BMW’S DIESEL-SIPPING 730d luxury sedan will arrive in Australian showrooms next month, rounding out the new 7 Series range and giving well-heeled buyers a genuinely frugal option for their next large-car purchase.

With 180kW and a huge 540Nm coming from its 3.0 litre twin-turbocharged diesel inline six, the 730d won’t exactly be a slouch either. The 0-100km/h run is dispatched in a brisk 7.2 seconds - a happy coincidence considering the 730d uses 7.2 litres of diesel per 100km on the combined cycle.

The 730d emits a relatively low 192 grams of carbon dioxide per kilometre, which makes it one of the least polluting vehicles in its class. Indeed, it’s the first Australian-market car in the upper-echelons of the luxury segment to emit less than 200g/km.

It’s also greener that its most direct competitor, the Mercedes-Benz S320 CDI, which uses 7.7l/100km and emits 202 grams of carbon per kilometre.

The downside is that it misses out on qualifying for a green car exemption from the Federal Government’s luxury car tax, and by a narrow margin too. However, BMW is hopeful that further refinement of the 730d’s mechanical package should see it squeeze under the 7.0l/100km threshold in the near future.

Fuel-saving features already in use by the 730d include an active aerodynamic venting system which reduces drag and brake energy regeneration, which eases load on the alternator and allows the engine to direct most of its power to driving the wheels.

If that’s not efficient enough, then the 7 Series hybrid that’s rumoured to debut at Frankfurt in September may be more up your alley. Conversely, those of you who value power over economy may want to hold out until later this year, when the twin-turbocharged, V12-powered 760Li hits the market.