This help page provides step-by-step guidance on how to model additional energy reduction and decarbonisation measures using the ‘Model’ worksheet in the gap-to-target (GTT) spreadsheet model.
For a description of the GTT, including information on how to access it and an explanation of the different charts, see the help page GTT model - overview.
- Use the dropdown menu in row 11 in table M1 in the ‘Model’ worksheet to choose the energy units used in the model, i.e. kWh, MWh or GWh.
- All energy values displayed in the GTT are expressed in the unit that you choose.
- All energy values entered by you for decarbonisation initiatives must also be expressed in the chosen unit.
- Note that the CO2 unit used in the model changes automatically to align with the magnitude of the energy unit that you select.
By default the GTT uses the public sector GHG emissions target methodology, as implemented via SEAI's M&R system. If you wish, you can change the basis for the target calculation shown in the GTT using rows 12-14 in table M1 in the ‘Model’ worksheet:
- To use the default approach, choose ‘CAP 2021 (-51.0% fossil CO2 & electricity CO2 as per elec supply decarbonisation)’ from the dropdown menu in row 12.
- To define your own target, choose ‘Other (user-defined)’ in row 12 and complete rows 13 & 14:
- Row 13: enter the total % reduction in fossil CO2 targeted for the period between your GHG baseline and 2030.
- Row 14: enter the total % reduction in electricity CO2 targeted for the period between your GHG baseline and 2030, including electricity supply-side gains.
The targets configured by you are displayed in table M2 and throughout the GTT model. Note that the target(s) configured in the GTT are for modelling purposes only. Your organisation's actual GHG emissions reduction targets are as calculated by the M&R system.
- To model the impact of additional decarbonisation initiatives and/or other changes to your future energy use, you must first select ‘yes’ from the dropdown menu in row 15 in table M1 in the ‘Model’ worksheet.
- You can then choose to configure how your scenario will be modelled using rows 16-18:
- Row 16: enter a name for your scenario - the charts in the GTT will be labelled with the name you choose.
- Row 17: choose whether you want to count the impact of the additional energy reduction measures and decarbonisation initiatives that you model from the year in which the measure is implemented for from the first year after the measure is implemented.
- Row 18: choose whether you want to include the impact of anticipated changes to biofuel blend rates in standard road diesel and petrol (see supply-side decarbonisation below).
Supply-side decarbonisation refers to reductions in the CO2 intensity of certain energy supplies, i.e. the expectation that the amount of CO2 emitted per unit of energy consumption for certain energy types trends downwards over time.
Ireland’s electricity network will decarbonise significantly between 2016-18 and 2030, as fossil fuels are phased out of power generation, i.e. using the same amount of electricity in 2030 as your organisation did in 2016-18 (average) could produce significantly lower emissions. This supply-side decarbonisation is accounted for in all future emissions pathways shown in the GTT. This is calculated using SEAI forecasts for the CO2 emissions intensity of Ireland's electricity system out to 2050. SEAI updates these forecasts from time to time.
The CO2 intensity of Ireland’s electricity system over time (actual & forecast) is shown in the worksheet ‘CO2 intensity electricity’.
¶ Biofuel blending in diesel and petrol
Relatively small but increasing quantities of biofuels are blended into supplies of standard road diesel and petrol each year. This has the effect of reducing the CO2 emissions from each litre of diesel and petrol used. It is anticipated that biofuel blend rates will increase over the period to 2030, resulting in additional supply-side decarbonisation for diesel and petrol. By default, this supply-side decarbonisation is accounted for in all future emissions pathways shown in the GTT. This is calculated using forecasts for future biofuel blend rates out to 2030. You can exclude this supply-side decarbonisation from your emissions pathways using the dropdown menu in row 18 in table M1.
¶ Model energy reduction measures and decarbonisation initiatives
Use table M3 to include specific energy reduction and decarbonisation initiatives in your modelled 2030 scenario. Note that you must first select ‘yes’ from the dropdown menu in row 15 in table M1 - this ‘switches on’ the 2030 modelled scenario.
