Come what may, the State-owned company is likely to remain the dominant player in the industry, with at least 60 per cent of generating capacity.

ESB:

Currently led by Mr Pádraig McManus, the company's tariffs will be regulated by the energy regulator, Mr Tom Reeves, for the foreseeable future, while its competitors will be able to set their own rates. The company has already acknowledged it will lose some market share when the market opens up, but believes its prices will withstand competition.

Bord Gáis Éireann:

The company has said it is considering entering the domestic market. It already has a strong presence in the industrial and commercial markets, with about 17 per cent market share.

It lost a competition in 2003 to build a new generating station and since then it has struggled to find a way to generate its own electricity. However it accesses electricity via the auction process, known as the Virtual Independent Power Producer (VIPP) process.

Viridian:

The main competitor to ESB at this point. It already operates a large gas-fired station at Huntstown, in north Co Dublin, and is planning a second station on the same site. It has grabbed significant market share already via its supply arm Energia. With expansion opportunities somewhat limited in Northern Ireland, the company is keen to increase its presence in the Republic. However so far it has shied away from entering the domestic sector of the market.

Direct Energy:

A small Irish company which has been awarded a licence to supply electricity. Headed by some former telecoms executives, the firm has so far stayed quiet about its plans. But according to industry sources, it is looking at opportunities in the small business and domestic sectors.

RWE:

This German company is one of the largest energy groups in Europe. In August it signed a 10-year deal to operate the Tynagh Energy station in Co Galway. The deal involves RWE operating and managing the station and supplying it with gas. RWE will also sell any excess electricity on behalf of Tynagh.

Airtricity:

The wind energy company is prepared to supply householders, but tends to concentrate on small- and medium-sized enterprises. Headed by the former boss of Bord na Móna, Mr Eddie O'Connor, Airtricity currently has three wind farms in operation, two in construction as well as planning permission for over 300 megawatts of power.