: center" | 80
 +
|}
 +
 +
<br/>
 +
 +
*For Existing Sites see also [[Hydropower Sites - GPS Coordinates|GPS coordinates - Hydropower sites]]
 +
 +
[[Hydro Power Basics#toc|►Go to Top]]
  
 +
<br/>
  
 +
== Hydropower Potential ==
  
 +
Hydropower potential means: an <u>amount of water</u> (flow) which flows down a certain <u>height</u>.<br/>To utilise such, the produced electricity is to be transportet by powerline to potential users.
  
 +
Hydropower offers a significant potential of renewable energy production. In 2009 electricity production from hydropower was about 16% of the global electricity production. The undeveloped capacity ranges from 30% in Europe up to 88% in Africa.
  
 +
<u>If reading such numbers please keep in mind:</u>
  
 +
*There is a structural difference between small and big hydropower;<br/>the first is mainly decentralised - the later is usually utilized by big structures, which have usually massive environmental impacts
 +
*Hydropower potential is bound to specific sites, which may be far from potential energy usage
  
 +
<br/>
  
 +
Small hydropower potential is given in hilly or mountainous regions, where rivers do not fall dry during the year.<br/>Where gravity fed irrigation is practiced small and micro power plants find suiting conditions.
  
 +
Mountainous regions often have bad infrastructure and are least to be connected to a electric grid. If there is water available it may be a suitable source for decentralised hydro power electrification. Such setups may even get support from governmental or major electricity supplier. The costs to connect remote areas are high, whereby the revenue, due to little amount of electricity utilised, is low.
  
 +
[[Hydro Power Basics#toc|►Go to Top]]<br/>
  
 +
<br/>
  
 +
= Micro Hydro Power Schemes =
  
 +
== <span>Components of a Micro</span> Hydro System (MHS) - Overview ==
  
 +
=== Grid connection for MHP's ===
  
 +
Hydropower usually operates 24 h / day. Most mhp's are connected by a grid to their consumers. If a connection towards the national or main grid is available, electricity can be fed in there. Often micro or pico hydropower units are installed in remote areas. There they feed an isolated grid. In such grid the MHP is usually the only power source. The power produced has to be leveled equal with the power consumed (see controller).
  
 +
Battery storage is no must like at solar or wind power projects. This is a big advantage as it reduces costs and maintenance significantly. Charging stations can nevertheless extend a mhp's effectiveness by utilising power in times of low demand (late night). Like this, even consumers which are too far from the station to be connected by transmission cable can be served via rechargeable batteries.
  
<![endif]-->[http://www.howtopedia.org/en/Image:Micropowerplante02.jpg [[Image:|Image:Micropowerplante02.jpg]]]<span><!--[if gte vml 1]>
+
[[Hydro Power Basics#toc|►Go to Top]]
  
<![endif]-->[[Image:]]</span>  
+
<br/>
  
<br>
+
=== Storage Basin or Dams ===
  
== '''<span>Suitable conditions for</span> micro-hydro power'''  ==
+
Small hydropower plants usually use (part-) river flow as driving force. Storage basins or even dams can buffer water. So demand peaks or (short) periods of water shortage can be bridged. As such infrastructures is costly and sophisticated, it's only used if there is a clear financial revenue; e.g. electricity supply for remote industries. Standard elements for mhp
  
<span>The best geographical areas for
+
<u>'''Construction''' a MHP consists of:</u>
exploiting small-scale hydro power are those where there are steep rivers
 
flowing all year round, for example, the hill areas of countries with high
 
year-round rainfall, or the great mountain ranges and their foothills, like the
 
Andes and the Himalayas. Islands with moist marine climates, such as the
 
Caribbean Islands, the Philippines and Indonesia are also suitable. Low-head
 
turbines have been developed for small-scale exploitation of rivers where there
 
is a small head but sufficient flow to provide adequate power. </span>  
 
  
<span>To assess the suitability of a potential site, the hydrology of the site
+
divertion constructions in the river, Guiding water per canal and pipe, the '''electrical-mechanical''' '''equipment''' to turn water power into electricity plus transmission lines and house connections.
needs to be known and a site survey carried out, to determine actual flow and
 
head data. Hydrological information can be obtained from the meteorology or
 
irrigation department usually run by the national government. This data gives a
 
good overall picture of annual rain patterns and likely fluctuations in
 
precipitation and, therefore, flow patterns. The site survey gives more
 
detailed information of the site conditions to allow power calculation to be
 
done and design work to begin. Flow data should be gathered over a period of at
 
least one full year where possible, so as to ascertain the fluctuation in river
 
flow over the various seasons. There are many methods for carrying out flow and
 
head measurements and these can be found in the relevant texts.</span>
 
  
&lt;span /&gt;
+
Nevertheless if it is community based, main challenge will be the '''social setup'''. The people of the community who will build / use the MHP have to be introduced, trained, learned and encouraged to organise, operate and manage their power station. A sustainable working mhp scheme requires users who are enabled to understand "their" system.
  
