It’s no exaggeration to say that the Fukushima nuclear reactor disaster in March has cast a shadow over plans for new nuclear power capacity globally, and it is too early to say whether this will fade with time. But it’s also having much wider indirect consequences which could yet cause a shift in Europe’s energy and climate policy and complicate global climate talks.

Many of the accident’s extreme circumstances were unique to Japan, so there may or may not be lessons to learn in other countries. But, rightly or wrongly, that message is rapidly becoming politically irrelevant amid the understandable trauma.

Nuclear power programmes have always been hostage to fortune, sensitive to public concern over accidents anywhere in the world. Three Mile Island in the US in 1979 and Chernobyl in 1986 all but killed off global nuclear plant construction for two decades, with the unresolved problem of nuclear waste further complicating matters. As a result, a new nuclear programme in the UK was held back until the white paper of 2008.

Most major economies are already engaged in urgent new safety reviews of nuclear power, but some such as the EU have already gone further. The European Commission is re-examining its assumptions that nuclear power will continue to play a key role in its Low Carbon Roadmap to 2050 (ENDS Report, March 2011). And Fukushima was a major factor leading to the March political earthquake in Germany which brought unprecedented success for the Greens. That has already led to 7 gigawatts of nuclear capacity coming off-line for checks. Some older plants are now thought unlikely to reopen and a reinstatement of Germany’s phase-out of nuclear power is on the cards. China has already paused its huge new construction programme, though France remains committed.

So what does all this mean for climate policy and energy efficiency? Depending on the extent to which the current nuclear construction pause lasts – and the ultimate bill for the disaster – it could seriously reduce energy policy options for the EU, particularly for baseload electricity. On the positive side, there would need to be a far greater push on energy efficiency and energy-efficient products, a lower cost option, on renewable energy and on carbon capture and storage technology. There could also be more rapid progress on a European Grid, helping to smooth out the intermittency of renewable-dominated power supplies.

But in the meantime, there would be greater reliance on fossil fuels. The advent of shale gas in the USA had led to surpluses of conventional natural gas on the international market, but much of this may be needed in Japan for the foreseeable future. That is likely to lead EU power generators to shift to more carbon-intensive coal, raising emissions, at least until CCS is proven.

Increased demand for emission allowances within the EU emissions trading scheme will be good news for carbon traders facing surpluses after the recession, but it will put upward pressure on energy prices at a sensitive time and make it harder for the commission to justify an early shift from its current 20% greenhouse gas reduction target by 2020 relative to 1990 to 30%. In turn, restrained EU ambition on mitigation, policy paralysis in the US and a more passive role for Japan on mitigation for the foreseeable future will not help prospects for a global climate agreement in Durban this December. Money for the crucial UN Green Climate Fund for developing economies (ENDS Report, March 2011) may be harder to find.

For the UK, the effects are likely to be more muted, but still significant. Not least as Britain is in the throes of fundamental electricity market reform (ENDS Report, March 2011) aimed at boosting investment in low carbon. In reality, the reforms, including long-term capacity contracts and a carbon floor price, are aimed at boosting nuclear power, which has been stagnating, while the Renewable Obligation that will be phased out has been fairly successful.

Energy and climate secretary Chris Huhne, no long-term supporter of nuclear power, has commissioned a report on the implications of Fukushima for both new build and existing nuclear plant. The full report is due out in September 2011, but it will be taken into account in the government’s streamlined Generic Design Assessment for proposed nuclear plants. This was due to report in June 2011, but the timetable could easily slip, potentially delaying new build and raising costs. The introduction of a new nuclear national policy statement for fast-track planning approval of new plants will also need to take stock of Fukushima, not least in relation to evacuation policy, and is also likely to be delayed to allay public concern.

The greatest regulatory and cost risks are probably for older plants, as in Germany, but the economics of nuclear power are already marginal even for new plant, and public opposition could still impact on planning. On the other hand, a worldwide pause on nuclear could in time ease the acute skills and components shortage for a new UK programme.

Without new nuclear power, Britain’s road to a decarbonised grid by 2030 would be harder and less predictable as ageing fossil and nuclear plant are phased out, though certainly not impossible. But the far more likely outcome is a delayed nuclear programme at higher cost, putting pressure on gas resources in the interim. We may come to regret our dash-for-gas as that market tightens.

But as the implications, if any, for Britain’s longer term energy options are thrashed out, the strongest message should be that low cost energy efficiency needs to be the first port of call – and not the last. If an event thousands of miles away can boost the Green Deal in homes and small businesses and other energy efficiency measures, some good could still come out of the policy uncertainty it threatens.