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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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-- Dr. P. S. KulkarniElectrical Engineering Department, Visvesvaraya National Institute of
Technology [Deemed University],
Nagpur 440 010, INDIA (e-mail : pskulkarni@eee.vnit.ac.in).
ENERGY FROM TIDES AND WAVES
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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FAQs What is Tidal / Wave Energy? How Tidal / Wave Energy is generated? What are the current developments in the
Tidal / Wave Energy technology? What are the difficulties in Energy
Conversion process? How is the Energy stored? What is the Impact on the Environment ?. .
.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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I. INTRODUCTION
Renewable Resources: Sources of Energy that are virtually Inexhaustible and Pollution-free.
Role of Renewable Energy (RE) Meeting energy demand, Enhancing
energy security, Reducing greenhouse gas (GHG) emissions and, as a result, contributing to Sustainable Development.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Energy for Sustainable Development Sustainable development demands a sustainable supply of energy resources that in the long term, is readily and sustainably available at reasonable cost in the country.
Sustainable development could only be achieved by provision of high quality and environmentally responsible energy on time, at a reasonable price.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Global Estimated Energy Consumption (in 10 ^ 15 kWh)Country 1990 A.D. 2000 A.D. 2010 A.D.United States
40 80 160
Germany 10 20 40Canada 10 20 40France 8 20 40Japan 7 15 35India 5 15 40U.K. 5 10 25
Others 50 150 300
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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INDIAN POWER SCENARIO Second highest global population Ranked as the sixth largest energy consumer in
the world Need $170 billion for generation and transmission
projects to meet power demand by 2012. Natural Gas - Preferred fuel Wind Power to make a contribution of as much as
20,000 MW to the fuel mix. Nuclear Power is also a critical element of the
government’s strategy to avoid dependence on energy imports in the future.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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INDIAN POWER SCENARIOInstalled Gen. Capacity : As on (31.3.04)
Steam (72 %) 79,838 MW Hydro (26 %) 29,500 MW Nuclear (02 %) 2,720 MW---------------------------------------------------Total : 1,12,058 MW---------------------------------------------------
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Modewise Gen. of Electricity in India (As on 31.3.04)
Thermal (84 %) 4,66,618 GWh Hydro (13 %) 73,796 GWh Nuclear (03 %) 17,720 GWh---------------------------------------------------------Total : 5,58,134 GWh ---------------------------------------------------------
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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SOLAR ENERGY UTILIZATION
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Ocean Energy Systems Energy conversion technologies that
harness the energy in tides, waves, and thermal gradients in the oceans.
OTEC : Ocean Thermal Energy Conversion: The process or technologies for producing energy by harnessing the temperature differences (thermal gradients) between ocean surface waters and that of ocean depths. OTEC plants are used in both Japan, and in Hawaii, Atlantic coast in some demonstration projects.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Suitability of site for Tidal Power Plant The tidal range R should be large. The storage area should be large. The site should allow the
development of the necessary plant for reasonable cost.
It should be environmentally acceptable.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Energy The tides offer a source of energy because of
the potential energy of the raised tide water or the kinetic energy of tidal stream.
Tidal Energy is a Renewable Energy. Tidal Energy is a form of Hydro Energy
recurring with every tide. Tide is a periodic rise and fall of the water level of sea which is carried by the gravitational attraction between the earth, the sun and the moon.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Principle of Tidal Power A tidal power plant works on the
principle of a dam or barrage that captures water in a basin at the peak of a tidal flow, then directs the water through a hydroelectric turbine as the tide ebbs.
