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presentation by George Gross
University of Illinois at Champaign–Urbana
for the PSERC Webinar
February 13, 2018
LARGE – SCALE ELECTRIC ENERGY
STORAGE INTEGRATION IN GRIDS
WITH INTEGRATED RENEWABLE
ENERGY RESOURCES
© 2018 George Gross, All Rights Reserved
2
OUTLINE OF THE PRESENTATION
The critical importance of energy storage
Overview of ESR technologies
ESR roles and applications to power systems
The current status of storage
The California push for storage deployment
The opportunities and the challenges ahead
3
ESRs IN THE NEWS
4
THE DIRE NEED FOR STORAGE
The electricity business is the only industry sector that sells a commodity without sizeable inventory
The lack of utility–scale storage in today’s power system drives electricity to be a highly perishablecommodity
The deepening renewable resource penetrationsexacerbate the challenges to maintain the demand–supply equilibrium for every time scale
Storage provides added flexibility to maintaindemand–supply balance around the clock
5
CHANGING REALITY IN POWER SYSTEMS
Mitigation of climate change impacts and sustainability
are key drivers of the growing deployment of
renewable resources to reduce CO2 emissions
In various jurisdictions, legislative/regulatory
initiatives stipulate specific targets with the dates
by which they must be met to result in a cleaner
environment
6
RENEWABLE PORTFOLIO STANDARDS (RPS)
Source: http://www.dsireusa.org/resources/detailed-summary-maps/; February 2017 6
7
MISALIGNMENT OF WIND POWER OUTPUT AND LOAD
0
50
100
150
200
250
win
d po
wer
out
put (
MW
)
24 48 72 96 120 144 168 3,000
4,000
50,00
6,000
7,000
8,000
load
(MW
)
hour
wind power
load
8
NEED FOR LARGER AND FASTER RAMPING RESERVES
day
peak
load
frac
tion
1.0
0.5
0
load
loadminus windoutput
large ramp up required
Adapted from: M. Lange & U. Focken, “Physical Approach to Short-Term Wind Power Prediction”, Springer, 2006
large ramp down required
9
0
2,000
4,000
6,000
8,000
0
6,000
12,000
18,000
24,000
30,000
0:00 4:00 8:00 12:00 16:00 20:00
net load = load − wind − solar output (MW)load (MW)
INCREASED FLEXIBILITY NEEDS
load
wind output solar output
net load
time
8,300 MW over 3 hours
10,600 MW over 5 hours
12,200 MW over 3 hours
10
26,000
0
22,000
18,000
14,000
10,000
0:00 4:00 8:00 12:00 16:00 20:00
CAISO DAILY NET LOAD CURVEUNDER DEEPENING PENETRATION
net load (MW)
hourSource: CAISO
11
CURTAILMENT PERCENTAGES OF WIND GENERATION : 2007 – 2013
0
2
4
10
win
d en
ergy
cur
tailm
ents
(%)
2007 2008 2009 2010 2011 2012 2013
6
8
12
14
16
18
MISO
ERCOT
PJMNYISO
12
CAISO NEGATIVE RTM PRICES
0
20
40
100
nega
tive
RTM
pri
ce o
ccur
renc
es
60
80
120
140
160
2013
2012
2014
0:00 4:00 8:00 12:00 16:00 20:00 24:00
major shift of increases in negative real–time price
occurrences to mid–day hours
hour
1313
ENERGY STORAGE TECHNOLOGIES
increasing capacityincreasing capability
CAES
lead–acid batteryflywheel
NaS battery
SMESLi–ion battery
Ni–Cd battery
pumped storage
flow battery
advanced lead acid battery
EC capacitor
14
THE STORAGE RESOURCE PHASES
charging phase
idle phase
discharging phase
15
PRINCIPAL ROLES ESRs CAN PLAY
Storage enables deferral of investments in:
new generation resources
new transmission lines
distribution circuit upgrades
Storage is key to the development of microgrids in
both grid–connected and autonomous situations
16
MORE ROLES ESRs CAN PLAY In short–term operations, storage provides:
flexibility in time of energy consumption: demand shift; peak–load shaving
ability to delay the start up of cycling units levelization of substation load reserves and frequency regulation services demand response action capability to provide voltage support
Storage can, also, provide virtual inertia service to replace part of the missing inertia in grids with integrated renewable resources
17
