Price spike highlights Irish power transmission constraints

LONDON (ICIS)–Low wind generation, a plant outage and transmission constraints in Northern Ireland drove the Irish balancing power market settlement price to a record €3,773.69/MWh on Thursday afternoon.

The dramatic balancing price will raise fresh questions about grid restrictions between Ireland’s two jurisdictions and could renew concerns surrounding potential generation shortfalls in Northern Ireland. Exports to Britain piled further pressure on Northern Ireland’s system margins, with data from transmission system operator (TSO) National Grid showing a net 200MW flow across the Moyle interconnector to the UK market at 13:00 when the price spike occurred.

Thursday’s price occurred as a result of a marginal action offered by one of the units at the Ballylumford gas-fired power station and was generated despite comfortable system margins south of the border in the Republic of Ireland.

The integrated single electricity market (I-SEM) imbalance price is calculated for five-minute periods based on the cost of the marginal 60MW of actions required to keep the system balanced. The half-hourly price is then worked out as an average of the six five-minute periods within that 30 minutes.

The spike highlighted the disproportionate sway held by Northern Ireland in influencing the all-Irish balancing market and will galvanise calls for increased transmission capacity between the island’s jurisdictions.

Projections by Irish TSO EirGrid indicate that the north will face a supply deficit by 2021, with its capacity pipeline failing to keep pace with the decommissioning of old generation units.

The country was dealt a further blow last year, when one third of its thermal units failed to win contracts in the first Irish capacity market auction.

A new 1.5GW interconnector between the north and south has been described by MPs as essential, however its 2021 targeted commissioning is all but impossible.

The new link was initially granted planning permission in the Republic of Ireland in 2016, but has been struck by repeated legal battles and opposition from local interest groups.