== '''<span>Measuring</span> Head &amp; Flow'''  ==
+
<br/>
  
'''<span><!--[if gte vml 1]>
+
[[File:Depok.jpg|thumb|center|400px|alt=Depok.jpg]]
 +
 
 +
<br/>
 +
 
 +
{| style="width: 500px" cellspacing="1" cellpadding="5" align="center"
 +
|-
 +
| [[File:Forbay trashrack pennstock.jpg|thumb|left|300px|Forbay trashrack pennstock.jpg]]
 +
| [[File:Powerhouse 2.jpg|thumb|left|300px|Powerhouse 2.jpg]]<br/><br/>
 +
|}
 +
 
 +
<br/>
 +
 
 +
{| style="width: 501px" cellspacing="1" cellpadding="5" align="center"
 +
|-
 +
| [[File:Management-Poster.jpg|thumb|left|200px|alt=Management-Poster.jpg]]<br/><br/>
 +
| style="width: 237px" | [[File:Canal-participation-2.jpg|thumb|left|200px|Canal-participation-2.jpg]]
 +
|}
  
 +
[[File:Introduction-hydro.jpg|thumb|center|250px|Introduction-hydro.jpg]]
  
 +
<br/>
 +
<div>
 +
*<span style="line-height: 1.5em;  font-size: 0.85em">For an overview or possible impacts on a mhp's success, check out the </span>'''[[:File:Mhp-tree-3.jpg|mhp-tree-diagram]]'''
  
 +
[[Hydro Power Basics#toc|►Go to Top]]
  
 +
<br/>
  
 +
== <span>Suitable Conditions for</span> Micro Hydro Power ==
  
 +
Again, "'''head and flow'''" matter. The best geographical areas for exploiting small-scale hydro power are those where there are steep rivers flowing all year round. The Andes, the Himalayas, islands with moist marine climates, such as the Caribbean Islands, the Philippines and Indonesia are widely suitable. Laos, Vietnam and wide parts of China use Micro Hydro Power in large numbers.<br/>A locations, head, flow and number of consumers allow to calculate the available power share per consumer<br/>Minimal Head may be 1-2 m. For considerable power then much water (> 1 m3) is required<br/>Minimal Flow may be 20 l/s. Power is according to head output (see [[Hydro Power Basics#Measuring Head .26 Flow|power estimation]]).<br/>Mini Hydropower operates constantly and requires little maintenance. It is ideal for powering remote regions. Although grid connection is very feasible due to its very low operational costs.
  
 +
[[Hydro Power Basics#toc|►Go to Top]]
  
 +
<br/>
  
 +
==== Brief Site Assessment ====
  
 +
*location Data
 +
*head, flow
 +
*length of powerline
 +
*length of penstock
 +
*land use
  
 +
[[:File:Brief site assessment.pdf|=> a two page condensed site assessment]]
  
 +
<br/>
  
 +
<u>'''Flow measures '''in feasibility studies:</u><br/>Flow data should be gathered over a period of at least one year where possible, so as to ascertain the fluctuation in river flow over the various seasons.<br/>At least '''measures must be taken during dry season''' to assure that there is always enough water to power the turbine. Too little water results in power cut. If such is not clear to consumers from begin with it can seriously endanger the projects success.
  
 +
[[Hydro Power Basics#toc|►Go to Top]]
  
 +
<br/>
  
 +
== Economics of Micro Hydro Systems ==
  
 +
=== Productive Use ===
  
 +
Electricity is a key factor for productive businesses. Experience shows, this isn't an automatism very commonly. Additional income is generated only if the revenue is made from outside the community. Typically added value is created by subsequent processing of commodities. Exemplary: coffee roasting, fruit drying, freezing fish, ...
  
<![endif]-->[[Image:|Stream Illustration]]</span>'''
+
► find more information here: [[Micro Hydro Power (MHP) Plants#Use of Micro Hydro Power Plants|Micro Hydro Power (MHP) Plants - Use of MHP]]
  
&nbsp;
+
[[Hydro Power Basics#toc|►Go to Top]]
  
<span>Before
+
<br/>
designing a hydro system or estimating how much electricity it will
 
produce,&nbsp;four essential measurements
 
should be taken:</span>  
 
  
<span>•
+
=== Cost ===
Head (the vertical distance between the intake and turbine)
 
</span>
 
  
• Flow (how much water comes down the stream)  
+
The major cost of a MHP scheme is for its site preparation and equipment. It's nearly 100&nbsp;% upfront investment and very low running cost (operation and maintenance).
  
• Pipeline (penstock) length
+
Cash usually is a scarce resource in rural areas of development countries. Part of a feasibility study has to be: how high tariffs have to be set to cover the costs. Its a must to, at least, break even operation & maintenance expenses. This money has to come from the users for electricity or el. services. A mhp can operate many decades if tariffs cover repair costs. In the long run a mhp's management is the crucial factor for its success.
  
