PHEV Operation Experience and Expectations

Transcription

1 PHEV Operation Experience and Expectations by Tony Markel National Renewable Energy Laboratory November 1, 27 With support from the U.S. Department of Energy Office of Energy Efficiency i and Renewable Energy FreedomCAR and Vehicle Technologies Program

2 Key Message There is a need to understand the interaction between PHEV vehicle attributes and the vehicle usage pattern 2

3 PHEV Benefits Tied to Usage Pattern PHEV Benefits Efficiency in Charge-Sustaining Mode Petroleum Displacement in Charge-Depleting Mode ption nsump uel Con Fu Conventional Hybrid Plug-In Hybrid ~1-35% ~35-7% Charge-Depleting g Mode Distance Charge-Sustaining Mode 3

4 Outline Travel Profile Database PHEV Impact on Components Energy Storage Power Electronics Engine Emissions Integration of Vehicles and Renewables 4

5 Travel Profile Database Development Objective Collect and use data from regional travel surveys with GPS components for simulation to better quantify real-world benefits of advanced vehicle technologies 5

6 Summary of Available Data Los Angeles (21-22) 6 Counties near LA 47 households» 631 vehicles» 1225 days of travel 48% of vehicles include multiple l days» 2% with more than 1 week Primarily weekdays» 8 units collected weekend travel too St. Louis 147 households» 227 vehicles Kansas City (24) 368 vehicles Laredo 234 vehicles Tyler/Longview 343 vehicles Rio Grande 376 vehicles 6 Each data set stored in a different format Automated processing more challenging than expected

7 St. Louis Travel Data Analysis Daily Driving Distance Similar to 1995 NPTS Data Frequency (%) St. Louis HHTS Data ~29 mi Daily Travel Distance (miles) Frequency (%) Cumulative Freq. (%) Cumulative Freq quency (%) Frequenc cy (%) 1995 NPTS Data ~33 mi Daily Distance (mi) St. Louis data set includes 227 vehicles from 147 households Complete second by second driving profile for one day for each traveler 865 miles of travel St. Louis data is a small representative sample of real data NPTS data is generated from mileage estimates Cummulative Fre equency (%) 7 ** HHTS Household Travel Survey NPTS National Personal Travel Survey

8 Sample Real World Duty Cycle 8 Sp peed (mph h) Time (hr) eed (mph h) Sp Distance (mi) 8

9 Vehicle in-use activity pattern and simulated fuel consumption In-use bars show morning, midday and evening usage peaks; at most 12% of vehicles in use at once Cumulative fuel consumption lines consider entire fleet using specified architecture PHEVs Reduce Fuel Consumption By >5% On Real-World Driving Cycles St. Louis Data Sample = 227 Vehicles Assumptions PHEVs begin fully charged and do not charge until they finish driving for the day Gasoline is $2.41/gallon and electricity is $.9/kWh for energy cost comparison (purchase price differences not included) 9 Published at Transportation Research Board Annual Meeting, 27.

10 Four Potential Daily Recharge Strategies Immediate Do End Nothing of Travel Day Delay to 1pm kw/1 Vehicles kw/1 Vehicles Hour Ending Hour Ending 3 ways to control a single daily charge Multiple charging events per day Optimized to Off-Peak Opportunity Charging kw/1 Vehicles kw/1 Vehicles Hour Ending Hour Ending 1

11 Recharge Scenario Impacts on PHEV Petroleum Consumption Benefits Opportunity charge: connect PHEV charger to grid any time that the vehicle is parked. Base Case assumes one full charge per day No Charge (PHEV2) Opportunity Charge (PHEV2) ~71% 11 PHEV2 with Opportunity Charge provides greater benefits than PHEV4 with a single daily recharge.

12 PHEV Component Impacts Summary Energy Storage (Dave Howell) PHEV introduces more long duration power pulses Time at SOC depends on recharge behavior Power Electronics (Susan Rogers) PHEVs produce higher thermal loads on PEEMs and increase battery bus voltage fluctuation Engine/Emissions Control (Lee Slezak) CDE PHEV simulations suggest potential reduction in emissions by reducing initial daily cold starts and total daily engine starts 12

13 Operating Strategy Impacts Pulse Power Characteristics Charge Depleting Electric (CDE) Real-world sims consider this scenario so far Peak Pulse Power Duration Engine Battery Po ower Energy Equiv. Pulse Power UDDS CDE Time Total Event Duration Charge depleting electric (CDE) is likely to have short high power events and moderate long duration energy equiv. events. 13

14 Operating Strategy Impacts Pulse Power Characteristics Charge Depleting Hybrid (CDH) Future sims should consider this scenario Peak Pulse Power Duration Engine Battery Po ower Energy Equiv. Pulse Power CDH Time Total Event Duration Charge depleting hybrid (CDH) will have lower but longer peak pulse and slightly lower energy equiv. pulse power requirements 14

15 Operating Strategy Impacts Pulse Power Characteristics Low Power Charge Depleting Hybrid (Low CDH) Peak Pulse Power Duration PHEV Test Bed is like this. Engine Battery Po ower Energy Equiv. Pulse Power Low CDH Time Total Event Duration In CDH lower power case, the Peak and Energy Equiv. Pulse Powers may have similar level and duration 15

