Without qualifiers, we'd assume Blume's actually thinking of a number beyond 700 hp, because the 911 GT2 RS already makes seven centuries of ponies. If we qualify the statement to standard series models, then engineers only need to beat the 607 hp in the Porsche 911 Turbo S Exclusive Series.
A couple of items lead us to believe the plug-in 911 will go to the other side of 700 hp. First, a Motor Trend report from four years ago predicted it, telling us to "expect hybridized, plug-in 700-plus-hp versions of both the Panamera Turbo S and the 911 Turbo S" by 2017. Those two vehicles would begin to showcase everything Porsche created and learned with the 918 Spyder and 919 Hybrid Le Mans racer. The timing was a tad off, the sentiment apparently spot on.
Second, the present Panamera Turbo S E-Hybrid already makes 680 hp with the help of a 136-hp electric motor. True, the Panamera uses a 4.0-liter V8 making 550 on its own. However, with the 3.8-liter flat-six in the Turbo S Executive at 607 hp, slipping the e-motor into that car would surpass the target right now. The question now is whether the 911 hybrid becomes the new Turbo S, or if it commands the new, higher top step. Blume also said the electrified coupe will contain "a special button for the electric punch." We hope that button is mounted on the steering wheel.
The 911 plug-in comes "a couple of years" after the next 911, which could mean an unveil at the end of 2020, with deliveries toward the end of 2021.