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITHOUT ESRs
Source: ISO–NE
(MW
)
time of day0 2 4 6 8 10 12 14 16 18 20 22 24
20,000reserves
17,000
16,000
15,000
14,000
13,000
12,000
18
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITHOUT ESRs
Source: ISO–NE
(MW
)
time of day0 2 4 6 8 10 12 14 16 18 20 22 24
20,000reserves
peaking units17,000
16,000
15,000
14,000
13,000
12,000
19
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITHOUT ESRs
Source: ISO–NE
(MW
)
time of day
cycling units
0 2 4 6 8 10 12 14 16 18 20 22 24
20,000reserves
peaking units17,000
16,000
15,000
14,000
13,000
12,000
20
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITHOUT ESRs
Source: ISO–NE
(MW
)
time of day
start–up the cycling units
cycling units
0 2 4 6 8 10 12 14 16 18 20 22 24
20,000reserves
peaking units17,000
16,000
15,000
14,000
13,000
12,000
21
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITH ESRs
Source: ISO–NE
(MW
)
start–up the cycling units
time of day
cycling units
20,000
0 2 4 6 8 10 12 14 16 18 20 22 24
peaking units
17,000
16,000
15,000
14,000
13,000
12,000
reserves
22
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITH ESRs
Source: ISO–NE
(MW
)
start–up the cycling units
time of day
cycling units
20,000
0 2 4 6 8 10 12 14 16 18 20 22 24
peaking units
17,000
16,000
15,000
14,000
13,000
12,000
supplied by ESRs
reserves
23
12,000
13,000
14,000
15,000
16,000
17,000
CYCLING UNITS WITH ESRs
Source: ISO–NE
(MW
)
start–up the cycling units
delay
time of day
cycling units
20,000
0 2 4 6 8 10 12 14 16 18 20 22 24
peaking units
the ESRs contribute
to the reserves
17,000
16,000
15,000
14,000
13,000
12,000
supplied by ESRs
reserves
24
LOAD AND LMP
Source: NE ISOtime of day
load
(M
W)
0 2 4 6 8 10 12 14 16 18 20 22 2411,000
12,000
13,000
14,000
15,000
16,000
17,000
25
0 2 4 6 8 10 12 14 16 18 20 22 2411,000
12,000
13,000
14,000
15,000
16,000
17,000
LOAD AND LMPlo
ad (
MW
)
time of day
average load
Source: NE ISO
26
LOAD AND LMP
Source: NE ISO
pric
e (
$/M
Wh
)
time of day
load
(M
W)
average demand
0 2 4 6 8 10 12 14 16 18 20 22 2411,000
12,000
13,000
14,000
15,000
16,000
17,000
50
60
70
80
90
100
110
120
130
27
LOAD AND LMP
Source: NE ISO
average price
time of day
load
(M
W)
average demand
pric
e (
$/M
Wh
)
0 2 4 6 8 10 12 14 16 18 20 22 2411,000
12,000
13,000
14,000
15,000
16,000
17,000
50
60
70
80
90
100
110
120
130
average price
average load
28
STORAGE UTILIZATION
Source: NE ISO time of day
load
(M
W)
pric
e (
$/M
Wh
)
0 2 4 6 8 10 12 14 16 18 20 22 2411,000
12,000
13,000
14,000
15,000
16,000
17,000
50
60
70
80
90
100
110
120
130charging phase idle phase discharging phase
29
RTM demand
LMP IN A SYSTEM WITHOUT STORAGE
$/MWh
LMP
MWh/h
RTM supply
Source: http://oasis.caiso.com/, hub TH_SP15 (June 9, 2015)
30
RTM demand
$/MWh
LMP
MWh/h
ESR discharge output
RTM supply
Source: http://oasis.caiso.com/, hub TH_SP15 (June 9, 2015)
ESR DEPLOYMENT IMPACT ON LMP
LMP with ESR
31
0
200
400
600
800
1,000
1,200
12 AM 5 AM 10 AM 3 PM 8 PM
$/M
Wh
hour
low – price hours
ESR DEPLOYMENT IN RTMs
high – price hours
Source: http://oasis.caiso.com/, hub TH_SP15 (June 9, 2015)
32
IMPACTS OF CALIFORNIA ROOFTOP SOLAR
GWh
05
1015202530 other renewables
20 64 12108 181614 242220$/MWh
distributed solarutility-scale solar
imports
thermalnuclear
hydroelectric
CALIFORNIA ROOFTOP SOLAR IMPACTS: MARCH 11, 2017
-200
204060
226420 1412108 201816 24
real-time average hourly prices
hour of day
Source: US EIA based on https://www.eia.gov/electricity/data/eia861m/index.html and http://www.caiso.co
hour of day
33
26,000
0
22,000
18,000
14,000
10,000
0:00 4:00 8:00 12:00 16:00 20:00
CAISO DAILY NET LOAD CURVEUNDER DEEPENING PENETRATION
net load (MW)
hourSource: CAISO
10,386 MW April 9, 2017
34
INTEGRATION OF STORAGE WITH SOLAR RESOURCES
13:56 14:10
sola
r pla
nt o
utpu
t (M
W)
ESR energy discharged
