Hydro Power Group No.02 3rd year(6th term) Mechanical Engg. UCE&T,BZU Multan
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Contents • Introduction • Scale of Hydro Power Production • Hydro Power Design • Turbine Design • Hydro Power Calculations • Environmental Impacts 2
Introduction
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World Energy Sources
hydropower.org
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Hydrologic Cycle
http://www1.eere.energy.gov/windandhydro/hydro_how.html
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Hydro Power • Hydro Power, Hydraulic Power or Water Power is the power that
is derived from the force or energy of moving water, which may be harnessed for useful purposes. • Hydro Power can be converted into Mechanical Power to operate machines like Water Mills, Textile Machines, Sawmills, Dock Cranes, Domestic Lifts, Irrigation etc. • Hydro Power can be converted into Electric Power indirectly.
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Water Wheels
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Early Roman Water Mill
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Early Norse Water Mill
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Fourneyron’s Turbine
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Early Irrigation Waterwheel
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Hydro Power to Electric Power Electrical Energy
Potential Energy
Electricity
Kinetic Energy
Mechanical Energy 12
Gravitational
Mechanical
Electrical
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Scale of Hydro Power Projects
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Scale of Hydropower Projects • Large-hydro
– More than 100 MW feeding into a large electricity grid
• Medium-hydro
– 15 - 100 MW usually feeding 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 – Usually provided power for a small community or rural industry in remote areas away from the grid.
• Pico-hydro
– From a few hundred watts up to 5kW – Remote areas away from the grid. 15
Micro Run-of-River Hydropower
http://www1.eere.energy.gov/windandhydro/hydro_plant_types.html
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Micro Hydro Power Example
Used in remote locations in northern Canada http://www.electrovent.com/#hydrofr
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Large Hydro Power Example
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World Hydropower
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Regional Hydropower Potential
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Hydropower Design
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Terminology (Jargon) • 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 (800 or more feet) medium-head (100 to 800 feet) low-head (less than 100 feet)
• Power is proportional to the product of head x flow
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Parts of Hydro Electric Plant 1. Dam. Raises the water level of the river to create falling water. Also controls the flow of water. The reservoir that is formed is, in effect, stored energy. 2. Turbine. The force of falling water pushing against the turbine's blades causes the turbine to spin. A water turbine is much like a windmill, except the energy is provided by falling water instead of wind. The turbine converts the kinetic energy of falling water into mechanical energy. 3. Generator. Connected to the turbine by shafts and possibly gears so when the turbine spins it causes the generator to spin also. Converts the mechanical energy from the turbine into electric energy. Generators in hydropower plants work just like the generators in other types of power plants.
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Types of Hydroelectric Installation
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Types of Systems 1. Impoundment Dam 2. Diversion or run-of-river systems 3. Pumped Storage
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1: Impoundment Dam
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Conventional Impoundment Dam
http://www1.eere.energy.gov/windandhydro/hydro_plant_types.html
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Hoover Dam (US)
http://las-vegas.travelnice.com/dbi/hooverdam-225x300.jpg
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Itaipú Dam (Brazil & Paraguay)
“Itaipu,” Wikipedia.org
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Three Gorges Dam (China)
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Grand Coulee Dam (US)
www.swehs.co.uk/ docs/coulee.html
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World’s Largest Dams Name
Country
Year
Three Gorges
China
2009
18,200 MW
Itaipú
Brazil/Paraguay
1983
12,600 MW 93.4 TW-hrs
Guri
Venezuela
1986
10,200 MW
Grand Coulee
United States
Sayano Shushenskaya
Russia
1983
6,400 MW
Robert-Bourassa
Canada
1981
5,616 MW
1971
5,429 MW
1970
2,280 MW 11.3 TW-hrs
Canada Ranked by maximum power. Romania/Serbia Iron Gates
Churchill Falls
“Hydroelectricity,” Wikipedia.org
1942/80
Max Annual Generation Production
46 TW-hrs
6,809 MW 22.6 TW-hrs
35 TW-hrs
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2: Diversion(Run-of-River)
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Diversion (Run-of-River) Hydropower
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Diversion Hydropower (Tazimina, Alaska)
http://www1.eere.energy.gov/windandhydro/hydro_plant_types.html
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3: Pumped Storage
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Pumped Storage Schematic
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Pumped Storage System
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Cabin Creek Pumped Hydro (Colorado) • Completed 1967 • Capacity – 324 MW – Two 162 MW units
• Purpose – energy storage
