Transcript Vehicles

EE379K/EE394V Smart Grids:
Electric Vehicles and the Grid
Mike Legatt, Ph.D., CPT
CEO & Founder
ResilientGrid, Inc.
Spring 2017
Ross Baldick,
Department of
Electrical and
Computer
Engineering
Copyright © 2017, Mike Legatt, PhD., CPT
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Outline
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Emerging bulk power system
Electric vehicle emissions
Air quality and human health
Electric Vehicle types
Electric Vehicle charging
Electric vehicle-grid integration
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Emerging bulk power system
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Controlled and uncontrolled load and generation
Intermittent renewables in Texas:
 Wind capacity 17 GW
 Peak generation: 48.24% (3/23/16) and 14,023 MW
(2/18/16).
 Significant growth in solar photovoltaics at grid and
distribution levels
Reduced ability to forecast net load due to efficiencies
(e.g., LEDs, higher SEER HVACs) and behind-the-meter
distributed generation.
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Emerging bulk power system
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Emerging bulk power system
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Distributed energy resources leading to changing
paradigms of control (“duck curve”)
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Air Quality & Human Health
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Electric Vehicles and Emissions
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Implications of transportation electrification
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Harmful UFPM (largely unaffected by wind) moved
away from major population centers
Source: Jag9889
Source: Calderon-Garcuidenas et al, 2008
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Air Quality & Human Health
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Emissions and sunlight interacting to form smog
Jan 13, 2013 – Smog levels in Beijing
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AQI (O3 + PM2.5) at 866 µg/M (highest prior scale 500-755)
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Visibility reduced to < 50 meters (164 feet / ½ a football field)
Source: South China Morning Post
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EVs and Emissions
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Implications of transportation electrification
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Per-mile emissions reductions for all except SO2
Strategies (e.g., aligning against distributed PV,
SOFC microgrid generation) reduce per-mile
emissions further, including the SO2 reductions.
Legatt, 2015
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Benefits of EVs
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Environmental benefits of EVs:
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Fewer vehicle parts to maintain
Gas cars now tending to outlast emissions limiting equipment
Even with monitoring (check engine light), many people don’t repair
emissions problems until required annually (inspection) vs. power
plants with 24/7 monitoring
Not all cars produce same emissions (e.g., 50% of PM measured
from 13% of vehicles) – variations due to temperature, fuel quality,
altitude, etc.
Degradation over time of equipment that limits ICE vehicle
emissions is not well understood
End-to-end efficiency increase (21% vs 62%)
Source: Tuttle Consulting, U.S. Department of Energy
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Benefits of EVs
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Cost per mile generally
lower: 2-4¢ vs 10-15 ¢ per
mile
Less volatility in energy
prices as compared to
gasoline prices
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Fewer parts to maintain
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Battery replacements expensive, but less than new vehicle
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In eREVs, no relationship required between engine and wheel rotation
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Primary expense (battery) costs continuing to decrease, new innovations
may lead to lower costs
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EV Types
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Hybrid Electric Vehicle
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Parallel Hybrid
 Prius (Power-split)
 Civic Hybrid
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Series Hybrid (eREV)
 Chevrolet Volt
 VIA Motors truck/van
 Fisker Karma
Battery EV
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Tesla
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Nisan Leaf
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Ford Focus
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Smith Newton
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Zero S
Neighborhood EV
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EV Charging
Sources: SAE, CHAdeMO alliance, GreenCarReports
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EV Charging
Sources: Volvo, Infiniti, Plugless Power
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EV Charging
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Five pins (four connected to Electric Vehicle Supply
Equipment; EVSE)
Source: Eric Tischer
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EV Charging
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Electric Vehicle Charging
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EV provides EVSE resistance levels corresponding to state (pins 3-4)
Diode checking ensures (-) peak voltage -12V
Resistance Level
State
Positive Peak Voltage
State A
+12 V (no PWM)
Open
EV not connected
State B
+9 V
2.74 kΩ
EV connected and ready
State C
+6 V
882 Ω
EV charging
State D
+3 V
246 Ω
EV Charging, ventilation required
State E
0 V to 0V
Error
State F
-12V to -12V
Unknown error
seen by EVSE
Description
Source: OpenEVSE Project
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EV Charging
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The majority of energy drawn from the EVSE is associated
with charging.
Some vehicles with battery thermal management (e.g.,
Volt, Tesla) may periodically draw lower power for short
periods of time.
Remote start activities also can draw power just before the
driver gets into the vehicle, to precondition the cabin
and/or battery pack.
On the Volt, for example, this is drawn from the charging
cable at Level 2, but not at Level 1.
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EV – Grid Interaction
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Immediate charging
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Most common charging strategy / “curse of the default”
Creates additional risks to system stability due to on-peak charging
(“birthday cake curve”)
However, delayed charging may lead to distribution transformer
loss of cool-down time.
10.2 kW
HVAC
5.3 kW
EV
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EV – Grid Interaction
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Charge Control
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Most commercially-available EVs, and many EVSEs offer internet-connectivity, which
provides load control capabilities.
However, these devices typically lack the speed and accuracy necessary to provide
real-time services other than emergency full load shedding.
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EV – Grid Interaction
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Charge Control
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Legatt, 2016
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EV – Grid Interaction
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Custom-developed load controller
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Legatt, 2016
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EV – Grid Interaction
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Custom-developed load controller
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Legatt, 2016
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EV – Grid Interaction
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It may be possible to determine vehicle type based on
charge behavior.
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Legatt, 2016
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EV – Grid Interaction
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It may be possible to determine vehicle type based on
charge behavior.
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Legatt, 2016
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Summary
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EVs offer several benefits to society:
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Centralization on electric power, which can
continue to “green”, based on renewable
integration and energy storage.
A more price-stable domestic fuel source.
Provide additional controls to system operators
(e.g. MSO, DSO, ISO) to offset the
intermittency of renewables
More efficient (kWh/km traveled)
transportation source.
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Homework Exercises:
Due April 11
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Give three examples of ways in which
electric vehicles can destabilize the grid.
Give three examples of ways in which
electric vehicles can strengthen the grid.
What would make you more likely to have
your next vehicle purchase be an electric
vehicle?
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