The Bord Gáis energy index was unchanged last month but rose by 27 per cent compared to August 2010. The index stood at 139 last month as a fall in oil and natural gas prices was offset by increases in both coal and electricity prices.

The oil element of the Bord Gáis Energy index is down 2 per cent to 146 after oil prices fell sharply early on in August due to fears of a double-dip recession in the US and Europe.

The natural gas element of the index was down 4 per cent to 173, while the coal element was up 1 per cent to 150.

The electricity element of the index was up 5 per cent to 119, driven by an outage on the Moyle interconnector to the UK and other generator outages which created a need for more expensive generation plants to be scheduled on at peak demand times.

The Bord Gáis energy index has risen sharply over the past few years and is now 57 per cent higher than in August 2009.