My understanding is that the Taycan was seriously screwed by having its track modes, which are genuinely very inefficient, blended equally in to the test.
It's a bit of a shame to see so many Tesla fans point to its supposed inefficiency based on the EPA range. It feels like the tables have turned 180 since the Top Gear scripted test days; it was shitty when Tesla was attacked with FUD back then and it's shitty when the Taycan is today.
Unfortunately I'm struggling to find a source, so take it with a grain of salt. My memory is that the highway speed test for one of the modes had it running in first gear (of two).
But regardless of the reason, its EPA range proportional to WLTP and real world driving is very low compared to other EVs. It doesn't point to poor efficiency, just a corner case of EPA testing.
While extrapolated from 100 miles, this Car and Driver test [1] puts a 6% gap between the 2020 Model S and Taycan, compared to a 70% difference in EPA range. Extrapolation sucks as a method, but there's no way it would mask a true 70% range difference - the Porsche would be close to empty at the end of the test.
Considering the Tesla costs just over half as much, it's still a home run for Tesla. They're the ones to beat and by all accounts are likely to stay that way.
It makes sense to me, as otherwise a manufacturer could supply the car with a 50mph speed limiter (which users would instantly disable) to boost their EPA-measured range.
My memory (and I don't have a citation for this) is that if the manufacturer gives you multiple range modes (like Eco and Sport) EPA tests in both, then averages them together somehow.
It's a bit of a shame to see so many Tesla fans point to its supposed inefficiency based on the EPA range. It feels like the tables have turned 180 since the Top Gear scripted test days; it was shitty when Tesla was attacked with FUD back then and it's shitty when the Taycan is today.