16 PHEV Time At SOC Impacted by Charging Scenario Day at State of Charge Based on Simulation of 227 duty cycles from St. Louis How will differences in time at SOC impact battery life? HEV PHEV2-base PHEV2-opchg PHEV2-nochg % of Fully Discharged State of Charge Zone Fully Charged

17 PHEV impacts on APEEM Objective: How will PHEV operation impact the APEEM system requirements? 17

18 PHEV Motor Operation From Real-World Simulations PHEVs more closely match an EV as PHEV AER increases. 1kW 227 cycles. >9, data points. Limited to key on data 18

19 Output Battery Voltage Fluctuation % Relative to Median HEV: 3% PHEV2: 22% 9% of Operation PHEV4: 24% Based on simulation results for CDE PHEV Today s CDH PHEV maybe different 19

20 --); rrent (I); SOC (- rature (C) Voltage (V); Cur Temper V I 4 SOC AvgT Speed Elevation 35 HEV Elevat tion (m) HEV current and voltage fluctuations greater than PHEV Impacts usage and thermal trends of DC/DC converter Results are battery chemistry dependent V I 4 SOC AvgT Time (s) Speed Elevation Voltage (V); Current (I); SO OC (--); Tem mperature (C) levation (m) El 2 PHEV Time (s)

21 PHEV Impacts on Engine/Emissions Control Objective: How is the engine used differently in a PHEV and how might this impact emissions? Simulations Test Bed 21

22 Cycles with at Least One Daily Engine Start Simulations Suggest PHEVs Will Reduce Initial Cold Starts Cycles Percent Reduction % 25% 2% 15% 1% 5% % CV HEV PHEV2 PHEV2 PHEV2 PHEV4 No Chg. Opp. Chg. Initial Cold Start Percent Reduction 8% more 1% CV HEV PHEV2 No Chg. 26% PHEV2 Opp. Chg. 18% PHEV2 PHEV simulations assume CDE scenario electric operation on UDDS 18% PHEV4

23 23 Engine Starts (1 s) Percent Re eduction % 5% 4% 3% 2% 1% % 9. Simulation Results Show PHEVs Reduce Total Daily Engine Starts Total Daily Engine Starts for All Cycles HEV PHEV2 No PHEV2 PHEV2 PHEV4 Chg. Opp. Chg. Total Engine Starts Percent Reduction Relative to HEV (All Cycles) HEV 19% PHEV2 No Chg. 483% PHEV2 Opp. Chg % PHEV % PHEV4 How many of these starts are: Cold Warm Hot

24 Sample Urban Driving Data from PHEV Test Bed ; Cat ); Speed (k kmph); Altit tude (ft/1) Te mp (C) SOC (%* ~9s ~2s ~2s Engine on Due to Cat Temp? BlueLED Speed SOC Altitude Limit Speed Cat1 Gas nsumptio on (gal) Gas soline Co Much of drive below speed threshold Time (s)

25 PHEV Economic Analysis Objective: Evaluate alternative economic factors that could influence PHEV marketability» Ancillary services» Incentives and battery replacement 25

26 Ancillary Services Services that make the electric power system stable and reliable Examples: Regulation Reserve: the instantaneous response to demand variation Spinning Reserve: the instantaneous response to generator failure Both require units operating but not producing energy 26

27 Ancillary Services: Frequency Response 1,5 Reg. UP Reg. Down 1, Reg Up = Discharge Vehicle AGC Signal :15: AM 1:: AM 1:45: AM 2:3: AM 3:15: AM 4:: AM 4:45: AM 5:3: AM 6:15: AM -1, -1,5 Reg Down = Charge Vehicle At saturation the charge/discharge rates are ~ ½ C rate (moderate) 7:: AM 7:45: AM 8:3: AM 9:15: AM 1:: AM 1:45: AM 11:3: AM 12:15: PM 1:: PM 1:45: PM 2:3: PM 3:15: PM 4:: PM 4:45: PM 5:3: PM 6:15: PM 7:: PM 7:45: PM 8:3: PM 9:15: PM 1:: PM 1:45: PM 11:3: PM ERCOT Regulation: Requirement vs. Deployed 1,MW ~ 5, 2kW (12V 2A) Closer to a million vehicles to account for availability. MW 27

28 Potential V2G Values ue ($) Annua al Reven kW Reg 8kW Spin 2kW Reg 2kW Spin 2 kw = 12 V 2A Household Circuit 8 kw = 24 V 4 A Appliance Circuit Connected at Night Only Opportunity Charge 4% 5% 6% 7% 8% 9% % Time Plugged Assume Regulation =$3/MW-h; Spin = $1/MW-h 28 Denholm, Lillienthal, Letendre. Public Utilities Fortnightly 27.

29 PHEVs Marketable with V2G? 4 PHEV 2 Single Charge Cumu ulative Co ost (k$) Broad Spectrum PHEV 2 Midday Charge PHEV 2 V2G low HEV IC PHEV 2 V2G High Years after Purchase Gasoline $3/gal 29 Electricity $.6/kWh 6/kWh off peak, $.12/kWh on peak Ancillary Services: $15/year low, $15/year high

30 Remember the purpose: Conclusions Reduce dependence and demand for petroleum for transportation» National impacts maybe more important than personal economics PHEVs offer potential to impact dependence Understanding di usage pattern and component impacts is key to well designed and effective PHEV 3