Trends in Redox Flow Battery Technology and project REDOX2015

Trends in Redox Flow Battery Technology and project REDOX2015 International Workshop on Energy Storage in the grid. Barcelona, 9 January 2014 Luis Santos <<Nome Do Documento>

Agenda 1. EDP in Spain 2. Conventional approach to storage: price arbitrage 3. New approach: grid services and reserves 4. Redox flow batteries are a promising option 5. Redox2015 project 6. Conclusions 2

1. EDP in Spain #1 Portugal First Portuguese company by market capitalisation #1 Europe ~ 3 GW of hydraulic projects under construction 4º Electricity producer and Distribution System Operator 2º Operator of natural gas #3 Worldwile More than 6.4 GW of wind capacity 3

1. EDP in Spain Innovation strategic lines Flexible generation and with high availability Environmental innovation Electric mobility Grids and storage Energy intelligence 4

Agenda 1. EDP in Spain 2. Conventional approach to storage: price arbitrage 3. New approach: grid services and reserves 4. Redox flow batteries are a promising option 5. Redox2015 project 6. Conclusions 5

(MW) 2. Conventional approach to storage: price arbitrage As a first approach, the economics of energy storage ar assessed by price arbitrage Price arbitrage - charging during off peak hours and discharging at peak hours 45000 Load diagram 40000 35000 30000 Charging period Discharging period 25000 20000 15000 10000 5000 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 6

2. Conventional approach to storage: price arbitrage Wind power has grown dramaticaly in Spain over the past years Capacity mix in Spain (%) 2012 CCGT Wind Hydro Coal Nuclear Special Regime Thermal no renewable Wind power + photovoltaics had reached the 25% threshold in Spain Solar PV Fuel/gas Solar thermoelectric Special Regime Thermal renewable 0% 5% 10% 15% 20% 25% 30% 7

2. Conventional approach to storage: price arbitrage Now there is a Supply Side Management problem Sometimes wind power grows a lot 25-Febrero 2010: Actualmente recortes debidos a Balance and has to be disconnected P 6.000 MW 4 h Wind power production in Spain 29.03.2010 Wind power production in Spain 25.02.2010 8

2. Conventional approach to storage: price arbitrage Supply peak shaving is the problem now There is a lot of energy wasted but other fuels also suffer 50.000 45.000 44.000 60 53 40.000 50 35.000 30.000 25.000 40 30 32 20.000 15.000 20 10.000 5.000 0 4.000 6.000 2008 2009 2010 10 0 3 1 2 2006 2007 2008 2009 2010 Energy lost due to disconnection of wind Thermal units disconnected to allow wind (MWh) in Spain production in Spain 9

1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136 145 154 163 172 181 190 199 208 217 226 235 244 253 262 271 280 289 298 307 316 325 334 343 352 361 2. Conventional approach to storage: price arbitrage Peak and off Peak prices are getting closer: the spread for price arbitrage is reducing 90 80 Spread ( /MWh) in Spain (Peak - Off peak Prices) 70 60 50 Spread 2006 Spread 2011 40 30 20 10 0 Days in a year Excess of capacity The number of days with a spread good enough to recover costs is reducing This puts more pressure on the economics of price arbitrage 10

Agenda 1. EDP in Spain 2. Conventional approach to storage: price arbitrage 3. New approach: grid services and reserves 4. Redox flow batteries are a promising option 5. Redox2015 project 6. Conclusions 11

3. New approach: grid services and reserves Threats and opportunities for energy storage Energy storage point of view RES have reduced energy spreads Grid Services Need for quicker and longer reserves Intermittent incontrollable generating capacity 12

3. New approach: grid services and reserves Wind farms are far away from demand: more grids are needed Demand Wind 13

(MW) 3. New approach: grid services and reserves Services to transmission & distribution Investment deferral Grid stability Contingency support 45000 40000 35000 30000 25000 20000 15000 10000 5000 Voltage control Frequency control 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 0 Charge management But all these services deserve a proper retribution 14

3. New approach: grid services and reserves Need for fast and longer reserves 1. Future loads cannot be perfectly predicted 2. Generator ouputs can vary substantially in different time frames 3. Power system equipment can fail without notice Forecast demand Real demand Operating reserves: real power capability that can be given (upward) or taken (downward) to assist in generation and load balance and frequency control 15

Agenda 1.EDP in Spain 2. Conventional approach to storage: price arbitrage 3. New approach: grid services and reserves 4. Redox flow batteries are a promising option 5. Redox2015 project 6. Conclusions 16

4. Redox flow batteries are a promising option Different needs imply different technologies and approaches What do you need storage for? Large-scale electricity storage tecnologies Fast power quality applications Reserve applications Energy management applications Improve reliability power quality and uninterrupted power supply (UPS) applications Electric power grid stability and switching between energy sources Improve profitability load leveling, peak shaving Energy discharges from a fraction of a second Stored energy is used in minutes rather than seconds or hours Energy discharges that last hours High Power Applications Bridging Power Applications High Energy Applications 17

