The controversial moratorium on new wind farms connecting to the national grid has been lifted by the Commission for Energy Regulation (CER) after almost six months.

In consultation with ESB National Grid, the CER has decided that four key criteria have been addressed and the moratorium can be lifted. This is likely to be welcomed by the wind energy industry which has strenuously opposed the moratorium.

The biggest wind company, Airtricity, has previously warned the moratorium could have disastrous consequences for the wind industry in Ireland and force wind investment towards other markets like Britain, Denmark and the US.

On December 3rd the electricity regulator Mr Tom Reeves took unprecedented emergency measures to curb the amount of wind power on the electricity grid, following major concerns about the "security and stability of the power system."

Acting on advice from ESB National Grid, the regulator halted - with immediate effect - allowing new wind farms to connect to the system.

The advice from the ESB National Grid said the "intermittent" nature of wind power was creating some difficulties.

In the latest direction from Mr Reeves wind energy projects will have to leave the electricity system (known as "constraint") at certain times in order to ensure stability.

Already there is 211 megawatts of wind power connected to the national grid and over 800 megawatts with agreements to do so. In the next few years about 1,500 megawatts of wind power is expected to feed into the national grid. This is the equivalent of several large conventional power stations.

ESB National Grid, which manages the national grid, noted the CER decision to end the moratorium.

"The decision is a key development in that the whole industry has been awaiting it for a significant amount of time. We will be carefully considering the draft decision by the CER and expect to be responding with comments on issues where appropriate," said a statement.

"We take our responsibilities extremely seriously in our role of ensuring that the security and stability of the Irish power system is protected. Major blackouts in other power systems worldwide have underlined the importance of our commitment to this," it added.