Download 4.Hydro-energy-team.

MSE0290 – SUSTAINABLE
ENERGY TECHNOLOGIES
Hydro Power
Büsra Yilmaz
Rafael Osorio
Holger Part
Nature of the Hydro Power
• Hydropower or water power (from the
Greek: ύδωρ, "water") is power derived
from the energy of falling water or fast
running water, which may be harnessed
for useful purposes.
• Since ancient times, hydropower from
many kinds of watermills has been used as
a renewable energy source for irrigation
and the operation of various mechanical
devices, such as gristmills, sawmills, textile
mills, trip hammers, dock cranes, domestic
lifts, and ore mills.
History behind the Hydro Power
• In Imperial Rome, water powered mills produced flour from grain,
and were also used for sawing timber and stone; in China, watermills
were widely used since the Han dynasty.
• In China and the rest of the Far East, hydraulically operated "pot
wheel" pumps raised water into crop or irrigation canals.
• The power of a wave of water released from a tank was used for
extraction of metal ores. The method was first used in Wales from 75
AD onwards, but had been developed in Spain, Britain in
the Medieval and later periods to extract lead and tin ores. It later
evolved into hydraulic mining when used during the California Gold
Rush.
History behind the Hydro Power
• Technological advances had moved the open water wheel into an
enclosed turbine or water motor.
• In 1848 James B. Francis, while working as head engineer of Lowell's Locks
and Canals company, improved on these designs to create a turbine with
90% efficiency. He applied scientific principles and testing methods to the
problem of turbine design. His mathematical and graphical calculation
methods allowed confident design of high efficiency turbines to exactly
match a site's specific flow conditions. The Francis reaction turbine is still in
wide use today.
• In the 1870s, deriving from uses in the California mining industry, Lester
Allan Pelton developed the high efficiency Pelton wheel impulse turbine,
which utilized hydropower from the high head streams.
Usage and mechanisms behind hydropower
• Run-of-the-river power plants/river power plants
Run-of-the-river/river power plants are the most common type worldwide. They use the
flow energy of a river, and are normally used to cover the base load. Their capacity is
determined mostly by the gradient and the water level. Some run-of-the-river power
plants can also dam water at times of low energy demand in order to use it as a reserve
when demand is higher.
• The so-called diversion hydropower plant is a special type of run-of-the-river plant. The
water is dammed in a barrier and redirected onto the turbines by means of a separate
feeder channel. In the case of a standard run-of-the-river power plant, there is only a
slight difference in the height between the upper and lower water levels, but a diversion
hydropower plant exploits the greater height difference created by the diversion.
• Storage power plants
Storage power plants store the water in a natural or artificial lake and feed it via pipelines
into a lower-lying power plant. Such plants can operate independently of natural water
inflow, and are particularly suited to balancing fluctuations in regional and national
electricity generation and consumption. They are used both to cover the electrical base
load and for peak load operation.
Usage and mechanisms behind Hydropower
• Pumped storage power plants
A pumped storage power plant uses two reservoirs to store water, with the
greatest possible height difference between the upper and lower reservoirs.
During off-peak periods, e.g. at night or when there is a large amount of solar or
wind energy in the grid, water is pumped from the lower to the upper reservoir.
There, it is once again available for electricity generation at peak load times.
Pelton turbines are used to drive the generator.
• Types of power plants for exploiting marine energy
The kinetic energy of waves, tidal range and tidal flow can also be used to
generate electricity. One advantage of using marine energy is the uniform energy
supply and the ensuing balancing effect on the renewable energy mix. While tidal
range power plants are already technically mature, other technologies such as
the so-called wave power plants are still at the development stage.
Hydropower Usage - Today
https://www.hydropower.org/world-hydropower-statistics
Hydropower Usage – Future Potential
The potential for additional
hydropower remains
considerable, especially in
Africa, Asia and Latin America.
This roadmap foresees, by
2050, a doubling of global
capacity up to almost 2 000
GW and of global electricity
generation over 7 000 TWh.
Pumped storage hydropower
capacities would be multiplied
by a factor of 3 to 5.
Hydropower Usage – Future Potential
• Most of the growth in hydroelectricity generation will come from
large projects in emerging economies and developing countries. In
these countries, large and small hydropower projects can improve
access to modern energy services and alleviate poverty, and foster
social and economic development, especially for local communities.
• In industrialised countries, upgrading or redevelopment of existing
plants can deliver additional benefits.
Working principles
• Principle
• Use of gravitational
force of falling or
flowing water
Principle
Potential energy - 1
Kinetic energy - 2
Mechanical energy - 3
Electric energy - 4
Turbine – kinetic to
mechanical
• A water turbine is a rotary
machine that converts kinetic
energy and potential energy of
water into mechanical work.