• Electrical transmission line length (from turbine to home or battery bank)  
+
► Find more information here: [[Micro Hydro Power (MHP) Plants#Costs|Micro Hydro Power (MHP) Plants - Costs]]
  
<span>Head
+
[[Hydro Power Basics#toc|►Go to Top]]
and flow are the two most important facts of a &nbsp;hydro site. &nbsp;This will determine everything about the hydro
 
system—pipeline size, turbine type, rotational speed, and generator size. Even
 
rough cost estimates will be impossible until &nbsp;head and flow are measured. Accuracy is
 
important when measuring head and flow.&nbsp;Inaccurate
 
measurements can result in a hydro system designed to the wrong specifications,
 
and one that produces less electricity at a greater expense.</span>
 
  
&lt;span /&gt;
+
<br/>
  
== &nbsp;'''Calculation o Hydro Power'''  ==
+
=== Tariff Setting ===
  
<span>Power
+
Tariff setting is a crucial element. In case the mhp management is community based, tariffs have to be set in acceptance with the community. Ensure sufficient high tariffs! Community discussion may be lengthy, be patient. Never leave the impression that mhp-electricity may be "for free".
is measured in watts or Kilowatts.</span>
 
  
<span>I
+
Examples: Compare the cost for oil wig lighting with a single bulb. Compare "luxury" expenses with the comfort of el. lighting (cigarettes, drinking, ...). Explain the management function like how to run a business. Minimally the revenue has to cover the expenses. Check download section for an excel-tool which shows cost coverage.
kW = 1000W</span>
 
  
<span>Flow:
+
► Links: [[Tariffs|Tariffs]], [[Metering and Billing Systems|Metering and Billing]]
1 m³/s = 1000 l/s</span>
 
  
<span>Gross
+
[[Hydro Power Basics#toc|►Go to Top]]
head = Head of the water</span>
 
  
<span>Net
+
<br/>
head&nbsp;: Deducted the energy loss from forebay through penstock to hydro turbine,
 
a little smaller than gross head.</span>  
 
  
<span>The
+
=== Revenues ===
hydro power in a stream or a river can be calculated as follows:</span>
 
  
<span>Hydro
+
<u>Within a community based scheme extra revenue can be used for:</u>
power ( kW ) = Net head ( m ) x Flow ( m³/s ) x Gravity&nbsp;( 9.81 m/s² )*</span>  
 
  
&nbsp;
+
*social tariffs (elder, poor, school, ...)
 +
*street lighting
 +
*powering a drinking water pump
 +
*community services (washing, freezing, ironing)
  
<span>(
+
<br/>
9.81 is acceleration due to gravity which can be assumed to be constant )</span>  
 
  
&nbsp;  
+
Availability of cash gives also other possibilities to gain additional revenues. E.g. to build storage capacities which can house a communities harvest; by gross deals during off season prices are high.<br/>Financial benefits to the communities served are usually reduced expenses for oil, batteries and petrol to power lamps, radios and machines. Check potentials for productive use during feasibility study. Existing and planned machinery (type and power?)
  
<span>For
+
[[Hydro Power Basics#toc|►Go to Top]]
example, If the available flow is 0.15 cubic meters per second and the net head
 
is 4.7 metres, the hydro power is= 4.7 x 0.15 x 9.81 = 6.9 kW</span>
 
  
<span>If
+
<br/>
the flow in litres per second ( l/s ) is used, then the power will be given in
 
watts instead of kilowatts.</span>  
 
  
<span>To
+
=== Efforts ===
estimate the electrical power produced by a generator, the efficiency of the
 
system must be taken into consideration. Efficiency is the word used to
 
describe how well the power is converted from one form to&nbsp;another. A turbine that has an efficiency of
 
70&nbsp;% will convert 70&nbsp;% of the hydraulic power into mechanical power ( 30% being
 
lost ). The system efficiency is the combined efficiency of all the processes
 
together. The system efficiency for electricity generation using micro hydro is
 
typically between 50% and 60%.</span>
 
  
&nbsp;  
+
Main non financial efforts at microhydro installations are: the right choice of sites, their specific planning and supervision of quality standards; all this is esp. laborious in remote areas. If a scheme is community based, such plays a key role.
  
<span>Electrical
+
[[Hydro Power Basics#toc|►Go to Top]]
power = Hydro power X System efficiency</span>
 
