Distribution Capacity Impacts of Plug In Electric Vehicles · 2014. 11. 5. · Distribution...
Transcript of Distribution Capacity Impacts of Plug In Electric Vehicles · 2014. 11. 5. · Distribution...
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Distribution Capacity Impacts of Plug In Electric Vehicles
Chris Punt, P.E.
MIPSYCON 2014
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Outline
►EV Benefits
►EV Growth
►Where are we today?
►Where are we going?
►Potential Distribution Capacity Issues
►Feeder
►Sub Transformer
►Service Transformer
►Other Activities
►Conclusion
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Benefits of Electric Vehicles ►Environmental Impacts
►Can run on renewables
►Higher conversion efficiency
►Emissions - Easier to filter pollutants
►Economics
►Energy cost is 1/3 compared to gas
►Can make up for Utility revenue reductions
►Energy Independence
►North American Electricity
►Eliminate Price Volatility
►Driving Experience
►Smooth
►Low noise
►Instant Torque - Acceleration
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Most Popular U.S. EVs - 2014
22 EV Models
►Nissan Leaf
►Chevrolet Volt
►Toyota Prius PHV
►Tesla Model S
►Ford Fusion Energi
►Ford C-Max Energi
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Electric Drive Transportation Association - http://en.wikipedia.org/wiki/File:US_PEV_Sales_2010_2013.png
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2400 EVs in MN through 2013
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Xcel Energy Area EV Interest and Gas Prices
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3.2
3.4
3.6
3.8
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Jun-
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Jul-
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Aug-
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Sep-
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Oct-
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Nov-
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Dec-
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Jan-
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Feb-
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Mar-
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Apr-
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Date
$/g
allo
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-90
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110
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410
510
610
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# o
f E
V In
qu
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MN Gas Prices XCEL EV Interest
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Where are we today?
►Minnesota Public Charging
► 165 electric stations
► 360 charging outlets
►ChargePoint
►Tesla
►Dealerships
►Goodwill
►United States
► 8,672 electric stations
►21,525 charging outlets Department of Energy - http://www.afdc.energy.gov/fuels/electricity_locations.html
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Where are we going?
► Initial Xcel Energy Estimates
►Tesla Charging Stations: 100,000 kWh per year
►Home Charging: 56,000,000 kWh to date
► 2014 Legislation in MN – EV Charging Tariff
►All Public Utilities will file an application to the MNPUC by February 1, 2015
►Must contain TOD or off-peak rate
►Must offer customer opportunity to purchase from renewable sources
►Must be made available to residential class
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Annual Energy
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Charging
►Level 1
►120V – 1.1 to 1.8 kW
►11 - 20 hours for full charge
►Level 2
►240V - 3.3 to 7.7 kW, 19.2 kW
►3 - 8 hours for full charge
►Level 3 – DC Fast Charge
►Three phase
►15 to 240 kW
►1/2 - 2 hours
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Charging – Tesla Supercharger
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Chevy Volt Charge Profile
►Level 1
►9 hours
►Li-ion Am
ps
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Distribution Capacity Analysis
►Feeder
►Substation Transformer
►Service Transformer
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Feeder Analysis
►Two St. Paul Feeders – served from same substation transformer
►Typical, indicative of Xcel Energy’s planning philosophy
►Feeder A
►36% residential load (multi-family)
►77% loaded
►13.8kV
►Feeder B
►80% residential load (single family)
►65% loaded
►13.8kV
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Feeder Analysis
►Varying Level 2 residential penetration rates
►3.3 kW
►6.6 kW
►Assume all charging occurs at peak.
