The greenest Jaguar we've driven here on GreenCarReports is the European-market XF 2.2D, but the smooth, economical diesel certainly isn't the limit of what Jaguar can achieve.
Despite cutting a significantly larger figure on the road, the Jaguar XJ_e plug-in hybrid makes the fuel-sipping XF look like a positive gas-guzzler.
For that reason, it's the perfect car to enter the annual RAC Future Car Challenge, taking place in London this November.
The Future Car Challenge showcases the best of green vehicle technology, with everything from hybrids and electric vehicles to fuel-cell cars taking part.
The Jaguar XJ_e swaps out the usual supercharged V-8s and V-6s for a specially developed 2.0-liter, turbocharged four-cylinder engine, 69 kW electric motor and 12.3 kWh lithium-ion battery pack.
That gasoline engine makes it a little different from the Range_e plug-in hybrid Range Rover Sport we drove earlier this year, which uses that model's 3.0-liter V-6 to supplement electric propulsion, rather than a small gasoline engine.
There's enough juice in the battery for a 25-mile all-electric range, but traditional Jaguar buyers are unlikely to be disappointed with the car's pace either--it'll top 150mph and reach 60mph in only 6.5 seconds.
Jaguar claims combined economy of 61.2 mpg and CO2 emissions of only 75 grams per kilometer--that's 70 percent less than the gasoline V-8 pumps out. It's more economical than that diesel XF too, which manages 43.5 mpg on the European combined cycle.
Jaguar Land Rover is beginning to take a serious look at tailpipe emissions, and aims to reduce emissions by tackling three main areas: Parasitic losses such as aerodynamics and rolling resistance; vehicle weight through advanced structures and lightweight materials; and propulsion--combustion efficiency, hybrid technology and electric propulsion.
The Future Car Challenge will be a very public platform on which to demonstrate the group's technology, and it'll allow Jaguar to demonstrate the XJ_e's capabilities in the real world.
The 2012 RAC Future Car Challenge takes place on the weekend of 3-4 November.