1. Electrical Vehicles Effects on Residential Distribution Systems Research Assistant: Paul Haley Research Supervisor: Dr. Leszeck Czarnecki August 31, 2012 Department of Electrical and Computer Engineering

2. Motivation Department of Electrical and Computer Engineering

3. Motivation Government and environmental groups endorse EVs. – energy efficiency – dependence on oil – CO 2 emissions EVs are competitors in the market Department of Electrical and Computer Engineering

4. Motivation EV battery chargers are large loads. – 2 to 4 kW – Possible reduction of voltage profile EVs use AC/DC converters to charge batteries. – Possible increase in voltage harmonic distortion Department of Electrical and Computer Engineering

5. Objectives Department of Electrical and Computer Engineering

6. Objectives Estimate the environmental impact of EVs – Compare energy flow of EVs and GVs – Use efficiency data from best sources accessible Department of Electrical and Computer Engineering

7. Objectives Evaluate the effects of EV chargers on residential distribution systems – Measure EV battery charging cycle – Model selected residential system Department of Electrical and Computer Engineering

8. Objectives Research the current state of the EV market – Compile data from various literature Department of Electrical and Computer Engineering

9. Conclusions Department of Electrical and Computer Engineering

10. Conclusions Department of Electrical and Computer Engineering From an environmental perspective, EVs are beneficial. – The use of EVs is more efficient than GVs. – Use of EVs will reduce burning of carbon-rich fossil fuels.

11. Conclusions Department of Electrical and Computer Engineering EVs not likely to cause problems in residential distribution systems in the near future

12. Conclusions Department of Electrical and Computer Engineering At current prices, EVs cannot compete with GVs, especially hybrids. – Only 0.01% of vehicles in U.S. are EVs.

13. Environmental Effects of EVs Department of Electrical and Computer Engineering

14. Efficiency Comparison Department of Electrical and Computer Engineering Compared efficiencies of the all steps of energy transfer for GVs and EVs. Due to many unknown factors the estimated efficiencies are debatable.

15. Efficiency Comparison Department of Electrical and Computer Engineering Electric car efficiency calculation involves four parts. – Charger and Inverter: 85% each – Battery: 94% – Motor: 90% EV energy efficiency: 61%

16. Efficiency Comparison Department of Electrical and Computer Engineering Final Result – EVs use 74% of the energy used by GVs to do the same amount of work.

17. Efficiency and Environmental Impact Department of Electrical and Computer Engineering EVs are more efficient. Energy from fossils in U.S. is 69.3%. EVs burn 51% of the CO 2 producing fossils that GVs consume.

18. Impact of EV Chargers on Residential Distribution Systems Department of Electrical and Computer Engineering

19. Measurements during EV Charging Cycle Department of Electrical and Computer Engineering Low distortion Nearly unity power factor

20. Measurements during EV Charging Cycle Department of Electrical and Computer Engineering Current RMS relatively constant

21. Residential Power System Modeling Department of Electrical and Computer Engineering Expensive neighborhood – more likely to have EVs in the near future

22. Residential Power System Modeling Department of Electrical and Computer Engineering

23. Residential Power System Modeling Department of Electrical and Computer Engineering Computer model run for worst case – 20% current THD per charger – 95% power factor – 100% EV penetration charged simultaneously

24. Residential Power System Modeling Department of Electrical and Computer Engineering Voltage RMS at end of feeder: 95% Voltage THD at end of feeder: 6% Computer modeling repeated for varying penetration levels – At 60% penetration voltage THD reached 5%.

25. Residential Power System Modeling Department of Electrical and Computer Engineering These worst case parameters are unlikely. No problems expected in the near future.

26. Current EV Market Department of Electrical and Computer Engineering

27. EVs & PHEVs on the Market Nissan Leaf: 75 miles/charge - $35,200 Mitsubishi i MiEV: 62 miles/charge - $29,125 Chevy Volt: 35 miles/charge - $39,145 Government incentive: $7,500 Department of Electrical and Computer Engineering

28. EVs: Consumers Perspective Department of Electrical and Computer Engineering Limited range Lack of convenient charging infrastructure Best suited as second car for family PHEVs more convenient for most consumers

29. PHEVs: Consumers Perspective Department of Electrical and Computer Engineering

30. Government and Political Forces Department of Electrical and Computer Engineering Federal and state incentives not permanent Future cost of EVs uncertain – China’s monopoly on lithium and neodymium

31. Review Department of Electrical and Computer Engineering EVs are environmentally beneficial. – Could reduce burning of fossil fuels by half EVs should not cause problems in residential distribution systems in the near future. At current prices, EVs cannot compete with GVs.

32. Thank you! Department of Electrical and Computer Engineering