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

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

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.

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

VRFB 5kW Stack – Building block

All polymer materials, high integrity sealed system

Low impedance membrane electrodestructure Charge/discharge ratio 1:1

5kWe nominal, 8.5kWe peak (15 mins)

Future target of 15kW

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% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%0

2,000

4,000

6,000

8,000

10,000

12,000

Battery Life Cycle based on Depth of Discharge

VRFBLithiumPolynomial (Lithium)Deep Cycle Lead AcidPolynomial (Deep Cycle Lead Acid)GEL Lead Acid

Timeline of development

R&D phase

Demonstration phase

Low cost manufactured product launch phase

2014: 7 units 15-18010 demo unit facility launchTested quality process productionR&D cost down plan

2015-17: Volume productionAutomation Large volumeR&D cost down

2013:60kWhsystem in Portugal

Original 30kWh VRFB pilot system – 2011

Containerised modular VRFB system designs -standardised for volume production

5-3010-30

5-6010-60

15-18030-18045-18060-180

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

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

Regional Context – The Western Isles

• Argyll generation severely constrained

• SSE cable upgrades scheduled for 2015

• Test site for VRFB selected by CES

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%

VRFB Applications – Grid balancing services

Typical Energy Storage application for grid peak shaving with baseload power

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.

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

Short term operational reserve (STOR) Profile

Arbitrage Profile

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

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

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…?

Thank you for your attention – Questions ?

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