Minister for Energy Eamon Ryan has said a "massive investment" will be necessary to virtually replace the national electricity grid to allow for large-scale increases in the generation of renewable energy.
Speaking at a conference in Dublin yesterday of Irish and UK local authorities opposed to nuclear power, Mr Ryan also said he saw the future of the ESB as a "green utility company focusing on energy reduction".
He said the EU target of generating 20 per cent of electricity from renewable sources by 2020 "requires that the investment is massive".
Industry sources put the cost of the upgrade of the Republic's grid at about €1 billion, but in the context of an all-Ireland electricity market the work could cost up to €1.5 billion.
However, Mr Ryan said the European Investment Bank "has doubled lending for energy, and half of that is for renewables".
The Minister said an all-Ireland study of the electricity grid was due to be published "in about five weeks".
An upgraded grid would offer "a whole range of options" for meeting renewable targets. These included wind and biomass energy, as well as imposing obligations on supply companies to generate a proportion of their power from renewable resources.
EirGrid, the operator of the transmission grid in the Republic, said its current capacity for renewable energy was limited by issues of storage and back-up.
However, a spokesman added that agreements had been approved to more than triple the amount of renewable energy from the current 800 megawatts to 2,600 megawatts, with a further 6,000 megawatts "in the queue".
The current situation was that where wind energy was supplied a similar level of back-up generation capacity had to be available to the grid in the event of the wind not blowing.
However, in the future, with different types of renewable energy such as biomass or hydro-electricity, it would be possible to back-up one form of renewable energy with another.
The spokesman said an obvious solution was wind generated electricity being used at a pumped water-storage station. This would give the option of releasing the water to generate electricity as and when desired - in effect storing the energy which had initially been created by wind.
On the future of the ESB, a spokesman for the Minister later explained that the replacement of ageing ESB plants offered scope for the ESB to develop next-generation plants which were more efficient.
The company would also promote the reduction of electricity by firms and households. It was wrong, he said, to suggest that an expanding economy had to constantly use more electricity.