35
STORAGE APPLICATION IN MICROGRIDS (μgs)
A μg is a time–varying network in the distribution
grid with control of its resources to either consume
or generate electricity or act as an idle entity with
zero injection/withdrawal in the isolated mode
Storage plays an integral role in the management
of generation and load resources in a μg and thus
is a critical component in the development of grid–
connected, autonomous and community μgs
36
MICROGRID: DEFINITION
A microgrid (μ g) is a network of interconnected
loads and distributed energy resources, within
clearly defined geographic boundaries, with the
properties that it is a single controllable entity,
from the grid perspective, and that it operates
either connected to or disconnected from the grid,
i.e., either in the parallel or in the islanded mode.
37
APPLICATION IN MICROGRIDS
Santa Rita Jail Microgrid
38
ESR GRID APPLICATIONS
application ESR owner interest grid impacts
substation transformer overload avoidance
economic overload condition mitigation
reliability improvement
variable energy generation curtailment
avoidance/reduction
more effective renewable energy
resource harnessing
increase of fraction of green energy used and reduce pollution
energy shift from low – to high – demand periods
collect arbitrage benefits
low–load condition mitigation and cost
reductionreplacement of reserves requirements from the
units in a generation plant
relaxation of reserve requirements limits on the plant units
reliability improvement
39
CHALLENGES THAT STORAGE CAN EFFECTIVELY ADDRESS
variable energy resource integration challenge
the way storage addresses the challenge
the pressing needs for adequate ramping capability incontrollable resources
fast ms–order ESR response timescan meet the steep raise/lower
ramping requirements
variability, intermittency and uncertainty associated with renewable resource outputs
ESRs are instrumental in smoothing renewable outputs and in higher renewable energy harnessing
increased need for frequency regulation resources for
flexibility in grid operations
ESRs provide regulation with 2 – 3 times faster response times
than gas turbines
40
STORAGE TO THE RESCUEtoday’s electricity grid with
limited storage capacity/capability
future electricity grid with measurably increased
storage capacity/capability
any increment in peak demand requires use of polluting and
inefficient power plants
additional peak demand is met by ESRs that shift the times of
energy consumption
reserves requirements are met by expensive and polluting
fossil–fired generators
reserves provided by ESRs reduce dependence on the contributions to reserves by conventional units
renewable generation has to be “spilled” whenever the supply exceeds the demand or under
congestion situations
clean, renewable energy is stored in ESRs during low–demand periods, leading to reduced
dependence on conventional units
41
KEY BENEFITS OF GRID – INTEGRATED ESR DEPLOYMENT Deployment of ESRs
raises system reliability
improves operational economics
provides operators with additional flexibility
to optimize grid operations and manage grid
congestion
increases renewable output utilization
42
KEY BENEFITS OF GRID – INTEGRATED ESRs
ESR deployment reduces GHG emissions because
ESRs
facilitate renewable resource integration
reduce the system reserves requirements on
the conventional fossil–fired resources
displace the generation of inefficient and
dirty units used to meet peak loads
43
CURRENT WORLD STORAGE STATUS
There are currently 1,619
ESR projects implemented
throughout the world with a
total capacity of 193,127 MW
288 out of these projects
are in California with a
capacity of 7,512 MW
California: 4 %
rest of the world: 96 %Source: DOE Global Energy Storage Database, http://www.energystorageexchange.org/projects
global storage capacity
44
