Monthly Electricity Data. Generation and Availability

Recent Indigenous Electricity Generated

The top half of this panel shows the monthly totals of indigenous electricity generated and exported to the grid in Ireland, broken down by generation source, over the latest twelve months for which data is available. The bottom half of this panel provides a provisional estimate of the CO₂ arising from electricity generation by source, both monthly and as the sum of the latest twelve months. The twelve-month total is a useful running indicator because it acts to average-out summer and winter consumption patterns. Estimates of CO₂ emissions based on monthly data are useful in giving 'fast feedback' and in highlighting seasonal patterns, but they are provisional results, not definitive results. The EPA’s GHG Inventory is the definitive source of CO₂ emissions in Ireland. The emission estimates in this panel act only to supplement and support the EPA’s definitive annual GHG inventory.

Recent Indigenous Electricity Generated - Emissions

The top half of this panel shows two sets of bubble plots. The top line of bubbles shows the summed emissions from different types of generation plants, over the latest twelve months for which data is available. The bottom line of bubbles is similar but shows emissions from the single latest month for which data is available. The bottom half of this panel shows a stacked bar-chart of electricity emissions over the latest twelve months for which data is available, broken down by type of generation plant. Again, estimates of CO₂ emissions based on monthly data are useful in giving 'fast feedback' and in highlighting seasonal patterns, but they are provisional results, not definitive results. The EPA’s GHG Inventory is the definitive source of CO2 emissions in Ireland. The emission estimates in this panel act only to supplement and support the EPA’s definitive annual GHG inventory.

Recent Indigenous Electricity Generated - Breakdown

The top half of this panel shows the percentage-breakdown of indigenous electricity generated over the latest twelve months for which data is available. The bottom half of this panel shows a pair of pie-charts. The left pie-chart shows the percentage breakdown of indigenous electricity generated averaged over the latest twelve months for which data is available. The right pie-chart shows the same breakdown for the single latest month for which data is available.

Recent Indigenous Electricity Generated - Renewable Split

The top half of this panel shows a pair of pie-charts that illustrate the renewable / non-renewable split of indigenous electricity generated in Ireland. The left pie-chart shows the split averaged over the latest twelve months for which data is available. The right pie-chart shows the same split for the single latest month for which data is available. The bottom half of this panel shows a stacked bar-chart of the renewable / non-renewable split over the latest twelve months for which data is available. It is important to note that the renewable / non-renewable split of indigenous electricity generated is not equivalent to the 'Renewable Energy Share of Electricity' (RES-E) indicator used in national and European targets. The RES-E value includes data not captured by monthly surveys (i.e. auto-production and estimates of embedded solar generation) and is based on calculations that average across multiple calendar years (to normalise-out weather effects and granularity in capacity roll-out). The RES-E value for a calendar year typically becomes available in September of the following year, e.g. Ireland's 2021 RES-E value was available in September 2022.

Long-term Trends in Monthly Indigenous Electricity Generated

The top half of this panel shows the monthly total of indigenous electricity generated going back several years. The bar-chart shows the total electricity generated in each month, and the black line shows a twelve-month moving-average of those values. The bar-chart element helps identify seasonal variations (and any short-term “shocks”) in monthly total of electricity generated. The moving average helps identify underlying long-term trends. To improve visual clarity, the latest calendar year is shown in orange, the previous calendar year in yellow, and all preceding years in different shades of blue. The bottom half of this panel shows the “seasonal envelope” of monthly total of indigenous electricity generated over the last five years. This plot allows for easy comparison of indigenous electricity generated in a given month of the current year (orange) with the previous year (yellow) and the preceding years (blue). It also acts to highlight seasonal variations in the monthly total of indigenous electricity generated across the twelve calendar months.

Long-term Trends in Monthly Indigenous Electricity Generated - By Source

This panel lets users choose a particular generation source (e.g. Wind, Natural Gas, Hydro, etc.) from the drop-down menu in the top right corner, to explore monthly indigenous electricity generated from that source over several years. By default, the panel shows monthly electricity generated from Wind. The top half of this panel shows the monthly indigenous electricity generated from the selected source going back several years. The bar-chart shows the electricity generated from the selected source in each month, and the black line shows a twelve-month moving-average of those values. The bar-chart element helps identify seasonal variations (and any short-term “shocks”) in the monthly electricity generated from the selected source. The moving average helps identify underlying long-term trends. To improve visual clarity, the latest calendar year is shown in orange, the previous calendar year in yellow, and all preceding years in different shades of blue. The bottom half of this panel shows the “seasonal envelope” of the monthly indigenous electricity generated from the selected source over the last five years. This plot allows for easy comparison of indigenous electricity generated from the selected source in a given month of the current year (orange) with the previous year (yellow) and the preceding years (blue). It also acts to highlight seasonal variations in the monthly indigenous electricity generated from the selected source across the twelve calendar months.

