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

2.
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

3.
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

4.
Mini-grids – Tuvalu northern islands
4 of xx slides

5.
Case study – Tuvalu northern islands
5 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

6.
Case study – Tuvalu northern islands
6 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

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
• Storage required
• Can have integration
problems with generator

8.
Generator efficiency
8 of xx slides

9.
Generators
9 of xx slides

10.
Nanumea power station
10 of xx slides

11.
Village
11 of xx slides

12.
Village
12 of xx slides

13.
Tuvalu northern islands- key issues
13 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 heavily 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

14.
Transportation
14 of xx slides

15.
Unloading
15 of xx slides

16.
Transportation
16 of xx slides

17.
Vulnerability to weather
17 of xx slides

18.
Aims of outer islands solar project
18 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

19.
Load curve – Nanumea island
19 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

20.
Load curve – Vaitupu island
20 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

21.
Load estimate - Nanumea
21 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.

22.
Design schematic
22 of xx slides

23.
Design features
23 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

24.
Completed system
24 of xx slides
Photo credit: Heather Logie

25.
Display
25 of xx slides

26.
Modular inverter/chargers
26 of xx slides

27.
Sealed batteries
27 of xx slides

28.
Passive cooling
28 of xx slides

29.
Performance so far
29 of xx slides
• System is very large for current loads – no diesel needed
• 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

30.
Training and operation
30 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 and are adapting well with
support from the manufacturers
• Very challenging for the outer island operators to adapt to
the new technology
• Local operators call head office (if possible) for support
from more skilled technicians

31.
Lessons/challenges
31 of xx slides
Some challenges ITP has seen over the years:
• Skill level of staff on outer islands is usually low
• 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)
• Communications difficult
• Limited market for companies with experience in designing
and building renewable energy systems on island
environments

32.
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