Discharge Time (Hr) 4. Redox flow batteries are a promising option Power vs Capacity SYSTEM RATINGS 100 Local back up Transmission&Distribution back up Energy management 10 1 Peak shaving, load leveling and price arbitrage Li-Ion VR Zn-Br v Na-S CAES PSH 0.1 0.01 0.001 0.0001 Stability Power Quality Ni-MH L/A 0.001 0.01 0.1 1 10 100 v Ni-Cd FW Na-S EDLC v CAES EDLC FW L/A Li-Ion Na-S Ni-Cd Ni-Mh PSH VR Zn-Br Compressed Air Dbl-Layer Capacitors Flywheels Lead-Acid Lithium-Ion Sodium-Sulfur Nickel-Cadmium Nickel Metal Hydride Pumped Hydro Vanadium Redox Zinc- Bromine 1,000 Rated Power (MW) 18

4. Redox flow batteries are a promising option Pumping and Compressed Air are for the lucky ones Pumping hydro and Compressed Air Energy Storage fall apart from other technologies: Heavy reliance on geology (site dependent) (Portugal, Austria, Switzerland, Slovenia) Massive capital costs and long comissioning periods Mature technology Enviromental issues involved Other technologies are needed to address the storage problem from a distributed & site-independent approach

4. Redox flow batteries are a promising option Redox flow battery Half-celd Electrode V 4+ + CHARGE - DISCHARGE H + VO 2+ Membrane H + V 2+ Half-celd - Electrode Reduction Oxidation Oxidation Reduction e - V 5+ VO 2 + V 3+ e - e - e - e - e - e - e - ANODE CATHODE CATHODE ANODE V 3+ + e - V 2+ V 2+ V 3+ + e - V 4+ V 5+ + e - CHARGE V 5+ + e - V 4+ DISCHARGE

4. Redox flow batteries are a promising option Capacity costs and power costs are independent Redox Flow Batteries show better cost performance for large systems Cost Benefit over other technologies Power dependent costs E 1 Energy stored kwh 21

4. Redox flow batteries are a promising option Redox flow batteries show more opportunities to bring costs down Tendency of published patents shows better perspective for Redox Flow Batteries NaS battery VRF battery No. of Patents NaS Battery No. of Patents VRF Battery 250 30 200 25 150 20 15 100 10 50 5 0 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 0 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 From a fire incident in 2011 NGK has asked nearly every customer to suspend the use of NAS batteries or restrict its use 22

Agenda 1.EDP in Spain 2. Conventional approach to storage: price arbitrage 3. New approach: grid services and reserves 4. Redox flow batteries are a promising option 5. Redox2015 project 6. Conclusions 23

5. Redox2015 project Consortium and funding Objective: develop a Vanadium Redox Flow Battery by spanish partners Budget :2,7 M Project length: 27 months (2011-2013) Funded by the Economy and Competitiveness Ministry of Spain with FEDER funding from the European Commission (IPT-2011-1690-900000) 24

Capital Cost per Unit Energy ($/kwh-output) (Cost/Capacity/Efficiency) 10 100 1,000 10,000 5. Redox2015 project Questions to answer by the project: metrics to evaluate Cost metrics High Power E.C. Capacitors High Power Flywheels Lead Acid Batteries Ni-Cd Na-S Batteries Li-Ion Zinc-Air Bat. Long Duration Flywheels capex in /kw and /kwh Performance metrics real efficiency Long Duration E.C. Capacitors Flow Batteries CAES Pumped Hydro Metal-Air Batteries ciclability stability 100 1,000 Capital Cost per Unit Power ($/kw) 10,000 calendar and cycle lifes 25

Transpo rting Generation Distribution 5. Redox2015 project Findings so far Service Required power Required discharge time Required response time Frequency of use MV connection LV connection A B C D E F G H I Capacity support 500 kw MV Occasional some MW 2 10 h Minutes (peaks) LV hundreds kw Local voltage control 100 kw MV some MW Occasional 2 10 h Minutes 10 kw (peaks) LV hundreds kw Contingency support 100 kw MV some MW 2 10 h Minutes Unusual 10 kw LV hundreds kw 100 kw 10 MV Island mode MW 4 10 h 20 ms Unusual LV 10 kw 1 MW Reactive hundreds kvar some MVar. Minutes Daily compensation Peak capacity More than 1 MW 1-10 h Minutes Daily Local generation support More than 1 MW variable Variable Variable Services to DER hundreds kw 2 MW 20 min. 1h30 15 30 seconds Continual 20 min. 15 30 Frequency control More than 1 MW Continual 1h30 seconds Frecuency stability Tens of Less than 1 More than 1 MW Unusual on island seconds second Consumer. Managing peak demand 0,5 10 MW 1-10 h Minutes Daily Feasible High value for storage ( specific for island mode) Inappropriate Other applications are feasible ( specific for island mode) 26

