The Recharge plug-in S90 variants achieve an EAER-rated all-electric driving range of between 31.7 and 54.7 miles, assuming you limit yourself to the car's 'Pure' all-EV mode. As for the WLTP fuel and CO2 stats, well the figures are up to 104.6mpg and between 19 and 61g/km. As with any plug-in hybrid, there's little point in purchase unless you establish a regular recharging regime for the battery pack, which in this case is 11.6kWh in size. Customers will be able to buy a wallbox from Volvo that will charge their cars on 16-amp power in about two and a half hours. If you're out and about and find a 10-amp pubic charging point, the charging time will be slightly longer - three and a half hours - while connecting up to a normal domestic three-pin 6-amp supply will take six hours.The important thing of course, is that the government believes the fantasy-land CO2 stats, so business users will be able to write down as much as 100% of the cost of an S90 T8 against their tax liability. And thanks to a BiK rating of 7%, a 40% tax payer could be driving this variant while incurring a BIK tax bill of no more than around£100 a month. If you're a business buyer browsing in this segment, these are figures that'll reward a bit of thought if you're just about to blindly sign on the dotted line for a conventional six cylinder diesel model from a rival brand.What else? Residual values? They're key in this segment of course and you'd expect those of a big, relatively expensive Volvo luxury saloon to lag severely behind the kind of figures you could realise in a rival BMW or Mercedes. You'd be wrong though. The S90 is selling here in very restricted numbers and that, along with this model's many other attributes, has turned around Volvo's performance in the Executive sector when it comes to depreciation. To the point where independent experts reckon that after owning a typical B4 model for the usual three year/60,000 mile ownership period, you'd get around 38% of your original purchase price back, depending in the trim level chosen. That's pretty close to the kind of return you'd get from a rival Mercedes E-Class.