Lecturette Akram Ali.ppt

Renewable Energy Resources Hydropower

Renewable Energy Resources

Akram Ali 75th JMC

Prepared by

Wapda Administrative Staff CollegeIslamabad

Hydropower


Hydrologic Cycle


Hydropower to Electric Power

Kinetic Energy

Mechanical Energy

Potential Energy

Electrical Energy


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


World Trends in Hydropower


Facts About Hydropower


World hydro production


Major Hydropower Producers


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


Three Gorges Dam (China)


Itaipú Dam (Brazil & Paraguay)


Guri Dam (Venezuela)


Grand Coulee Dam (US)


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


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


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


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


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


Types of Hydroelectric Installation






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.


Types of Water Wheels






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


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


Turbine Design Ranges

Kaplan 2 m < H < 40 m

Francis 10 m < H < 350 m

Pelton 50 m < H < 1300 m


Turbine Application Ranges


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


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


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


Economics of Hydropower


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


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


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


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


Thank you


Conventional Impoundment Dam


Schematic of Impound Hydropower


Diversion Hydropower (Run-of-River)


Diversion Hydropower (Run-of-River)


Micro Run-of-River Hydropower


Pumped Storage Schematic


Pumped Storage System

At time of low demand

At time of high demand


Pumped Storage Power Spectrum


Schematic of Francis Turbine

Cutaway diagram

Flow through guide vanes and runner blades


Francis Turbine Cross-Section


Small Francis Turbine & Generator


Francis Turbine


Kaplan Turbine Schematic


Kaplan Turbine Cross Section


Vertical Kaplan Turbine Setup


Horizontal Kaplan Turbine


Pelton Wheel Turbine


Turgo Turbine


Types of Hydropower Turbines

Documents

Lecturette Akram Ali.ppt