In the continuing disaster at Fukushima, Japan's nuclear safety agency has now raised the crisis level to seven: the highest category of nuclear accident. The government is widening the evacuation zone. The unpalatable truth is that the legacy of Fukushima will be with us for a long time to come.

The numbers are staggering. Latest information from nuclear consulting engineer John Large tells us the six reactor cores held 487 tonnes of uranium (of which 95 tonnes includes 230kg of plutonium, an even nastier substance, from the Mox assemblies), with a further 1,838 tonnes of stored spent fuel, including 1,097 tonnes in the central pool store. There is no question there have been very significant and "ongoing" releases of this radioactive inventory.

But even away from this disaster, facts about the industry's cost and scope to meet Europe's energy needs should be enough to give nuclear supporters pause. For instance, government figures state that a very ambitious new nuclear-build programme will give us only 4% of the energy we need. Electricity provides only 20% of our energy, and at its peak nuclear only provided 20% of electricity.

Energy policy professor Steve Thomas points out that the scale of problems at newbuild reactors in Finland and France has taken even sceptics by surprise. Originally priced at €3bn, the Finnish reactor's cost is estimated to be at least €5.7bn, and the French reactor is doing just as badly. Britain's nuclear waste bill is still growing too: liability estimates have grown from £50bn in the mid-2000s to as much as £80bn at present.

In stark contrast to the "measured exit" from nuclear power of Angela Merkel, the German chancellor, the chief executive of EDF insists that new UK reactors "will have to go ahead" – maybe something to do with the £12.4bn they've already spent on buying UK nuclear sites. And when Nick Clegg suggested that the next generation of nuclear power stations may never be built because the recommended higher and more costly safety standards would make them too expensive, Chris Huhne launched an astonishing attack on his party leader, accusing him of behaving like a "headless chicken" on the issue.

Huhne's more considered move was to call on the Health and Safety Executive's chief nuclear inspector, Mike Weightman, to do a "thorough report on the implications of the situation in Japan and the lessons to be learned". Sadly, compared to other countries, the HSE review is looking increasingly narrow, with fact-finding and weighing of evidence limited to the usual suspects, excluding involvement from energy experts who are not nuclear power proponents. It almost goes without saying that this has important consequences for public confidence in nuclear regulation and public trust in government.

All this points to a key difference between the rhetoric and reality of nuclear risk management. Despite an unending round of nuclear consultations there remain fundamental questions about "what if" issues such as fuel supply and manufacture, vulnerability to attack, radioactive waste management, radiation risk, decommissioning, reactor coastal siting, flooding, nuclear costs and accident liabilities.

However, as the E3G director Tom Burke points out, implications for the future of energy and climate policy cannot be simply reduced to the calculus of technological causation and human casualties. There is now a growing debate around the world about whether nuclear power has any role in resolving energy security and climate dilemmas.

Since the challenge of achieving a transition to sustainable energy will involve a series of different options, Sussex University's Andy Stirling has suggested a range of technically and economically viable alternatives, including new European-scale networks for energy distribution ("big grids"); small-scale distributed energy ("smart grids"); large-scale infrastructures for carbon sequestration; energy market innovations from supply to services; restructuring the built and transport environment to provide for more distributed and integrated energy services; and the generation of increasingly evolving forms of renewable energy.

Again Germany seems to be leading the way with viable renewable technology. The Imperial College physicist Keith Barnham notes that Germany has installed more windpower capacity than the entire UK nuclear capacity, and is adding to it at a rate equivalent to more than one reactor a year. In 2009 alone Germany installed solar photovoltaic systems with capacity equivalent to approximately four nuclear reactors.

The UK is obliged under EU directives to reduce its energy intensity through efficiency and to increase its proportion of renewables to 15% by 2020, providing the foundation on which a non-nuclear, demand-side management, low carbon future can be constructed.

Since we're not all energy technology and policy practitioners, it may come down to who you trust. As Andrew Warren, the director of the Association for the Conservation of Energy, asks: given Germany has the confidence to go down a non-nuclear route with the same carbon objective as the UK, have EDF and Huhne really got it so right, and has Europe's most successful economy really got it so wrong?