 An area in which the island operates as a single market is electricity . For much of their existence electricity networks in the Republic of Ireland and Northern Ireland were entirely separate . Both networks were designed and constructed independently post partition . However , as a result of changes over recent years they are now connected with three interlinks and also connected through Great Britain to mainland Europe . The situation in Northern Ireland is complicated by the issue of private companies not supplying Northern Ireland Electricity ( NIE ) with enough power . In the Republic of Ireland , the ESB has failed to modernise its power stations and the availability of power plants has recently averaged only 66 % , one of the worst such rates in Western Europe . EirGrid is building a HVDC transmission line between Ireland and Great Britain with a capacity of 500 MW , about 10 % of Ireland 's peak demand . 
 An area in which the island <a href='uninflect' title='1'><mark>operates</mark></a> as a single market <a href='drop_aux' title='2'><mark>is</mark></a>electricity . For much of their existence electricity networks in the Republic of Ireland and Northern Ireland <a href='uninflect' title='3'><mark>were</mark></a> entirely separate . Both networks <a href='uninflect' title='4'><mark>were</mark></a> designed and constructed independently post partition . However , as a result of changes over recent years they are now connected with three interlinks and also connected through Great Britain to mainland Europe . The situation in Northern Ireland is complicated by the issue of private companies not supplying Northern Ireland Electricity ( NIE ) with enough power . In the Republic of Ireland , the ESB <a href='been_done' title='5'><mark>has</mark></a> failed to modernise its power stations and the availability of power plants <a href='been_done' title='6'><mark>has</mark></a> recently averaged only 66 % , one of the worst such rates in Western Europe . EirGrid is building a HVDC transmission line between Ireland and Great Britain with a capacity of 500 MW , about 10 % of Ireland <a href='null_genetive' title='7'><mark>'s</mark></a>peak demand . 
An area in which da island operate as a single market electricity . For much of their existence electricity networks in the Republic of Ireland and Northern Ireland was entirely separate . Both networks was designed and constructed independently post partition . However , as a result of changes over recent yrs they r now connected w three interlinks and also connected thru Great Britain to mainland Europe . Tdasituation in Northern Ireland is complicated by the issue of private companies not supplying Northern Ireland Electricity ( NIE ) witwidough power . In thdaepublic of Ireland , thedaB done failed to modernise its power stations and the dailability of power plants done recently averaged only 66 % , one of the wdat such rates in Western Europe . EirGrid is building a HVDC transmission line between Ireland and Great Britain with a capacity of 500 MW , bout 10 % of Ireland  peak demand .