Electricity group Viridian, which is ESB's main rival, has increased its profit from the Republic by 64 per cent in the year to March 31st.

The company, which owns the Huntstown plant in north Co Dublin, increased operating profits in the Republic from £14.9 million (€21.7 million) to £24.5 million. Turnover from the Republic was up almost 40 per cent to £203 million.

Viridian's engineering firm, Powerteam, posted turnover of £23 million in the Republic. Work on the ESB's transmission and distribution system made a major contribution to this.

Group turnover at the company, North and South, was up 13 per cent to £943 million, while profit before interest and tax was up 15 per cent to £129 million.

Huntstown One is the company's main asset in the Republic and it was operating 98 per cent of the time during the period under review. The company plans to build a second plant at Huntstown this year, which should be operational in 2007.

The power produced from the first Huntstown plant is sold by supply company Energia, which has 33 per cent of the corporate and industrial market by volume.

Until the new plant is operational, Viridian is able to import power into the Republic via the interconnector with Northern Ireland. It sells electricity and gas to customers in the South.

It said that, until 2007, the Government should concentrate on reducing the ESB's dominance. The Government and the Commission for Energy Regulation should insist that ESB is not allowed to build any new plants in the Republic, it added.

Chief executive Dr Patrick Haren said this included replacing the power station in Aghada in Co Cork.