Transcript THE IMPACT OF FLEXIBLE LOADS IN INCREASINGLY RENEWABLE GRIDS Jay Taneja*, Ken Lutz, David Culler University of California, Berkeley *IBM Research, Africa IEEE SmartGridComm Oct 24, 2013

THE IMPACT OF FLEXIBLE
LOADS IN INCREASINGLY
RENEWABLE GRIDS
Jay Taneja*, Ken Lutz, David Culler
University of California, Berkeley
*IBM Research, Africa
IEEE SmartGridComm
Oct 24, 2013
THE CHALLENGE: MAINTAINING A DELICATE
BALANCE
Baseline + Dispatchable Tiers
Generation
Non-Dispatchable
Sources
Transmission
Oblivious Loads
Distribution
Demand
Aware Interactive
Loads
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CA2050: GHG 90% BELOW 1990
GHG Emissions (MtCO2e/yr)
But, …
1,000
800
600
Energy emissions
400
Non-energy
emissions
2020 Target
200
2050 Target
0
1990
2005
Historical
2020
2050
BAU
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1
/
3
/
THE LOWLY FRIDGE AS A GRID SCALE
INTERACTIVE STORAGE RESOURCE
Billions in use
Relative short replacement cycle
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LOWLY FRIDGE GRID STORAGE SYSTEM
Weather Data
Internet
sMAP
Streaming
Data
Warehouse
millions
plus ice
batteries
with Sensors &
Communication
Generators
Grid Operator
Refrigerators
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THE “ROSENFELD EFFECT”
~10% of California’s 26.3 GW average demand
Storage
• Pumped Hydro - US capacity ~22 GW, world 110
• Mechanical - Turn-around efficiencies ~70%
• Chemical - Limited recharge cycles
• Thermal …
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CURRENT DEMAND-FOLLOWING CHALLENGES
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STEPS TOWARD SUPPLY-FOLLOWING
▪ Time-of-use Pricing
▪ Critical Peak Pricing
▪ Demand Response
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CRITICAL PEAK DEMANDS TODAY
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FUTURE CHALLENGES
Summer cooling crunch
becomes excess
Winter deficits, very
steep duration curves
Intermittent excess and
deficit in spring and fall
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SLACK
▪ a measure of the potential of an energy load to be
advanced or deferred while maintaining adequate
operation.
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LOAD SLACK CLASSIFICATION
Load Type
Slack Characteristic
Examples
On-demand
Must respond immediately
and remain available
Lights, Interactive computing,
critical services
Deferrrable
Exploit ability to delay
Washers/Driers, Batch
Computing, HVAC
Flexible
Takes advantage of energy
storage, continuous
adaptation within constraints
EVs, laptops, Refrigerators
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THE FRIDGE - A BUILDING WITHIN A BUILDING
Set Point
Guard band
Wireless Sensor network
Plus Battery backup
Thermostatically Controlled Load
Sensible heat thermal mass is limited
• < hour in fridges
• > hour in buildings
• large but short lived
• COP is working against you
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NORMAL FRIDGE OPERATION
• Fridge Whirlpool/KitchenAid
Model #KTRD18KDWH00)
• 13.1 ft3 refrigerator
compartment
• 5.0 ft3 freezer
• Sensor Network
• Type K thermocouples
• ACME power meters
• LoWPAN/IP network
Average Power
77 Watts
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“ICE BATTERY” – LATENT HEAT OF PCM
•
•
•
Freeze just above freezer set point
• Like thermal mass in normal operation
Maintains temperature while it melts under
low-power condition
Consumes power on refreeze
Time of Use (TOU) requires no communication
Schedule-driven control
Brings value to both consumer and utility
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EXPERIMENTAL THERMAL STORAGE
Phase Change
Material Storage
Tanks
- NH4Cl in 19.1%
aqueous solution
Pump + Tubing for
Fridge Heat
Removal
Fan for Convection
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PROTOTYPE THERMAL STORAGE REFRIGERATOR
Average Power
87 Watts
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SUPPLY-FOLLOWING FRIDGE
Thermal performance =>
Measured power=>
Real Time CAISO signal =>
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MACROSCOPIC EFFECTS
▪ Baseline is hourly generation measurements over year
▪ Model of collective fridge behavior scaled by penetration hour by hour
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Duration Curve vs TOU Fridge Penetration
Fraction of Time
MACROSCOPIC
IMPACT: TOU
Fridge Penetration
0%
0% max
0.1%
0.5%
1%
5%
10%
50% median
100% min
10%
20%
33%
50%
100%
GW
reduction
47.13
45.05
42.33
39.76
34.83
32.07
26.17
18.79
46.82
44.74
42.01
39.61
34.70
31.97
26.11
18.83
46.51
44.43
41.75
39.55
34.62
31.94
26.02
18.87
46.10
44.02
41.42
39.38
34.50
31.84
25.90
18.93
45.58
43.85
41.00
39.25
34.31
31.75
25.72
18.99
44.09
43.24
39.88
38.49
33.99
31.57
25.37
19.20
3.04
1.82
2.44
1.27
0.84
0.50
0.80
-0.40
26.31
26.29
26.27
26.24
26.20
26.09
0.22
50.00
45.00
mean
40.00
GW Generated
35.00
0%
30.00
10%
25.00
20%
20.00
33%
15.00
50%
10.00
100%
5.00
0.00
0%
20%
40%
60%
Fraction of Time
80%
100%
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IMPACT IN FUTURE GRIDS
▪ At increased renewable penetration, the
duration curve of remaining thermal
generation becomes even steeper.
▪ Target fridge storage response to flatten
fossil fuel profile
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IMPACT ON NATURAL GAS PEAK
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CONCLUSIONS
▪ Conceivable to build GWs of flex out of millions of everyday
appliances
▪ EVs 100x the power swing at 1/10,000 the population (today)
▪ Leveraging trend toward greater sensing, intelligence,
connectivity
▪ Modulation of latent heat (PCM) is essential
▪ It’s a better fridge
▪ Value today for both customer and utility
▪ Greater value as renewable penetration increases
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