By Julia McDonald Off-grid electrification for development of small islands represents a number of unique challenges under the broad category of rural electrification. Small, off-grid island communities are particularly vulnerable to diesel price fluctuations and natural disasters, and thus, enhancing resilience through more sustainable and cheaper energy technologies should be a key priority. Financing the transition to these technologies – usually photovoltaic, micro-hydro or sometimes wind – is an essential hurdle to overcome. Once electricity systems are in place it is equally important that they are sustained in the longer term with effective arrangements for operation and maintenance, cost recovery etc. Related to this, is the productive use of the energy provided to increase islander incomes. The workshop on Bunaken Island, Sulawesi, Indonesia from 3 to 5 November 2015, organised by the Smart Villages Initiative in collaboration with Kopernik, will explore these issues and develop recommendations for policy makers, development agencies and other stakeholders in energy provision to island communities. More info: http://e4sv.org/events/off-grid-islands-electricity-workshop/

1. Renewable Energy in Small Island Grids
Design and Case study - Tuvalu

2. Overview
1. About ITP
2. Types of grid
3. Solar and storage integration
4. Case Study – Tuvalu northern islands
5. Long term operation

3. About ITP
•Specialist renewable energy consulting firm
•Over 30 years international experience and 1,000 projects
•Head office in UK
•Major regional offices in India, China and Australia

4. About ITP - Australia
• Head office in Canberra, offices in South Australia and
NSW
• Active in Australia and the Pacific region for over 10
years
• Involved in RE projects of all scales (1 kW to 50+ MW)
• Services
• Engineering Consultancy
• Project Engineering
• Energy Markets and Advisory
• International Aid and Development

5. Types of island grid
5 of xx slides
• Generally speaking, a micro-grid is self-contained and
limited by geography
• Loads can vary from being very small (e.g. a few houses)
to very large (e.g. a remote town with a large energy
user)
• Smallest form is individual home energy systems (1
house)
• Mini-grids (100 – 1,000 kWh/day) – eg remote islands
• Small grids (1,000 – 30,000 kWh/day) – eg larger rural
town centre or “main” island
• Medium grids (30,000 kWh/day – 100,000 kWh/day)
• Large grids (100,000 kWh/day +)

6. Mini-grids
6 of xx slides
• Small, remote islands in the Pacific (pop. 200 – 2000)
• Typically one or two villages
• Mostly residential/rural energy use
• Small power station operated by trained staff
• In the past, typically diesel generators

7. Why renewable energy?
7 of xx slides
• Reduce reliance on
imported diesel
• Reduce running costs
• Cleaner
• Quieter
• Improve reliability
• But:
• Upfront cost can be high
• Only works during day
• Storage required
• Can have integration
problems with generator

8. Generator efficiency
8 of xx slides

9. Integrating renewable energy
9 of xx slides
Three broad diesel/PV hybrid design options:
• PV fuel-save (no battery storage, providing
~10% annual load contribution),
• PV fuel-save plus (sometimes utilising a small
amount of battery storage, providing up to 30%
annual load contribution), or
• PV primary (utilising a large amount battery
storage, providing >50% annual load
contribution).

10. PV fuel save
10 of xx slides
•Sized to supply about 30% of the average midday load.
•Diesel generators run continuously. PV reduces their loading during
the day.
•No batteries or specialist integration equipment.
•Lowest initial capital cost.
•Reduce annual fuel bills by around 10%.

11. PV fuel save plus
11 of xx slides
• Intelligent control system that occasionally spills some PV output
to ensure that the generators are kept sufficiently loaded.
• Diesel generators still run continuously, but over the year, the PV
makes a much larger contribution (~30% total, 60% in the middle
of the day).
• Sometimes include a small battery bank to optimise loadings.

12. PV primary
12 of xx slides
• Large battery bank able to meet load with all generators off.
• Relatively high integration costs
• Highest annual contribution from renewable energy sources (can go to 100%)
• Economically viable for smaller loads or where diesel costs are unusually
high or supply is uncertain.

13. Economics of renewable energy in mini-grids
13 of xx slides
Grid size Diesel Efficiency Cost of generation Economic level of RE
Mini 1-2 kWh/L $0.70 - $2.00 / kWh 90% +
Small 2-3 kWh/L $0.50- $0.70 / kWh 30% - 70%
Medium 3-4 kWh/L $0.20- $0.50 / kWh 20% - 50%
Large 4+ kWh/L $0.20- $0.30 / kWh 10% – 30%

14. Case study – Tuvalu northern islands
14 of xx slides

15. Case study – Tuvalu northern islands
15 of xx slides
• Nine small atoll islands
• Total population approx. 10,000
• 6,000 on the capital, Funafuti
• Other islands populations 100-1,500
• Outer islands only accessible by boat, typically 24hrs by
boat to each island
• Irregular shipping (every 3-6 weeks)
• Shipping often disrupted by weather or boat unavailability

16. Case study – Tuvalu northern islands
16 of xx slides
• Existing low voltage AC
electricity grids (diesel)
since 2001
• Grids operated by
electricity utility (Tuvalu
Electricity Corporation)
• Local operators (TEC
employees) deal with day
to day running
• Technicians from the
capital visit periodically or
for repairs when required