BATTERY ENERGY STORAGE SYSTEMS (BESSs)
Many practitioners consider the installation of BESSs to most effectively address the challenges to integrate deepening penetrations of renewable resources – the holy grail of energy storage
A BESS may be highly efficient and can discharge the stored energy with high ramp rates
The development of new, very large, highly effi–cient batteries, appropriate for utility–scale storage, is predicted to grow into a huge business
45
BESS
Source: http://www.bbc.com/news/business-42090991
46
US UTILITY – SCALE ANNUAL BATTERY INSTALLATIONS
Source: EIA https://www.eia.gov/todayinenergy/detail.php?id=34432
47
US UTILITY – SCALE BATTERY INSTALLATIONS
Source: EIA https://www.eia.gov/todayinenergy/detail.php?id=34432
48
NOTREES PROJECT – GOLDSMITH, TX(36 MW / 23.8 MWh)
Source: http://www.energystorageexchange.org/projects
An advanced lead–acid battery system project with the objective to reduce the output variability of the
153–MW wind power plant
49
AES LAUREL MOUNTAIN – ELKINS, VA(32 MW / 8 MWh)
Source: http://www.energystorageexchange.org/projects
The Li–ion batteries are installed in a 98–MW wind farm to provide operating reserves and frequency
regulation in the PJM system
50
SCE PILOT PROJECT – ORANGE, CA(2.4 MW / 3.9 MWh)
Source: http://www.energystorageexchange.org/projects
The set of Li–ion batteries relieves transformer overloads and defers distribution network upgrades to ensure summer–time demand peak loads are met
51
BUZEN SUBSTATION – BUZEN, FUKUOKAPREFECTURE (50 MW / 300 MWh)
Source: http://www.energystorageexchange.org/projects
The world’s largest BESS serves to provide demand – supply balance
52
NEW PUSH IN ESR DEPLOYMENT
Advancements in storage technology, cost reduc–
tions and regulatory initiatives have invigorated
the interest in large–scale grid–connected ESRs
The push to deeper renewable resource penetra–
tions leads to the wider deployment of storage –
as both a distributed and a grid resource
Major deployments include utility–scale batteries,
flywheels and battery vehicle (BV) aggregations
53
THE VEHICLE–TO–GRID (V2G)FRAMEWORK AS A PRACTICAL ESR
The use of bidirectional power flow interconnec–
tions of the BVs under the V2G framework allows
aggregations of BVs to constitute a storage project
whose total capacity and capability can provide a
valuable resource to the grid
54
EVs ON THE ROAD
1,200
800
600
400
0
200
1,000
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Source: Financial Timeshttps://www.ft.com/content/31d68af8-6e0a-11e6-9ac1-1055824ca907
number in use (’000)
otherGermanyUKFranceNorwayNetherlandsJapanChinaUS
55
SALES OF NEW EVs
0 5 10 15 20 25
Source: Financial Timeshttps://www.ft.com/content/31d68af8-6e0a-11e6-9ac1-1055824ca907
as % of new registrations
Norway
Netherlands
Sweden
France
China
UK
Germany
US
Japan
total
56
TESLA MODEL 3 RESERVATIONS
116151
181 200232
254280
325
050
100150200250300350400
0 2 11 15 24 34 50 168
num
ber
of re
serv
atio
ns
number of hours after announcementSource: http://electrek.co/2016/04/03/tesla-model-3-reservations-timeline/, issued April 2015
57
BARRIERS TO LARGE–SCALE STORAGE DEPLOYMENT
The pace of energy storage deployment has been very slow in the past, mainly due to the extremely high costs of storage
The reductions in storage costs over the past decade have remained inadequate to stimulate the large–scale deployment of ESRs
The high costs of storage present a chicken and egg
problem: costs remain high due to low demand and the high costs impede any growth in demand
58
CALIFORNIA
Sour
ce: h
ttp://
ww
w.us
amap
s201
5.xy
z/ca
lifor
nia-
map
/
59
CALIFORNIA163,696 square miles; 3rd
largest US state by area;
4 % of the size of Europe
Sour
ce: h
ttp://
ww
w.us
amap
s201
5.xy
z/ca
lifor
nia-
map
/
60
CALIFORNIA163,696 square miles; 3rd
largest US state by area;
4 % of the size of Europe
