We buy energy well in advance to protect customers from volatile price movements.

Such large facilities are susceptible to high capital costs, high operation and maintenance costs, the uncertain and volatile price of crude oil, and environmental concerns.

Manufacturers said that an increased reliance on imports of liquefied natural gas would result in more volatile prices.

Before prices collapsed last year, oil markets had been becalmed, marking a lean period for hedge funds that make their biggest profits from volatile prices.

Core inflation, which excludes items that are subject to volatile prices, stood at 0.7 per cent.