We started tracking data from EirGrid’s Smart Grid Dashboard in 2020, and the real-time 15-minute SCADA readings via the dashboard have been immensely helpful in illustrating wind energy’s role in Irish electricity generation.
We have been hoping such detailed data would also be available for all generation types, and we are still (im)patiently waiting. However, a few weeks ago, we received a tip about a data set of recent and detailed unit-level generation published by the Single Electricity Market Operator (SEMO), a joint venture of grid operators in the Republic of Ireland and Northern Ireland.
While the data set excludes generation units smaller than 5MW and doesn’t update on weekends, this newly found data source has greatly improved our visibility of non-wind generation in Ireland.
Take the 7-day period from July 13 to 19 for example (chart below), utility-scale solar met 2% of demand, and maximum output reached 302MW on July 16 at 1pm. To benchmark, based on data from Q1 2023, utility-scale solar capacity in Ireland is around 335MW.
Chart 1: All-island generation and demand, July 13-19, 2023
Source: Green Collective; EirGrid (wind and demand); SEMO (all non-wind generation types)
The solar numbers might seem low, but it’s important to keep in mind that the first utility-scale solar farm was only connected to the grid in 2022. Moreover, the Irish Solar Energy Association estimates around 310MW of distributed solar, including rooftop solar at 59,500 homes and businesses, which contribute to some of the dip in demand during the day.
Outside of solar generation details, we are particularly excited about being able to observe how battery energy storage currently works in Ireland. Total battery energy storage capacity is now almost 750MW. Depending on the unit, they are able to discharge into the grid for between 30 minutes and 2 hours.
Although they are short-duration energy storage, it is still puzzling to see batteries discharging down to zero seemingly randomly throughout the day and re-charging from the grid almost immediately. It’s also worth noting the peak discharge (56.9MW on July 18 at 11am) during the selected period is at only 7.5% of total battery capacity. Since current revenue streams for batteries primarily come from system services (e.g. frequency response), while opportunities in capacity and energy markets are limited, perhaps it’s not so puzzling to see batteries behave in the patterns shown below after all.
Chart 2: Charging and discharging of batteries in Ireland, July 13-19, 2023
Source: Green Collective; SEMO
Batteries can effectively integrate more renewables and alleviate stress during peak demand hours. However, without adequate market access and incentives, batteries do not operate optimally for the benefit of the grid and consumers.
In markets with a large portfolio of battery energy storage such as California, batteries charge during the day and mostly discharge during evening peak hours. The chart below shows how batteries charge and discharge on June 30, when California Independent System Operator (CAISO) witnessed a record 4,216MW of batteries discharging back into the grid at one point.
Chart 3: Charging and discharging of battery energy storage in California Independent System Operator (CAISO), June 30, 2023
Source: Green Collective; CAISO
Comparing to the patterns of batteries observed in California, an example day with battery discharge in Ireland (shown below based on July 18 data) demonstrates the contrast when resources don't have the appropriate incentives to help beat the peak.
Chart 4: Charging and discharging of batteries in Ireland, July 18, 2023
Source: Green Collective; SEMO
As of June 2023, in the Republic of Ireland alone, 2GW of wind and 2.6GW of solar have been contracted. Batteries are going to be critical in accelerating integration of new renewable capacity, meeting peak demand, and reducing renewable curtailment. Ireland already has a sizable energy storage fleet with more in the pipeline, and appropriate access to revenue streams in all markets (capacity, wholesale/energy, and system services) for battery energy storage is of the utmost importance.