1. Quelle:
Prudent Energy
Storage for a sustainable future The Global Leader in Advanced Energy Storage
Large scale Energy storage – applications of the VRB-ESS® in providing electrical grid power solutions
Frame cut
Timothy Hennessy June 1 1

2. Quelle:
About Prudent Energy
Provides proprietary VRB® Energy Storage Systems (VRB-ESS®) for grid and renewable energy storage applications between 200kW to 10MW 100MWh
10 years operation with the VRB® technology: 200 employees
Over 20MWh commercial sales and installations in last year across 11 countries
VRB® and storage application Patents: control all substantial patents including 51 issued patents and 48 pending patent applications in 34 countries
Major Investors: MITSUI Corporation, GS Caltex, State Power Group, DFJ and DT Capital, CEL, Northern Light
Company Overview

3. Prudent VRB® Technology
Quelle:
Prudent VRB® Technology
What is a Flow Battery?
Regenerative fuel cell or “Cell Stack”
Independent electrolyte storage tanks
Pumps to circulate electrolyte
Control system to manage electrolyte circulation
Flow battery technologies are distinguished by electrolyte composition

4. Prudent VRB® Technology
Quelle:
Prudent VRB® Technology
Flow Battery Cell Stack
Array or “stack” of individual cells in series
Each cell consists of
bipolar plate
2 electrodes
Membrane separator
Colors of Vanadium at different ionic states
Non Toxic
Readily available from waste streams such as flyash
V+5 -> V+2

5. Prudent VRB Technology
Quelle:
Prudent VRB Technology
Flow Battery Advantages and Disadvantages
Advantages
No daily “off periods” - always on
Power and energy capacity can be sized independently of one another
Operates at any SOC without life impact
Any Depth of Discharge (DOD)
Lowest LCOE (unlimited cycles of electrolyte)
Large surge capability possible
Efficient over 100% DOD range
< 1 cycle responses
Low pressure and low temperature=safe
Disadvantages
Low energy storage density = big footprint
Not mobile

6. The modular assembly of a MW scale VRB-ESS® in California
Quelle:
The modular assembly of a MW scale VRB-ESS® in California

7. The modular assembly of a MW scale VRB-ESS® in California
Quelle:
The modular assembly of a MW scale VRB-ESS® in California
Peak Shaving
Using bio gas from onion plant
Gills Onion’s California

8. MW scale VRB-ESS® in China - wind and PV smoothing
Quelle:
MW scale VRB-ESS® in China - wind and PV smoothing
500kW 750kW pulse (10 minutes) / 1MWh
Results – one of other technologies has had performance issues within a year
Our performance has been solid
Ambient temperatures down to -30C
Provides continuous reactive energy (MVAR)
2MW * 8MWH system being commissioned in September 2012 – wind PV - grid connected

9. Microgrids – island and hybrid systems
Quelle:
Microgrids – island and hybrid systems
400kW x 500kWh diesel, PV and micro-hydro, Hybrid in Indonesia
Slovakia – smart grid 600kWh
Hawaii – islanded PV
China – smart grid wind and PV
Korea Smart grid Jeju island

10. KW class VRB-ESS® for Telecoms and commercial sites
Quelle:
KW class VRB-ESS® for Telecoms and commercial sites
5 to 10kW
No refuelling costs
Long Life (10+ years)- electrolyte never wears out
No degradation on deep cycling
Low maintenance
Always on – no bridging power needed - SOC always known
Long duration storage independent of power – scalable up to 10 hours
Closed loop no emissions – no disposal issues

11. VRB® characteristics from field testing
Quelle:
VRB® characteristics from field testing
Response time ms
Short circuit test
Response time full charge to discharge < 50ms
Stack Coulombic efficiency
Short circuit test – stack shorted max 2000 Amps. Discharged over 140 seconds. System recovered after short removed
Longest field operation 6 years un-manned

12. Cell stack evolution - 2002: 2012
Quelle:
Cell stack evolution : 2012
SEI 42kW stack
VRB P3 5kW- 10kW
VRB P3 2010
VRB P1 5kW 2004
S5 stack 2012

13. Schematic of a conventional battery and PCS are separate
Quelle:
Schematic of a conventional battery and PCS are separate
VRB-ESS is a system