38 million people
Sour
ce: h
ttp://
ww
w.us
amap
s201
5.xy
z/ca
lifor
nia-
map
/
61
CALIFORNIA163,696 square miles; 3rd
largest US state by area;
4 % of the size of Europe
38 million people
Sour
ce: h
ttp://
ww
w.us
amap
s201
5.xy
z/ca
lifor
nia-
map
/
electricity consumption
is 8 % of US total of
293,269 GWh
62
CALIFORNIA PUSH FOR STORAGE DEPLOYMENT
The CA government has recognized the significant
role storage can play in the grid and the need for a
bold move on storage to drastically reduce the storage
price through a sharp increase in demand
The recent CPUC mandate to deploy 1,325 MW of
cost–effective energy storage by 2020 in California
launches a major push for the global storage sector
63
CALIFORNIA PUSH FOR STORAGE DEPLOYMENT
The CPUC energy storage requirements arise from the 2010 Assembly Bill 2514 (AB 2514)
AB 2514 required the CPUC to “open a proceeding to determine appropriate targets, if any, for each load–serving entity to procure viable and cost–effective energy storage systems and, by October 1, 2013, to adopt an energy storage system procure–ment target, if determined to be appropriate, to be achieved by each load–serving entity by December31, 2015, and a second target to be achieved by December 31, 2020”
64
GUIDING PRINCIPLES
1. The optimization of the grid, including peak
reduction, contribution to reliability needs, or
deferment of transmission and distribution
upgrade investments;
2. The integration of renewable energy; and
3. The reduction of greenhouse gas emissions to
80 percent below 1990 levels by 2050, per
California’s goals”
“
65
THE CPUC STORAGE REQUIREMENTS
In Decision 13-10-040, CPUC has mandated a target
by 2020 of 1,325 MW of energy storage to be
installed by the three major jurisdictional investor
owned utilities (IOUs) by 2024
The CPUC Decision provides the framework with
whose specifications the procurement and
deployment of storage projects must comply
66
THE CPUC STORAGE PROCUREMENT FRAMEWORK SPECIFICATIONS
Storage capacity targets for each of the 3 major
California IOUs
Procurement schedule for the authorized storage
projects
Storage capacity targets at each of the specified
grid interconnection point given below:
transmission
distribution
customer side of the meter
67
THE CPUC STORAGE PROCUREMENT FRAMEWORK SPECIFICATIONS
Allowed deviations to meet the CPUC targets by:
shifts of the targets among the grid
interconnection points
ownership of storage resources by
IOUs, customers and third parties
deferral of IOU targets in the CPUC–
specified schedule
68
IOU STORAGE CAPACITY TARGETS
IOU target(MW) %
PG&E 580 43.77
SCE 580 43.77
SDG&E 165 12.26
69
STORAGE CAPACITY TARGETS AND GRID INTERCONNECTION POINTS
grid intercon–nection point
target(MW) %
customer side of meter 200 15.09
distribution 425 32.08
transmission 700 52.83
customer side of meter
distribution
transmission
70
PROCUREMENT SCHEDULE
90
120
160
210
90
120
160
210
2030
45
70
0
50
100
150
200
250
2014 2016 2018 2020
stor
age
capa
city
pro
cure
d (M
W)
PG&E
SCE
SDG&E
71
CUMULATIVE PROCURED CAPACITY
0
200
400
600
800
1,000
1,200
1,400
2014 2016 2018 2020
cum
ulat
ive
proc
urem
ent t
arge
t (M
W)
year
SDG&E
PG&E
SCE
total = 1,325 MW
72
TOTAL PROCURED CAPACITY VERSUS TARGET CAPACITY
tota
l cap
acity
(MW
)
0
100
200
300
400
500
2014 2016procured procuredtarget target
PG&ESCESDG&E
73
CPUC STORAGE PROCUREMENT FRAMEWORK FEATURES
The procurement targets are mandated for each
IOU and may not be traded among the IOUs
Biannual procurement applications are to be filed
by each IOU by March of each applicable year
At least 50 % of each project approved to meet the
targets must be owned by third parties, customers
or joint third party/customer ownership
74
CPUC STORAGE PROCUREMENT FRAMEWORK FEATURES
The CPUC Decision 13-10-040 also sets the energy
storage procurement targets for Community Choice