- You can model the impact of energy reduction measures, other energy decarbonisation initiatives that do not necessarily reduce consumption (e.g. switching to renewable energy) and of increases in consumption (e.g. arising from adding a new building to your portfolio).
- The GTT calculates the impact of these additional actions on your organisation's gap to the two GHG emissions targets and to the energy efficiency target. It also compares the modelled energy consumption with a 1.9% per annum energy reduction trajectory.
- Use a separate green row in table M4 for each initiative. An initiative could be a standalone project at one facility (e.g. replacing a specific gas boiler with a heat pump) or it could be portfolio of projects (e.g. replacing 30 boilers with heat pumps).
- Different inputs are required (green cells) for different types of initiatives. The headings are shown in rows 136-137.
- Column C is for specifying the name of the initiative (optional).
- Column D indicates whether you have entered sufficient data for the initiative (‘complete’ or ‘incomplete’), or whether you have excluded a previously entered initiative from the scenario (‘excluded’). Column D must show ‘complete’ for the initiative to be counted in the modelled scenario.
- Column E allows you to exclude a previously entered initiative from the scenario, i.e. to easily ‘switch off’ the impact of a particular initiative. The default is that the initiative is included in the modelled scenario (cell value = ‘yes’).
- Column F is used to specify the implementation year for the initiative. The impact of the initiative on your energy and emissions is calculated from this year onwards or from the year after this year onwards, depending on your selection in row 17 (see ‘Model a future scenario’ above).
- Columns G-I are for specifying the type and quantity of energy consumption that will be displaced by the proposed initiative.
- Column J shows the % of existing energy consumption that will be displaced by the initiative. It will warn in red if you try to displace more than 100% of existing consumption.
- Columns K-S are for technical details of the initiative. Different details are required for different types of initiative.
- Columns T-V are for the additional energy consumption that will arise because of the initiative (if any).
- The model includes simple calculations for several types of initiative, each of which is described below.
- Use rows 138-189 to model the impact of energy efficiency gains from retrofits & other decreases in consumption.
- This is for modelling initiatives that result in absolute reductions in energy consumption, as opposed to fuel switching or electrification. Examples include upgrades to building fabric, efficiency gains from improving control of heating systems, LED lighting retrofits, etc. You can also use this option to model the closure of an energy-using facility.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. natural gas, gasoil.
- Column I: enter the amount of existing final energy consumption that will be displaced by the initiative, in the unit shown in cell I136.
- See ‘Modelling tips’ below for guidance on modelling an initiative that includes both fabric upgrade(s) and heat pump(s).
- Use rows 190-241 to model the impact of switching from fossil-fuel boilers to heat pumps.
- This is for modelling ‘fuel switching’ from fossil boilers to heat pumps and does not account for energy demand reduction arising from fabric upgrades that may be required as part of heat pump projects.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. natural gas, gasoil.
- Column I: enter the amount of existing final energy consumption that will be displaced by the heat pump, in the unit shown in cell I136.
- Columns K & L: specify the efficiency of the existing fossil-fuel boiler(s) that is/are being replaced. You can do this by either:
- Selecting ‘legacy’ or ‘recent’ from the dropdown in column K, in which case the model assumes that the efficiency is 70% (legacy) or 90% (recent).
- Entering the efficiency of the existing boiler(s) in column L.
- Column N: specify the seasonal coefficient of performance (SCOP) for the new heat pump(s). The SCOP is an engineering estimate of the ratio of the amount of heat delivered by a heat pump to the amount of electricity consumed in a year. In Ireland, SCOPs are typically between 2.5 and 4.0. The model uses a default value of 2.7, but this can be overwritten if you have a more appropriate value.
- See ‘Modelling tips’ below for guidance on modelling an initiative that includes both fabric upgrade(s) and heat pump(s).
- Use rows 242-293 to model the impact of switching from fossil-fuel boilers to biomass boilers.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. natural gas, gasoil.
- Column I: enter the amount of existing final energy consumption that will be displaced by the biomass boiler, in the unit shown in cell I136.
