lecturette akram ali.ppt
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Renewable Energy Resources Hydropower
Renewable Energy Resources
Akram Ali 75th JMC
Prepared by
Wapda Administrative Staff CollegeIslamabad
Hydropower
Renewable Energy Resources Hydropower
Hydrologic Cycle
Renewable Energy Resources Hydropower
Hydropower to Electric Power
Kinetic Energy
Mechanical Energy
Potential Energy
Electrical Energy
Renewable Energy Resources Hydropower
Facts About Hydropower
Hydropower; Is
clean, Does not produce greenhouse gasses or other air pollution, Leaves behind no waste
Is the most efficient way to generate electricity, water energy comes directly in mechanical form, with an efficiency can be made close to 1.
Is the leading source of renewable energy Water is a naturally returning domestic product
A cubic meter of water gives 9800 J of mechanical energy for every meter it descends, and a flow of a cubic meter per second in a fall of 1 m can provide 9800 W, or 13 hp
Start easily and quickly and change power output rapidly
Save millions of barrels of oil
Renewable Energy Resources Hydropower
World Trends in Hydropower
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Facts About Hydropower
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World hydro production
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Major Hydropower Producers
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World’s Largest Dams
Name Country Year Max Generation Annual
Production
Three Gorges China 2009 18,200 MW Ü
Itaipú Brazil/Paraguay 1983 12,600 MW 93.4 TW-hrs
Guri Venezuela 1986 10,200 MW 46 TW-hrs
Grand Coulee United States 1942/80 6,809 MW 22.6 TW-hrs
Sayano Shushenskaya Russia 1983 6,400 MW
Robert-Bourassa Canada 1981 5,616 MW
Churchill Falls Canada 1971 5,429 MW 35 TW-hrs
Iron Gates Romania/Serbia 1970 2,280 MW 11.3 TW-hrs
Renewable Energy Resources Hydropower
Three Gorges Dam (China)
Renewable Energy Resources Hydropower
Itaipú Dam (Brazil & Paraguay)
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Guri Dam (Venezuela)
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Grand Coulee Dam (US)
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The first use of the water wheel may possibly have occurred in 4th century BC in India Shortage of labor made machines such as the water wheel cost effective during the Middle Ages. Water wheels in ancient Rome and ancient China found many practical uses in powering mills for grinding grain . World-wide, about 20% of all electricity is generated by hydropower
Norway produces more than 99% of its electricity with hydropower.
History of Hydro Power
Renewable Energy Resources Hydropower
Early Irrigation Waterwheel
A noria
In this earliest water-wheel the paddles dip into the flowing water stream and rotating the wheel lifting a series of jars raising water for irrigation
Renewable Energy Resources Hydropower
Early Water Mill
This corn mill with horizontal axis wheel was described in the first century BC. Note the use of gear chain
A water mill
Renewable Energy Resources Hydropower
Early Norse Water Mill
Mill of this early vertical-axis type are still in use for mechanical power in remote mountainous regions
A Norse mill
Renewable Energy Resources Hydropower
Terminologies
Head Water must fall from a higher elevation to a
lower one to release its stored energy. The difference between these elevations (the
water levels in the forebay and the tailbay) is called “Head” Dams: three categories
high-head (600 m or more m) medium-head (75m to 600 m) low-head (less than 75 m)
Power is proportional to the product of = head x flow rate
Renewable Energy Resources Hydropower
Types of Hydroelectric Installation
Renewable Energy Resources Hydropower
Types of Hydroelectric Installation
Renewable Energy Resources Hydropower
Types of Hydroelectric Installation
Renewable Energy Resources Hydropower
Scale of Hydropower Projects Large-hydro
More than 100 MW feeding into a large electricity grid Medium-hydro
15 - 100 MW usually feeding into a grid Small-hydro
1 - 15 MW - usually feeding into a grid Mini-hydro Above 100 kW, but below 1 MW
Either stand alone schemes or more often feeding into the grid Micro-hydro
From 5kW up to 100 kW
Pico-hydro From a few hundred watts up to 5kW
Usually provided power for a small community or rural industry in remote areas away from the grid.
Remote areas away from the grid.
Renewable Energy Resources Hydropower
Types of Water Wheels
Renewable Energy Resources Hydropower
Types of Water Wheels
Renewable Energy Resources Hydropower
Types of Water Wheels
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Types of Systems Impoundment
Diversion or run-of-river systems
Facility channels is a portion of a river or through a canal or penstock.
The most common type of hydroelectric power plant. Large system, uses a dam to store river water in
a reservoir.
Most significantly smaller.
It may not require the use of a dam.
The water may be released either to meet changing electricity needs or to maintain a constant reservoir level.
Reversible turbine/generator assemblies act as pump and turbine (usually a Francis turbine design). Excess generation capacity is used to pump water into the higher reservoir.
Pumped Storage
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Types of Systems
Pure pumped-storage plants just shift the water between reservoirs.
