Ireland and Northern Ireland are expected to miss their goal of generating 80% of electricity from renewable sources by 2030.
Forecasts from Cornwall Insight show that only 70% of the power grid will be renewable by then, with the rest mostly from gas plants.
Despite progress, with the Single Electricity Market having the highest wind generation contribution globally, the 80% target is likely to be achieved by 2032 instead.
Predictions show renewable electricity rising from just over 40% in 2023 to 82% in 2032.
Several problems have caused delays, according to the report.
These include planning issues and a lack of grid connections.
Last year’s Renewable Electricity Support Scheme (RESS) auction saw only three successful onshore wind projects.
The final RESS4 auction before 2030 will have a lower price cap for onshore wind, which may deter bidders.
Wind Energy Ireland has also warned that many wind farms may close before the end of the decade if their planning permissions aren’t extended, causing more delays.
Northern Ireland is creating its own renewable support scheme, with the first auction expected in 2025/26.
However, much of the capacity will come online after 2030.