- Columns K & L: specify the efficiency of the existing fossil-fuel boiler(s) that is/are being replaced. You can do this by either:
- Selecting ‘legacy’ or ‘recent’ from the dropdown in column K, in which case the model assumes that the efficiency is 70% (legacy) or 90% (recent).
- Entering the efficiency of the existing boiler(s) in column L.
- Column M: specify the efficiency of the new biomass boiler(s). The model uses a default value of 90%, but this can be overwritten if you have a more appropriate value.
- Use rows 294-345 to model the impact of other thermal (heat) fuel switching, e.g. changing from an oil boiler to a bioLPG boiler. You can use this initiative for fuel-switching to bioLPG, biomass, biomethane, district heating, fuel oil, gasoil (thermal), kerosene, LPG & natural gas.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. natural gas, gasoil.
- Column I: enter the amount of existing final energy consumption that will be displaced, in the unit shown in cell I136.
- Column O: specify the ratio of new energy use to displaced fuel use, e.g. if you wish to model a fuel switch from heating oil to bioLPG as part of a boiler upgrade that will result in a 10% reduction in energy use (in kWh), then you would enter 90%. The model uses a default value of 100%.
- Column T: select the new energy type that will displace the existing consumption.
- Use rows 346-397 to model the impact of switching from fossil transport fuel to electric vehicles.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. diesel (blend).
- Column I: enter the amount of existing final energy consumption that will be displaced, in the unit shown in cell I136.
- Column P: specify the ratio of electricity use to displaced fossil-fuel use. The model uses a default value of 40%, but this can be overwritten if you have a more appropriate value.
- Use rows 398-449 to model the impact of switching from fossil transport fuel to HVO or other high-blend biofuels.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. diesel (blend).
- Column I: enter the amount of existing final energy consumption that will be displaced, in the unit shown in cell I136.
- Column Q: specify the biofuel blend rate in the new energy type, i.e. % of new fuel that is biofuel (by volume).
- Use rows 450-501 to model the impact of switching from fossil transport fuel to compressed natural gas (CNG).
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column G: select the existing energy type for which consumption will be displaced, e.g. diesel (blend).
- Column I: enter the amount of existing final energy consumption that will be displaced, in the unit shown in cell I136.
- Column S: specify the ratio of CNG consumption to the consumption of fossil fuel that will be displaced.
- Use rows 502-553 to model the impact of switching from grid electricity to onsite renewable electricity (RE), e.g. onsite solar PV, onsite wind.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column I: enter the amount of existing grid electricity consumption that will be displaced, in the unit shown in cell I136.
- Column T: select the type of onsite renewable electricity generation that will displace the existing consumption.
- Use rows 554-605 to model the impact of increases in energy consumption.
- This is for accounting for changes to your organisation that will give rise to increased in consumption between now and 2030, e.g. arising from expansions, new facilities or growth in activity.
- You should model an initiative of this type as follows:
- Column F: enter the year in which the initiative will be implemented.
- Column T: select the energy type for which there will be additional consumption.
- Column V: enter the amount of additional final energy consumption, in the unit shown in cell I136.
- If you wish to model an initiative that will be implemented over several years, then you should use separate rows to model different phases of the initiative. For example, for a multi-phase energy efficiency renovation programme across a portfolio of buildings, you would model the anticipated reductions for each phase on separate rows (e.g. X MWh reduction in 2025, another Y MWh reduction in 2026 & another Z MWh reduction in 2027).
- If you wish to model an initiative that will result in the displacement of different energy types, then you should use separate rows to model different elements of the initiative. For example, for a renovation programme across a portfolio of buildings that will reduce consumption of electricity, oil and gas, you would model the anticipated reductions for each energy type on a separate row.
- If you wish to model an initiative that includes both fabric upgrade(s) and heat pump(s), then you should adopt the following approach:
- Use the functionality for modelling energy efficiency gains from retrofits described above to back-out the fossil fuel consumption that will be displaced (avoided) arising from the fabric upgrade.
