prudent energy at intersolar2012
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Large scale Energy storage. Applications of the VRB-ESS® in providing electrical grid power solutionsTRANSCRIPT
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
Intersolar 2012
Timothy Hennessy June 11 2012
2
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
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
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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
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Prudent VRB Technology
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
Flow Battery Advantages and Disadvantages
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The modular assembly of a MW scale VRB-ESS® in California
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The modular assembly of a MW scale VRB-ESS® in California
• Peak Shaving
• Using bio gas from
onion plant
• Gills Onion’s
California
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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
MW scale VRB-ESS® in China - wind and PV smoothing
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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
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VRB® characteristics from field testing
1. Response time full charge
to discharge < 50ms
2. Stack Coulombic efficiency
3. Short circuit test – stack
shorted max 2000 Amps.
Discharged over 140
seconds. System recovered
after short removed
4. Longest field operation 6
years un-manned
Short circuit test
Response time ms
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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.
• 40% footprint reduction
2011 to 2013
• Modular 250kW
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Implications of community based generation in Distribution System
• 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
storage
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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 20121..
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
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Comparisons of Wind and PV systems with energy storage for municipal
owned microgrids
0 100 200 300 400 500 600 700 800
-2
0
2
4
6
8
10Net Power with 9MW PV and No Wind
Time, Days
Po
we
r, M
W
4 Hours Storage Duration
6 Hours Storage Duration
0 100 200 300 400 500 600 700 800
-2
0
2
4
6
8
10
12Net Power with 9MW Wind and No PV
Time, Days
Po
we
r, M
W
4 Hours Storage Duration
6 Hours Storage Duration
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.
15
Firmness provided by storage in islanded micro grids
0 100 200 300 400 500 600 700 800
-2
0
2
4
6
8
10
12Net Power with 5MW Wind and 4MW PV
Time, Days
Po
we
r, M
W
1 Hour Storage Duration
6 Hours Storage Duration
0 100 200 300 400 500 600 700 800
-2
0
2
4
6
8
10
12Net Power with 5MW Wind and 4MW PV
Time, Days
Po
we
r, M
W
4 Hours Storage Duration
6 Hours Storage Duration
Wind (MW) 5
PV (MW) 4
1 hour storage duration Grid purchase (times/year) 230 Energy purchases (MWh) 604.7
4 hours storage duration Grid purchase (times/year) 152 Energy purchases (MWh) 35.8
6 hours storage duration Grid purchase (times/year) 8 Energy purchases (MWh) 2.7
Grid purchases when
storage sized at 1hour
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Peaking generation enhancing the value of OCGT using Energy Storage
Also reduces CO2 emissions
Ref: PJM USA markets
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Energy trading using flow batteries in Germany
IRR over ten
years > 15%
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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 lead time
• Large scale
• Long duration
• Expensive with
low efficiency
• Risky
• Highest energy
density
• Central type
plant
• 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
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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
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