We'll get to drive the new Porsche Panamera S E-Hybrid later this year, but this week What Car? was invited to Germany to ride in a pre-production car that demonstrates the company's latest hybrid technology.
The outgoing Porsche Panamera S Hybrid was by no means the cheapest way to run the company's luxury four-seater despite CO2 emissions of 159g/km and average economy of 41.5mpg, it cost 24,000 more than the equally economical V6 diesel.
The S E-Hybrid model won't have a lower purchase price, but Porsche has improved its efficiency; average economy jumps to 91mpg, while CO2 emissions drop to 71g/km.
Porsche says the new car combines 'typical Porsche performance' with the fuel economy of a 'compact car'. Like its predecessor, it uses a supercharged 3.0-litre V6 petrol engine mated to an electric motor, but the output of the motor has been increased from 46bhp to 94bhp, giving a combined total of 410bhp. This propels the car from 0-62mph in 5.5 seconds half a second quicker than the outgoing Panamera S Hybrid.
The quickest acceleration is achieved in Sport mode using the boost function, which can be activated by a button on the centre console or will activate automatically beyond 80% throttle. In this mode, the engine and motor work together to provide maximum power during acceleration.
In electric-only E-Power mode the default setting when starting the car the 94bhp motor works independently. This allows a 0-31mph time of 6.1 seconds and a top speed of 84mph. Porsche says the electric range is between 11 and 23 miles depending on conditions.
The first part of our passenger ride was in E-Power mode. Using only the electric motor, 229lb ft of torque is available instantly, which makes acceleration seem more rapid than it actually is. Once on the motorway in Hybrid mode, the switch between the engine and electric motor is seamless and helps to increase fuel economy.
The boost function is activated in kickdown the effect from this combination gives the car far more urgency than its predecessor. The mix of supercharger whine and the whizz of the motor can be heard in the cabin, but it doesn't make the car feel any less refined.
Air suspension is standard on the S E-Hybrid, which means the car rides well at high speed and feels composed in fast corners. The ride is firm around town, but by no means uncomfortable.
The car will automatically disengage E-Power mode and switch to the Hybrid setting when there is 2km of electric range left. If you want to recharge the battery on the move, you can press the E-Charge button, which changes the transmission settings so that the engine tops it up. E-Power mode becomes available again once the battery has more than 20% charge.
Over an 18-mile route, our test car's trip computer showed an average 58.9mpg, which included 13 miles of electric-only propulsion and five miles using petrol. That suggests the engine had fuel economy of just 16mpg so it's clear what a huge difference the hybrid system makes.
The S E-Hybrid's battery can be fully charged in less than four hours using a domestic socket, or around two-and-a-half hours using an industrial connection. All cars are supplied with a Porsche Design wall box, which keeps the power adapter and leads tidy, although they can be removed and put in the boot to allow charging when out and about.
A new mobile app called Porsche Car Connect can monitor and activate various functions on the Panamera S E-Hybrid. These include a charging status indicator and the ability to preheat or cool the car remotely using the climate control. This means that the cabin temperature can be adjusted using the mains when plugged in, which preserves power for electric driving.
The app will also send you an alert if the charging cable is unplugged from the mains, or if the power supply is interrupted. Other functions include a tyre pressure monitoring system and vehicle tracking. The app will be available for all Panamera models later in the year.
Porsche is still in negotiations with the UK Government to ensure that the Panamera S E-Hybrid qualifies for the plug-in car grant. We expect UK pricing to be announced once these discussions are complete, with an increase in cost of between 3% and 6% compared with the outgoing car.
The car's astonishingly low official CO2 figure means that even at the top end of this price increase, annual company car tax liability at the 40% rate should be a similar to that of a BMW 320d.
Porsche is taking expressions of interest through dealers now, with the first customer cars scheduled for delivery from August.