- Use the functionality for modelling heat pumps described above to replace the fossil fuel consumption that would hypothetically remain after the fabric upgrade with a heat pump.
- Importantly the sum of the values entered across both rows in column I must equal the total amount of fossil fuel displaced by the initiative.
- Row 41 in table M2 will show an error message (in red) if you have configured your decarbonisation initiatives in such a way that they will displace more consumption of any energy type than you are currently using, e.g. if you consumed 100 units of natural gas in your reporting year and you configured multiple decarbonisation initiatives that will displace 120 units of gas between then and 2030, an error message will be generated. The message will indicate which energy type(s) triggered the error.
- You can review summary results of your modelled scenario in tables M2 and M3 (descriptions below).
- You can review various charts and tables showing the results of your modelled 2030 scenario by exploring the blue worksheet tabs.
- Table M1 is for configuring the a 2030 scenario for analysis.
- The configuration options are described above on this page under the following headings:
- ‘Choose your units’
- ‘Configure basis for 2030 emissions targets’
- ‘Configure a 2030 scenario’
- ‘Supply-side decarbonisation’
- Table M2 is for reviewing your emissions targets, the reductions required to reach the targets, your gap to target and the impact of your modelled scenario.
- This table cannot be edited.
- The targets are highlighted in pink.
- Row 41 shows an error message (in red) if you have configured your decarbonisation initiatives in such a way that they will displace more consumption of any energy type than you are currently using, e.g. if you consumed 100 units of natural gas in your reporting year and you configured multiple decarbonisation initiatives that will displace 120 units of gas between then and 2030, an error message will be generated. The message will indicate which energy type(s) triggered the error.
- Table M3 summarises your organisation’s energy and emissions pathways to 2030.
- This table cannot be edited.
- Rows 44-59 show your actual consumption and emissions data for your organisation since your energy efficiency baseline.
- Final energy consumption (rows 44-48)
- Primary energy (rows 49-53)
- CO2 emissions (rows 54-59)
- Rows 60-75 show your future consumption and emissions on a business-as-usual (BAU) basis since your organisation's energy efficiency baseline. BAU assumes that: (1) your final energy consumption remains constant between the reporting year and 2030; (2) your activity levels remain constant between the reporting year and 2030; (3) the primary energy conversion factor for grid electricity changes in line with SEAI forecasts to 2030. These forecasts are shown in row 125 and incorporate several variables and assumptions, and are refined periodically. BAU data is presented for:
- Final energy consumption (rows 60-64)
- Primary energy (rows 65-69)
- CO2 emissions (rows 70-75)
- Rows 76-91 show your future consumption and emissions for a modelled scenario that incorporates additional energy reduction and decarbonisation measures with (modelled) implementation years over the period to 2030. This modelled scenario must be switched on (row 15) and the initiatives must be specified using table M4. The scenario accounts for changes to emissions arising from these initiatives as well as those already made and those arising from anticipated supply-side changes (electricity & biofuels). Scenario data is presented for:
- Final energy consumption (rows 76-80)
- Primary energy (rows 81-85)
- CO2 emissions (rows 86-91)
- Rows 92-99 show your organisation's progress towards the 2030 fossil CO2 target:
- Row 93 shows your baseline fossil CO2 emissions and your 2030 fossil CO2 target.
- Rows 94 and 95 show your actual fossil CO2 to date and your gap to the target. Positive values indicate the gap to the 2030 fossil CO2 target in the units shown.
- Rows 96 and 97 show your BAU fossil CO2 for future years and your gap from BAU to the target. Positive values indicate the gap to the 2030 target.
- Rows 98 and 99 show the future fossil CO2 for your modelled scenario and your modelled gap to the target. Positive values indicate the gap from your modelled scenario to the 2030 fossil CO2 target.
- Rows 100-107 show your organisation's progress towards the 2030 total CO2 target:
- Row 101 shows your baseline total CO2 emissions and your 2030 total CO2 target.
