Contribution of various factors to the difference in observed versus theoretical utility factor

Notes

Data extracted from a study that examined driving and charging behaviour for 153 PHEVs in California. Four models were considered: Prius (MY12-14), Energi (MY12-17), Gen1Volt (MY11-15) and Gen2Volt (MY16-17). A weighted average of each contributing factor is derived here based on the number of each model in the total data set. The percentages look at the average absolute standard deviation. ZE Trip Efficiency = Zero Emission Trip Efficiency represented in kWh/mile represents the amount of electrical energy used over an hour per mile driven; VMT = vehicle miles travelled; Range utilisation = the amount of daily VMT driven on the vehicle’s electric range; Unobservable factors = deviations in the utility factor that cannot be accounted for by charging, VMT, ZE trip efficiency or range utilisation. Theoretical utility factor is based on the SAE J2841 standard.