The familiar cluttering sound of motorbike scooters that has reigned in southern European for more than a century may be ending as an electric scooter silently takes over the streets.

Until a few years ago, the electric scooter was considered an inventors' joke with a cumbersome heavyweight battery pack that made it about as manoeuvrable as a loaded Bedford truck. But the latest battery-driven scooters and bikes can hardly be distinguished from their petrol-driven cousins with the new battery technology making it possible to hide the battery pack in the bodywork, giving it the same optimal weight distribution as in conventional bikes.

Sales of electric bikes still only make up a small proportion of total bike sales, but are picking up rapidly as consumers seek alternatives to expensive fossil fuels.

Vectrix Corp. based in Rhode Island in the United States, claims to be the world leader in zero emission electric scooters and high-performance bikes and becoming quite a sensation among biking enthusiasts.

It has a conventional design with only the "electric" sticker on the front, distinguishing it from other bikes. Vectrix reported in September a 738 per cent rise in revenues compared to the last business year.

It sold 1,184 bikes to dealers, representing an increase of 156 per cent over the previous financial year. Electric Vx1 and Vx1e scooters are built at a plant in Poland but the company said it had also entered into an agreement for a final assembly in China.

SYM Corporation, a major bike producer in Taiwan, is also planning to produce several thousand electric bikes at its plant in China. The company is looking optimistically at the potential of zero-emission bikes because many cities in the world are imposing bans or high taxation on polluting vehicles.

Bicycles with an electric-power back-up are gaining in popularity, especially in flat countries such as the Netherlands. But companies are seeing more potential in high-powered electric motor bikes. Police in the Scottish city of Edinburgh have just bought their first Vectrix maxi-scooter with fleet manager Dignan McCulloch, saying that "organisations across the country are focussing on improving their carbon footprint. The implementation of the Vectrix, as a direct replacement for a car, is a substantial achievement and goes a long way in helping us to reduce our carbon output."

At present, the Vectrix battery pack is a nickel metal hydride unit (NiMH). It can be recharged in two hours from a normal electric socket, giving it a range of 109 kilometres based on urban driving at 40 km/h. The top speed is listed at 100 km/h. One big stumbling block is the sales price at 10,000 euros in Europe and 11,000 dollars in the United States. A replacement battery costs about 2,232 euros (3,000 dollars).

The company has announced that it is looking at introducing lithium-ion battery technology for new models. It is also experimenting with fuel-cells. The high cost however has to be weighed up against the drive to the petrol filling station, oil and maintenance that falls away with the electric scooter. Generally insurance and tax are also lower for zero-emission vehicles.