Thursday, December 12, 2013

The Remarkable Energy Efficiency of Electric Cars [Peugeot ]

Five Peugeot Ions drive over 42,000 miles in two year-long test to measure their energy efficiency.
A Belgium research group called Laborelec, with support from Brussels' Vrije University, set out two years ago to collect extensive data on the energy use of electric cars. Funded by Electrabel, the Belgian utility, they acquired five Peugeot Ion EVs, essentially clones of Mitsubishi's i-MiEV, some 30,000 of which have been sold worldwide.
Various volunteers drove the mini-cars for a total of 42,953 miles, onboard sensors collecting reams of data on energy use from how much power propelled the cars to how much regenerative braking contributed to added driving range.
The results are impressive. Measured in watt hours per mile, the five cars averaged, respectively: 289.62 ; 336.28 ; 249.39 ; 291.23 ; 299.27. Collectively for the five car fleet, the average came out to be 293.16 wH/m. Assuming there are some 34,000 Watt hours of energy in a gallon of gasoline, that works out to be the equivalent of 115 miles per gallon in real world daily operation, not on some isolated test track or laboratory dynamometer.
The researchers also found that regenerative braking helped improve the efficiency of the fleet by an 11.86%. The biggest draw down the study found was the energy needed to provide the driver and passengers with cabin heat. Early cars used current-sucking resistive heat, but carmakers have shifted now to more efficient heat pump systems. Overall the percentage of energy diverted to run the support systems worked out to be, again respectively: 40.1 ; 35.8 ; 21.6 ; 22.0 ; 36.4.
But even at this rate, the cars proved dramatically more efficient than either their gasoline/petrol or diesel counterparts. In terms of their plug-to-wheel efficiency they averaged, as a fleet a rate of 54.12%.
Apparently, one of the test drivers was so impressed with the performance of his company electric car, he went out and bought one for himself.