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Maximising the Use of Renewable Energy in Rural Villages of Sundarbans Delta, through Numerical modelling of
Tidal Energy Resources
EPSRC Institutional Fund - Global Challenges Research Fund (GCRF) for international development research
24 Oct 2017 Edinburgh University
Venki Venugopal
Insititute for Energy Systems, School of Engineering, University of Edinburgh,
United Kingdom
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Project Collaborators
Prasad K BhaskaranIndian Institute of Technology Kharagpur, West Bengal.
Sugata Hazra, Jadavpur University, Kolkata.
Venki VenugopalDavid IngramRobin Wallace The University of Edinburgh
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• Sundarbans, is world’s largest inter-tidal delta region containing huge areas of mangrove forests.
• Intersected by a complex network of tidal waterways, mudflats and small islands of salt-tolerant mangrove forests.
• Eco-geography of this area is dependent on the tidal effect, of two flood and two ebb tides occurring each day, with a tidal range of ~ 3-8m.
• About 106150 households distributed across 131 villages in 20 islands have no access to electricity.
• India - great potential of ocean based renewable energies, the current energy tapping from marine energy sources appears to be nil.
• Collaboration between Edinburgh University and Indian academics, will assist India in achieving some of its renewable energy targets.
Background - The Sundarbans
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Background – The Sundarbans
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• Numerical modelling of tidal energy resource assessment to identify high energy resource sites in the delta;
• Quantify and analyse the extractable tidal energy potential;• Develop numerical model(s) representing the energy extraction
process of tidal turbines at candidate sites;
• Estimate and quantify electricity generated from tidal machines at key sites;
• Conduct an electrical load analysis and a cost benefit analysis.
Key objectives
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Numerical Modelling
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Challenge: Bathymetry Data
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Computational domain for Telemac3D models
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Challenge: Selection of bottom friction values
Domain 1 Domain 6
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Calibration – Tidal surface elevationdomain-1 and 2
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Mean current velocity 27th Feb 2016 – 30th Mar 2016
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UV velocity : 2.56m/sDepth : ~7m
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UV velocity : 1.3m/sDepth : ~5m
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UV velocity : 2.2m/sDepth : ~5m
UV velocity : 1.3m/sDepth : ~11m
UV velocity : 1.2m/sDepth : ~5m
C
Mean velocity and depth for selected sites(hotpots)
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Tidal Current Profile at Hotspot
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Tidal Power Profile with 5 m turbine
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Challenge: Implementation of 3D turbine via actuator disc method
Turbine criterion – 3 to 5 meter in diameter
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Theory of the RANS actuator disc• RANS equations of momentum (1) and mass conservation (2).
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𝛿𝛿(𝜌𝜌𝑈𝑈𝑖𝑖)𝛿𝛿𝛿𝛿
+𝛿𝛿(𝜌𝜌𝑈𝑈𝑖𝑖𝑈𝑈𝑗𝑗)𝛿𝛿𝑥𝑥𝑗𝑗
= −𝛿𝛿𝛿𝛿𝛿𝛿𝑥𝑥𝑖𝑖
+𝛿𝛿𝛿𝛿𝑥𝑥𝑗𝑗
𝜇𝜇𝛿𝛿𝑈𝑈𝑖𝑖𝛿𝛿𝑥𝑥𝑗𝑗
+𝛿𝛿𝑈𝑈𝑗𝑗𝛿𝛿𝑥𝑥𝑖𝑖
+𝛿𝛿𝛿𝛿𝑥𝑥𝑗𝑗
−𝜌𝜌𝑢𝑢𝑖𝑖′𝑢𝑢𝑗𝑗′ + 𝜌𝜌𝑔𝑔𝑖𝑖 + 𝑆𝑆𝑖𝑖 (1)
𝛿𝛿𝑈𝑈𝑖𝑖𝛿𝛿𝑥𝑥𝑖𝑖
= 0 (2)
𝑆𝑆𝑖𝑖 = −12𝜌𝜌 KΔ𝑥𝑥𝑡𝑡
𝑈𝑈𝑖𝑖|𝑈𝑈𝑖𝑖 (3)
CT =K
1+0.25𝐾𝐾 2= 4a(1 - a) (4)
At Betz limit, a = 1/3
• CT = 0.89
• K = 2
Resistance coefficient
Disc thickness
Induction factor
Reynold’s stress
Source term
Thrust coefficient
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Requires refined structured grid
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Turbine Drag Force
• Thus, the total force from a tidal turbine is:
𝐹𝐹𝑇𝑇𝑇𝑇𝑇𝑇 = 𝐹𝐹𝐷𝐷 + 𝐹𝐹𝑇𝑇 =12𝜌𝜌𝐴𝐴𝑠𝑠𝐶𝐶𝐷𝐷𝑈𝑈2 +
12𝜌𝜌𝐴𝐴𝑇𝑇𝐶𝐶𝑇𝑇𝑈𝑈2
• AS = area of the turbine supporting structure • AT = turbine rotor swept area• 𝐶𝐶𝐷𝐷 = drag coefficient of a smooth cylinder + bio-fouling
(0.9)• 𝐶𝐶𝑇𝑇 = turbine thrust coefficient
• UC = cut-in velocity• UD = rated velocity
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Domain for simple channel testusing 4m structured grid
600m
2000m
Q = 6000 m3/s(U = 1m/s)
inlet
H = 10m
outlet
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Effect of turbine installation at Satjelia
Without turbine turbine deployed
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Electrical demand modelling in the Sundarbans
• Generated electrical demand profiles for 6 villages• Analysis of weekday-weekend, seasonal variability in
the profiles • Assessed how well the demand profiles match with the
power generated by the tidal array• Suggested technological interventions to solve the
problems of any mismatch
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Methodology
Electrical demand in villages (base case) [1]
• Residential – lighting, water pumping
• Agricultural – agro-processing, land preparation etc.