5. Redox2015 project Findings so far SIMPLE CELL DESIGN 1. Components screening 2. Cell design 3. Charger/Discharger prototipe 4. Flow dynamics modelling 5. Single cell optimizing tests 6. Stack development 27

j (macm -2 ) j (macm -2 ) j/ macm -2 j/ macm -2 j/ macm -2 <I>/mA 5. Redox2015 project Findings so far ELECTRODE ACTIVE MATERIALS SCREENING FOR VRFB INSTITUTO NACIONAL DEL CARBÓN (INCAR) 20 15 10 5 0-5 -10-15 0 0.2 0.4 ARGF GFOx GFOxQN 0.6 0.8 36 32 24 24 16 12 8 j ( macm-2) 2 00-2 GO GO TRG700 _ TRGO700 _ TRG1000 TRGO1000-8 -12-16 -24-24 -32 0 0.20 0.40 0.60 0.80 1.00 1.20 Ewe /V GO: Graphite Oxide TRG700: GO reduced at 700 ºC TRG1000: GO reduced at 1000 ºC GRAPHENES E (V) vs. Hg /Hg 2 SO 4 E (V) vs. Hg /Hg 2 SO 4 6 4 2 0 CNW1 CNW1 CNW2 CNW3 CARBON NANOWALLS POSITIVE HALF-CELD (V 4+/5+ ) -2-4 (a) 0 0.2 0.4 0.6 20 30 SEMICELDA NEGATIVE NEGATIVA HALF-CELD(V(V 2+/3+ 2+/3+ ) ) 10 0-10 -20-30 -1.1-1 -0.9-0.8-0.7 ARGF TTGF BiGF -0.6 20 10 0-10 -20-30 -40 ARGF GFOx GFOxQN ARGF: Felt untreated TTFF: Thermal felt BiGF: Modified felt using bismuth GFOx: Electrochemically oxidized felt GFOxQN: chemically oxidized felt -1.3-1.2-1.1-1 -0.9-0.8-0.7-0.6 E (V) vs. Hg/Hg 2 SO 4 E (V) vs. Hg/Hg 2 SO 4 28

5. Redox2015 project Findings so far Electrodes development Synthesis Functionalization PAN based flexible nanofiber Electrospinning Graphene nanoparticles PAN commercial felt VRFB PROTOTYPE High energy density electrolyte Innovative membranes Polymeric additives in aqueous electrolytes Coulombic Efficiency Voltage Efficiency Energy Efficiency standard electrolyte 0.6% additive-containing electrolyte PAN commercial felt with standard electrolyte (3M H 2 SO 4 and 1M VOSO 4 ) Objective: High energy and power efficiency, long life and cyclability (excellent> 30,000), 5 times the charge density of the typical solutions Use of additives to improve the electrolyte standard electrolyte additive-containing electrolyte 29

Ew e/v 5. Redox2015 project Findings so far MEMBRANES FOR REDOX FLOW BATTERIES Objective: To minimize vanadium crossover through the membrane by surface plasma activation. These treatments cause changes in the polymer material: Inversion of surface polarity Surface crosslinking Ew e vs. <I> AR-1-REP_03_LSV_06.mpr AR-2-REP_03_LSV_06.mpr AR-3-REP_03_LSV_06.mpr AR-4-REP_03_LSV_06.mpr AR-5-rep_03_LSV_06.mpr AR-6-rep_03_LSV_06.mpr AR-7-rep_03_LSV_06.mpr NAFION 115 NUEVO + GFD5 NUEVO+ELECTROLITO NUEVO_03_LSV_06.mpr # 1,5 1,45 1,4 1,35 1,3 1,25 1,2 1,15 1,1 1,05 1 0,95 0,9 0,85 0,8-150 -100-50 0 REDOX FLOW BATTERY <J>/m A/cm ² SINGLE CELL Single cell set-up to test new materials in flow battery operation Development of testing protocols for membranes and electrodes 30

Agenda 1.EDP in Spain 2. Conventional approach to storage: price arbitrage 3. New approach: grid services and reserves 4. Redox flow batteries are a promising option 5. Redox2015 project 6. Conclusions 31

6. Conclusions Energy storage for price arbitrage, at the current state of art and current prices, is not competitive But the increase of penetration of wind power implies different conditions to take into account Reserve markets are a good opportunity for energy storage economics Where pumping is not an option, other applications of distributed energy storage are necessary R&D projects like REDOX2015 are needed to meet performance and cost requirements 32

Thanks for your attention! lsantos@edpenergia.es <<Nome Do Documento> 33