  
&nbsp;
+
<br/>
  
<span>I.e.
+
== Some Hints ==
as a rough estimate, if there is found to be 6.9 kW of hydro power in a small
 
river, the electrical power is = 6.9 x 50% = 6.9 x 0.5 = 3.45 kW</span>
 
  
(<span>the theoretical power must be multiplied by 0.50 for a more realistic
+
*use run-of-the-river schemes where possible - storing water by dams is usually big(!) effort and expensive
figure).</span>  
+
*use existing infrastructure, e.g. irrigation canals, mills, old mhp-sites (rehabilitation).
 +
*integrate local workshops (=> productive use);
 +
*use locally manufactured equipment where possible - it reduces costs and creates local capacity (replicable know how)
 +
*use of local materials for the civil works
 +
*use of community labor not only reduces required money, it's absolute necessary to establish local commitment towards the installations
 +
*use of HDPE (plastic) penstock reduces costs, has reduced lifetime and requires protection of sunlight
 +
*electronic load controller - ensure stable voltage and frequency which does no harm to appliances. It allows additional automatized features like battery charging or freezing. As more sophisticated the appliances become as more required a load controller will be.
 +
*high plant factor (efficiency) requires some planning for a well balanced load pattern of usually: machinery and consumptive use
 +
*a mhp plant close to village avoids expensive distribution lines or even transformers.
 +
*using pumps as turbines (PAT) - for pico hydro, it's reducing equipment costs, but also efficiency
 +
*using motors as generators -<span>it's widely available, reducing equipment costs, but also efficiency</span>
  
<span>If a machine &nbsp;is operated under conditions other than
+
[[Hydro Power Basics#toc|►Go to Top]]
full-load or full-flow then other significant inefficiencies must be
 
considered. Part flow and part load characteristics of the equipment needs to
 
be known to assess the performance under these conditions. It is always
 
preferable to run all equipment at the rated design flow and load conditions,
 
but it is not always practical or possible where river flow fluctuates
 
throughout the year or where daily load patterns vary considerably. </span>
 
  
<span>Depending
+
<br/>
on the end use requirements of the generated power, the output from the turbine
+
</div>
shaft can be used directly as mechanical power or the turbine can be connected
+
= Further Information =
to an electrical generator to produce electricity. For many rural industrial
 
applications shaft power is suitable (for food processing such as milling or
 
oil extraction, sawmill, carpentry workshop, small scale mining equipment,
 
etc.), but many applications require conversion to electrical power. For domestic
 
applications electricity is preferred. This can be provided either:</span>  
 
  
<span>
+
*[[:File:Hydropower enginneering.pdf|Hydropower Enginering]]<br/>
directly to the home via a small electrical distribution system or,</span>  
+
*[[Portal:Hydro|Hydro Portal on energypedia]]<br/>
 +
*[http://www.ich.no/ International Centre for Hydropower]
 +
*[http://www.british-hydro.org/ British Hydropower Association]
 +
*[http://en.wikipedia.org/wiki/Hydroelectricity Wikipedia: Hydroelectricity]
 +
*[http://microhydropower.net/ Micro Hydropower]
 +
*[http://practicalaction.org/hydro-power-answers Practical Action: Hydro Power Answers]
 +
*[[Using Hydro Power Plants for Flood Prevention|Using Hydro Power Plants for Flood Prevention]]
 +
*For more links on MHP, click [[Micro Hydro Power (MHP) - Further Links|here]].
  
<span>&nbsp;• can be supplied by means of batteries which
+
<br/>
are returned periodically to the power house for recharging - this system is
 
common where the cost of direct electrification is prohibitive due to scattered
 
housing (and hence an expensive distribution system), </span>  
 
  
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Where a generator is used alternating current (a.c.) electricity is normally produced. Singlephase power is satisfactory on small installations up to 20kW, but beyond this, 3-phase power is used to reduce transmission losses and to be suitable for larger electric motors. An a.c. power supply must be maintained at a constant 50 or 60 cycles/second for the reliable operation of any electrical equipment using the supply. This frequency is determined by the speed of the turbine which must be very accurately governed. &lt;/meta&gt;&lt;/meta&gt;&lt;/meta&gt;&lt;/meta&gt;
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[[Category:Hydro]]
 
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[[Category:Large_Hydro]]

Latest revision as of 08:05, 22 March 2022

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Overview

A mass of water moving down a height difference contains energy which can be harvested using some waterwheel or turbine. The moving water drives the waterwheel and this rotation either drives machinery directly (e.g. mill, pump, hammer, thresher, ...) or is coupled with a generator which produces electric power.



Principle of Hydro Power

Hydro power is probably the first form of automated power production which is not human / animal driven. Moving a grind stone for milling first, developed into the driving of an electrical generator. Next to steam it was for long the main power source for electricity.Its continual availability does not require any power storage (unlike wind / solar power). It is mainly mechanical hardware. This makes it relative easy to understand and repair-/maintainable. In smaller units its environmental impact becomes neglect-able (see: environmental impact assessment and pros and cons of micro hydropower).


Head & Flow

In order to create electricity from hydropower, two parameters are critical:

  • Flow; or the minimum amount of water that is constantly available throughout the entire year
  • Head; the difference in height

These specific conditions limit generalising and standartisation of "how to install hydropower plants". Choosing the right location and planning requires some specific knowledge. With knowledge of water flow and height difference the potential power can be estimated.

Measuring Head & Flow

The first step to judge a sites hydropower potential is to measure/estimate head and flow.

  • Head (the vertical distance between the intake and turbine)
  • Flow (how much water comes down the stream)


Head is very often exaggerated as is the flow rate, which varies over the year!