• Commercial (shops, saw mills, tourism) – lighting, water pumping, milling
[1] Tidal Energy Resource Mapping in the Sundarban Biosphere Area, Tech. Report, June 2016
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Methodology
Residential lighting modelling inputs • No. of rooms • No. of bulbs• Types of bulbs• No. of people active in house• Occupancy in household (0 or 1)• Target irradiance• External irradiance
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Distribution of household size and number of dwelling rooms
Household size
Percentage of households having number of dwelling rooms
No exclusive room
1 room
2 rooms
3 rooms
4 rooms 5 rooms
6 rooms +
1 0.16 1.80 0.18 0.03 0.01 0.00 0.012 0.47 6.06 0.88 0.13 0.05 0.01 0.023 0.89 13.25 2.81 0.40 0.15 0.03 0.044 1.22 18.87 5.28 0.73 0.30 0.05 0.075 0.86 12.64 4.74 0.74 0.30 0.05 0.06
6-8 0.93 12.29 6.59 1.57 0.61 0.12 0.139+ 0.15 1.60 1.29 0.74 0.43 0.12 0.15
[4] Houselisting and Housing Census 2011, Table HH-4: Households by Ownership Status of the Census Houses, Size of the Household and Number of Dwelling Rooms . Available: http://www.censusindia.gov.in/2011census/Hlo-series/HH04.html
http://www.censusindia.gov.in/2011census/Hlo-series/HH04.html
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Distribution of Bulb types
Number and types [5,6,7] of bulbs assumption
• 1 bulb for each room (inc. kitchen, toilet and bathroom)
• Maximum of 2 bulbs for dwelling rooms per house
Type Power range (W) LumensIL 40, 60, 100 1600FL 28, 36, 40 2600
CFL 8 to 23 1400LED 4 to 13 1400
Note: • IL = incandescent lamp, • FL = linear fluorescent lamp (tube light), • CFL = compact fluorescent lamp, • Led = light emitting diode based lamp.
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TypePower range (W)Lumens
IL40, 60, 100 1600
FL28, 36, 402600
CFL8 to 231400
LED4 to 131400
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Key outcomes
• A numerical model for resource assessment of tidal energy for the Sundarbans is completed.
• Impact of energy extraction by tidal energy devices at the delta has been investigated.
• Electrical demand for 6 villages in the delta analysed.• A Phd from IITK was trained on numerical modelling.
• Collaboration brought a new UKIERI project ~ £200 k.• A PhD student placement for 3 months at Edinburgh
through Newton-Bhaba scheme. • Indian Partners are now in a GCRF Hub bid.
Slide Number 1Slide Number 2Slide Number 3Background – The Sundarbans Slide Number 5Slide Number 6Challenge: Bathymetry Data Computational domain for Telemac3D modelsChallenge: Selection of bottom friction values Calibration – Tidal surface elevation�domain-1 and 2Mean current velocity �27th Feb 2016 – 30th Mar 2016Mean velocity and depth for selected sites�(hotpots)Tidal Current Profile at HotspotTidal Power Profile with 5 m turbineChallenge: Implementation of 3D turbine via actuator disc methodTheory of the RANS actuator discRequires refined structured grid Turbine Drag Force Domain for simple channel test�using 4m structured gridEffect of turbine installation at SatjeliaElectrical demand modelling in the SundarbansMethodologyMethodologyDistribution of household size and number of dwelling rooms Distribution of Bulb typesKey outcomes