Controlled charging of electric vehicles under power constraints

1. Controlled charging of electric vehicles under power constraints M.Sc. (Tech.) Juuso Lindgren Aalto University, Dept. of Applied Physics juuso.lindgren@aalto.fi

2. 2012 Controlled charging of electric vehicles under power constraints 2 articles written • 1 journal • 1 conference Planned EV review article to become part of a larger review article • written in collaboration with Prof. Lund and 2 doctoral students from the same research group • working title: Energy system flexibility – a review of measures to increase variable renewable electricity in the power system • should be ready by end of summer • (EV part might later be extended to its own review article)

3. Charging Strategies for Electric Mobility Coupled to Electricity System Controlled charging of electric vehicles under power constraints Journal article About • How to allocate limited charging power between different EVs? smart VS dumb charging • (Estimating effects of EV charging to electricity price) smart VS dumb charging Submitted to IEEE Transactions on Smart Grid • Review feedback received on February, revision in progress

4. Charging Strategies for Electric Mobility Coupled to Electricity System Controlled charging of electric vehicles under power constraints Methods • Trip generation model tries to simulate car traffic in Helsinki area Selected assumptions • 10 000 plug-in hybrid electric vehicles • Charging only possible at work and home • Max charging power for one socket = 7.4 kW • Total charging power at work is limited to 0.1 kW per EV low value selected to make differences between strategies more visible Conclusions • Smart charging can improve electric mileage in Helsinki byat least 5% reqs. knowledge of parking time and distance driven before next power grid connection “theoretical maximum”: ~10% increase • unlimited total charging power at nodes • charging strategy becomes irrelevant

5. PV-to-EV Schemes for Photovoltaics Integration and Power Balance Controlled charging of electric vehicles under power constraints Conference article “What was left out of the journal article” Submitted to 2nd International Workshop on Integration of Solar Power into Power Systems

6. PV-to-EV Schemes for Photovoltaics Integration and Power Balance Controlled charging of electric vehicles under power constraints Methods & assumptions largely same, but trip generation algorithm was updated Conclusions • There is a region in (battery capacity,charging power)-space where smart charging is effective Outside this region, dumb charging is almost indistinguishable from smart charging

7. In-progress article:Charging infrastructure at workplace Controlled charging of electric vehicles under power constraints In previous submissions, we assumed sufficient charging sockets • Each vehicle starts recharging with 0 queuing time Sockets are now insufficient • There will now be queueing Level of detail is increased greatly • Ncharging poles that have Mwires and Xserviceable slots M vehicles can charge simultaneously at one pole a pole can only charge vehicles parked at the serviceable slots vehicles cannot be moved except by driver, but the wire can • delay for moving the wire (15 minutes) • each pole has its own queue

8. Charging infrastructure at workplace: Preliminary results Increased e-km per EV (km) Max power of single wire (kW) Amount of charging poles per EV 3 4 1000 cars simulated, battery capacity 5 kWh, 2 wires per pole, wire switching delay 15 minutes 1 2 1 2 Controlled charging of electric vehicles under power constraints How much will the electric mileage improve when charging infrastructure is added at work?

9. Same data with Excel Controlled charging of electric vehicles under power constraints

10. Extra slides Controlled charging of electric vehicles under power constraints

11. Shape of “significance map” Controlled charging of electric vehicles under power constraints

12. PV-to-EV Schemes for Photovoltaics Integration and Power Balance Controlled charging of electric vehicles under power constraints

13. Trajectories in elasticity field Controlled charging of electric vehicles under power constraints

14. Schedule Controlled charging of electric vehicles under power constraints

15. Charging Strategies for Electric Mobility Coupled to Electricity System *) Sounds a bit high and should be taken with a grain of salt. The model starts to break down at around 10% penetration. Controlled charging of electric vehicles under power constraints Methods • Trip generation model (used in Master’s thesis) tries to describe car traffic in Helsinki area • Absolute electricity price-electricity consumption elasticity field Selected assumptions • 10 000 vehicles • Max charging power for one socket = 7.4 kW • Total charging power at a node is limited Conclusions • Smart charging can improve electric mileage in Helsinki by at least 5% “Theoretical maximum”: ~10% increase • Infinite total charging power at nodes • At 10% EV penetration, controlled charging can decrease the standard deviation of yearly electricity price profile by 16% compared to 0% penetration Uncontrolled charging (business as usual) would increase it by 60%*

16. PV-to-EV Schemes for Photovoltaics Integration and Power Balance *) Should be taken with a grain of salt. The model starts to break down at around 10% penetration. Controlled charging of electric vehicles under power constraints Methods & assumptions largely same, but trip generation algorithm was updated Conclusions • There is a region in (battery capacity,charging power)-space where smart charging is effective Outside this region, dumb charging is almost indistinguishable from smart charging • At 10% EV penetration, controlled charging can slightly reduce average electricity price (-0.5%) Uncontrolled charging causes it to increase (+2%*)