14. PCS – Power Conversion system
Quelle:
PCS – Power Conversion system
Sized in modular form ABB PCS-100 provides 4 quadrant operation, P&Q and F&S modes of operation ABB PCS 100

15. HMI Power Screen for the VRB-ESS

16. Future enhancements to VRB® Technology
Quelle:
Future enhancements to VRB® Technology
Energy density of electrolyte being improved – reduces footprint and costs
Footprint reduction of plant – higher efficiency of cell stacks
Market driven cost reductions depends on application e.g. renewable power smoothing, peak shaving etc.
Modular 250kW
40% footprint reduction 2011 to 2013

17. 4MW 16MWh Plant
33m x 35m for delivery 2013

18. Implications of community based generation in Distribution System
Quelle:
Implications of community based generation in Distribution System
storage
Power flows no longer in one direction due to multiple sources
Complex protection coordination due to multiple generation sources
Microgrid or community grids contains both generation and load
Managed independently of main distribution system and can operate even if main transmission source is cut
Courtesy Brad Williams Oracle

19. Germany Current Situation
Quelle:
Germany Current Situation
Reports on critical grid conditions [Reference: Paul-Fredrik Bach: Frequent wind power curtailments 14 April 2012]
Recently “Welt Online” reported on “alarm level yellow” for German power grids on 28 and 29 March
During first quarter EON Netz has issued 257 interventions.. Thus there have been interventions active for 23.1% of the hours in first quarter.
Part of the solution is storage backed microgrids owned by communities

20. Quelle:
Comparisons of Wind and PV systems with energy storage for municipal owned microgrids
4 cases: Objective to minimize grid demand and reduce volatility of power sold to grid.
PCC= 9MW: Below zero in graphs indicates grid purchases i.e. NON FIRM renewable resource
Smoothing effects and ramp rate (stability) management provided by energy storage
Cases examine mixes of PV and wind generation along with 2.5MW of storage with durations of 1, 2, 4 and 6 hours all at 2.5MW FIRM PPA with utility
Finding is that between 4 to 6 hours of storage yields lowest volatility and minimum grid purchases.

21. Firmness provided by storage in islanded micro grids
Quelle:
Firmness provided by storage in islanded micro grids
Grid purchases when storage sized at 1hour
Wind (MW) 5
PV (MW) 4
1 hour storage duration
Grid purchase (times/year)
230
Energy purchases (MWh)
604.7
4 hours storage duration
152
35.8
6 hours storage duration 8
2.7

22. Peaking generation enhancing the value of OCGT using Energy Storage
Quelle:
Peaking generation enhancing the value of OCGT using Energy Storage
Also reduces CO2 emissions
Ref: PJM USA markets

23. Energy trading using flow batteries in Germany
Quelle:
Energy trading using flow batteries in Germany
IRR over ten years > 15%

24. Summary of Alternative Grid Energy Storage Solutions
Electrochemical energy storage is the most preferred practical solution for distributed grid energy storage applications but one size does NOT fit all
Pumped Storage
Compressed Air Energy Storage
(CAES)
Hydrogen
Open Cycle Gas Turbines, Diesels or Coal Fire Station
Electrochemical Energy Storage
Solutions
Comments
Mature
Long lead time
Geographical limitation
Large scale
Lowest cost
Limited by geology
Central type plant
Long duration
Expensive with low efficiency
Risky
Highest energy density
Medium CAPEX
High impact on environment
Low average efficiency
Risky gas supply
Fast delivery
Low operating cost
Environmentally friendly
Higher initial CAPEX
Fit for Commercial Grid Storage Applications
Exists – part of mix not distributed
Possible part of mix
Possible part solution
Yes part of mix
Distributed essential part of solution

25. Summary and observations
Energy Storage can be used to “FIRM” variable generation resources both centrally and distributed
Electrochemical Storage prices are coming down
GAS fired generation combined with storage for fast acting reserve is more economic than standalone gas fired generation alone.
Distributed Storage must form part of any SMART GRID in order to manage power flows
An approach to microgrids allowing communities to island their resources will occur and regulations applying to these should be developed
Long term storage is essential for stability and energy management in distributed generation grids
Government and regulatory bodies must lead the way in setting appropriate policy and tariffs such as locational marginal pricing to direct storage investments 25