Wrong data occurs frequently. Confirmation of existing data is highly recommended!

Head and flow are the two most important facts of a hydro site. This will determine everything about the hydro system - volume of civil constructions, pipeline size, turbine type and power output. Inaccurate measurements result in low efficiency, high cost and scarcity of power.



Methods of Head and Flow Measurement without Sophisticated Tools

  • Estimation of height can be done easiest if there is a steep slope (waterfall) by rope.


Principle of a step by step head measurement:

Head measurement.jpg


By measuring total height step by step, it's crucial to do the bearing strictly horizontally. Ensure that by using a level or a water filled hose. Widely available are hoses and pressure gauges which allow the easiest method of height measurement. As longer the hose as less steps have to be taken to measure the total head.


Height measure by level.jpg

Head by pressure gauge.jpg

Height measure by hose.jpg


  • Estimation of flow is very difficult without measurement.


A quick and easy way to measure is the floating method:

  1. First, measure the waters speed at an steady flowing part of the river. Therefore drop some item and stop the time it needs for a certain distance to float.
  2. Second, do a sketch of the rivers cross section by measuring its depth every 20-50 cm so you come up with a grid showing the rivers profile from side to side. With this data its cross sections area can be calculated easily.
  3. Finally the flow volume results from (water) speed x (section) area.


Flow measurement.jpg


Example:

A ball drifts 10 m in 12 s => speed = 10m/12s = 0.12 m/s.
Cross section => A1= 25 cm * 40 cm (0.25 m * 0.4 m) = 0.1 m2 ; A1+A2+ ... = A = 0.5 m2
Flow volume = 0.12 m/s * 0.5 m2 = 0.06 m3/s => 60 l/s


  • To estimate a sites potential cost its necessary to know additionally:
  • Pipeline (penstock) length
  • Electrical transmission line length (from turbine to consumer). As smaller the sites power output as higher the power lines cost share
  • Number of potential customers
  • ►Go to Top

    Units and Power Estimations

    Power: watts [W] or Kilowatts [kW] 1 kW = 1000W
    Flow: 1 m³/s = 1000 l/s
    Gross heat: height difference the water "falls down"
    Net head: a little smaller than gross head. Gross head deducted by energy loss due to friction in penstock


    Potential power ('electric)' is calculated as follows:
    Power [W] = Net head [m] x Flow [ l/s] x 9.81 [m/s²] (est. gravity constant) x 0.5 (turbine/generator efficiency)
    Potential power is estimated as follows:
    Power output [W] = height [m] * flow [l/s] * 5


    More accurate estimations take into consideration:

    • exact net head (intake to powerhouse)
    • exact flow (constant during the year?)
    • combined efficiency of turbine and generator (depends on quality, est. 60% = 0.6)


    Example:
    A 6 m high waterfall has 300 liter/sec => potential power est. : 6 m * 300 l/s * 5 = 9000 W = 9 kW

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    Classification of Hydro Power

    By Size

    Hydropower installations can be classified by size of power output, although the power output is only an approximate diversion between different classes. There is no international consensus for setting the size threshold between small and large hydropower.

    For the United Nations Industrial Development Organization (UNIDO) and the European Small Hydropower Association (ESHA) and the International Association for Small Hydro (IASH) a capacity of up to 10 MW total is becoming the generally accepted norm for small hydropower plants (SHP). In China, it can refer to capacities of up to 25 MW, in India up to 15 MW and in Sweden small means up to 1.5 MW, in Canada 'small' can refer to upper limit capacities of between 20 and 25 MW, and in the United States 'small' can mean 30 MW.

    The German Federal Ministry for Environment, Nature Conservation and Nuclear Safety mentioned that a SHP is <1 MW, everything above is a large hydro electric plant and usually comes along with a large dam. The International Commission on Large Dams (ICOLD) defines a large dam as a dam with a height of 15 m or more from the foundation. If dams are between 5-15 m high and have a reservoir volume of more than 3 million m3, they are also classified as large dams. Using this definition, there are over 45 000 large dams around the world.


    Small hydro can be further subdivided into mini, micro and pico:

    • Mini (MH)
    < 1 MW grid connected special know how required
    • Micro
    < 100 kW partially grid con.
    professional know how required
    • Pico (PH)
    < 10 kW island grids small series units produced locally; professional equipment available
    • Family (FH)
    < ~1 kW single households/clusters often locally handmade solutions; professional equipment available


    There is no binding definition how mini hydro power output is to be classified. Rules for communication avoiding misunderstandings: Generally the terms can be used "downwards compatible". Pico- is also Mini- but not visa versa. Specific terms (Pico, Family) should be used only if they are required to indicate specifics. The spectrum needs higher diversification as smaller it becomes as there are certain differences in technique, usage, applicability and the grade of of ability to replicate them.