Long-term Trends in Monthly Indigenous Electricity Generated - Explorer

This panel allows users to select multiple generation sources and explore the resulting sum of monthly indigenous electricity generated from those sources. Users can choose their preferred 'unit-of-supply' and zoom-in on a date-range that best suits their interest.

Changes in Monthly Indigenous Electricity Generated

The top half of this panel shows the percentage change in monthly total of indigenous electricity generated relative to the previous month. For example, the percentage change value for April 2022 is the monthly total of indigenous electricity generated in April 2022, less the monthly total of indigenous electricity generated in March 2022, divided by the monthly total of indigenous electricity generated in March 2022. This plot helps identify the typical month-to-month variance in total indigenous electricity generated, which is typically in the +/-10% range. The bottom half of this panel shows the percentage change in monthly total of indigenous electricity generated relative to same month in the previous year. For example, the percentage change value for April 2022 is the monthly total of indigenous electricity generated in April 2022, less the monthly total of indigenous electricity generated in April 2021, divided by the monthly total of indigenous electricity generated in April 2021. This plot helps identify year-to-year changes in total indigenous electricity generated and underlying long-term trends.

Changes in Monthly Indigenous Electricity Generated - By Source

This panel lets users choose a particular generation source (e.g. Wind, Natural Gas, Hydro, etc.) from the drop-down menu in the top right corner, to explore changes in monthly indigenous electricity generated from that source over several years. By default, the panel shows the changes in monthly electricity generated from Wind. As above, the top half of this panel shows the percentage change in monthly indigenous electricity generated from the selected source relative to the previous month. For example, the percentage change value for Wind in April 2022 is the monthly total of indigenous electricity generated from Wind in April 2022, less the monthly total of indigenous electricity generated from Wind in March 2022, divided by the monthly total of indigenous electricity generated from Wind in March 2022. This plot helps identify the typical month-to-month variance in the indigenous electricity generated from the selected source. The bottom half of this panel shows the percentage change in monthly indigenous electricity generated from the selected source relative to the same month in the previous year. For example, the percentage change value for Wind in April 2022 is the monthly total of indigenous electricity generated from Wind in April 2022, less the monthly total of indigenous electricity generated from Wind in April 2021, divided by the monthly total of indigenous electricity generated from Wind in April 2021. This plot helps identify year-to-year changes in the indigenous electricity generated from the selected source.

Electricity Available to the Grid

The top half of this panel shows the monthly total of “grid available” electricity going back several years. Grid available electricity is defined as the sum of three components:

• Indigenous Electricity Generation (as explored in the above data panels)
• Net Imports through Interconnections (i.e. imported electricity, less exported electricity)
• Net Pumped Storage (i.e. electricity output from pumped storage, less electricity input to pumped storage)

The bar-chart shows the total grid available electricity in each month, and the black line shows a twelve-month moving-average of those values. The bar-chart element helps identify seasonal variations (and any short-term “shocks”) in monthly grid available electricity. The moving average helps identify underlying long-term trends. To improve visual clarity, the latest calendar year is shown in orange, the previous calendar year in yellow, and all preceding years in different shades of blue. The bottom half of this panel shows the “seasonal envelope” of monthly grid available electricity over the last five years. This plot allows for easy comparison of the grid available electricity in a given month of the current year (orange) with the previous year (yellow) and the preceding years (blue). It also acts to highlight seasonal variations in the grid available electricity across the twelve calendar months.

Electricity Available to the Grid - Breakdown

This panel shows the monthly totals of the three components of “grid available” electricity going back several years. Indigenous electricity generation (blue) is by far the largest component, followed by net imports from interconnections (orange), and net pumped storage (red). The following data panel provides additional details on net imports from interconnections, and net pumped storage.

Net imports from Interconnections and Net Pumped Storage

The top half of this panel shows the monthly import (dark orange) and export (light orange) of electricity to-and-from Ireland through international interconnections. The resulting 'net import 'of electricity through the interconnections is shown by the black line. A positive net import value for a given month means that Ireland imported more electricity than it exported that month. The top half of this panel shows the monthly input (light red) and output (dark red) of electricity to-and-from Ireland's grid-connected pumped storage infrastructure. Input corresponds to the use of electricity needed to pump water uphill, while output corresponds to the electricity generated from releasing the water downhill. The resulting 'net pumped storage 'of electricity is shown by the black line. Net pumped storage is always negative (or zero), because output cannot exceed the input.