• Reaction turbines
• Impulse turbines
https://water.usgs.gov/edu/hyhowworks.html
Turbine classification
• 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
Turbine classification
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003
Francis turbine
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Most common water turbine in use today
Water head from 10 to 350m
Few KW up to 800MW
Hybrid type
• Both reaction and impulse
https://en.wikipedia.org/wiki/Francis_turbine
Kaplan turbine
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High-flow, low-head
Propeller type with adjustable blades
Head 2– 40 m
5 – 200 MW
Runner diameeter 2 – 11 m
Reaction type turbine
https://en.wikipedia.org/wiki/Kaplan_turbine
Pelton turbine
• Impulse type turbine
• High head, low flow
• Head 50– 1300 m
• Up to 400 MW
https://en.wikipedia.org/wiki/Pelton_wheel
Turgo turbine
• Medium head
applications(50 – 250 m)
• Impulse water turbine
• Lower efficiency, lower
cost
https://en.wikipedia.org/wiki/Turgo_turbine
Crossflow
turbine
• Heads less than 200 m
• Flat efficiency curve
• Lower peak efficiency
Water wheel
• For free-flowing or falling water
• No longer in common use
• Up to 60% efficiency
Hydropower calculations
• P = power in kilowatts (kW)
• g = gravitational acceleration (9.81 m/s2)
• ŋ = turbo-generator efficiency (0<n<1)
• Q = quantity of water flowing (m3/sec)
• H = effective head (m)
Marine energy
• Tidal power
• Wave power
• Marine current power
• Osmotic power
• Ocean thermal energy
Hydopower Advantages
• It is fueled by water, so it's a clean fuel source, meaning it won't
pollute the air like power plants that burn fossil fuels, such as coal
or natural gas.
• It is a domestic source of energy, allowing each state to produce
their own energy without being reliant on international fuel
sources.
• The energy generated through hydropower relies on the water
cycle, which is driven by the sun, making it a renewable power
source, making it a more reliable and affordable source than fossil
fuels that are rapidly being depleted.
Hydro Advantages
• Impoudment hydropower creates reservoirs that offer a variety of
recreational opportunities, notably fishing, swimming, and boating. Most
water power installations are required to provide some public access to the
reservoir to allow the public to take advantage of these opportunities.
• Some hydropower facilities can quickly go from zero power to maximum
output. Because hydropower plants can generate power to the grid
immediately, they provide essential back-up power during major electricity
outages or disruptions.
• In addition to a sustainable fuel source, hydropower efforts produce a
number of benefits, such as flood control, irrigation, and water supply.
Effects of Dams on Biodiversity
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About 60% of the world’s river flow is regulated.
There are more than 40,000 large dams with heights >150 m.
Reservoirs cover a total area in excess of 500,000 km2.
Large hydroelectric dams are among the most controversial of
alltypes of development projects.
• Focus - criticism of the World Bank and other
internationalfinancing agencies.
• Critics point out - destruction of biodiversity
What dams do?
• Anthropogenic alterations that disrupts dynamic processes and
so impact on ecological integrity of natural system.
• Dams disrupt the river continuum and cause upstream and
downstream shifts in biotic and abiotic parameters.
Impact order
• 1st order impacts:
Immediate
abioticeffects
• 2nd order impacts:
Changes in channel
and flood plain
biology
• 3rd order impacts:
Long term biotic
changes and “new
equilibrium”
Biodiversity
• Fresh waters are home to a relatively high proportion of
species, with more per unit area than other environments
(10% more than land and 150% more than the oceans).
• only about 45,000 species of freshwater animals, plants and
microorganisms have been scientifically described
• at least an additional million more species remain to be
named.
Biological Impacts
• Blocking migratory
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species.
• Changing turbidity.
• Filtering out of woody
debris which provides
habitat and sustains a
food chain.
• Trapping silt in reservoirs
and reducing
downstream productivity.
Changing conditions
of underwater terrain
– running water
becomes still
– deep water zones,
– temperature and
oxygen conditions
changes
Hydropower Disadvantages
• Unstable for riverine species.
• Possibly fostering exotic species.
• Reservoirs may be colonised by species which are vectors of human
and animal diseases.
• Dam management diminishes or stops normal river flooding and
affecting biodiversity.
• Changing the normal seasonal estuarine discharge which can
reduce the supply of nutrients, impacting the food chains that
sustain fisheries in inland and estuarine deltas.
• Modifying water quality and flow patterns downstream.
Migration
• Anadromous fishes (salmon and hilsa) catadromous
fishes (eels)
• Many stocks of Salmonidae and Clupeidae have been
lost as aconsequence.
• Eg. Columbia River, USA, more than 200 stocks of
anadromous, Pacific salmonids became extinct.
