At first glance the Californian firm's 2015 range of bikes — officially unveiled at Intermot in Cologne, Germany — looks a lot like its current range. However, pull away the fairing and the changes are massive.

Chief among them is a 10% boost in range across the model line, meaning that when rode responsibly, they can go up to 185 miles (297 km) before the batteries need charging.

That sort of range improvement is enough to make the new bikes attractive for something other than inner-city commuting or a bit of off-road fun.

However, it's not just better battery tech, the new bikes boast the sorts of fittings and features that its petrol-powered counterparts have been offering for some time — Showa suspension, Bosch ABS systems and Pirelli tires.

"Zero worked in close collaboration with Showa to develop suspension systems that are optimized for each specific model," said Abe Askenazi, CTO of Zero Motorcycles.

"The resulting ride quality is fantastic. When combined with Bosch's carefully tuned ABS on newly engineered brake systems and Pirelli tires, every Zero has once again been transformed."

All of which means that they'll handle and stop like a normal bike. But that's all that they do have in common with most of the other marques on display at this year's event.

Electric engines might be poorer than fossil fuel engines in terms of range and in terms of the time it takes to refill but those are the only areas where electric bike owners face a disadvantage.

The acceleration from an electric motor is immediate and all of the torque and power generated by the motor is available all of the time — no need to wring it through a gearbox.

That's why when Zero was just a Californian startup back in 2006, it chose to target dirt biking and scrambling first where that electric immediacy is a huge advantage.

Some eight years on, the FX is still an important model in the range but it has been joined by a serious hot-rod in the form of the SR, the S (which promises the looks and the grunt of a Naked bike), and the DS (which is aimed at those that commute during the week then head for the hills each weekend).

"The new lineup will arrive at North American dealerships in December and during late February for Europe," announced Richard Walker, CEO of Zero Motorcycles.

Although all major motorcycle manufacturers are taking their environmental responsibilities more seriously, very few are actively developing electric engines as alternatives to internal combustion engines.

However, stricter EU emissions legislation means that smaller, more efficient engines are coming to market as are more accurate representations of performance and figures regarding fuel consumption and CO2 emissions. — AFP/Relaxnews 2014