KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

Institute of Electric Energy Systems and High Voltage Technology

www.kit.edu

Impact of E-Mobility on the Electrical Grid

Outlook for future Integration Strategies

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

2

Electromobility and Renewable Energy Resources in Germany: Political Framework

Technological aims for Germany:

2020: 1 Million Electric Vehicles (EV)

2030: 5 Million EV

2030: 30% of electric demand generated by

renewable resources

source: handelsblatt.com

Electromobility:

key element for future energy system,

with a high rate of renewable energy sources

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

3

Effects of increasing Renewable Generation

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predicted wind power infeed

actual infeed power

Tomorrow: Increasing Fluctuating Renewable Generation:Power Generation not depending on Demand

Challenge for todays energy system:

1) Adapt demand to current generation situation, flexiblisation of demand

2) Electrical energy storage

Todays Electric Energy System:

„Generation follows electrical Demand“

-> conventional power plants provide power when needed

Example:

wind power infeed

in northern Germany

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

4

Battery Storage solutions: Central Approach

Source: www.electricitystorage.org

Northern Japan:34 MW, 245 MWh unit for wind

stabilization

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

5

Battery Storage Solutions: Distributed Approach

40 million cars in Germany:

Assumption: 10 % EV = 4 million cars- Power: 3 kW average household plug

- Battery capacity: 20 kWh battery (100km)

Simplified mathematic experiment:-> Power = 3kW x 4 mio cars = 12 GW

(~10 nuclear power plants)

-> Energy = 20kWh x 4 mio cars = 80 GWh

(1 nuclear power plant running 3 days)

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

6

Uncontrolled Charging of EV0

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distribution grid, load curve

charging power 20 EVsUncontrolled Charging:

Charging starts when car

is plugged-in

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

7

Uncontrolled Charging of EV

Distribution Grid:

•suburban german area

•~100 households

Electric Vehicles:•20 Electric Vehicles

•power demand= 10kW

•charging after last trip

•high simultaneity expected in

the evening

Simulation:

Conclusions:- Even a small rate of Electric Vehicles could strongly affect the power

demand of a distribution grid.

- Increasing stress of grid equipment expected, overload is possible

20 kV

/ 0,4 kV

PLadung

PPV

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

8

Low voltage grid: Load effects

solar power

Voltagegrid

MV LV

line

length

load

house connection

With increasing load demand – decreasing voltage

• voltage no longer within specification

• transformer or line overload

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

9

Low voltage grid: Infeed effects

grid

MV LV

line

length

loadsolar power

house connection

Voltage

With increasing infeed – increasing voltage

• voltage no longer within specification

• transformer or line overload

Smart distribution grid: Control of loads and generation

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

10

Battery Storage: Distributed Approach

20 kV

/ 0,4 kV

PLadung

PEinspeisung

PPV

NAS

SB

SB

PCharge

/Infeed

Power exchange of EVs with grid

is controlled by distribution grid

substation (NAS)

Fluctuating renewable power

generation is stored in distributed

vehicle batteries

EV infeed in case of peak load demand

-> only parked and plugged-in EVs are

able to support the electrical grid

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

11

Integration Strategies: Simulation

1) Controlled Drive Energy Charging:Controlled EV charging during low power demand

-> avoiding charge peak loads in the evening

2) EV<-> Grid Energy Exchange:Using free battery capacities for distributed storage,

high renewable energy infeed is stored and used to limit local peak loads

-> fluctuating renewable generation can be balanced by EV

Strategy:

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

12

Integration Strategies: Simulation Tool

Grid Simulation considers:

-dynamical load demand of 100

households

- 20 Electric Vehicles:

PCharge/Infeed=10 kW

EBattery=20 kWh

-dynamical driving behavior:

- typical drive ranges

- typical departure/arrival times

Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

13

Integration Strategies: Load Balancing Potential

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EV <-> Grid Exchange

Charging/Infeed

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original grid load curve

Solar power

infeed-50

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Drive Energy Charging

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Impact of E-Mobility on the Electrical Grid – Outlook for future Integration

Strategies

Institute of Electric Energy Systems and High Voltage

Technology

14

Conclusion:

Electric Vehicles form a new class of consumer loads in thedistribution grid

Uncontrolled charging can lead to:

increasing peak loads

overload of grid structure

decreasing grid quality

Integration of EVs in grid management can:

improve grid quality

form distributed storage

support renewable energy sources