Tidal Power is proportional to square of Tidal Range ‘R’.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Power
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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29.5 d
New moon First quarter Full moon Third quarter New moon
Spring tide Neap tide Neap tideSpring tide Spring tide
Relative high and low tides showing variation in range during lunar month
12h, 25m
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Important Terms Spring Tide: Tide when the tidal range is
maximum on full moon and new moon. Neap Tide: Tide when the tidal range is minimum
on first quarter and third quarter moon. Diurnal Tide : Tide occurring during the daytime
than at night; Daily. Tidal Range (m): Diff. betn consecutive high tide
and low tide water levels. Dam — A structure for impeding and controlling
the flow of water in a water course, and which increases the water elevation to create the hydraulic head. The reservoir creates, in effect, stored energy.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Important Terms Barrage: A Dam. Barrages are usually of
smaller heights than the dams. Barrage is designed for lesser head of water.
Ebb Tide: Tide associated with decreasing level of water.
Estuary: 1) A part of river or stream which is influenced by tide in the main sea. 2) Mouth of river where river current meets the tidal current.
Sluice Way: Passage-way (gated) or artificial channel to let water through.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Gravitational effect of the Sun and the Moon on tidal range
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Power Plants in World 1966 – At La Rance Estuary (France*) (240 MW, 24 units of Bulb Turbine, Mean ‘R’ = 8.4 m;
Max. ‘R’ =13.5 m; Effective ‘A’ = 20 sq. km; Basin vol.=1.84x108 sq.m., Turbine Dia. = 7.6 m) Bay of Fundy Betn. USA and Canada (16 MW)* Kislaya inlet on the Barents sea in the USSR
(< 500 kW)*
The English Channel * :Power plants in operation
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Bulb type Turbine Plants Axial-flow tur. –Propeller / Kaplan
with Hor. Shaft. High Hyd. Eff. Low Inertia Stable operation Low Average Temp. High Generator Losses
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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FOUR POSSIBLE SITES IN INDIA
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The estimated potential of important Renewable Sources of Energy in West Bengal
Sl. No. Sources/Systems Potential 1. Biogas Plants (Nos.) 0.7 Million 2. Improved Chulhas (Nos) 6.6 Million 3. Biomass Based Power 200 MW 4. Solar Energy 20 MW per sq. K.M. 5. Wind Energy 115 MW 6. Small Hydro Power 250 MW 7. Tidal Power 100 MW 8. Urban & Industrial Wastes 250 MW
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Renewable Energy Power Projects in the pipelineIn West Bengal
1. Tidel Power Plants 3 MW 2. Biomass Based Power Plants 1 MW 3. Wind Power Generation 2 MW 4. Small Hydel Power Generation 12 MW 5. Solar PV Power Generation 400 MW
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Energy Conversion Schemes Single Basin Schemes:1 or 2 effect
scheme Modified Single Effect Scheme Two Basin Scheme Multiple Basin Scheme Pumped Water Storage Scheme
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Gravitational Attraction
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Energy The gravitational force F between two bodies
(say between sun and a water molecule on the earth) is given by
whereM = mass of sunm = mass of water moleculer = distance betn. sun and water molecule, mK = gravitational constant.
)1(r
KMmF 2
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Energy The tides arise twice a day. The difference in Potential Energy during High
tide and Low Tide is Tidal Energy. The tides are rhythmic but not constant, nor do
they occur on a regular daily schedule. Their occurrence is due to a balance of forces, mainly the gravitational force of the moon but also that of the sun, both acting together with that of the earth to balance the centrifugal force on the water due to the earth’s rotation. The result is the rhythmic rise and fall of water.
The tides are characterized by their schedule and range ‘R’ (m).
