Table 1
A selection of relevant literature studying the potential of retrofitting in reducing energy consumption and greenhouse gas (GHG) emissions for buildings in Norway.
| PERSPECTIVE | STUDY | FINDINGS |
|---|---|---|
| Individual building(s) | Wrålsen et al. (2018) | Retrofitting of an apartment building to near-passive house standards (improved insulation, triple-glazed windows and modern ventilation) could reduce operational energy demand and environmental impact over 30 years by 56–96% |
| Hrynyszyn & Felius (2019) | Upgrades of windows, insulation and ventilation following the EnerPHit Standard could reduce heating energy demand by nearly 80% in a 1960s wooden Norwegian house | |
| Chen et al. (2020) | Moderate retrofits were cost-effective, while extensive retrofits incorporating renewable energy yielded the greatest emissions reductions for residential buildings in Oslo | |
| Felius et al. (2020b) | Air-source heat pumps outperformed envelope retrofits alone. Combining these measures with building automation control systems achieved total energy savings of up to 57% | |
| Tian & Hrynyszyn (2020) | High airtightness increases overheating risks, while enhanced insulation slightly reduces overheating | |
| Rabani et al. (2021) | Retrofitting heating, ventilation and air-conditioning (HVAC) systems could cut emissions by up to 52% in office buildings | |
| National building stock | Sartori et al. (2009) | Introducing retrofit measures combined with heat pumps for all buildings could save up to 17 TWh/yr between 2005 and 2035 |
| Pauliuk et al. (2013) | Retrofitting the residential building stock has lower upstream GHG emissions than demolishing existing buildings and replacing them with passive houses, due to the high emissions of building envelope construction | |
| Sandberg et al. (2017) | The use of heat pumps and on-site electricity production with solar panels could cut half of delivered energy, and further reduction (up to 65% compared with a baseline scenario) could be achieved with retrofit activities by 2050 |
Figure 1
Methodological framework and its different phases, including modelling, simulation, scenario development and comparison.
Note: Only space heating-related energy demand was considered as the retrofit activities modelled in this research focus on buildings’ construction.
DMFA = dynamic material flow analysis.
Table 2
Scenarios.
| SCENARIO | RETROFIT OF ENVELOPES | RETROFIT OF ENERGY SYSTEM | POPULATION SCENARIO | ELECTRICITY PRODUCTION MIX |
|---|---|---|---|---|
| NoRen (baseline) | None | None | Mid | Norway |
| Win | Win | None | Mid | Norway |
| Ren | Ren | None | Mid | Norway |
| Vent | Vent | None | Mid | Norway |
| HP | None | Heat pumps | Mid | Norway |
| Win_HP | Win | Heat pumps | Mid | Norway |
| Ren_HP | Ren | Heat pumps | Mid | Norway |
| Vent_HP | Vent | Heat pumps | Mid | Norway |
| NoRen_HighPop | None | None | High | Norway |
| NoRen_NordicEl | None | None | Mid | Nordic |
[i] Note: Win = replacing the windows and external doors with TEK-17-compliant options as well as improving the airtightness of the openings; Ren = Win plus replacing and increasing the insulation for external walls and roof matching TEK-17 criteria as well as improving the airtightness of the whole building envelop; and Vent = Ren plus a balanced ventilation system with 80% heat recovery.
Figure 2
(a) Quantities of materials added for the three types of retrofit (Win, Ren and Vent); and (b) space heating demand for the base case and the three types of retrofit (Win, Ren and Vent) in 2023 and 2050 (simulated under an Oslo climate) per archetype classified by typology.
Note: SFH = single-family house; MFH = multi-family house; AB = apartment block. Construction cohort (1995, pre-1955; 5670, 1956–70; 7180, 1971–80; 8190, 1981–90; 9100, 1991–2000; 0110, 2001–10; and 1120, 2011–20). The results are presented per m2 of utility floor area (area within the outer walls). Space heating demand for other climate zones is not shown but available with underlying data.
Figure 3
(a) Residential building stock by type; (b) final energy consumption for space heating by energy carrier; (c) material use (final consumption of materials) for new construction by material type; and (d) greenhouse gas (GHG) emissions by source of emissions of Norwegian residential buildings between 2023 and 2050 following the baseline scenario.
Note: Material production and GHG emissions are estimated only from 2024.
SFH = single-family house; MFH = multi-family house; AB = apartment block.
Figure 4
Composition of residential building stock between 2023 and 2050 for (a) a scenario with no retrofit, (b) scenarios with retrofit of energy systems and (c) scenarios with retrofit of envelopes.
Figure 5
(a) Cumulative final energy consumption for space heating between 2023 and 2050; (b) cumulative material use (final consumption of materials) for retrofit between 2024 and 2050; (c) cumulative greenhouse gas (GHG) emissions from energy consumption for space heating between 2023 and 2050; and (d) cumulative GHG emissions from material use for retrofit between 2024 and 2050.
Note: Cumulative material use for new construction and the associated GHG emissions from production are not shown.
Figure 6
(a) Annual final energy consumption for space heating in residential buildings; (b) annual material use (final material consumption) for new construction and retrofit of residential buildings; (c) annual greenhouse gas (GHG) emissions from energy consumption for space heating in residential buildings; (d) annual GHG emissions for production of materials for new construction and retrofit of residential buildings; and (e) annual GHG emissions for the combination of energy consumption and production of materials.
Figure 7
Final energy consumption per capita for space heating in residential buildings for individual Norwegian municipalities in 2023 and 2050 (with the associated scenario).
Note: For an enlarged version of the figure, see Figure S4 in the supplemental data online.
Table 3
Results of the sensitivity analysis with high growth of population and a Nordic electricity mix.
| SCENARIO | RESIDENTIAL BUILDING STOCK IN 2050 (millions m2) | CUMULATIVE FINAL ENERGY CONSUMPTION BY RESIDENTIAL BUILDINGS BETWEEN 2023 AND 2050 (TWh) | CUMULATIVE GREENHOUSE GAS EMISSIONS DUE TO FINAL ENERGY CONSUMPTION BY RESIDENTIAL BUILDINGS BETWEEN 2023 AND 2050 (MtCO2-eq) |
|---|---|---|---|
| NoRen (baseline) | 363 | 538 | 93 |
| NoRen_HighPop | 406 | 555 | 119 |
| NoRen_NordicEl | 363 | 538 | 96 |