The ESB is planning to ship two massive mobile generators into Ireland in October to prevent potential power blackouts this winter.

As part of its plan to prevent shortfalls in supply, the company has decided to purchase, rather than lease, the two units. One will be located at the ESB station at Aghada, Co Cork, and the other at the former Asahi plant near Killala, Co Mayo. They will come into Ireland in several articulated trucks, said a spokesman.

The company is currently in negotiations to buy the units and the whole deal could cost €25 million, according to electricity industry experts. In a few years when a new power station comes into operation the ESB hopes to sell the units to another electricity company.

After internal discussion and talks with the Commission for Energy Regulation (CER), the company hopes the units, plus power from the Ballylumford generating station near Larne, Co Antrim, will prevent problems this winter.

The two units will produce 100 megawatts of power, while Ballylumford can provide 170 megawatts.

The cost of buying the units will be levied on all customers, although it is not expected to have much impact on overall prices. The ESB has received agreement for the plan from the Department of Communications, Marine & Natural Resources.

While the units will be brought into Ireland in October they will not be in place until January, when demand peaks annually.

The generators, which are fuelled by diesel, will have to meet planning and environmental standards. The units, known as "peaking capacity", are similar to models used in the United States. However, the ESB points out that the units are needed to boost capacity and have nothing to do with grid problems which caused huge blackouts in the US last week.

The generators will be used to meet the peak needs of the whole market in the Republic.

The ESB is purchasing the units, rather than leasing them, because they will be in Ireland for possibly three years and that makes purchasing more cost effective than leasing, said the spokesman.

The units are only to be used at peak times of the day. With all stations working efficiently the Republic is capable of producing over 5,000 megawatts of power at any one time and peak demand in winter is about 4,300 megawatts.

Despite this it is normal to have extra capacity available because maintenance and repair often means some stations are not operational.

The organisation that operates the electricity transmission system, Eirgrid, has said extra capacity must be put in place to meet demand in the next three years, as a new power plant will not be up running until then.

The CER is currently in the middle of a competition for the development of such a plant, with several leading consortiums expressing an interest.