The Frankfurt motor show, for male visitors at least, is about the interplay of hormones and horse-power. They head for the biggest and the fastest, stroke bonnets and then retire for a glass or two of some of the strongest beer in Europe.

This year is different. The world’s largest car show has gone green and all the top manufacturers are scrambling over each other to show that they are not destroying the planet.

After sizing up the hybrids and comparing carbon emissions, visitors can refresh themselves with a vitamin-packed Green Sun Rise at the Biofuel Bar. The gocart track, an annual favourite with bored sales reps, has a new agenda: the aim is to be the most economical rather than the fastest driver. A new racing car - the Bio-Concept-Car, powered by biofuel and with a natural-fibre chassis – will be presented by a German hip-hop artist named Smudo. All that is missing from this green landscape are grazing Alpine cows.

It is not, in short, the kind of place that would have instant appeal for Jeremy Clarkson, nor the barons of the fuel-guzzling German car industry.

Dieter Zetsche, chief executive of the about-to-be-divorced Daimler-Chrysler, was on the defensive in his preshow interviews. Toyota has been making the running on hybrid engines and the heavy German cars are being branded, even in the popular press, as “Klima-Killer” – climate killers.

“Hybrids are being hyped as the technological holy of holies,” he told Der Spiegel, “but they can’t be that, if only because the high pricing restricts their chances on the market”. He calculates that one million cars with hybrid engines will be sold annually by 2010. “That would be barely 2 per cent of car sales. Compare that with the worldwide production of clean diesel vehicles – around 13 million diesels by 2010.”

Daimler is betting on diesel. It may be cooperating with BMW on developing a hybrid engine and may be using the technology in its urban buses, but to listen to Mr Zetsche the future is in Bluetec diesel. Mr Zetsche, to drive home his eco-credentials, also outed himself this week as a Smart owner, driving the smallest model in the Daimler range.

All the German manufacturers will struggle to meet the European Union target of an average carbon dioxide emission of 120g per kilometre by 2012. BMW will present plans for lower-emission vehicles and Volkswagen is unveiling its VW Up, to be on the road in two years. According to Stern, “it has the size and thirst of a sparrow”. Even Porsche emphasises that its Cayenne will be equipped with a hybrid engine. “We are not the dirty dogs of the industry,” Wendelin Wiedeking, the Porsche chief, said.

The non-German manufacturers will have an easier time of it. Citroën is showing its C-Cactus, billed as an ecological hatchback. It has a hybrid diesel drivetrain, weighs only 1,306kg and is made partly from recycled materials. The company claims that it will emit only 78g per kilometre of CO2 gas. General Motors is rolling out its concept of a plug-in electric car, the Flextreme, designed for commuters.

This will be the show of the shrinking car – even SUVs are getting smaller – but for the unreformed, “the cavemen” in the words of one exhibitor, it will still be possible to slink away and inspect the nongreen Ferrari 430 Scuderia, with its 510 horse-power and Formula One software, or the GT Speed Bentley, described as the fastest Bentley of all time, top speed 202mph. The Bentley costs £139,000, which buys a lot of cave.

All green

— BMW is launching the X6 sport utility vehicle/car crossover, which has a hybrid engine, at the Frankfurt show. Norbert Reithofer, BMW chief executive, said: “We will reduce the CO2 emissions from our fleet by 25 per cent from the 1995 levels by 2008”

— Volkswagen plans to offer a car with fuel consumption of only 1 litre per 100 kilometres in 2010

— GM displayed an Opel Flextreme concept vehicle that aims to run for about 55km (34 miles) on electricity and only use a small diesel engine when the battery needs to be recharged