maximising the use of renewable energy in rural villages ......number and types [5,6,7] of bulbs...

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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

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

Numerical Modelling

Challenge: Bathymetry Data

Computational domain for Telemac3D models

Challenge: Selection of bottom friction values

Domain 1 Domain 6

Calibration – Tidal surface elevationdomain-1 and 2

Mean current velocity 27th Feb 2016 – 30th Mar 2016

UV velocity : 2.56m/sDepth : ~7m

A


B




C

Mean velocity and depth for selected sites(hotpots)

Tidal Current Profile at Hotspot

Tidal Power Profile with 5 m turbine

Challenge: Implementation of 3D turbine via actuator disc method

Turbine criterion – 3 to 5 meter in diameter

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

Requires refined structured grid

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

Domain for simple channel testusing 4m structured grid

600m

2000m

Q = 6000 m3/s(U = 1m/s)

inlet

H = 10m

outlet

Effect of turbine installation at Satjelia

Without turbine turbine deployed

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

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

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

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

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

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

maximising the use of renewable energy in rural villages ......number and types [5,6,7] of bulbs...

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