Automakers worldwide are making contingency plans to replace components lost by Japan's earthquake and tsunami disaster.

But the shutdown of several of the country's nuclear reactors amid growing fears of a major radiation catastrophe will have a much greater long-term impact on the auto industry than a temporary cut in global car output. It may trigger a major rethink of the industry's electrification plans.

The car industry is in the midst of one of the biggest transformations in its 125 year history. Global warming, the prospect of dwindling oil supplies and higher gasoline prices have pushed carmakers into developing new electric-motor based propulsion technologies.

The most viable short-term alternative to the traditional combustion engine was - and is - the battery or plugin electric vehicle, either in its pure state or as a hybrid. At auto shows worldwide, electric vehicles are promoted as the most exciting new products on the market today.

iaea update.automotiveIT

The International Atomic Energy Agency provides update on the Fukushima emergency at www.iaea.org

But CO2 emissions of electric vehicles, which are seen as major contributors to global warming, are directly tied to the way that electricity is produced. In France, for example, where 75 pc of all electric power comes from nuclear generators, average so-called "well-to-wheel" CO2 emissions of an electric vehicle are minimal and definitely much lower than those of the smallest gasoline engines. But in Berlin, where most electricity comes from burning coal, CO2 emissions of electric vehicles are barely lower than those of cars burning gasoline or diesel.

No-one knows what the world's energy mix will look in five, 10 or 25 years. At the moment, roughly 22 pc of the world's electricity is generated by nuclear reactors, according to the OECD's Nuclear Energy Agency. That electricity is relatively clean, when compared with oil and gas generators. And nuclear power generation was set to increase as high-growth big countries such as China build new reactors to fuel their need for electricity.

China has indicated it will continue its nuclear power generation strategy despite sharing in global safety concerns following the Japanese accidents. The US also will likely continue building new reactors. And France, where 75 pc of all electricity is nuclear, isn't likely to shut down reactors any time soon.

But in other countries the situation is different. Across most of Europe, public sentiment is leaning more and more toward phasing out nuclear energy. Countries with little or no nuclear energy probably will be in no hurry to start up new reactors.

All this will mean a big increase in oil, gas and coal burning electricity generation. CO2 emissions will rise. Electric vehicles suddenly look a lot less attractive.

By Arjen Bongard