Vanadium Redox Flow Battery

1. John Ward, REDT Energy Ltd. Dublin.
REDT Vanadium Redox Flow Battery (VRFB)
‘Firming Up’ Wind Energy & The DECC Gigha Project in
Scotland
Meitheal Na Gaoithe Conference, Kilkenny

2. Agenda
• Background to the Technology Development
• VRFB – What is it ?
• Review of VRFB technology - performance at stack level and scale
up to grid systems
• Applications in Brief & Progress to date
• Demonstration Project – Gigha
• Conclusion

3. VRFB – What is it ?
Key features for reliability:
• Power and energy independent
Scalable from 5kW to 10MW, with
3 to18 hours discharge duration
• Deep discharge capability
Capable of 10,000 cycle life with
minimal degradation >20 year life
Partial cycles have no effect on system life
• Safe operation
Ambient temperature, non-
flammable, environmentally sound
– zero emissions.

4. Vanadium – What is it ?
The 23rd element in the periodic table
Vanadium is a silverish transition metal (the valence
electrons exist in more than one shell). In normal
states, vanadium atoms have 23 protons, 23 electrons,
and 28 neutrons. Very High Columbic Efficiency -98%
23 P 28 N
Electron shells

5. VRFB 5kW Stack – Building block
All polymer materials, high
integrity sealed system
Low impedance
membrane electrode
structure
Charge/discharge ratio 1:1
5kWe nominal,
8.5kWe peak (15 mins)
Future target of 15kW

6. Vanadium Redox Flow Battery Benefits
 Low LCOE >20 year life
– Lowest cost over life in class
– Modular from 5kW to 5MW to
match loads, scale duration
from hours to days
– Stack life > 10,000 cycles,
electrolyte indefinite life, re-
usable & recyclable
• Performance
– Deep discharge cycles, uses
100% of available capacity
– Charge retention, almost
indefinite in standby mode
– 75-85% round trip efficiency
– Partial cycles have 0 effect
0
2,000
4,000
6,000
8,000
10,000
12,000
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Battery Life Cycle based on Depth of
Discharge
VRFB
Lithium
Deep Cycle
Lead Acid
GEL Lead
Acid

7. Timeline of development
2000:
REDT
Started
2003-08:
Small 5kW
stack
developed
2012:
Technology
proven
2013:
Large stack
1.2MWh
order
2014:
Low cost
outsourced
manufacturing
JABIL
R&D phase
Demonstration phase
Low cost manufactured
product launch phase
2014:
7 units 15-180
10 demo unit
facility launch
Tested quality
process
production
R&D cost down
plan
2015-17:
Volume production
Automation
Large volume
R&D cost down
2013:
60kWh
system in Portugal

8. Original 30kWh VRFB pilot system – 2011

9. Containerised modular VRFB system designs -
standardised for volume production
5-30
10-30
5-60
10-60
15-180
30-180
45-180
60-180

10. ISO Standard 20’ container section – 60kW x 180kWh
• 12 x 5kW rated stacks per battery
• Insulated air flow thermal control system
• Argon blanketed electrolyte
• Safety – leakage, fire, hydrogen detection
• 96,000 Litres of electrolyte per container
• Excess electrolyte enables deep discharge

11. The Isle of Gigha and the Application
• Community owned Wind
• Population ~150
• Tourism, Farming, Brewing
• Renewables potential
• Sub-sea cable
• One of the longest 11 kV feeders to
mainland
• Remote and wild

12. Regional Context – The Western Isles
• Argyll generation severely constrained
• SSE cable upgrades scheduled for 2015
• Test site for VRFB selected by CES

13. The Isle of Gigha and the Application
Current position:
• New (4th) wind turbine installed -
exceeds T&D limits
• 330 kW constrained to 225 kW at 0.85 p.f.
• Line capacity upgrades not yet available
• Lose 3 GWh over asset life
Primary objective:
• Constrained energy recovery with on-
peak dispatch
• Enhanced FIT benefit
• Opportunity to increase RE generation by
30%

14. VRFB Applications – Grid balancing services
Typical Energy Storage application for grid peak shaving with baseload power

15. Parker SSD EGT Control System
Parker SSD PCS working with the REDT VRFB has a system response time of less
than 5m/s and can therefore perform multiple intra-cycle control functions.
Electronics and cable inductance are limiting factors not the energy storage system
itself.

16. Firm Frequency Response (FFR) Profile
Gigha 105kW rated system - RoCoF

17. Short term operational reserve (STOR) Profile

18. Arbitrage Profile

19. Constrained Energy Profile – Typical day
Gigha system 105kW x 1.26MWh
Blue = ESS kW, Charging when negative Red = Stored energy MWh start/finish @ zero SOC

20. System Services Summary
Frequency Control
Voltage Control
Regulation of Curtailment
Arbitrage
Improvement of output prediction
Post demonstration stage the technology will be rolled out
to other islands

21. Conclusions
• Energy storage is entering the mainstream
• The Technology is constantly evolving and becoming cheaper
– full suite of services and dispatch for c.5 euro/Mwh
• REDT will be ready for large scale deployment supporting
wind energy & Solar in Q3 2015
• Within 5 years there will be large scale deployment of
distributed storage worldwide
• Market for storage globally is $10Bn by 2017(19), 33% of this
is estimated to be flow batteries
• Possibility of an entirely renewable power system…?

22. Thank you for your attention – Questions ?
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