Solar energy in Northern Ireland is facing record levels of dispatch reduction (curtailment) in 2024, according to preliminary data from EirGrid. This phenomenon, which prevents part of the generated electricity from reaching the grid, has doubled compared to 2023, raising concerns within the energy sector about the viability of renewable projects in the region.

EirGrid’s report indicates that while in 2023, 4.8% of solar generation was curtailed, this figure has risen to 11.2% in some months of 2024. This increase in solar dispatch reduction mirrors the structural issues that have long affected wind energy in Northern Ireland.

“The rise in dispatch reduction is due to a lack of grid flexibility and insufficient storage capacity to manage surplus solar generation,” warns the system operator in its preliminary findings.

Factors driving the increase in solar curtailment

Experts have identified three main causes behind the sharp rise in solar energy curtailment in Northern Ireland:

1. Inadequate grid infrastructure

   • Transmission capacity has not expanded at the same pace as renewable generation. This creates bottlenecks in the grid, particularly during periods of high solar output and low electricity demand.

2. Lack of energy storage

   • Large-scale battery storage and other solutions are still insufficient, meaning excess solar energy cannot be stored for later use. Without adequate backup systems, the grid resorts to curtailing solar output instead of storing it.

3. Market regulations and grid constraints

   • Current rules prioritise other energy sources at certain times, leading to a situation where, during high-generation periods, solar energy is the first to be curtailed.

Impact on the energy transition and renewable sector

The increase in solar curtailment poses a major challenge for Northern Ireland’s energy transition, as the country aims for a 100% renewable electricity system by 2035. Despite significant growth in solar capacity, inefficient grid integration risks delaying decarbonisation targets.

Additionally, curtailment undermines the financial viability of solar projects, as curtailed energy cannot be sold on the market. “If developers see that the energy they produce is not being used, they will be less inclined to continue investing in the sector,” warns an energy market analyst.

Moreover, the rise in solar dispatch reduction could extend reliance on fossil fuels during periods of low renewable availability. Without sufficient storage, the system is forced to rely on conventional power generation to meet demand at certain times of the day.

What can be done to solve the problem?

To address the doubling of solar curtailment, the energy sector is proposing several key solutions:

• Investment in grid infrastructure: Enhancing transmission capacity to reduce congestion and enable greater renewable energy uptake.
• Development of large-scale storage: Deploying long-duration battery systems to capture excess solar energy and use it during periods of low demand.
• Reforming electricity market regulations: Adjusting rules to prioritise renewable energy dispatch instead of curtailing it.
• Implementing smart demand management technologies: Encouraging flexible electricity consumption to better match solar energy production peaks.

The increase in solar curtailment in 2024 is a critical challenge for renewable energy development in Northern Ireland. While the country has made significant progress in expanding solar capacity, its infrastructure and policies have yet to fully adapt.

Although viable solutions exist, swift action is required from the government and the energy sector to prevent this trend from becoming a long-term barrier to the energy transition. Northern Ireland has the potential to become a leader in clean energy, but it must overcome these challenges to fully harness its solar capacity.