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2014 IEEE Power & Energy Society General
Meeting
July 27-31, 2014
Sustainable Microgrids in Less
Economically Developed Communities
Dr. Henry Louie
Seattle University
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Rural Microgrid Architectures
Community
Microgrid
Community
Charging Station
•1kW-100kW
•Wired distribution
•Multiple households
•Entity operated
•1kW-20kW
•Battery distribution
•Multiple households
•Entity operated
Dr. Louie
Improvised
Microgrid
•<1kW
•Wired distribution
•Single or few
houses
•Individual operated
3
Energy Access Tiers
Tier
kWh/year
Service
0
<3
1
3-66
2
3
4
5
--
Community
Microgrid
Radio, Mobile phone, Task
Lighting
Improvised
Microgrid
66-321 General lighting, TV, Fan
321-1317 Low power appliances
1317-2120 Medium power appliances
>2120 High power appliances
Dr. Louie
Community
Microgrid
4
The Energy
Ladder
Energy
Repurposing
Dr. Louie
5
Dr. Louie
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Community Microgrid
Low Voltage
DC Bus
Low Voltage
AC Bus
Petrol
Generator
Station
Batteries
meters/
fuses
…
Customers
Charge
Controllers
Monitoring
and
Broadcast
Dr. Louie
Local
Loads
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Community Charging Station
Low Voltage
DC Bus
Low Voltage
AC Bus
Petrol
Generator
Station
Batteries
Charge
Controllers
…
Charge
Controllers
Monitoring
and
Broadcast
Dr. Louie
Portable
Battery Kits
(PBK)
Local
Loads
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Portable Battery Kits
• Sealed lead-acid battery
– 12Ah (144 Wh) – 17Ah (204 Wh)
– Low voltage disconnect
• Weight
bboxx.co.uk
– 5- 8kg
• Common features
– USB ports + adapters for mobile phone charging
– LED lights (1-2W, 100-200 Lumens)
• Sturdy Case
• Cost: US$100 (600Nkr) to US$150 (900Nkr)
Dr. Louie
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Community Charging Stations
• Advantages
– Strategic location
– No metering
– Minimal/no distribution system
• Disadvantages
– PBKs require replacement every 2-3 years
– Battery disposal
– Lower energy provision
– Greater maintenance/replacement costs
– More complex business management
• Costs
– About US$5000 to US$8000 per kW installed
Dr. Louie
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Community Charging Stations
Benefactor/
Government/
Microfinance
Entity
(NGO, clinic, school, etc)
Operation,
Maintenance,
Replacement
Community
Charging Station
…
Dr. Louie
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Case Study: Zambia
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Improvised Rural Microgrid Systems
Solar Panel
Inverter
AC Loads
Lights
Radio
TV
Phone Charger
Charge
Controller
Generator
Battery
Spare Batteries
Characteristics
DC Loads
Lights
Radio
TV
Modified sine wave inverter
Lead acid battery <30Ah
<30 W Solar panel
No meters, fuses
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“Flying Blind” Operation
Charging
Battery Obtained
?
unknown SOC
unknown condition
?
Time-based charging
Discharging
Lowest load voltage threshold
<11V
?
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Sustainability of Microgrids
Sustainability is the perceived potential for a system or project
to endure, build a self-perpetuating capacity within a community,
and ultimately reach the end of its predefined life span or evolve
into another beneficial form.
Technical
Economic
Environmental
Sustainability Pillars
Dr. Louie
Social
Organizational
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Statshot: Kristy’s Cape Academy
Location: Muhuru Bay, Kenya
Surrounding Population: 4000
Students in 2010: 12
Students in 2013: 300
Students Orphaned due to HIV/AIDS: 40
Tuition: 150 KES (1.3€)/month
Dr. Louie
Grid Connection: None
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Energy Expenditure
Energy expenditure survey results
Muhuru Bay, Kenya, Dec. 2013, N = 69
Monthly Expense
(US$)
Item
Batteries
3.50
Candles
0.65
Kerosene
4.65
Phone Charging
2.06
Total US$10.86/month
Dr. Louie
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System Design
System to be implemented by a Kenyan vendor
Each: 1 kW
Total: 2 kW
Each: 400Ah @ 6VDC
Total: 400Ah@ 48VDC (19.20 kWh)
3kW
PBK (65)
Each: 17Ah @ 12VDC
Total: 1105Ah @ 12VDC (13.26kWh)
Each: 235 W
Total: 2.82 kW
Published to a web page
for condition monitoring
100W continuous
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PBK
•
•
•
•
17 Ah @ 12VDC (204 Wh)
Weight: 5.7kg
Two, 2.2W LED (>128 Lm) bulbs
Low voltage disconnect
– 35 hours of continuous two bulb illumination
– ~75% depth of discharge
• Energy required for full charge after disconnect: 330
Wh (47% efficient)
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Charging Characteristic
voltage
16V
Maximum power: ~60 W
Total time: ~9 hrs
Total energy: 330Wh
14V
3.5A
0A
current
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Energy Flows
• Energy in: 14.1 kWh/day (solar only)
• Energy out:
– PBK (33): 10.9 kWh/day
– School Load: 2.4 kWh/day
• Energy input and output profiles generally
coincide
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Business Plan (Projections)
• Income:
– Rental Fee: 1100 KES/month (US$12.81)
– Enrollment Fee: 500 KES (US$5.82) (one time)
– Mobile Charging Fee: 20 KES (US$0.23)
Total Income: 77557(US$902.85)
• Expenditures:
– Salary (3 employees): 17355 KES/month (US$202.03)
– Depreciation: 50213 KES/month (US$584.54)
– Minor part replacement: 859 KES/month (US$10)
Total Expenditures: 68427 (US$796.6)
• Disposable Income: 9130 KES/month ($106.29)
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Comments
• Financial and technical stability not a given
• Training (technical and business) a significant
part of the project, but not covered here
• Approximately 1 year of planning
• Two follow-up trips (6 month, 1 year)
• Inspiration and advice from IEEE PES
Community Solutions Initiative
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Questions?
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Supporters
Special thanks to Steve J. Szablya and Dr. Vincent Van Acker
Henry Louie, PhD
Associate Professor
Department of Electrical and
Computer Engineering
901 12th Avenue, Bannan 219
P.O. Box 222000
Seattle, WA 98122-1090
www.seattleu.edu
COLLEGE OF
SCIENCE AND
ENGINEERING
Tel: (206) 398-4619
Fax: (206) 296-5962
louieh@seattleu.edu
@henrylouie