For higher demand, water is released back into the lower reservoir through a turbine, generating electricity
Combined pump-storage plants also generate their own electricity like conventional hydroelectric plants through natural stream-flow. Approximately 70% to 85% of the electrical energy used to pump the water into the elevated reservoir can be regained. The technique is currently the most cost-effective means of storing large amounts of electrical energy
Pumped Storage
Renewable Energy Resources Hydropower
Turbine Design Ranges
Kaplan 2 m < H < 40 m
Francis 10 m < H < 350 m
Pelton 50 m < H < 1300 m
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Turbine Application Ranges
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Hydro Power Calculations
Hydropower is very efficient
Typical losses are due to
Overall efficiency ranges from 75-95%
Frictional drag and turbulence of flow Friction and magnetic losses in turbine &
generator
water)head of energy (potential “busbar”) the to delivered power l(electrica
Efficiency
Renewable Energy Resources Hydropower
Where P = power in kilowatts (kW) g = gravitational acceleration (9.81
m/s2) = turbo-generator efficiency (0<n<1) Q = quantity of water flowing (m3/sec) H = effective head (m)
HQgP
Hydro Power Calculations
HQ81.9P
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Consider a mountain stream with an effective head of 25 meters (m) and a flow rate of 600 liters (ℓ) per minute. How much power could a hydro plant generate? Assume plant efficiency () of 83%.
Example 1
H = 25 m Q = 600 ℓ/min × 1 m3/1000 ℓ × 1 min/60sec
Q = 0.01 m3/sec = 0.83
P 10QH = 10(0.83)(0.01)(25) = 2.075P 2.1 kW
How much energy (E) will the hydro plant generate each year?
E = P*tE = 2.1 kW × 24 hrs/day × 365 days/yrE = 18,396 kWh annually
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Economics of Hydropower
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High Capital Expenses
Construction cost of ~$20 million Negligible operation costs Additional benefits from dam
5 MW hydro plant with 25 m low head
flood control, recreation, irrigation, etc.
~$20 million purchase cost of equipment Significant operating fuel costs
50 MW combined-cycle gas turbine
Short-term pressures may favor fossil fuel energy production
Renewable Energy Resources Hydropower
Hydropower – Adv. and Disadv.Positive Negative
Emissions-free, with virtually no CO2, NOX, SOX, hydrocarbons, or particulates
Frequently involves impoundment of large amounts of water with loss of habitat due to land inundation
Renewable resource with high conversion efficiency to electricity (80+%)
Variable output – dependent on rainfall and snowfall
Dispatchable with storage capacity Impacts on river flows and aquatic ecology, including fish migration and oxygen depletion
Usable for base load, peaking and pumped storage applications
Social impacts of displacing indigenous people
Scalable from 10 KW to 20,000 MW Health impacts in developing countries
Low operating and maintenance costs High initial capital costs
Long lifetimes Long lead time in construction of large projects
Renewable Energy Resources Hydropower
Hydropower – Adv. and Disadv.Positive Negative
Emissions-free, with virtually no CO2, NOX, SOX, hydrocarbons, or particulates
Frequently involves impoundment of large amounts of water with loss of habitat due to land inundation
Renewable resource with high conversion efficiency to electricity (80+%)
Variable output – dependent on rainfall and snowfall
Dispatchable with storage capacity Impacts on river flows and aquatic ecology, including fish migration and oxygen depletion
Usable for base load, peaking and pumped storage applications
Social impacts of displacing indigenous people
Scalable from 10 KW to 20,000 MW Health impacts in developing countries
Low operating and maintenance costs High initial capital costs
Long lifetimes Long lead time in construction of large projects
Renewable Energy Resources Hydropower
Classification of Hydro Turbines Reaction Turbines
Derive power from pressure drop across turbine
Impulse Turbines
No pressure drop across turbines
Totally immersed in water Angular & linear motion converted to shaft power
Propeller, Francis, and Kaplan turbines
Convert kinetic energy of water jet hitting buckets
Pelton, Turgo, and crossflow turbines Types of Hydropower Turbines
Francis Turbine Kaplan Turbine Pelton Turbine Turgo Turbine New Designs
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Thank you
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Conventional Impoundment Dam
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Schematic of Impound Hydropower
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Diversion Hydropower (Run-of-River)
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Diversion Hydropower (Run-of-River)
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Micro Run-of-River Hydropower
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Pumped Storage Schematic
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Pumped Storage System
At time of low demand
At time of high demand
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Pumped Storage Power Spectrum
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Schematic of Francis Turbine
Cutaway diagram
Flow through guide vanes and runner blades
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Francis Turbine Cross-Section
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Small Francis Turbine & Generator
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Francis Turbine
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Kaplan Turbine Schematic
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Kaplan Turbine Cross Section
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Vertical Kaplan Turbine Setup
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Horizontal Kaplan Turbine
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Pelton Wheel Turbine
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Turgo Turbine
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Types of Hydropower Turbines