• Sturgeon populations in the Caspian Sea rely on
hatcheries mainly in Iran, since Russian dams block
natural spawning migrations.
• Hydroelectric dams in the Amazon basin have halted
the long distance upstream migration of several
species of catfishes and interrupted the downstream
migration of their larvae
Turbidity
• Reservoirs trap suspended particles, reducing turbidity
downstream.
• Many species are adapted to natural turbidity.
• Eg. turbid water catfishes have small eyes, refined senses of
smell and touch in their sensitive barbels.
• Downstram biota changes
• Clear water increases visual predator attack (birds).
• Indigenous species affected adversely.
• Other animal species may move in
– filter feeders and aquatic vegetation may flourish.
– sediment burrowing species reduces due to lack of sediment
• increased turbidity, above natural levels, can interfere with
primary production (Arthington & Welcomme 1995).
Sedimentation
• Reservoirs tend to serve as sediment traps since river velocities and
carrying capacity for particles decrease in reservoirs (McCartney et
al. 1999)
• Sedimentation can degrade habitat both in the reservoir and below
the dam, as well as reduce storage capacity.
• Many of the mollus can extinctions in the Mobile Bay (USA) due to
siltation
• Suspended silt may reduce the feeding efficiency of filter-feeding
bivalves and other species.
• About 50 km3 of sediment, nearly 1% of global reservoir capacity,
was estimated in 1997 to be trapped behind dams.
Seasional Variability of Flow and Flood Plains
• The pattern of flow of a river undergoes a regular series of changes
with the seasons. The patterns can differ profoundly from region to
region
• e.g. in an Indian river the peak flow may be during the monsoon,in
an Arctic river during snow-melt or ice breakup.
• The expansion and contraction of the river controls living space and
access to particular habitats.
• Species in a drainage basin adapt to the seasonal patterns .
• It is from river flow events that species take cues to migrate,spawn,
etc.
• Some species are adapted to strongly seasonal flow regimes
with flooding.
• Changes in flow patterns through intensive flow regulation
after impoundments and possible changes in algae, bacteria
and fungi, which form potential mollusc food sources.
Inland Deltas
• Naga Hammadi barrage area of the lower Nile, Egypt
• Perch- Zingel streber and Zingel zingel (IUCN -vulnerable)
• Salmonids- Hucho hucho, (endangered, and salmon -Salmo
trutta.
• The European beaver, Castor fiber, has left the territories
influenced by the dam.
• The mean annual fish catch has dropped by 87%
Estuarine and Marine Impacts
• Many of the effects in estuaries are similar to upstream, e.g.
loss of habitat and changes in seasonal flow, turbidity and
productivity.
• Total shifting of ecosystem
Is Hydropower really sustainable?
• Siltation reduces a dam’s water storage so water stored in the
wet season cannot be stored for use in the dry season
• The life of dams can be extended by sediment bypassing,
special weirs, and forestation project to reduce silt production.
At some point, it becomes uneconomic to operate in most
cases.
Is Hydropower really sustainable?
• Water flow can decrease in areas due to environmental problems such as
global warming
• The North Cascades glaciers have lost a third of their volume since 1950,
resulting in stream flows that have decreased by as much as 34%
• No burning of fossil fuels
• Even though water sources can eventually be reduced, other water
resources will always be available due to the water cycle
Conclusion
• Dams alter river ecosystems and subsequently require
development of new relationships between human kind and
natural resources associated with these ecosystems.
• Dams built to receive benefits will accrue humans with energy,
water supply, transportation, flood control, fishing, recreation,
aesthetics, and so on.
• https://www.youtube.com/watch?v=nvzx1QCXCes
References
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https://en.wikipedia.org/wiki/Francis_turbine
https://en.wikipedia.org/wiki/Kaplan_turbine
https://en.wikipedia.org/wiki/Turgo_turbine
https://www.renewablesfirst.co.uk/wp-content/cache/page_enhanced/www.renewablesfirst.co.uk//hydropower/hydropower-learning-centre/crossflowturbines//_index.html_gzip
https://en.wikipedia.org/wiki/Pelton_wheel
https://en.wikipedia.org/wiki/Cross-flow_turbine
https://water.usgs.gov/edu/hyhowworks.html
https://en.wikipedia.org/wiki/Hydroelectricity
http://www.iea.org/publications/freepublications/publication/technology-roadmap-hydropower.html
https://www.hydropower.org/world-hydropower-statistics
http://www.renewables-made-in-germany.com/en/renewables-made-in-germany/technologies/hydropower/hydropower/technologies-and-applications.html
http://energyinformative.org/the-history-of-hydroelectric-power/
Boyle, Renewable Energy, 2nd edition, Oxford University Press, 2003