“A very powerful electric performance automobile is less efficient than a hyper-efficient E.V. but still far cleaner than a comparably powerful car that burns gasoline,” Mr. Reichmuth said in a telephone interview. He added that a Model S driven in California, which has some of the nation’s cleanest electrical power, is about equivalent to a gasoline vehicle that achieves 120 m.p.g. In other words, in an area with relatively clean electric plants, this extremely powerful machine can be cleaner than even the most efficient gas car.
The numbers Mr. Reichmuth cited assume that the Model S is driven responsibly. With the throttle held wide open, a Model S will gobble up the watt-hours. While Tesla doesn’t provide data for aggressive driving, some Tesla owners have explored the extremes. One estimate on Tesla’s web forums claims that at full throttle the car will use about 869 watt-hours of electricity per mile and have a range of about 88 miles on a full charge. In simple terms, that means driving 30 miles at full throttle would require about the same amount of electrical energy that an average American home uses in one day.
Driving at wide-open throttle at length would quickly heat the Tesla’s battery, triggering electronic safeguards that would slow the vehicle. So the Tesla isn’t going to take on gasoline rivals in an endurance race. But its fun-to-drive factor is very high, and in short sprints, it is nearly unbeatable. In one 2016 drag race captured on YouTube, a Model S takes on a 707-horsepower Dodge Challenger Hellcat, and emerges the victor.
The Taycan, according to Car and Driver magazine, is rated even quicker, but the magazine editors recorded identical 70 MPGe power consumption with both cars on a 300-mile trip at 75 miles an hour. (MPGe is an acronym for miles per gallon equivalent, and it’s the government’s way of quantifying the efficiency of electric vehicles. The Environmental Protection Agency, officially, pegs the Tesla at 97 MPGe combined city and highway driving, and the Porsche at 68 MPGe combined.)
The discrepancy in the Tesla and Porsche E.P.A. ratings is likely due to the structure of the test and appears to indicate that the Tesla has an efficiency advantage over the Porsche in stop-and-go city driving. No gasoline-powered high-performance car can be driven anywhere near as economically as the Tesla or Porsche electric.
A comparison of E.P.A. ratings suggests that the least economical gasoline-powered cars emit more than twice the emissions of the most economical gas car. For example, the Mitsubishi Mirage G4, with its three-cylinder engine, is E.P.A. rated at 35 m.p.g. combined, while a Ford Shelby GT 500 Mustang earns a 14 m.p.g. combined rating.
The spread between the electric extremes is much narrower. The Hyundai Ioniq Electric, one of the most efficient electric vehicles, is E.P.A. rated at 122 MPGe, yet the Tesla Model S Performance car earns a 98 MPGe rating.