The spruikers for nuclear energy never say die. Climate change has given them a whole new lease of life. No-emission nuclear power should, they say, be part of Australia’s response to climate change. This week ANSTO chief Ziggy Switkowski said we should aim for 50 nuclear plants by 2050.

It won’t happen until the ALP fundamentally changes its policy on nuclear power. The Coalition is too scarred by their experience in the last election, when John Howard’s flirtation with the debate led to a Labor scare campaign about nuclear reactors in every backyard. Alas, that wasn’t quite how the right-wing media hoped the issue would play out when the Switkowski Report was released in 2006.

Still, hope springs eternal in Liberal hearts. In Tuesday’s joint partyroom meeting, Julie Bishop pointed out that “19 out of 20” G20 countries are pursuing nuclear power. Australia, self-evidently, is the nuclear laggard.

Tomorrow we’ll look at just how much it would cost for Australia to seriously embrace nuclear power as a response to climate change. Today, let’s consider whether the rest of the world is going nuclear in the way that proponents suggest.

First, some bald numbers taken from the German Government-commissioned World Nuclear Industry Status Report from August this year.

There are currently 435 reactors operating worldwide, nine less than in 2002. There are 52 reactors listed as “under construction” (more on that later), down from a peak in 1979 of 233 and 120 in 1987. No new plants were connected anywhere in 2008. The last plant to come online was the Romanian plant Cernavoda-2, which took 24 years to build. Reactors now provide slightly less power worldwide than they did two years ago.

By way of context, the 2 GW of nuclear power connected in 2006-07 was equal to one tenth of the wind power installed globally in 2007. More than double the amount of wind power was installed in the U.S. alone in 2007.

Clearly the nuclear industry is yet to begin recovering from the slump in reactor building worldwide after its peak in the mid-1980s.

That poses two problems for any “nuclear renaissance” and its capacity to provide a legitimate, timely response to climate change.

Firstly, the global “fleet” of reactors is ageing. The average age of plants worldwide is 25 years. The industry maintains that reactors have a lifetime of 40 years (and that of new generations of reactors 60 years), but the average age of the 123 reactors that have been closed across the world has been 22 years. Even assuming a lifetime of 40 years, and assuming all 52 reactors “under construction” proceed, 42 reactors need to be planned and built between now and 2015, and a further 192 built out to 2025, to replace the current nuclear power capacity.

It is highly unlikely that nuclear power will therefore play anything other than a declining role in the provision of the world’s power supply in coming decades.

Then there’s the second, and more problematic issue: nuclear power plants take an extraordinarily long time to build. The 24-year gestation of the Romanian plant was unusual – plants have been built in five years in China, Russia and South Korea. The global average construction period for recent connections in 9 years. This means that even if Australia adopted a crash course of nuclear reactor building, there wouldn’t be a single watt of power available until late next decade at the earliest.

However, reactor construction is subject to costly delays. Some reactors are listed as “under construction” for decades and then simply abandoned. The Generation III Olkiluoto-3 reactor in Finland – the flagship of the nuclear renaissance in Europe – has been under construction for four years. It is currently three years behind schedule, €1.7b over its €3.3b budget and mired in litigation. A new plant under construction in Flamanville in France was halted last year by safety authorities and is scheduled to start in 2012-13, with the cost likely to finish at €4.5b, up from its initial €3.3b cost.

The industry faces other problems. The long downturn in reactor construction and operation has created bottlenecks and skill shortages. For example, there is only one facility in the world, in Japan, that makes the large forgings required for reactor pressure vessels. And the ageing of the western workforce has particular implications for the nuclear industry, which has failed to attract many graduates in recent decades. In France, there are currently more than 1200 positions available within the industry and only 300 nuclear science graduates a year.

There will also continue to be problems accessing capital for the industry. The long lead times for construction and uncertain economics of nuclear power prompted ratings agency Moody’s, in a bluntly-titled release in July, to declare that it would take “a more cautious view toward issuers that are actively pursuing new nuclear power generation. In a post-GFC world of constrained credit, nuclear power looks far riskier than it used to.

“Once operating, nuclear plants are viewed favourably due to their economics and no-carbon emission footprint,” Moody’s said, “but history gives us reason to be concerned about possible balance sheer challenges, the lack of tangible current efforts to defend the existing ratings, and the substantial execution of risk involved in building new nuclear power facilities.”

It’s not radioactivity or scare campaigns that are the nuclear industry’s biggest problem, it’s the maths. The numbers show that for decades to come, it will offer less and less of a solution to climate change, and it simply takes too long and costs too much to develop.

Tomorrow: what it would cost for Australia to go nuclear.