Off-grid Rural Area Electrification by Solar-Diesel Hybrid ... · Off-grid Rural Area...
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Off-grid Rural Area Electrification by
Solar-Diesel Hybrid Mini-grid in
Bangladesh : Design Considerations
Shahriar Ahmed Chowdhury Email: [email protected]
Director, Centre for Energy Research Assistant Professor, Department of Electrical and Electronic Engineering, UIU
Functional Structure of IDCOL
Solar-Diesel Hybrid Minigrid
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Financial Scheme of IDCOL Minigrid
Project
Grant Loan Equity Project Donors:
KfW, WB, ADB and JICA
Loan Scheme:
Interest rate: 6%
Tenure: 10 years
Principal grace: 2 years
Payment frequency: 3 months
Payment type: Annuity
Mini-Grid Design Steps
1 • Site Survey for Feasibility Study
2 • Demand Assessment (Load duration curve)
3 • Technical Design
4 • Financial Analysis
5 • Preparing Bankable Document
6 • Installation Supervision and Commissioning
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Typical Rural (Household and Shops) Load
Duration Curve
0 5
10 15 20 25 30 35 40 45 50 55 60
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
kW
h L
oad
Time of the day
Winter, kWh Summer, kWh
For 800 house holds and a village market having 200 shops
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Typical Rural Load Duration Curve With Productive
Day Loads
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
kW
h L
oa
d
Time of the Day (24 hours)
For 500 households, a village market having 150 shops and
industrial loads (Workshop, Saw mills and ice making industry)
Design Consideration
Solar-diesel Hybrid
Mini-grid
RE fraction
>80% or above
Payback period 10
years
Financial
Model
Reduced CoE by
increasing productive day loads
Battery Manageme
nt
Voltage drop at the end of distribution
feeders <5% of rated
Project life 20 years
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Energy Mix for Rural mini-grid
Energy share curve of a 200kWp Solar-Diesel Hybrid Mini-
grid
Renewable Fraction > 90% April 12, 2014 8
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
Mo
nth
ly L
oad
(kW
h)
Electricity Generation Mix
Supply from diesel generator Datenreihen2
Project cost breakup Generation Equipment
(Solar Panel+ Generator)
19.7%
Electronics (Controller & Inverter)
17.3%
Storage System (Battery and Protection)
20.5%
Land and Infrastructure (Land+Land
Dev.+Building) 14.4%
Distribution Systems 15.9%
Other 4.3%
Technical Assistace
3.2%
Contigency 4.8%
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Cost Reduction Potential
Increase of daytime load (does not require battery storage) Solar irrigation
Cottage industries (Sewing or weaving machine etc.)
Husking mills
Sawmills
Lathe machine
Welding machines
Grinding machines (spice)
Photocopier machine
Computer training centres
Poultry firms
Cold storages
Ice making industry (for fish preservation in island areas)
Offices /Schools/Madrasas etc. April 12, 2014 10
Storage system Most difficult part of designing an off grid solar system for rural
electrification is the storage system managements.
Bottle necks:
1. Limitation of charging and discharging currents limits the
design
flexibility.
2. Limitation of DoD of battery operation increases the
size of battery bank
3. Higher ambient temperature reduces the designed battery
life
Advantages of adding a diesel generator is included in mini-grid to
1. Increase the reliability of power
2. Reduce the storage requirement
3. Avoid autonomy requirements
4. Reduce project cost (reduced battery size reduces the
project cost)
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Single line diagram of PV –diesel minigrid
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Consumer type (Household) and approximate
monthly bill
Package type Load Quantity Power
/unit Approximate monthly
bill in USD
Package-1
(Small Households 550)
LED light 4 7 5.75
Ceiling Fan 2 25
Package-2
(Medium Households 205)
LED light 5 7
8.75 Ceiling Fan 2 25
TV 1 50
DVD 1 20
Package-3
(Well off households 85)
LED light 5 7
18.85
Ceiling fan 3 25
TV 1 50
Refrigerator* 1 100
CD/ DVD 1 20
Package-4 shops
LED light 3 7 2.6
Ceiling Fan 1 25
Package-5 shops
LED light 3 7
12.75 Ceiling Fan 2 25
TV 1 50
Refrigerator* 1 100
Package-6 School LED light 20 7
23.07 Ceiling Fan 10 25
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Considering IDCOL model tariff varies from USD 0.35 – 0.45 depending
upon the size and load pattern of the minigrids
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