    Comments:

    • all installations require "special" knowhow
    • there are "over the counter" pico turbines available for "self installation"
    • Micro hydro is perhaps the most mature of the modern small-scale energy supply technologies used in developing countries. There are thought to be tens of thousands of plant in the “micro” range operating successfully in China[1], Nepal, Sri Lanka, Pakistan, Vietnam and Peru.
    • Historically the term hydropower developed from naming very small units towards nowadays huge dams. Then there where new terms created to separate different clusters. All of them are hydropower. What is considered "mini or "micro" may be defined once and forever ... or not. If there are different opinions on this topic you're welcome to open a discussion group on this.


    Comments on the Debate “small” versus “large” Hydro Power:

    Classification according to size has led to concepts such as ‘small hydro’ and ‘large hydro’, based on installed capacity measured in MW as the defining criterion. Defining hydropower by size is somewhat arbitrary, as there are no clear relationships between installed capacity and general properties of hydro power or its impacts. Hydro power comes in manifold project types (see Classification By Facility Type) and is a highly site-specific technology, where each project is a tailor-made outcome for a particular location within a given river basin to meet specific needs for energy and water management services.


    Large hydropower developments involve large dams and huge water storage reservoirs. They are typically grid connected supplying large grids. Preference for large hydro is on the decline due to the high investment costs, long payback periods and huge environmental impacts (losses of arable land, forced migration, diseases and damage to biodiversity). Many social and environmental impacts are related to the impoundment and existence of a reservoir, and therefore are greater for 'large hydro' plants with reservoir.


    Small hydropower stations are typically run-of-the-river. They combine the advantages of hydropower with those of decentralised power generation, without the disadvantages of large scale installations. Advantages include: low distribution costs, no/low environmental costs as with large hydro, low maintenance and local implementation and management. Power generated with small hydro station can be used for agro-processing, local lighting, water pumps and small businesses[1].


    The constructions and integration into local environments of Small Hydro Power (SHP) schemes typically takes less time and effort compared to large hydropower plants. For this reason, the deployment of SHPs is increasing in many parts of the world, especially in remote areas where other energy sources are not viable or are not economically attractive.


    However, larger facilities will tend to have lower costs on a USD/kW basis due to economies of scale, even if that tendency will only hold on average. Moreover, one large-scale hydropower project of 2,000 MW located in a remote area of one river basin might have fewer negative impacts than the cumulative impacts of four hundred 5 MW hydropower projects in many river basins (see also Negative Environmental Impacts


    General concepts like ‘small’ or ‘large hydro’ are not technically or scientifically rigorous indicators of impacts, economics or characteristics. Hydropower projects cover a continuum in scale, and it may be more useful to evaluate a hydropower project on its sustainability or economic performance, thus setting out more realistic indicators[2].

    ►Go to Top


    By Facility Type

    Hydropower plants can be classified in three categories according to operation and type of flow:[3]

    1. Run-of-river (RoR),
      Small and micro hydropower utilizes water that runs of a river and avoids big environmental impacts.
    2. Storage (reservoir)
    3. Pumped storage hydro power plants (HPPs) work as energy buffer and do not produce net energy.
    4. In-stream Hydropower Schemes use a rivers natural elevation drop without to dam a river.


    'Run-of-River Hydropower' Plant (RoR)[3]

    Run-of-River Hydropower Plant

    • RoR plant produce energy from the available flow and the natural elevation drop of a river
    • It is suitable for rivers that have at least a minimum flow all year round.
    • The water to powers th turbine is diverted and channeled into a penstock and then returned to the river
    • RoR plants usually have no or only small storage, allowing for some adaptations to the demand profile.
    • As bigger the storage capacity is as higher the environmental impacts are
    • Power generation is dictated by local river flow conditions and thus depends on precipitation and runoff and may have substantial daily, monthly or seasonal variations













    Hydropower Plant with Reservoir[3]

    Hydropower Plant with reservoir
    • Hydropower projects with a reservoir (storage hydropower) store water behind a dam for times when river flow is low
    • Therefore power generation is more stable and less variable than for RoR plants
    • The generating stations are located at the dam toe or further downstream, connected to the reservoir through tunnels or pipelines
    • Type and design of reservoirs are decided by the landscape and in many parts of the world are inundated river valleys where the reservoir is an artificial lake
    • Reservoir hydropower plants can have major environmental and social impacts due to the flooding of land for the reservoir

    Pump Storage Hydropower Plant[3]

    Pump Storage Project.JPG
    • Pumped storage plants are not energy sources, instead they are storage devices
    • Water is pumped from a lower reservoir into an upper reservoir, usually during off-peak hours, while flow is reversed to generate electricity during the daily peak load period or at other times of need
    • Although the losses of the pumping process make such a plant a net energy consumer, the plant provides large-scale energy storage system benefits
    • Pumped storage is the largest capacity form of grid energy storage now readily available worldwide

    In-stream Hydropower Scheme[3]

    n-storgare hydropower scheme
    non typical installation of an in-stream HPP
    • Basically in-stream Hydropower functions like a RoR scheme, but the turbine is mostly built within the dam in the riverbed. Usually the river flow is not diverted.
    • To optimize existing  weirs, barrages, canals or falls, small turbines or hydrokinetic turbines can be installed
    • At rivers close to the sea the technologies may operate bi-directional (tidal)

    ► Text and Figures of this chapter are originally mainly taken from the Chapter 5 of the IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation (2011).

