Another author, Julian Allwood, from Cambridge University, has been studying the five most energy-intensive sectors: steel, aluminium, cement, plastics and paper.

BBC: Savings needed to meet future demand for resources

China's leaders now worry about overcapacity in a number of sectors, from steel, cement and aluminium to crushed soyabeans.

ECONOMIST: China��s new five-year plan is at odds with itself

Besides increasing banks' reserve requirements, the central bank and the government have also instructed banks to curb new lending to sectors which officials believe are growing too fast, namely steel, cars, cement, aluminium and property.

ECONOMIST: China's economy

An investment boom from 2001-04, for example, paved the way for the ballooning surplus of 2004-07, according to Jonathan Anderson, formerly of UBS. That investment poured into heavy industries, such as aluminium, machine tools, cement, chemicals and steel.

ECONOMIST: China��s economy

With no need to pay dividends (state firms do not have to make any transfers to central government) and little shareholder pressure to ensure that their investment is cost-effective, Chinese firms went on a capital-spending binge, concentrated in industries such as aluminium, steel, car production and cement.

ECONOMIST: The frugal giant