By most commonly-held definitions, the Tesla Model S is a zero-emissions vehiclethe all-electric vehicle has no tailpipe, and emits no exhaust while driving. That's not a convincing argument for Singapore's Land Transport Authority, however: The agency hit Singapore's first Tesla Model S owner with a tax of S$15,000 (roughly $10,840), ranking his electric sedan in the dirtiest category of high-pollution automobiles.
Teslas might indeed be zero emission in the sense no exhaust is spewed out. But it is true that guzzling down electricity also generates emissions...typically at the power plant.
The question is whether the actual figures are accurate, or just conveniently chosen for government to make some pretty coin.
Most ICEs are around 20% efficient then they have a driveline loss of roughly 15%. Fossil fuel power plants are roughly 30% efficient for old technology and 50% for combined cycle. Then there are transmission losses through the grid of an average of 6% in the US. Charging a battery is normally around 90% efficient. An electric motor is roughly 80% efficient. Driveline losses are much less on an electric car due to direct drive, let's say 2%.
ICE total efficiency: 17%
Electric car: ~19% using traditional power generation
Then you need to add in the extra emissions used to build the batteries over the lifetime of the car and you likely get back to the efficiency of a normal ICE. The major gains come from being able to use solar, wind, tidal, or nuclear to power the car.
Most ICEs are around 20% efficient then they have a driveline loss of roughly 15%. Fossil fuel power plants are roughly 30% efficient for old technology and 50% for combined cycle. Then there are transmission losses through the grid of an average of 6% in the US. Charging a battery is normally around 90% efficient. An electric motor is roughly 80% efficient. Driveline losses are much less on an electric car due to direct drive, let's say 2%.
ICE total efficiency: 17%
Electric car: ~19% using traditional power generation
Then you need to add in the extra emissions used to build the batteries over the lifetime of the car and you likely get back to the efficiency of a normal ICE. The major gains come from being able to use solar, wind, tidal, or nuclear to power the car.