It was an incongruous sight – former oilman George W.?Bush committing billions of federal dollars in 2003 in the hope that children then being born would take their first drives in hydrogen-fuelled cars. Even stranger then is the far-greener Barack Obama slashing hydrogen funding after $2.5bn has been spent along with $11bn by US industry.

Utilising the most abundant element in the universe as an energy source while producing only water as waste has public appeal but many practical problems. Though fuel cell technology has improved vastly – Toyota, Daimler and Honda have plans for commercial vehicles by 2015 – hydrogen is merely a carrier of energy and faces daunting logistics. Only 58 US fuelling stations exist, mainly in southern California, despite grand promises of a 200 station “Hydrogen Highway” in the state. The main source, and the only cost-effective one, is natural gas – a fossil fuel, and its cost equivalency with petrol only prevails in the US and only due to a glut that has left its price to petroleum at a third the historical average. Electrolysis would cost three times as much and burn fossil fuel too if not powered by expensive renewables or controversial nuclear.

But advocates of competing biofuel and electric vehicles should not gloat as they are not prevailing on technological or environmental merit. They benefit from an existing power grid and retail fuel network that would cost hydrogen advocates tens of billions to replicate. Though fuel cell vehicles are quite pricey today, that would change with volume and hydrogen has practical advantages too.