Monthly Electricity Data - Customizable Download

This panel allows users to download the data underlying all the data panels on this webpage. Users can select their preferred 'unit of supply' (including multiple units) and zoom-in on a date-range that best suits their interest. The table will then show the corresponding monthly totals for each of the indigenous electricity generated sources, as well as the other "grid available" components. Users can download the table as a CSV or XLSX crosstab by clicking on the small “Download” icon (rectangle with an arrow pointing down) at the bottom right of the panel. Again, please note that while CO₂ emission estimates based on provisional monthly are useful in giving “fast feedback”, and in highlighting seasonal patterns, they are not definitive results. The EPA’s GHG is the definitive source of CO₂ emissions for Ireland. Due to a range of technical factors. the sum of SEAI’s provisional CO₂ emission estimates from January to December will not exactly equal the annual total of a given year.

Interacting with the Monthly Data Panels

In many of the data panels below, users can interact and customise the data views to suit their needs. Users can choose the unit-of-measure for the plot – ktoe (kilotonnes of oil equivalent), GWh (gigawatt hours), or TJ (terajoules). In some panels users can use a “slider” to select and zoom-in on a particular date-range of interest. In many cases, hovering the cursor over an element of a plot in a panel will invoke a tool tip that provides numerical detail of the underlying element. Users can download a panel as an image file (PNG), or its underlying data (CSV or XLSX crosstab) by clicking on the small “Download” icon (rectangle with an arrow pointing down) at the bottom right of the panel. Alternatively, users can customise and download the underlying data for all panels on this page, by using the Monthly Electricity Data - Customizable Download panel. Due to the detailed nature of the plots and tables, and how tool tips are optimised for a mouse, rather than a finger, this page is best viewed on a monitor rather than a smartphone.

Role and Value of Monthly Data

Provisional monthly data is not as robust as the definitive annual data published in SEAI’s Energy Balance or the EPA’s Greenhouse Gas Emission (GHG) Inventory. The surveys used to collect annual data are more inclusive and more exhaustive than those used to collect monthly data, and the detailed cross-agency reconciliation applied to annual data is not possible for monthly data. However, provisional monthly data has two advantages over annual data – it is available more quickly, and it allows seasonal variations (or market shocks, such as Covid-19 impacts) to be identified. The rapid provision of energy and emission data to Irish policymakers, journalists, researchers, and public is particularly important, given the relatively short 5-year windows of Ireland’s carbon budgets, and the significant emission reductions that need to be achieved within them. While CO₂ emission estimates based on provisional monthly are useful in giving “fast feedback”, and in highlighting seasonal patterns, they are not definitive results. The EPA’s GHG is the definitive source of CO₂ emissions for Ireland. Due to a range of technical factors. the sum of SEAI’s provisional CO₂ emission estimates from January to December will not exactly equal the annual total of a given year.

Data Provenance and Conversions

Monthly data on indigenous electricity generation, imports & exports across interconnections, and pumped storage is collected by SEAI from Eirgrid, our national electricity grid operator, and from other data suppliers, for statistical purposes, under the European Energy Statistics Regulation of 2008 (no.1099). Electricity data is collected and published by SEAI on a one-month retrospective basis. For example, data for March (i.e. covering electricity generation between 01-MAR and 31-MAR) is typically published on 30-APR. The exact date of publication is dictated by the timeliness of accurate submissions by energy suppliers. SEAI would like to thank all energy suppliers that participate in its statistical surveys.

Monthly electricity data is collected in units of MWh, with SEAI making the conversion to ktoe, TJ, and GWh. SEAI makes simple provisional estimates of the CO2 emissions from monthly indigenous generation by applying weighted effective emission factors. The effective emission factors applied to the monthly indigenous generation values are based on definitive annual emission data gathered by the EPA, under the EU Emission Trading System, and SEAI’s Energy Balance. Where these annual effective emission factors lag monthly reporting, the most recent annual data is used. The EPA’s GHG Inventory is the definitive source of CO2 emissions for Ireland. The energy emission estimates on this page, based on provisional monthly energy data from SEAI, act only to supplement and support the EPA’s definitive annual GHG inventory. SEAI’s provisional monthly emission estimates will ultimately be overwritten by the EPA’s definitive GHG inventory.

Note that the following electricity generation sources generally use a blend of renewable and non-renewable fuel inputs:

• Peat & BM (Biomass)
• Wastes
• Other

The exact blend of renewable and non-renewable fuels for each month is not available to SEAI. To improve the accuracy of its CO2 emissions, and its estimate of %-renewable indigenous generation, SEAI applies renewable / non-renewable “splits” to the monthly electricity generation from these sources. Theses splits are based on definitive annual data collected from SEAI’s Energy Balance. Where these annual splits lag monthly reporting, the most recent annual data is used.