17. Nanumea power station
17 of xx slides

18. Generators
18 of xx slides

19. Tuvalu northern islands- key issues
19 of xx slides
• Reliability
• Only 12-18 hours of power per day normally (down to 2-4 hrs
sometimes)
• Frequent diesel shortages due to shipping unreliability
• Generator breakdowns
• Long delays for repairs (can take weeks to send a technician from
Funafuti)
• Cost
• Estimated ~$1.20 to $1.50/kWh cost of supplying energy (possibly
more)
• Vulnerable to diesel price changes
• Vulnerable to utility cash flow issues
• Tariffs ~25c/kWh – outer islands subsidised by main island and by
government
• Remote diesel grids were built as a service to the community,
but are very expensive for the government

20. Transportation
20 of xx slides

21. Transportation
21 of xx slides

22. Vulnerability to weather
22 of xx slides

23. Aims of outer islands solar project
23 of xx slides
• Outer islands 100% renewable energy
• 24hr power
• System to last 20 years without need for major
modification
• Reduce operating costs of outer islands power systems
• Improve power reliability (and availability during
disasters)
• Grant-funded (NZ Govt)
• Eliminate need for aid fuel subsidies

24. Design
24 of xx slides
• Step 1 – collect data
• Load curve – very important for design
• Use whatever means you can – can be difficult
• Data logging
• Power station records
• Try to estimate from diesel purchases
• Appliance & equipment survey
• Fill in gaps
• Allowance for load growth
• Usually a more reliable power supply leads to more
people buying appliances

25. Load curve – Nanumea island
25 of xx slides
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00
Load(kW)
After load growth
Assumed loads
From data logger

26. Load curve – Vaitupu island
26 of xx slides
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00 00:00
Load(kW)
From logs
From data logger
Assumed loads

27. Load estimate - Nanumea
27 of xx slides
• Average 550 kWh per day
• Little seasonal variation, but some “busy” times of year.
• Highest demand around Christmas and special events
• 40% of demand during “solar” hours
• 60% evening/night time
• Allowance for extra days with poor sun – 2 days
• Use this to size battery bank
• Then size solar PV array to meet day time load plus
enough extra energy to fully charge the batteries.

28. System sizing overview
28 of xx slides
• 33,000 Ah battery bank (sealed lead acid batteries)
• 200 kW solar PV array
• SMA modular inverter/charger units
• Diesel generator to be switched off normally.

29. Design schematic
29 of xx slides

30. Design features
30 of xx slides
• Modular
• if one unit fails, most of the system can be kept online
• Spares kept on island, easy to swap out
• Off-the-shelf inverter/controller, easy to order a new one
• Robust and corrosion resistant
• Cyclone proof structure
• No air conditioning required
• Because the air conditioner is often a failure point
• Low maintenance

31. Completed system
31 of xx slides

32. Display
32 of xx slides

33. Modular inverter/chargers
33 of xx slides

34. Sealed batteries
34 of xx slides

35. Passive cooling
35 of xx slides

36. Passive cooling
36 of xx slides

37. Performance so far
37 of xx slides
• System is very large for current loads
• Batteries drop to 80% overnight, are fully charged before
midday if sunny
• Can go for 5 days of cloudy weather without generator
• 1 inverter failure – local operator successfully replaced it
and sent it back for warranty claim
• Effective cost of energy supply reduced to about
$0.55/kWh (from over $1)
• However this is still higher than the tariff ($0.25/kWh)

38. Training and operation
38 of xx slides
• Local operators involved from beginning of construction
• Training throughout construction and troubleshooting
• Other staff in Funafuti (capital) have been doing solar
training over a longer period
• Very challenging for the outer island operators to adapt to
the new technology

39. Community
39 of xx slides

40. Lessons/challenges
40 of xx slides
Less well-known challenges ITP has seen over the years:
• Systems becoming too reliable (operators stop maintaining
generators totally/ get lazy)
• Social problems with 24hr power (eg loud music at night)
• Logistics can be very complicated
• Getting accurate data and information is difficult (eg
powerhouse data, shipping schedules)
• Limited market for companies with experience in designing
and building renewable energy systems on island
environments

41. Training and accreditation - regional
41 of xx slides
• SEIAPI – Sustainable Energy Industry Association of the
Pacific Islands
• Runs training and accreditation program through the
region
• Aims to establish quality standards and recognised
qualifications for local companies and individuals

42. SEIAPI training and accreditation
42 of xx slides
Individuals are able to be
certified as:
i) designers;
ii) installation
(maintenance) technicians;
iii) energy efficiency
auditors; and
iv) inspectors (of system
installations).

43. Levels of certification
43 of xx slides
• PV Grid connect systems
• Stand Alone PV Power
systems
• Level 1- Solar Home
Systems
• Level 2- Stand alone
systems with/without
Inverters
• Level 3 Hybrid Power
systems
• Wind Systems
• Energy efficiency
• Biomass Systems

44. Further info on SEIAPI programs
44 of xx slides
• www.seiapi.com
• info@seiapi.com
•

45. Southern Cross House,
6/9 McKay St, Turner, ACT
PO Box 6127 O’Connor, ACT 2602
info@itpau.com.au
p +61 (0) 2 6257 3511
f +61 (0) 2 6257 3611
itpau.com.au
IT Power Renewable Energy Consulting
Questions