Congestion charges and other economic measures to discourage the use of private cars have been proposed by a Government-funded body responsible for promoting sustainable energy.
Transport now accounts for some 30 per cent of Ireland's primary energy consumption, with private cars responsible for 40 per cent of that figure, according to a new report by the national energy authority, Sustainable Energy Ireland (SEI).
SEI, which produces statistics on national and sectoral energy production, has found transport to be "by far the fastest growing energy end-use sector" in Ireland in the period 1990 to 2001, with average annual growth of 7.1. per cent.
The report looks at the impact of changes in car-buying behaviour that "might arise" from the Vehicle Registration Tax and road tax "rebalancing" measures proposed in the Government's National Climate Change strategy. It says annual carbon dioxide emissions could be reduced by up to 53,000 tonnes if 10 per cent of car buyers were to shift to the "nearest more efficient engine capacity band".
Speaking on the publication of the report today, Mr David Taylor, chief executive of SEI, said that while there had been "substantial growth" in Ireland's energy use over the last decade, trends in transport use were giving the greatest cause for concern.
"The most significant single influence has been the activity level of the economy, with growth in transport energy demand closely coupled to GDP," he said.
"In addition, road travel continues to be the dominant form of transport for passengers in Ireland. As a result, we have seen an increase in the number of cars on the road, an increase in car usage and changes in the structure of the vehicle fleet in Ireland towards larger cars."
The number of private cars in Ireland at the end of 2000 was 1.3 million, compared with fewer than 0.8 million in 1990, according to SEI.
SEI says some 441,000 tonnes of emissions could be avoided if the annual average mileage in private cars was reduced from 20,000km to 18,000km.
Mr Taylor said: "Securing significant emissions reductions in private cars depends more on usage than on purchasing patterns...The challenge is to make this happen by some combination of economic signals, regulatory signals or other motivation to shift to public transport and other choices. Measures that could be introduced to achieve such a reduction could include incentives for teleworking, parking tax and congestion charges. Of course such measures would need to work hand-in-hand with improved public transport options."
By 2001, energy-related carbon dioxide emissions from transport were 120 per cent above 1990 levels and represented 26 per cent of the State's energy related carbon dioxide emissions, according to SEI.
Under the so-called Kyoto Protocol, Ireland is expected to limit annual greenhouse gas emissions to 13 per cent above 1990 levels by the period 2008-2012. According to SEI, transport-related emissions will rise to 180 per cent above 1990 levels by 2010 "unless action is taken".