Almost one fifth of Ireland's power plants were not in use last month because they are old and unreliable.

A report from the Economic and Social Research Institute (ESRI) has found that unless there is immediate action taken to build more power stations, Ireland faces the threat of power cuts.

The report finds that electricity supply is having difficulty trying to keep up with demand.

All day every day, our use of electricity is surging.

The power plant at Poolbeg is 35 years old and is considered inefficient as it has to frequently shut for maintenance. While new power stations are being built, the authors of the report are concerned on the over reliance on old plants.

Laura Malaguzzi Valeri, ESRI, says their is a need to put contingency plans in place in the event of power cuts.

If traffic lights go out, then motorists do not have clear instructions on how to proceed.

The electricity transmission network is run by EirGrid, who say there is no immediate threat to our power supply. Pat Mangan, Director of Operations at EirGrid says there are plans for two new plants to be built in the Cork area.

We predict that the situation will be adequate until 2011.

The message from the report is that we need to start planning now for the future.

An RTÉ News report broadcast on 18 December 2006. The reporter is David Murphy.