Keynote Lecture UPES

7/29/2019 Keynote Lecture UPES

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HYDROPOWER

Dr. H Prashanth Reddy


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Renewable energy sources

http://www.wvic.com/content.cfm?PageID=686&Cat=0


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INTRODUCTION

Hydropower is generated from water moving in the

hydrological Cycle.

The potential energy of moving water from higher

elevation to lower elevation is used to generate the

hydropower.

Hydropower is a renewable energy source.

Presently, installed hydropower is 20% of worldwide

electricity.

It is anticipated that hydropower will be increased

significantly in 2020 and 2030s.


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History of hydropower

Before invention of electric power,Hydropower used to run watermills, textile

mills , flour mills and saw mills. Industrial use of hydropower begin from 1880.

Street lighting was connected to Hydropowerat Niagara falls, New York.

The worlds first hydro electric power station(12.5 kW) was installed in 1882 on Fox River,Appleton, Wisconsin, USA.


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Scale of Hydropower

Three gorges in China with 22,500 MW.

(98 TWH)

Hydropower plant, Itaipu in Brazil with

14,000 MW. (98 TWH)

Guri, Venezuela with 10,200 MW. (53

TWH)

Grand Coulee in USA 6,809 MW. (20

TWH)

Tehri Dam in India 2,400 MW ( 6 TWH)


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Three Gorges Dam (PRC)


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Itaipu in Brazil


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Guri, Venezuela


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Grand Coulee in USA


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Historic Hydropower Generation

Hydropower generation (TWH) by region


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Installed Hydropower


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Usage of %age of Hydropower


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Advantages of Hydropower stations

Water is available after power generation canbe used for irrigation, drinking water andindustrial use.

Most of the hydropower stations are formultiple purposes.

Recently, hydroelectricity has beeninvestigated for use in electrolysis process forhydrogen fuel production.

Money generated by hydroelectric power plantis used to pay for other utilities of that plant


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Hydropower potential

The total available flow in the mountainous

regions has been estimated as 28000 km3.

Theoretical potential of the hydropower is

40000 TWH annually.

IJHD (2010) estimated technically feasible

hydropower world wide is 14,576 TWH/yr.

Technical potential range from 47% in

Europe to 92% in Africa.


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Hydropower potential


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Climate change on hydropower potential

Changes in precipitation and runoff

1. At high latitudes and in tropics projection

of increased precipitation.

2. In subtropical and mid-lattitude regions

precipitation is projected to decrease.

3. In between these areas, precipitation may

increase or decrease.


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In Asia, it is projected that increased rainfallintensity of seasonal precipitation thereforeincreasing storage capacities may become of

particular importance. Hydropower potential of Europe by 2070s,

decline by 6% in Mediterranean region.Increase in 15-30% in North and East Europe.

No change in Western and Central Europe. In New Zealand, winter rain is projected to

increase in Waikato catchment.


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Hydropower in Latin America is vulnerable torainfall anomalies due to El Nino and La Nina.

Glacial retreat is also affect hydropower generation

in Chili. In North America, Colorado river hydropower and

Grate lakes hydropower likely decrease.

Hydropower in Northern Quebec will increase and it

decrease in Southern Quebec. Overall impacts of climate change on GHPgeneration may be expected to be small or positive.


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Hydropower technology

Main types of Hydropower

(1) Run off the river hydropower plant

The running water of river is used for the powergeneration. (Eg. Niagara falls)Rainy seasons: Maximum power

No flowing water: No power

(1a)Run off river hydroelectric plant with pond (peak

power plant)(1b) Run off river hydroelectric plants without pond(base load plant)


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(2) reservoir hydroelectric plants

The reservoir in the hydroelectric plants can

store extremely large quantities of water.

These are treated as peak load and base load

plants.

Most of the hydropower plants are belongs to

this category.


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(3) pumped storage hydropower plant


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Classification of Hydropower plants on the

basis of installed power.


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In the classification of head refers to thedifference between the u/s and d/s water levels

High head hydropower plant (> 800 ft)Pelton turbines are used in HHHPP

Medium head hydropower plant (100-800 ft)

Francis Turbines are used in MHHPP

Low head hydropower plant (< 100 ft)

Kaplon or Bulb Turbines are used in LHHPP


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Types of hydropower turbines

Boyle,Renewable Energy, 2nd edition, Oxford University Press, 2003


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Impulse turbines

Impulse turbines convert the kinetic energy of a jetof water to mechanical energy.

Nozzle converts pressurized water into a highvelocity jet.

Pelton wheel Suitable for low flow and high head

Turgo is suitable for medium flow and medium head

Crossflow is suitable for low head and high flow


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Reaction turbines

Reaction turbines convert potential energy

of pressurized water into mechanical

energy. Highflow rates and low head

High specific speed of turbine

Francis Turbine medium head

Propeller and Kaplan low head

Pump turbine Medium head


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Pelton wheel


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Hydropower technologyFrancis Turbine


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Kaplan turbine

"Water Turbine," Wikipedia.com


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Kaplan turbine


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Bulb turbine


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Turbine operational ranges


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Flow through a Francis turbine depends on

net head, rotational speed of turbine and

wicket gate opening.

Flow through a Kaplan turbine net head,

rotational speed of turbine, wicket gate and

runner blade angle.

Flow through a Pelton wheel is a function

of head and nozzle opening.


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Hill charts: Turbine characteristics

Runaway speed: Maximum speed of

turbine under no load conditions.

Turbine governor: Controls the flow by

opening and closing gates, speed of turbine

and loading of turbines.


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Power is proportional to net head multiplied

by discharge.

The efficiency of converting potentialenergy to electrical energy is very high in

hydropower plants as compared to

conversion between other energy sources. Overall efficiency is 75-95% in HPP.


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Efficiency of hydropower plant depends on

(i) Water losses due to leaks, by pass

requirements, flood spillage

(ii) Frictional losses and minor losses in

transport of water to the turbines

(iii)The efficiency of the electromechanical

equipment (losses in mech. energy of

turbine, losses in the generator)


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Causes for Transients in Hydropower

Stations

(1) load acceptance

(2) load rejection

(3) starting of the turbine


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Accident at Russias Biggest Hydro-

electric plant Sayano -Shushenskaya

2009 August 17 Number of units: 10

Francis Turbine

Rated power: 650 MW each

Discharge per unit 358.5 m3

/s Nominal speed: 142.8

Net Head: 194 m

Runner Weight: 156 ton

Runner diameter 6.77 m


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Hydropower technologyBefore the accident


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Hydropower technologyAfter accident


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Thank you


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References Kumar, A., T. Schei, A. Ahenkorah, R. Caceres Rodriguez, J.-M. Devernay, M. Freitas,

D. Hall, A. Killingtveit, Z. Liu, 2011: Hydropower. In IPCC Special Report on

Renewable Energy Sources and Climate Change Mitigation [O. Edenhofer, R. Pichs-

Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier,

G. Hansen, S. Schlomer, C. von Stechow (eds)], Cambridge University Press,

Cambridge, United Kingdom and New York, NY, USA.

Wikepedia

Chaudhry MH, Applied Hydraulic Transients

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