Mercedes-Benz S 500 Plug-In HybridThe Mercedes-Benz S 500 Plug-In Hybrid has officially set a new environmental benchmark for luxury cars after receiving an ISO-standard Environmental Certificate.

The £87,965 saloon, which averages 100.9mpg and emits just 65g/km CO2, joins the S 300 BlueTEC Hybrid (recently reviewed by MR) and S 400 Hybrid in receiving environmental certification.

The S 500 Plug-In Hybrid is the greenest of them all though; Mercedes-Benz’ first plug-in hybrid, it emits over 50 per cent fewer CO2 emissions across its lifecycle than a conventional luxury car, and travel more than 20 miles on battery power emitting zero local emissions.

The ISO certificate adds that external charging with the European electricity mix can, over a 186,000-mile lifecycle, “cut CO2 emissions by some 43 per cent (35 tonnes)”.

Switch that energy source to hydroelectricity and the 56 per cent reduction – 46 tonnes – is possible.

“Plug-in hybrids offer our customers the best of both worlds,” says Dr Herbert Kohler, chief environmental officer at Daimler AG.

“In the city they can drive in all-electric mode, while on long journeys they benefit from the combustion engine’s range.

“The new S 500 Plug-In Hybrid is the spearhead of our hybrid strategy. It offers the power and performance of a V8, but runs on as little fuel as a compact model.”