Carbon-dioxide emissions from the Republic's power stations increased from 12 million tonnes in 1993 to 13.8 million last year, but the ESB says that eliminating them is "currently not a practicable option".
In its first environmental review, published this week, the board maintains that emissions of CO 2, the principal "greenhouse gas" blamed for causing climate change, have not been rising as fast as the rate of growth in electricity demand.
Because of improved energy efficiency and greater use of natural gas, it says average annual CO 2 emissions from its power stations are 800,000 tonnes below the 1990 level, compared to what they would have been if these improvements had not been made.
Despite increased power generation to meet the growing demand for electricity, the report notes that the ESB has successfully met its obligations under EU directives and the Oslo and Sofia protocols to reduce emissions of sulphur and nitrogen dioxides.
At the huge Moneypoint coalfired plant on the Shannon Estuary, £8 million spent on new burners reduced NO x emissions from 29.6 million tonnes in 1993 to 23.9 million tonnes last year while the use of coal with a lower sulphur content helped to reduce SO 2 emissions.
Ash from Moneypoint, which burns two million tonnes of coal annually, is now being sold for use as a raw materials substitute in the cement industry, instead of being consigned to landfill sites.
Sales of ash have averaged between 55,000 and 70,000 tonnes in recent years.
It is clear from the report, however, that Moneypoint continues to be a major polluter of the atmosphere. Last year its emissions of SO 2, one of the principal causes of acid rain, amounted to 41.5 million tonnes, while CO 2 emissions were almost six million tonnes.
Though acid rain "has not proven to be a problem in Ireland", the ESB anticipates having to invest additional funds in pollution control because of "further reductions in allowable national emissions" as part of Ireland's contribution to solving this European problem.
The report notes that the first phase of a 470-megawatt extension of the Poolbeg power station in Dublin has already been constructed, using "combined cycle" gas turbines. The project would achieve an overall thermal efficiency of more than 50 per cent when completed. Referring to greenhouse gases such as CO 2, it says any agreement reached at the Kyoto summit on climate change would have "important implications" for Ireland because of the direct relationship between economic growth and rising energy consumption.
Electricity sales reached a record 15,700 million units in 1996, with a maximum demand of 3,180 megawatts. But the ESB says it has sought to reduce the rate of growth through energy efficiency and conservation while "seeking to avoid constraints on economic development".
The board is also involved in promoting the use of renewable energy technologies, such as wind power, waste-to-energy incineration, combined heat and power schemes and small hydro projects, which together should generate over 200 megawatts.
It has also established a corporate safety and environment unit, under the direction of Dr Owen Wilson, to oversee the implementation of its environmental programme, which includes annual "self-audits" of each of its power stations as well as of the distribution network.
Measures are being taken to reduce energy losses in the network by upgrading power lines at a cost of £250 million over five years. Routes for new lines are chosen by independent environmental consultants to minimise their impact on the landscape and natural habitats.
Referring to the controversy over the possible health effects of low-frequency electromagnetic radiation, the board says the two most recent US reports on this issue "did not support" such an association. But it intends to keep abreast of further research in this area.
Since 1990, the ESB says, it was only responsible for one environmental incident when the discharge of sodium hypochlorite from its Lanesboro power station caused a fish kill on the Shannon in May 1996. Steps were taken to ensure that this would not happen again.