– Water pumped uphill at night • Low usage – excess base load capacity – Water flows downhill during day/peak periods – Helps Xcel to meet surge demand • E.g., air conditioning demand on hot summer days
• Typical efficiency of 70 – 85%
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Cruachan Pumped Storage (Scotland)
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Pumped Storage Power Spectrum
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Turbine Design Francis Turbine Kaplan Turbine Pelton Turbine Turgo Turbine New Designs 42
Classification of Hydro Turbines • Reaction Turbines – – – –
Derive power from pressure drop across turbine Totally immersed in water Angular & linear motion converted to shaft power Propeller, Francis, and Kaplan turbines
• Impulse Turbines – – –
Convert kinetic energy of water jet hitting buckets No pressure drop across turbines Pelton, Turgo, and crossflow turbines
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Types of Hydropower Turbines
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Schematic of Francis Turbine
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Francis Turbine CrossSection
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Small Francis Turbine & Generator
"Water Turbine," Wikipedia.com
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Francis Turbine – Grand Coulee Dam
"Water Turbine," Wikipedia.com
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Fixed-Pitch Propeller Turbine
"Water Turbine," Wikipedia.com
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Kaplan Turbine Schematic
"Water Turbine," Wikipedia.com
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Kaplan Turbine Cross Section
"Water Turbine," Wikipedia.com
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Vertical Kaplan Turbine Setup
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Horizontal Kaplan Turbine
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Pelton Wheel Turbine
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Turgo Turbine
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Fish Friendly Turbine Design
www.eere.energy.gov/windandhydro/hydro_rd.html
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Turbine Design Ranges • Kaplan • Francis • Pelton • Turgo
2 < H < 40 10 < H < 350 50 < H < 1300 50 < H < 250 (H = head in meters)
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Turbine Ranges of Application
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Turbine Design Recommendations Head Pressure
Impulse
Reactio n
High
Medium
Low
Pelton Turgo Multi-jet Pelton
Crossflow Turgo Multi-jet Pelton
Crossflow
Francis Pump-asTurbine
Propeller Kaplan
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Hydro Power Calculations
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Efficiency of Hydropower Plants • Hydropower is very efficient – Efficiency = (electrical power delivered to the “busbar”) ÷ (potential energy of head water)
• Typical losses are due to – Frictional drag and turbulence of flow – Friction and magnetic losses in turbine & generator
• Overall efficiency ranges from 75-95%
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Hydropower Calculations P = g ×η × Q × H P ≅ 10 ×η × Q × H • P = power in kilowatts (kW) • g = gravitational acceleration (9.81 m/s2) ∀η = turbo-generator efficiency (0
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Example 1a 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 (η ) of 83%.
• H = 25 m • Q = 600 ℓ/min × 1 m3/1000 ℓ × 1 min/60sec Q = 0.01 m3/sec ∀ η = 0.83
• P ≅ 10η QH = 10(0.83)(0.01)(25) = 2.075 P ≅ 2.1 kW
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
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Example 1b How much energy (E) will the hydro plant generate each year?
• E = P×t
E = 2.1 kW × 24 hrs/day × 365 days/yr E = 18,396 kWh annually
About how many people will this energy support (assume approximately 3,000 kWh / person)?
• People = E÷3000 = 18396/3000 = 6.13 • About 6 people 64
Economics of Hydropower
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Production Expense Comparison
Wisconsin Valley Improvement Company, http://www.wvic.com/hydro-facts.htm
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Environmental Impacts
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Impacts of Hydroelectric Dams
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Ecological Impacts • Loss of forests, wildlife habitat, species • Degradation of upstream catchments areas due to inundation of • • • • •
reservoir area Rotting vegetation also emits greenhouse gases Loss of aquatic biodiversity, fisheries, other downstream services Cumulative impacts on water quality, natural flooding Disrupt transfer of energy, sediment, nutrients Sedimentation reduces reservoir life, erodes turbines – Creation of new wetland habitat – Fishing and recreational opportunities provided by new reservoirs
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Environmental and Social Issues • Land use – inundation and displacement of people • Impacts on natural hydrology – Increase evaporative losses – Altering river flows and natural flooding cycles – Sedimentation/silting
• Impacts on biodiversity
– Aquatic ecology, fish, plants, mammals
• Water chemistry changes
– Mercury, nitrates, oxygen – Bacterial and viral infections
• Tropics
• Seismic Risks • Structural dam failure risks
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Hydropower – Pros and Cons Positive
Negative
Emissions-free, with virtually no CO2, Frequently involves impoundment of NOX, SOX, hydrocarbons, or particulates large amounts of water with loss of habitat due to land inundation Renewable resource with high Variable output – dependent on rainfall conversion efficiency to electricity (80+ 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
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