In March 2007, Tesla reported the Roadster's efficiency on the EPA highway cycle as "135 mpg [U.S.] equivalent, per the conversion rate used by the EPA" or 1…
In March 2007, Tesla reported the Roadster's efficiency on the EPA highway cycle as "135 mpg [U.S.] equivalent, per the conversion rate used by the EPA" or 133 Wh/km (21.5 kWh/100 mi) battery-to-wheel and 155 Wh/km (24.9 kWh/100 mi) plug-to-wheel.
Event text from Wikipedia: “Tesla Roadster (first generation)” (linked citation above)