Ireland’s electricity grid’s inability to accommodate all of the renewable electricity being produced is likely to be a key cause of missing our 2030 Climate Action Plan target.

This is according to analysis from Cornwall Insight, which found that Ireland and Northern Ireland are on course to miss their 2030 power emissions targets by over 20%.

Ireland’s Climate Action Plan 2023 and 2024 set a goal to achieve a 75% reduction in electricity emissions from 2018 to 2030. However, new forecasts from Cornwall Insight show that Ireland is only on track to reduce power emissions by around 50% by the end of the decade.

Similarly, forecasts show that Northern Ireland is also likely to miss its emissions targets by around 20%. The Department for the Economy’s Energy Strategy has set a goal of a 73% reduction from 1990 to 2030, but forecasts indicate that Northern Ireland will likely only reach around a 50% reduction.

This highlights that wasted or unused renewable energy from dispatch downs — when the Transmission System Operator instructs renewable generators to reduce output or shut down entirely — is a key barrier to meeting emissions targets.

Tonnes of carbon dioxide

Emissions are measured by calculating the Million Tonnes of carbon dioxide equivalent (MtCO2eq). Ireland’s emissions are forecast to fall from 10 MtCO2eq in 2018, to 4.8 MtCO2eq in 2030.

The report states that, while this is an impressive reduction, this is a long way off the 3 MtCO2eq emissions ceiling.

Northern Ireland is expected to lower emissions from 5.3 MtCO2eq in 1990 to 2.7 MtCO2eq in 2030 – missing its 1.4 MtCO2eq target. While the level of renewables that could be produced in both regions, if they were operating at full capacity, would reduce emissions if utilised, dispatch down is causing fewer renewables to make it on to the grid.

Dispatch down

Dispatch down occurs for two reasons, firstly grid constraints - when excess energy risks overloading transmission lines, measured by the grid frequency.

Secondly curtailment – which involves challenges in integrating renewable electricity into the transmission system. Unlike fossil fuels, wind energy is not synchronized with the 50 hertz system, therefore the grid imposes limits to ensure frequency levels stay steady as too much wind on the system could cause damage to energy infrastructure.

The most well-known curtailment is the 'System Non-Synchronous Penetration' (SNSP) limit, currently set in Ireland at 75%. This means that even if wind could generate more energy, it cannot be used beyond this limit. In contrast, fossil fuels are easier to keep at the grid's standard frequency and are not subject to curtailment, the report states.

In December 2024, onshore wind faced a 10.9% Dispatch Down rate in Ireland and a substantial 38.4% in Northern Ireland.

The report concluded that increased investment in infrastructure and energy storage to lower dispatch down rates will be critical to meeting emissions and renewables targets and lowering current, and potential costs to the end consumer.