Aggregators and the Electric Service Providers at 1 %
of their year 2020 peak loads; projects must be
initiated by 2020, with installation to be completed
by the end of 2024
75
CURRENT STATUS OF ENERGY STORAGE PROCUREMENT IN CA
There has been an upsurge in behind–the–meter
projects that have helped the IOUs meet some of
their T&D storage targets in 2016 and 2017
Each IOU has invested also in large battery ESR
projects, currently under construction; the timely
completion of these projects is required to meet
the target of each IOU
76
FROM 60 Wh BATTERY CELLS TO A LARGE–SCALE 32 MWh ESR (BESS)
56 × 18 × 151 × 4 ×
cell(60 Wh)
module(3.2 kWh)
rack(58 kWh)
section(8.7 MWh)
system(32 MWh)
Source: M. Irwin,”SCE Energy Storage Activities,” Proc. IEEE PES General Meeting, Denver, July 26-30, 2015
77
PCS units
12 kV/66 kVtransformer
BESS building
LARGE – SCALE ESR
Source : SCE
78
CPUC DECISION RAMIFICATIONS
The CPUC Decision is a harbinger of regulatory
initiatives in the large–scale grid–connected
storage domain that signals the realization by the
government of the significant role storage plays
to further the smart grid implementation
The CPUC Decision stimulus to reduce ESR costs
by increased demand is likely to reappear in
many other venues to promote wider ESR
79
OPPORTUNITIES FOR LARGE–SCALE ESRs
The CPUC Decision is paving the way for new
opportunities in the storage sector The need for storage to meet the CPUC mandate
creates a strong push in the storage market and
considerably weakens the reluctance to invest in
the storage sector A key example is the new TESLA Gigafactory, the
large–scale NV plant in to manufacture storage
batteries for commercial and residential uses
80
Li – ION BATTERY PRICES AND DEMAND
200
400
600
800
1,000
1,200
2010 2012 2014 2016 2018 2020 2022 2014 2026 2028 2030 0
annual demand in GWh
Source: Bloomberg New Energy Finance https://www.bloomberg.com/news/articles/2016-06-13/batteries-storing-power-seen-as-big-as-rooftop-solar-in-12-years
200
400
600
800
1000
1200
0
EV Li-ion battery cost global EV Li-ion demand$/MWh
81
WILL STORAGE FOLLOW THE PATH OF PV SOLAR CAPACITY COSTS ?
80
0
60
40
20
1977 2017200719891983 1995 2001
$ / watt
0.24
year
76.00
Source: Bloomberg, New Energy Finance, and https://en.wikipedia.org/wiki/growth_of_photovoltaics
82
CHALLENGES TO LARGE–SCALE STORAGE DEPLOYMENT
The deployment of large–scale ESRs brings forth many economic, regulatory and technical challenges
that must be overcome to effectively harness the myriad benefits such resources provide
While the of large–scale ESR implementations are certainly beneficial to grid operations, the actual quantification of the various benefits and impacts and their allocation to the ISO, the ESR owners and the customers is a very difficult problem
83
analytic framework
appropriate metrics
new tools
battery life estimation
GRAND CHALLENGES
challenge
84
battery data analytics
limitations to large–scale deployment
symbiosis of ESR and DRR
environmental impacts
GRAND CHALLENGES
challenge
85
CONCLUDING REMARKS
In the development of sustainable paths to meet future energy needs, renewable resources must play a key role and storage is, by far, the most promising option to facilitate such paths
The CA mandate may provide the appropriate stimulus to jump start grid–connected storagedeployment and to further reduce storage prices
There remain daunting challenges at many levels – from science to engineering to policy – to effectively implement ESR deployment in the grid
86
CONCLUDING REMARKS
We need to systematically address the major
challenges in storage technology improvement,
modeling and tool development, regulatory,
environmental and policy formulation arenas – to
name just a few – in order to realize the goal of
large–scale deployment of storage in future grids