- Rows 102 and 103 show your actual total CO2 to date and your gap to the target. Positive values indicate the gap to the 2030 total CO2 target in the units shown.
- Rows 104 and 105 show your BAU total CO2 for future years and your gap from BAU to the target. Positive values indicate the gap to the 2030 target.
- Rows 106 and 107 show the future total CO2 for your modelled scenario and your modelled gap to the target. Positive values indicate the gap from your modelled scenario to the 2030 total CO2 target.
- Rows 108-115 show your organisation's progress towards the 2030 energy efficiency target:
- Row 109 ‘2030 target & trajectory (normalised EnPI)’ is a calculated trajectory for your normalised EnPI, from your energy efficiency baseline to your 2030 target. This trajectory is based on a constant improvement in energy performance from baseline to 2030.
- Rows 110 and 111 show your actual energy performance indicator (EnPI) to date (on a normalised basis) and your gap to the target. Positive values indicate percentage-point gap to the 2030 energy efficiency target.
- Rows 112 and 113 show your BAU energy performance for future years and your gap from BAU to the target. Positive values indicate the gap to the target.
- Rows 114 and 115 show the future energy performance for your modelled scenario and your modelled gap to the target. Positive values indicate percentage-point gap from your modelled scenario to the 2030 energy efficiency target.
- Rows 116-123 show additional calculations for a 1.9% pa energy reduction trajectory
- Row 117 ‘Baseline & trajectory’ shows your organisation's final energy consumption in 2021 as a ‘baseline’, and calculates an energy-reduction trajectory based on an annual reduction of 1.9% from this level from 2025 onwards.
- Rows 118 and 119 show your actual final energy consumption to date and the gap between this consumption and the 1.9% trajectory.
- Rows 120 and 121 show your BAU final energy consumption for future years and your gap from BAU to the 1.9% trajectory. Positive values indicate the gap to the trajectory in the units shown.
- Rows 122 and 123 show the final energy consumption for your modelled scenario, and the gap between this modelled consumption and the 1.9% trajectory. Positive values indicate the gap to the trajectory in the units shown.
- Rows 125 and 126 show the primary energy and CO2 emission factors used in the model for grid electricity.
- Table M1 is for incorporating additional energy reduction measures, decarbonisation initiatives and other changes into your 2030 scenario.
- There is step-by-step guidance on entering data in this table under ‘Model energy reduction measures and decarbonisation initiatives’ above.
- This table summarises the impacts of the energy reduction and decarbonisation initiatives on your organisation’s future energy use and GHG emissions.
- This table cannot be edited.
- These tables show detailed breakdown of your organisation’s:
- Final energy consumption (table M6)
- Weather-adjusted final energy consumption (table M7)
- CO2 emissions (table M8)
- These tables cannot be edited.
- These tables contains additional calculations required for the decarbonisation model.
- These tables cannot be edited.
- These tables show detailed breakdowns of your organisation’s BAU to 2050:
- Final energy consumption (table M12)
- Primary energy (table M13)
- CO2 emissions (table M14)
- These tables cannot be edited.
- Like all calculation models, the results (outputs) generated by the GTT are entirely dependent on the inputs entered by the user. It also incorporares several simplifying assumptions.
- Several key calculations, including the target configuration calculations for GHGs and the gap-to-target calculations are very sensitive to forecasts for future values of the primary energy conversion factor and the CO2 emission factor for Ireland’s electricity system. SEAI prepares forecasts for both these factors, which are refined continually. The forecasts incorporate a large number of variables and assumptions. You should carefully consider their appropriateness for use in your particular circumstances, particularly if using the forecast values for making investment decisions.
- The GHG and energy efficiency targets for every public sector organisation are calculated and presented in SEAI's M&R software. Every organisation's progress towards these targets, and its gap to the targets, are also calculated and presented in the M&R system. In any instance where values in the GTT spreadsheet differ from those presented in the M&R software, then the values and results shown in the M&R software are deemed to take precedence.
- Gap-to-target model - overview
- 2030 GHG emissions targets
- 2030 energy efficiency target