**3. Results**

#### *3.1. Current Emissions from Building and Infrastructure Construction*

As described in the Introduction the range of current estimates of GHG emissions linked to the construction of buildings in Sweden is notable (8.5 MtCO2e based on a process-based bottom-up LCA approach, 8.1 MtCO2e for territorial emissions, and 13.5 MtCO2e including imports based on EEIO data) with potential variances including different system boundaries (e.g., agricultural properties

not included in the bottom-up model) and possible overstating of the importance and emissions intensity of imports in the input-output analysis [7,8,11]. Further, a grea<sup>t</sup> majority of construction steel is imported [142], and, while the cement market is mostly domestic (85% of Swedish cement use) [143], the concrete market is turning more international, at least pertaining to precast elements [143–145].

To validate the estimates of the current GHG emissions, and to specify emissions components, further analysis into the existing estimates were combined with a literature review focused on relevant LCA studies detailing embodied emission sources for di fferent construction types.

#### 3.1.1. Estimate and Validation of Current Emissions from Building Construction

Around 2/3 of the construction emissions correspond to new buildings and 1/3 to refurbishments and maintenance. In addition, around 40–50% of the annual climate impact from building construction stem from construction of non-residential buildings, such as o ffices, schools, and other premises. A growing share of around 40–50% arise from multi-family dwellings and the remaining 10–15% from single family houses [7,52]. Multi-family buildings are predominantly constructed with concrete frames (85% in 2018), with smaller shares of timber frames (13%) and steel frames (2%) [146].

A detailed overview of the share of emissions components, and share of individual materials, related to new building construction for new builds of various building and frame types can be found in Tables A4 and A5 in Appendix A. The total share and amount of emissions for di fferent material/activities for building construction were calculated using estimates for di fferent life cycle stages for various building/frame types from the literature review, with the initial estimates shown in Table 3.


**Table 3.** Initial and updated annual emissions estimates per lifecycle stage for building construction in the base year of 2015.

Worth noting about these estimates is that ground preparation is often not included in LCA studies, which would increase the share of construction processes. On the other hand, the estimates do not include refurbishments, which would increase the share of material transports and certain materials.

The estimates can be compared to the approximate sector division for the building and real estate sector (territorial emissions including emissions associated with real estate managemen<sup>t</sup> during building use) from the Swedish EEIO analysis. The sector division include 3.9 Mt CO2 from building materials (only domestically produced materials), 0.9 Mt CO2 from construction equipment, and 1.5 Mt CO2 from transports, while the share of the transport emissions estimate belonging to construction versus real estate managemen<sup>t</sup> is not entirely clear [7]. The level of transport emissions nonetheless is significantly higher than the level and share of emissions allocated to transports resulting from the LCA studies in the literature review (~24% versus 5% or 0.4 Mt CO2), noting that the latter figure does not encompass refurbishments. Further, the process-based bottom-up approach estimates transport emissions from building construction of 0.9 Mt CO2 (17% of building construction emissions), while also including people transport in this estimate [8]. The initial emissions share and estimate for material transports is consequently adjusted upwards.

The initial and updated emissions estimates from materials are displayed in Table 4.

**Table 4.** Initial and updated annual emissions estimates per material for building construction in the base year of 2015. The initial estimates are based on a combination of emissions share data per lifecycle stage for construction of new buildings together with data on construction of different building/frame types, while the updated estimates are the data used in the model after adjustments for refurbishments and validation.


The sector division in the Swedish EEIO analysis further details an approximate 2.4 Mt CO2 from the mineral industry (predominantly cement) [7]. Regarding cement, emissions from Cementa were 2.5 Mt CO2 in 2015 [147], which corresponds to 85% of Swedish cement use [143]. In total, emissions from Swedish cement use were thus about 2.9 Mt CO2 in 2015. However, while the cement market is mostly domestic, the concrete market is turning more international, particularly pertaining to precast concrete. There is a lack of data and reporting to determine the extent of concrete imports, but an estimate can be made based on the import-export balance of concrete, cement and gypsum products of SEK 1.8 billion [143].

If these imports are considered to correspond to concrete elements and the concrete costs 60–70 EUR/ton (about SEK 600–700/ton) [148,149], this would correspond to concrete imports of 2.5–3 Mt per year, corresponding to emissions of about 0.4–0.5 Mt CO2, giving a total emissions estimate of 3.3 Mt CO2e from Swedish concrete use. With around 75% of concrete being used in building construction [150], the emissions from concrete use in building construction would correspond to around 2.5 Mt CO2. The emissions estimates of concrete and material production overall are adjusted accordingly in the model.

Additional upwards adjustments are based on literature detailing refurbishments which report the main embodied emissions resulting from insulation, windows and metals for new ventilation, and heating systems [55,151,152].

#### 3.1.2. Estimate of Current Emissions from Building and Transport Infrastructure Construction

The total climate impact of building and transport infrastructure construction in Sweden is estimated to around 9.8 Mt CO2 per year, with building construction responsible for 80% and transport infrastructure for 20%. This can be compared with the national territorial GHG emissions of 51.8 MtCO2e in 2018 [6]. As can be seen in Figure 6, this carbon impact derives predominantly from concrete and steel together with diesel use in construction processes and material transports.

**Figure 6.** Carbon impact from (**a**) construction of buildings and (**b**) construction of transport infrastructure with the size of the pie charts reflecting the relative magnitude of emissions.

#### 3.1.3. Validation of Building and Transport Infrastructure Construction Emissions Estimate

The total estimated emissions from buildings and transport infrastructure construction of 9.8 Mt CO2e is in the middle of the range of estimates of 8.1–13.5 Mt CO2e, as reported by Naturvårdsverket and Boverket [7,8].

Focusing in on concrete, the resulting concrete emissions estimate for building and transport infrastructure combined is 3.0 Mt CO2e, which corresponds well to the estimate of concrete use in Sweden discussed in the building construction Section 3.1.1 (considering the exclusion of utilities in this analysis).

Another validation can be made regarding steel use. A grea<sup>t</sup> majority of steel used in construction is imported [143]. Swedish steel imports were 3.2 Mt in 2015 [142,153] with research demonstrating that around 25–50% of steel consumption goes to the construction industry [154,155]. This would correspond to the use of 0.8–1.6 Mt steel in constructions, matching the model estimate of 1.4 Mt steel (based on the equivalent emissions intensities for reinforcement and construction steel).
