According to the firm, there are now 25 fuel stations across the country that are equipped with the facilities to pump hydrogen direct into fuel cell and hybrid vehicles, as the clean energy begins to take off.

Described as safer than pumping petrol or diesel into a car, hydrogen filling stations are set to become increasingly popular because of the growing interest in green technologies, particularly among business fleets as companies look to cut emissions to comply with government regulations.

Honda's count of refuelling stations has found that 16 of the current 25 in the US are located in California, where strict rules on emissions apply.

According to USA Today, Honda's FCX hybrid vehicle may be the future of fuel cell development, however the $1.5 million cost of building the car means it is currently not a viable option for the mainstream, with the company instead deciding to lease the cars for $500 per month.

While there may be a future for such cars, improvements will need to be made to bring down the cost, but also changes to the filling procedure will be required.

Currently, in Washington for example, motorists looking to fill up on hydrogen need to call the station in advance to find out if a specially-trained attendant is on hand to connect up the two hoses to the car.