    ►Go to Top


    Facts on Hydro Power

    Existing Generation[4][3]

    In 2010, in 161 countries hydropower is installed making up a worldwide installed hydro electric capacity of 926 GW which provide one-fifth of the world's electricity supply. Out of these 161 countries five countries make up more than the half of the world's hydropower production: China (~200 GW), Canada (74.4 GW), Brasil (84 GW), the USA (78.2 GW) and Russia (49.7 GW).

    Often hydropower is the main or even only source for electricity production in developing countries.
    Any other conventional energy source requires steady fuel. Such, like coal, gas or oil has to be purchased.


    Country[4] Installed Hydropower Capacity in MW  % of total electricity generation
    Burundi 50.5 100
    Bhutan 1488 100
    Congo, Dem. Rep. 2442 100
    Lesotho 76 100
    Namibia 249 100
    Paraguay 68000 100
    Mozambique 2179 100
    Zambia 1812 >99
    Norway 29636 99
    Albania 1450 98
    Lao PDR 2000 98
    Tajikistan 5200 96
    Ethiopia 784 >95
    Malawi 290 95
    Cameroon 720 94
    Nepal 660 92
    Kyrgyz Republic 2910 91
    Congo, Rep. 119 >90
    Georgia 2850 86
    Brazil 84000 84
    Swaziland 42 82
    Central afric. Rep. 24.6 80


    ►Go to Top


    Hydropower Potential

    Hydropower potential means: an amount of water (flow) which flows down a certain height.
    To utilise such, the produced electricity is to be transportet by powerline to potential users.

    Hydropower offers a significant potential of renewable energy production. In 2009 electricity production from hydropower was about 16% of the global electricity production. The undeveloped capacity ranges from 30% in Europe up to 88% in Africa.

    If reading such numbers please keep in mind:

    • There is a structural difference between small and big hydropower;
      the first is mainly decentralised - the later is usually utilized by big structures, which have usually massive environmental impacts
    • Hydropower potential is bound to specific sites, which may be far from potential energy usage


    Small hydropower potential is given in hilly or mountainous regions, where rivers do not fall dry during the year.
    Where gravity fed irrigation is practiced small and micro power plants find suiting conditions.

    Mountainous regions often have bad infrastructure and are least to be connected to a electric grid. If there is water available it may be a suitable source for decentralised hydro power electrification. Such setups may even get support from governmental or major electricity supplier. The costs to connect remote areas are high, whereby the revenue, due to little amount of electricity utilised, is low.

    ►Go to Top


    Micro Hydro Power Schemes

    Components of a Micro Hydro System (MHS) - Overview

    Grid connection for MHP's

    Hydropower usually operates 24 h / day. Most mhp's are connected by a grid to their consumers. If a connection towards the national or main grid is available, electricity can be fed in there. Often micro or pico hydropower units are installed in remote areas. There they feed an isolated grid. In such grid the MHP is usually the only power source. The power produced has to be leveled equal with the power consumed (see controller).

    Battery storage is no must like at solar or wind power projects. This is a big advantage as it reduces costs and maintenance significantly. Charging stations can nevertheless extend a mhp's effectiveness by utilising power in times of low demand (late night). Like this, even consumers which are too far from the station to be connected by transmission cable can be served via rechargeable batteries.

    ►Go to Top


    Storage Basin or Dams

    Small hydropower plants usually use (part-) river flow as driving force. Storage basins or even dams can buffer water. So demand peaks or (short) periods of water shortage can be bridged. As such infrastructures is costly and sophisticated, it's only used if there is a clear financial revenue; e.g. electricity supply for remote industries. Standard elements for mhp

    Construction a MHP consists of:

    divertion constructions in the river, Guiding water per canal and pipe, the electrical-mechanical equipment to turn water power into electricity plus transmission lines and house connections.

    Nevertheless if it is community based, main challenge will be the social setup. The people of the community who will build / use the MHP have to be introduced, trained, learned and encouraged to organise, operate and manage their power station. A sustainable working mhp scheme requires users who are enabled to understand "their" system.


    Depok.jpg


    Forbay trashrack pennstock.jpg
    Powerhouse 2.jpg



    Management-Poster.jpg


    Canal-participation-2.jpg
    Introduction-hydro.jpg


    • For an overview or possible impacts on a mhp's success, check out the mhp-tree-diagram

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    Suitable Conditions for Micro Hydro Power

    Again, "head and flow" matter. The best geographical areas for exploiting small-scale hydro power are those where there are steep rivers flowing all year round. The Andes, the Himalayas, islands with moist marine climates, such as the Caribbean Islands, the Philippines and Indonesia are widely suitable. Laos, Vietnam and wide parts of China use Micro Hydro Power in large numbers.
    A locations, head, flow and number of consumers allow to calculate the available power share per consumer
    Minimal Head may be 1-2 m. For considerable power then much water (> 1 m3) is required
    Minimal Flow may be 20 l/s. Power is according to head output (see power estimation).
    Mini Hydropower operates constantly and requires little maintenance. It is ideal for powering remote regions. Although grid connection is very feasible due to its very low operational costs.