►Penetration = EV/Residential Customer
►Assumption: 1 EV per customer
Penetrations
0%
1%
2%
5%
10%
15%
25%
35%
50%
75%
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Feeder Analysis – Feeder A
Feeder "A" Capacity vs 6.6 kW Penetration
70.0%
90.0%
110.0%
130.0%
150.0%
170.0%
0% 10% 20% 30% 40% 50% 60% 70% 80%
Feeder "A" Capacity vs 3.3 kW Penetration
70.0%
80.0%
90.0%
100.0%
110.0%
120.0%
0% 10% 20% 30% 40% 50% 60% 70% 80%
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Feeder Analysis – Feeder B
Feeder "B" Capacity vs 6.6 kW Penetration
60.0%
80.0%
100.0%
120.0%
140.0%
160.0%
0% 10% 20% 30% 40% 50% 60% 70% 80%
Feeder "B" Capacity vs 3.3 kW Penetration
60.0%
70.0%
80.0%
90.0%
100.0%
110.0%
120.0%
0% 10% 20% 30% 40% 50% 60% 70% 80%
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Feeder Analysis – Takeaways
►For every 1% penetration we see 0.5% - 1% demand growth on both feeders.
►Capacity significance starts around the 4% penetration mark.
►i.e. 2% - 4% demand growth
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Feeder Analysis Takeaways
kW per
customer
3.3 kW
slope
Load Normalized 3.3
kW slope
Feeder A 2.1 0.51 1.2
Feeder B 3.5 0.56 0.56
►Feeder makeup matters
►% residential
►Type of residential
►Areas with lower kW/customer will see more impact from same penetration levels.
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Sub Transformer Analysis – Present Case
Penetration 3.3 kW 6.6 kW
0% 46.6% 46.6%
1% 46.9% 47.2%
2% 47.2% 47.9%
5% 48.2% 49.8%
10% 49.9% 53.2%
15% 51.6% 56.5%
25% 55.0% 63.2%
35% 58.4% 69.9%
50% 63.5% 79.9%
75% 72.2% 96.6%
Diversity Factor of 81%
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Transformer Analysis – Worst Case
Penetration 3.3 kW 6.6 kW
0% 57.5% 57.5%
1% 57.9% 58.3%
2% 58.3% 59.1%
5% 59.5% 61.5%
10% 61.6% 65.7%
15% 63.7% 69.8%
25% 67.9% 78.0%
35% 72.1% 86.3%
50% 78.4% 98.6%
75% 89.1% 119.3%
Diversity Factor of 100%
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Transformer Analysis – Takeaways
►For every 1% penetration we see 0.3% - 0.8% demand growth.
►Less raw impact compared to feeders due to diversity
►Capacity Impact starts at over 5% penetration
►In most cases feeder limits will be reached before transformer limits (if designed/planned properly)
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Service Transformer Analysis Load Profile for XFMR "237412633" date: 7/14/10
0
20
40
60
80
0:00 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00
Time
kv
a
New Peak with Chargers
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Service Transformer Analysis – Known Additions
►Took 46 known EV owner locations and their service transformers
►Analyzed for addition of Level 2 Charging
Peak Load Addition % of Population Overloaded
1 – 3.3 kW charger 4%
1 – 6.6 kW charger 9%
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Service Transformer Analysis – All NSPM
►4%-5% penetration leads to $2.3M - $4.6M in upgrades
►Does not account for multiple installations per transformer
Additional Peak
Load
% of Population
Overloaded
Cost to
Replace (M) Penetration
1 – 3.3 kW charger 3% $4.7 8.8%
1 – 6.6 kW charger 5% $9.3 8.8%
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Projection
►2.5% EV share leads to 5% penetration (2024 on low adoption from previous slide)
►4% of transformer population overloaded
►$7M - $10.7M to upgrade (proactive – reactive)
►Revenue far exceeds costs over ten years
►No significant feeder or sub transformer impact for 10+ years
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PSCo EV Pilot Project
►Deliverables (early 2015)
►Determine residential charging characteristics
►Identify alignment with system peak
►Distinguish a potential strategy for minimizing distribution impact through control
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EV Project
►Funded by ECOtality and Department of Energy
► 13,000 Level 2 Chargers
►Feeder and EV Peaks don’t align
►Typically EV connected to EVSE 40% - 45% of time but draws power only 8% - 9% of time
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Conclusion
►EVs are here and growing
►Impact generally starts occurring at around 5% penetration when peak aligned
►Service transformers are of biggest concern, especially with multiple EVs
►Locating Level 2 charging and above necessary
►Charging at night desired with possibility to control later on
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