Today’s ruling by the UK Advertising Standards Authority (ASA) that Renault must pull an electric vehicle ad in its current form throws up some interesting questions.

The French automaker – says the ASA – had claimed CO2 emissions for its Fluence ZE electric vehicle would be 90% less than for a current diesel model – but the ASA begs to differ.

The issue appears to hinge on a difference of interpretation concerning how electricity is generated between France and the UK.

Britain has long had a mix of fossil fuel and nuclear power generation, while its neighbours across the English Channel have famously relied heavily on nuclear energy to supply its electricity needs.

The dispute goes to the heart of a debate currently raging about how green EV models really are.

The vehicle may be built using the latest carbon fibre composites and with a significant element of components able to be recycled, but its end function is propulsion and that clearly has to be fuelled somehow.

For the UK, it may not be as drastic as one recent caller to a radio station, who insisted electric vehicles were “coal-fired” but power source has to originate somewhere.

There is no free lunch. Virgin Trains ran a UK television campaign two years ago on a green, sustainability theme, but the recently-electrified West Coast Main Line obviously requires a massive amount of energy, which in the UK means a power generatioin mix.

This issue is not going to disappear. If electric vehicles really are going to be as prevalent as some predict – and Germany wants one million of them on its roads by 2020 – energy generation has to be addressed.

Renault has complied with the ASA and pulled its TV ad, although it has expressed its “disappointment” at the turn of events.

It also points out it electricity can be generated by sources other than fossil fuels. Citing “zero-emission renewable sources such as solar and wind power or purchased through carbon offset energy schemes,” Renault notes there is a choice.

But solar and wind power generation is surely a significant way off from providing EV propulsion in any meaningful quantity. And its inconsistency of supply will present be a massive challenge for energy capture.

The UK is mulling a huge increase in nuclear power generation as traditional sources either start to dwindle or fall foul of a tightening in environmental regulation.

Electric vehicle manufacturers will have to address power sourcing more widely. Nuclear power stations can’t be commissioned overnight.