China’s exports of steel and aluminium nearly doubled in the first half of this year even while the central government mounted a nationwide campaign to cut sales overseas of such energy-intensive products.

... Aluminium, steel and cement have been targeted because of the high use of energy in their production, and in the case of smaller and older mills and smelters, high levels of pollution.

Production of aluminum depends mostly on huge amounts.
of electricity - produced in China mostly by huge smelter-dedicated coal power plants.  Steel production does not use electricity, but smelts the material directly with massive quantities of high purity coal.

Besides the potential for trade friction from rising steel exports in particular, the government is under pressure to increase energy efficiency and reduce greenhouse gas emissions.

Chinese officials on Thursday defended the impact of measures introduced this year to bring the steel and aluminium sectors under control, consisting mainly of taxing such exports ...

“Without these measures, exports of these two products would have gone even higher,” said Wang Shouwen of the commerce ministry’s foreign trade department.

In the seven months to July, China exported 45m tonnes of steel, up from 25m over the same period last year. Aluminium product exports rose by 88 per cent to 1.18m tonnes in the first half of 2007, according to Macquarie Research.

To put 1.18 million tons of export (only a small fraction of Chinese total production), into perspective, this $8 billion project in the United Arab Emirates by Emirates Aluminum will be the largest Aluiminum smelting operation in the world, with its own 2,000 Megawatt power plant (more capacity than Alaska and Hawaii combined), and produce only slightly more, at 1.4 million tons a year.

... Thanks to effective subsidies from local authorities, most aluminium smelters pay $40-$55 a megawatt hour for power, about half of the amount the government says they should pay.

... China can also build new smelters for about half of the cost of foreign competitors, because of cheap land and labour, much of it made available by local governments chasing investment.

Environmental assessments of the kind that can hold up projects for years in the west are also comparatively weak. [That's a comparatively euphamistic way of putting things. -ed.]