Volvo has confirmed its XC90 plug-in hybrid will emit 49g/km of CO2 when it goes on sale in October.

The Swedish company previously announced the model – dubbed T8 – would emit 59g/km of CO2. Volvo said the improved figures were thanks to “the continuous innovation cycle and further testing”.

The T8 is powered by a modified version of the firm’s four-cylinder Drive E petrol engine, fitted with a supercharger and a turbocharger for a total power output of 407hp.

The engine is mated to an eight-speed automatic gearbox, which Volvo said is specially designed to fit the hybrid powertrain. Between the engine and gearbox sits a crankshaft-mounted starter generator, which Volvo said allows the car to go from pure electric drive to being powered by the engine.

Volvo claims it can deliver 26 miles of pure electric range, while returning 134.5mpg.

Volvo said the 65kW battery does not impact on the interior space of the car, and also said its position – it is placed centrally in the tunnel of the car – gives it a low centre of gravity, making the car easier and safer to drive.

“We have been working hard to earn our competitive edge and to give our customers the ultimate combination of performance and low fuel consumption,” said Dr Peter Mertens, senior vice president research & development at Volvo.

“Our twin engine technology has enabled us to build on our heritage of efficient powertrain development in a completely new way. Thanks to our new scalable product architecture, and our world class four-cylinder engines, we have a clear and leading position,” said Mertens.