Building regulations 2025 - new non-domestic buildings: energy standard improvements - modelling report

Appendix B Baseline Carbon Dioxide Emissions Results

As previously highlighted, carbon dioxide emission rates (BER and TER) are no longer used as the compliance metric for buildings using zero direct emission heating systems, as is the case for all buildings modelled.

However, Section 6 is one of the key methods by which the Scottish Government is driving reduced carbon from the built environment. Therefore, the following results are presented for comparison purposes only.

DLUHC has proposed updated CO₂ emission factors, which it is understood the Scottish Government will also adopt for the ongoing reporting of emissions as part of EPC production. The proposed new values, as reported in Table 124 move away from the current monthly emission factors for electricity to a single annual value. All other fuels currently use an annual carbon dioxide emission factor, and these will remain as such.

Source: (Department for Energy Security & Net Zero, 2023)

Comparing Table 124 with Table 126 it can be seen that, moving from a monthly CO₂ emission factor for electricity to a single annual factor means that, for the eight buildings using electric heating, either via heat pump or direct electric, the CO₂ pass margin using the proposed future factors equals the calculated delivered energy pass margin. In some cases, this is an improvement on the margin using the current emission factors; where there is less contribution from PV, the proposed future emission factors lead to a reduced margin.

Where buildings are heated by district heating, owing to the relative reduction in carbon dioxide emissions for electricity versus heat from a district heating network, where there is a smaller contribution from PV, the pass margin reduces, whereas in cases where the PV is making a bigger contribution the pass margin tends to increase under the proposed future CO₂ emissions factors.