COAL kills, especially in China. Up to half a million people die prematurely each year as a result of the country’s infamously foul air. Coal, from which China gets roughly four-fifths of its electricity, is the main contributor to that deadly pollution. And since the country’s power-generation may need to double by 2030 to keep pace with economic growth and more affluent lifestyles, the damage from coal will get worse before it gets better. Given that grim picture, it is understandable that the government wants to diversify its energy sources.

Nuclear power is central to this ambition. Even as doubts about it grow in the rest of the world, China has made its expansion a priority. With over two dozen reactors under construction, it wants to more than triple nuclear capacity by 2020. On December 10th China General Nuclear Power (CGN), the country’s biggest builder and operator of nuclear plants, plans to float shares on the Hong Kong stock exchange (see article). Since the government has no need for outside investors to fund its nuclear ambitions, CGN’s partial flotation is a statement of the industry’s political profile.

For most countries nuclear power is a poor option. Big reactors invariably cost more and take longer to build than predicted. As alternative sources of energy have proliferated, the economics of nuclear energy have worsened. The other worry is safety. Just as the memory of the Fukushima disaster in Japan was starting to fade, Europe’s biggest nuclear reactor, in Ukraine, was shut down this week. Such worries increase the risk of politicians cancelling projects, which also raises the costs.

China, however, faces none of these constraints. The government is willing to pay for countless loss-making infrastructure projects, most of its citizens worry more about air pollution than nuclear safety and there is no political opposition waiting to sweep to power and mothball the reactors. Nonetheless, the headlong rush to nuclear power is more dangerous and less necessary than China’s government admits.

One of the main lessons of Fukushima was that politicised, opaque regulation is dangerous. China’s rule-setting apparatus is also unaccountable and murky, and ambitious targets for a risky technology should ring warning bells. Earlier this year, a French nuclear-safety regulator, familiar with the Chinese situation, declared his counterparts to be “overwhelmed”. The regime has form in neglecting safety in the pursuit of techno-hubris: pressure to have the world’s fastest trains lay behind the regulatory failures that caused a catastrophic train crash near Wenzhou in 2011.

Beware bureaucrats setting bold targets

China’s approach to building capacity has added to the risk of an accident. Rather than picking a single proven design for new reactors from an experienced vendor and replicating it widely, the government has decided to “indigenise” Western designs. The advantage of this approach is that China can then patent its innovations and make money out of selling them to the world; the downside is that there are now several competing designs promoted by rival state-owned enterprises, none of which is well tested.

China should slow its nuclear ambitions to a pace its regulators can keep up with, and build its reactors using the best existing technology—which happens to be Western. That need not condemn it to more sooty, coal-fired years. The cost of renewable energy is dropping quickly and its efficiency is rising sharply. Last year, over half of all new power-generation capacity installed in China was hydro, wind or solar. If China wants to accelerate its move away from coal, ramping up those alternatives yet more would be a lot safer.