The data gives accurate emission figures for over 110 of the country's largest industrial installations. The emissions are calculated by the Irish EPA based on the amount of fuel each installation uses in a year.

The figures reveal that the ESB is by far the country's biggest polluter. In 2005, its plants released almost 12.3 million tonnes of the greenhouse gas into the atmosphere, more than the combined total for all the other Irish companies in the scheme.

This figure does not include Dublin Bay power station, which is run by Synergen, a private company which, although theoretically an independent power provider, is 70% owned by the ESB. It had emissions of around 1.1 million tonnes in 2005.

The second-largest emitter, construction material giant CRH, emitted less than 2.7 million tonnes, with its cement factories at Platin, Co Meath, and Castlemungret, Co Limerick, accounting for the majority of this total.

The Quinn Group, which recently purchased the Irish operations of Bupa Ireland, also features among the country's top emitters, due to its cement factory at Ballyconnell, Co Cavan, which emitted around 1.03 million tonnes.

Beyond the power and construction-material sectors, the country's sole aluminium plant, Aughinish Alumina, which is owned by Swiss multinational Glencore, was the state's largest industrial source of carbon dioxide.

It emitted over 1.1 million tonnes during 2005 but it only had to buy 51,091 tonnes worth of carbon credits. This is an encouraging figure for the plant, which faces serious competitive pressures from rivals based in nonEU countries that do not have trading schemes.

A string of high-profile food and drink firms also feature among the top 20 emitters, including Diageo, Glanbia, the Kerry Group and Dairygold. The most notable of these, however, is Greencore, whose nowclosed sugar factories accounted for over 112,000 tonnes of its emissions.

Last week, the EPA revealed that Ireland's total greenhouse gas emissions for 2005 were almost 70 million tonnes, an increase of 1.9% on 2004.

TOP 20 INDUSTRIAL EMITTERS

RANK COMPANY INDUSTRY CO 2EMISSIONS (tonnes) 1ESB Energy 12.30m 2 CRH Construction 2.65m materials 3 Aughinish Manufacturing 1.16m Alumina 4 Synergen Energy 1.13m 5 Quinn ruction 1.03m materials 6 Edenderry Power Energy 860,660 7Viridian Energy 851,847 8 Lagan Group Construction 492,732 materials 9ConocoPhillips Oil refining 411,369 Whitegate 10Greencore Food and drink 127,141 11 Bord Na Mona Manufacturing 111,179 12 Glanbia Food and drink 106,367 13 Kerry Group Food and drink 105,580 14Dairygold Food and drink 83,404 15Wyeth Pharmaceuticals 79,223 16. Diageo Food and drink 78,794 17 Kinsale Head Gas Exploration 76,841 18 ADM Manufacturing 75,914 19 Gypsum Manufacturing 45,592 Industries 20Carbery Milk Food and drink 41,961