    ►Go to Top


    Brief Site Assessment

    • location Data
    • head, flow
    • length of powerline
    • length of penstock
    • land use

    => a two page condensed site assessment


    Flow measures in feasibility studies:
    Flow data should be gathered over a period of at least one year where possible, so as to ascertain the fluctuation in river flow over the various seasons.
    At least measures must be taken during dry season to assure that there is always enough water to power the turbine. Too little water results in power cut. If such is not clear to consumers from begin with it can seriously endanger the projects success.

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    Economics of Micro Hydro Systems

    Productive Use

    Electricity is a key factor for productive businesses. Experience shows, this isn't an automatism very commonly. Additional income is generated only if the revenue is made from outside the community. Typically added value is created by subsequent processing of commodities. Exemplary: coffee roasting, fruit drying, freezing fish, ...

    ► find more information here: Micro Hydro Power (MHP) Plants - Use of MHP

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    Cost

    The major cost of a MHP scheme is for its site preparation and equipment. It's nearly 100 % upfront investment and very low running cost (operation and maintenance).

    Cash usually is a scarce resource in rural areas of development countries. Part of a feasibility study has to be: how high tariffs have to be set to cover the costs. Its a must to, at least, break even operation & maintenance expenses. This money has to come from the users for electricity or el. services. A mhp can operate many decades if tariffs cover repair costs. In the long run a mhp's management is the crucial factor for its success.

    ► Find more information here: Micro Hydro Power (MHP) Plants - Costs

    ►Go to Top


    Tariff Setting

    Tariff setting is a crucial element. In case the mhp management is community based, tariffs have to be set in acceptance with the community. Ensure sufficient high tariffs! Community discussion may be lengthy, be patient. Never leave the impression that mhp-electricity may be "for free".

    Examples: Compare the cost for oil wig lighting with a single bulb. Compare "luxury" expenses with the comfort of el. lighting (cigarettes, drinking, ...). Explain the management function like how to run a business. Minimally the revenue has to cover the expenses. Check download section for an excel-tool which shows cost coverage.

    ► Links: Tariffs, Metering and Billing

    ►Go to Top


    Revenues

    Within a community based scheme extra revenue can be used for:

    • social tariffs (elder, poor, school, ...)
    • street lighting
    • powering a drinking water pump
    • community services (washing, freezing, ironing)


    Availability of cash gives also other possibilities to gain additional revenues. E.g. to build storage capacities which can house a communities harvest; by gross deals during off season prices are high.
    Financial benefits to the communities served are usually reduced expenses for oil, batteries and petrol to power lamps, radios and machines. Check potentials for productive use during feasibility study. Existing and planned machinery (type and power?)

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    Efforts

    Main non financial efforts at microhydro installations are: the right choice of sites, their specific planning and supervision of quality standards; all this is esp. laborious in remote areas. If a scheme is community based, such plays a key role.

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    Some Hints

    • use run-of-the-river schemes where possible - storing water by dams is usually big(!) effort and expensive
    • use existing infrastructure, e.g. irrigation canals, mills, old mhp-sites (rehabilitation).
    • integrate local workshops (=> productive use);
    • use locally manufactured equipment where possible - it reduces costs and creates local capacity (replicable know how)
    • use of local materials for the civil works
    • use of community labor not only reduces required money, it's absolute necessary to establish local commitment towards the installations
    • use of HDPE (plastic) penstock reduces costs, has reduced lifetime and requires protection of sunlight
    • electronic load controller - ensure stable voltage and frequency which does no harm to appliances. It allows additional automatized features like battery charging or freezing. As more sophisticated the appliances become as more required a load controller will be.
    • high plant factor (efficiency) requires some planning for a well balanced load pattern of usually: machinery and consumptive use
    • a mhp plant close to village avoids expensive distribution lines or even transformers.
    • using pumps as turbines (PAT) - for pico hydro, it's reducing equipment costs, but also efficiency
    • using motors as generators -it's widely available, reducing equipment costs, but also efficiency

    ►Go to Top


    Further Information


    References

    1. GTZ (2007): Eastern Africa Resource Base: GTZ Online Regional Energy Resource Base: Regional and Country Specific Energy Resource Database: I - Energy Technology
    2. IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation, Chapter 5 Hydropower (2011). Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.
    3. 3.0 3.1 3.2 3.3 3.4 3.5 http://srren.ipcc-wg3.de/report - Prepared by Working Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.
    4. 4.0 4.1 http://www.hydropower-dams.com/world-atlas-industry-guide.php?c_id=159