Note: This article was updated July 17 2024 to incorporate adjusted solar SCADA data from Eirgrid.

Summary

Electricity from renewable generation and discharging storage met 29.5% of Ireland’s (all-island) electricity demand during May 2024:

• 20.5% wind
• 1% hydro
• 3.6% biomass/waste
• 3.3% solar
• 0.9% discharging pumped storage
• <0.1% discharging batteries

Despite record solar generation, this was renewables' lowest monthly share of demand so far in 2024; during the first four months of 2024, renewable generation was equivalent to 45.1% of electricity demand. Unusually low wind generation contributed heavily to this drop.

Exhibit 1: All-island demand met by different sources, May 2024

New solar records

May 2024 was the strongest month yet for solar generation in Ireland, with 105.5GWh equivalent to 3.3% of the month's all-island demand - both figures records. This is the second month in a row that Irish solar has set new records.

A number of new records were set in Irish solar on and around the weekend of May 11-12:

• peak solar output: 631MW, on Friday May 10
• highest solar generation in one day: 5.7GWh, on Friday May 10
• total percentage of demand met by solar power in one day: 5.5%, on Friday May 10
• peak percentage of demand being met by solar power at any instant in time: 14.5%, on Saturday May 11

County Meath continues to be the leader in Irish solar generation, with 52% of the month's solar generation taking place there. However, we see below that Rosspile, in County Wexford, had the second-largest generation of all Irish solar farms during the strong solar weekend of May 9-11.

Exhibit 2: Solar generation by farm, May 9-11 2024

Exhibit 3: Solar generation by county, May 2024

Low wind generation

Wind generation generally dips during the summer but, even so, winds in May 2024 were unusually low:

• 665MWh was the lowest amount of electricity generated from wind since 2019
• this was equivalent to 20.5% of the month's all-island demand, the lowest May percentage since 2017

Exhibit 4: All-island May wind generation, 2015-2024

Carbon Emissions

We estimate that for each KWh of electricity generated in May the Irish grid emitted between between 109g and 436g of CO2, for an average of 281gCO2/kWh.

While this is the highest monthly grid carbon intensity so far this year, it is significantly lower than May 2023's average of 332gCO2/kWh. This large year-on-year drop occurred despite the low winds discussed above and we can attribute this development to the following factors:

• the elimination of peat generation
• increased solar generation
• ongoing reliance on imports

Exhibit 5: All-island grid-carbon intensity, May 2024