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tides
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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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SINGLE BASIN TIDAL SCHEME
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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SINGLE BASIN TIDAL SCHEME
SINGLE BASIN TIDAL SCHEME
Disadvantages: Needs Small Size Plant Operation over a longer period Energy Generated = 1.5 * Energy (Tide Cycle System)
SINGLE EBB CYCLE SYSTEM
SINGLE TIDE CYCLE SYSTEM
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Ebb generating system with a bulb turbine
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Bulb Turbine
Rim Turbine(Straflo turbine used at Annapolis Royal TPP)
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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OCEAN AND POOL LEVELS AND POWER GENERATED IN A SIMPLE SINGLE-POOL TIDAL SYSTEM.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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AVERAGE POWER Pav
For a tidal range ‘R’, and an intermediate head ‘h’ at a given time
during the emptying process, the differential work done by the
water is equal to its potential energy at the time, or
where
)3(dhhAggdWthatso
)2(dhAdmbut
)1(hdmggdW
c
c
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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AVERAGE POWER Pav
m.sq,ttanconsconsidered,poolofareasurfaceAmkg,densitywater
m,headhkg,turbinethroughflowingmassm
s.Nkg0.1,factorconversiong
sm81.9,onacceleratinalgravitatiog
J,waterthebydoneworkW
3
2c
2
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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AVERAGE POWER Pav
The total theoretical work during a full
emptying (or filling) period is obtained by
integrating Eq. (3) as)4(RA
gg
21W
dhhAggdWW
2
c
0
Rc
0
R
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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AVERAGE POWER Pav
Thus the work is proportional to the range tothe power 2. the power generated during eachof the above periods is equal to W divided bythe time duration of that period. Zero power isgenerated during the rest of the time. Theaverage theoretical power delivered by thewater is W divided by the total time it takes each period to repeat itself, or 6h, 12.5m, or22,350 s. Thus
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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AVERAGE POWER Pav
W,powerltheoreticaaveragePwhere
)5(RAgg
447001RA
gg
21x
223501P
av
2
c
2
cav
Assuming an average seawater density of 1025 kg/m3, the average theoretical power per unit pool area would be given by
)6(m/WR225.0AP 22av
The actual power generated by a real tidal system would be less than the above because of frictional losses and inefficiencies in the turbines and electric generators and might only be 25-30 % of the above.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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POWER GENERATED AT BAY OF FUNDY
MW51480275.0x13000x8x225.0P
.effxAxRx225.0P
%5.27EfficiencygminAssum8R
km13000A
2av
2av
2
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Problems Prob. 1: The basin area of a tidal
power plant is 20 x106 m2. The tidal range is 8 m. Calculate the energy generated in kwh.
Soln:
kWh10x368.10E
3600xPEW10x28810x20x8x225.0AxRx225.0P
m8Rm10x20A
8
av
6622av
26
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Problems Prob. 2: A tidal power plant of the simple single
basin type, has a basin area of 30 x 106 m2. The tide has a range of 12 m. The turbine, however, stops operating when the head on it falls below 3 m. Calculate the energy generated in one filling (or emptying) process, in kWh if the turbine-gen. efficiency is 0.73.
Soln :The total theoretical work W is given by
where,R is the range =12 m.r is the head below which turbine stops operating = 3 m.
r
R
dWW
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Problems
kWh10x18.2394kWh73.0x10x7.3279generatedEnergy
,efficiencygeneratorturbinegConsiderin
kWh10x7.32793600x1000
10x04.911generatedEnergy
W10x04.911
312x10x30x1025x81.9x44700
144700
rRAgtimeWPpoweraveragetheThus
rRAg21dhhAgdhhAgW
66
66
6
226
22
av
22r
R
r
R
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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SINGLE POOL SINGLE EFFECT TIDAL SCHEME
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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SINGLE POOL DOUBLE EFFECT TIDAL SCHEME
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DOUBLE BASIN PAIRED BASIN SCHEME
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DOUBLE BASIN LINKED BASIN SCHEME
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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TWO BASIN SCHEME It involves additional investment into civil
structures and equipment. In addition, the power generating efficiency of the plant which is directly prop. to the basin area decreases by one half when the basin area is halved.
Although uninterrupted power generation would be possible, the natural capacity varies by 2 or 3 times, a phenomenon which cannot be obviated.
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Tidal Energy Storage
Dec. 18, 2004 ISTE STTP at Electrical Engg. Deptt, GCOE, Amravati
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Environmental Impacts Tidal energy systems can have
environmental impacts on tidal basins because of reduced tidal flow and silt buildup.