IN Brief:
- Grid constraints prevented approximately 15% of available Irish wind generation from being used during the first half of 2026.
- The curtailed electricity was equivalent to the annual consumption of around 667,000 homes.
- Additional networks, storage, interconnection, and flexible demand will be required to reduce dispatch down volumes.
Wind Energy Ireland has calculated that grid limitations prevented approximately 15% of the country’s available wind generation from reaching electricity users during the first half of 2026.
The lost output was equivalent to the annual electricity consumption of around 667,000 homes. Wind still provided more than one third of Ireland’s electricity across the six month period, but generation capacity is expanding faster than the system’s ability to transport and absorb all available production.
June set a new monthly record for Irish wind generation, with output reaching 985GWh, approximately 5% higher than in June 2025. Wind supplied 31% of national electricity demand during the month, while solar contributed a further 7%.
Wholesale electricity prices averaged €135.52/MWh in June, around 6% lower than a year earlier. Days with the highest wind generation recorded an average price of €111.20/MWh, compared with €175.83/MWh on the lowest wind days, reflecting the effect of high volumes of low marginal cost generation.
Dispatch down occurs when renewable generation that is available to produce electricity is instructed to reduce output. Local transmission constraints, system wide security limits, reserve needs, voltage conditions, minimum conventional generation requirements, and other operational restrictions can all contribute.
The 15% figure is based on EirGrid dispatch down and supervisory control and data acquisition information. It covers energy that could have been generated but was not accepted by the power system under the network and operating conditions prevailing at the time.
Generation growth exposes network limits
Ireland’s strongest wind resource is concentrated in regions that are often distant from the largest demand centres. New generating projects can be completed more quickly than major transmission reinforcement, particularly where new lines and substations require planning approval, land access, environmental assessment, and extensive public consultation.
When network capacity between a generation region and demand is fully used, additional wind output cannot simply be transferred elsewhere. Curtailment may therefore occur even while another part of the system imports power or retains conventional generation for stability, reserve, voltage support, or locational requirements.
Reducing dispatch down will require several forms of infrastructure rather than a single intervention. New transmission capacity can remove structural bottlenecks, while distribution upgrades can enable more local electrification and flexible demand.
Interconnectors provide another route for exports during periods of surplus, although neighbouring markets can experience similar weather at the same time. Their contribution also depends on domestic capacity between the wind producing region and the interconnector landing point.
Storage can absorb excess production and return it later, with the required duration determined by the pattern of the constraint. Short duration batteries can manage rapid balancing and intraday variation, while longer duration technologies can shift larger energy volumes across extended periods of high wind or low demand.
Energy Dome’s planned 23MW/200MWh carbon dioxide battery in County Offaly has secured land, planning consent, grid access, and a ten year capacity contract. Its eight hour duration addresses a different operating requirement from shorter lithium ion systems.
Flexible demand can also increase consumption when renewable output is abundant. Industrial processes, data centres, electrolysers, electric heating, vehicle charging, and other controllable loads can alter demand where commercial arrangements and operational constraints allow.
Reliable forecasting, communications, metering, and automation are essential because flexible load must respond predictably and in the correct location. Increasing demand behind the wrong network constraint can intensify congestion rather than relieve it.
System stability remains another limit as wind and solar connect through power electronic converters. These systems do not inherently provide the same rotating inertia, fault current, and voltage characteristics as synchronous generators.
Grid forming inverters, synchronous condensers, enhanced protection, and revised operating procedures can raise the amount of inverter based generation that the system accommodates securely. Ireland has already operated at high instantaneous levels of nonsynchronous renewable generation, making it an important practical test environment for these measures.
Persistent curtailment also alters project economics. Renewable generators lose production, constraint costs can rise, and the system forgoes electricity that could otherwise displace more expensive generation. High dispatch down volumes may eventually strengthen the case for more explicit locational signals in connections and market design.
Ireland has sufficient renewable energy during favourable conditions, but the ability to transport, store, and use that electricity is not keeping pace. Wind capacity, transmission, system services, flexible demand, interconnection, and storage now need to develop as a coordinated power system rather than as separate investment programmes.
