Discussion and research needs

It is important to acknowledge that there are significant uncertainties coupled to the projected figures, inherent to the global scope of the model and the long time frame over which the results are projected. While historical GDP and population data are more reliable, the data for U-value, build-ing vintages, space heatbuild-ing and coolbuild-ing energy consumption - in particular outside of Europe - were frequently unavail-able. The logic behind the assumptions that needed to be made as a consequence, and the calibration and validation of the model is discussed in the Supplementary Materials.

More consistent and structural data collection at the country level of variables related to building stock and building en-ergy use, however, would allow to for better model testing.

In this research useful energy requirement are related to

OY Edelenbosch et al.: Preprint submitted to Elsevier Page 9 of 11

3.5 Discussion and research needs 81

Long term, cross-regional effects of building insulation policies

U-values, which is a commonly used and reported measure of the level of insulation. For cooling this relation is however more complex, related also to the interaction with sunlight, and building geometry. This allows also for alternative pol-icy strategies to reduce cooling demand. Reflective coatings and adequate SHGC windows, for example, have the poten-tial to strongly reduce cooling loads. Given the global point of view of the model, and the strong local dependency of the impact of these technologies, this was not accounted for in the model.

6. Conclusions

In this paper a global, long term model of building stock development is presented, impacting buildings energy con-sumption, which has been neglected in the global studies so far. This new tool demonstrates key regional differences that should be considered when designing building energy pol-icy. The results give insight to where what kind of policy is the most effective, and how policy decisions carry out over time. The model is based on in depth data collection, has a transparent structure, while containing many country level details that reflect the different regional realities. The model is validated at intermediate output level, such as construction and building stock size, as well as final output levels, such as U-value and final energy consumption.

The model projections show that while globally the ma-jority of buildings in 2050 are build after 2015, in Europe, the opposite is true. This has major consequences for policy impact of building codes. In Europe and other OECD coun-tries, renovating the existing building stock results in sig-nificantly higher savings than implementing new construc-tion policies, due to the slower stock turnover and the rela-tively high current insulation levels of new build buildings.

In China and Africa, on the other hand, focusing on new construction policies can be extremely effective, saving on itself up to respectively 57% and 73% of space heating and cooling final energy demand in 2050. Subsequently, Europe and other OECD countries are more vulnerable to lock in ef-fects, therefore in these regions acting fast and implementing ambitious (nZEB level) standards is fundamental to reduce building sector emissions. Following EPBD policy ambition in 2020 would save 72% of Europe’s space heating and space cooling energy demand in 2050, while if policy implemen-tation is delayed to 2030 only half of that (37%) would be saved.

In particular in China, final energy for cooling is pro-jected to strongly increase in the decades to come, following the projected economic growth. As a result, in a no policy scenario, final energy demand for space heating and cool-ing would almost double in the comcool-ing 30 years. While climate change does further increase cooling demand, this effect is relatively small in the time period assessed (up to 2050). Only through the combined effort of new construc-tion and renovaconstruc-tion policies would space heating and cooling final energy demand be reduced compared to current levels.

Reducing energy demand growth has many environmental benefits, such as reducing air pollution and greenhouse gas

emissions.

References

[1] Energy Technology Perspectives, Technical Report, International En-ergy Agency, Paris France, 2017.

[2] Cox, Sadie, Building Energy Codes: Policy overview and good prac-tices, Technical Report, NREL, 2016.

[3] D. Urge-Vorsatz, K. Petrichenko, M. Staniec, J. Eom, Energy use in buildings in a long-term perspective, Current Opinion in Environ-mental Sustainability 5 (2013) 141–151.

[4] K. C. Seto, S. J. Davis, R. B. Mitchell, E. C. Stokes, G. Unruh, D. Ürge-Vorsatz, Carbon lock-in: types, causes, and policy impli-cations, Annual Review of Environment and Resources 41 (2016) 425–452.

[5] Transition to Sustainable Buildings - Strategies and Opportunities to 2050, Technical Report, IEA, 2011.

[6] O. Lucon, D. ÃIJrge Vorsatz, et al., Buildings. In Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Technical Report, IPCC, 2014.

[7] T. Loga, N. Diefenbach, B. Stein, et al., Typology Approach for Build-ing Stock Energy Assessment. Main Results of the TABULA project, Technical Report, 2012.

[8] Development of Commercial Building Shell Heating and Cooling Load Factors, Technical Report, EIA, 2018.

[9] B. J. van Ruijven, E. De Cian, I. S. Wing, Amplification of future en-ergy demand growth due to climate change, Nature Communications 10 (2019) 2762.

[10] Y. Zhou, L. Clarke, J. Eom, The effect of global climate change, population distribution, and climate mitigation on building energy use in the u.s. and china, Climatic Change 119 (2013).

[11] M. Olonscheck, A. Holsten, J. P. Kropp, Heating and cooling energy demand and related emissions of the german residential building stock under climate change, Energy Policy 39 (2011).

[12] M. Isaac, D. P. van Vuuren, Modeling global residential sector en-ergy demand for heating and air conditioning in the context of climate change, Energy Policy 37 (2009).

[13] L. Clarke, J. Eom, et al., Effects of long-term climate change on global building energy expenditures, Energy Economics 72 (2018).

[14] A. Levesque, R. C. Pietzcker, L. Baumstark, S. De Stercke, A. GrÃijbler, G. Luderer, How much energy will buildings consume in 2100? A global perspective within a scenario framework, Energy (2018).

[15] K. Riahi, D. P. Van Vuuren, E. Kriegler, J. Edmonds, B. C. OâĂŹneill, S. Fujimori, N. Bauer, K. Calvin, R. Dellink, O. Fricko, et al., The shared socioeconomic pathways and their energy, land use, and green-house gas emissions implications: an overview, Global Environmen-tal Change 42 (2017) 153–168.

[16] D. ÃIJrge Vorsatz, et al., Heating and cooling energy trends and drivers in buildings, Renewable and Sustainable Energy Reviews (2015).

[17] European commission buildings database, https://ec.europa.eu/

energy/en/eu-buildings-database, ???? [Online, accessed 16-March-2019].

[18] N. H. Sandberg, I. Sartori, O. Heidrich, Dynamic building stock mod-elling: Application to 11 European countries to support the energy efficiency and retrofit ambitions of the EU, Energy and Buildings (2016).

[19] C. A. Balaras, et al., European residential buildings and empirical as-sessment of the Hellenic building stock, energy consumption, emis-sions and potential energy savings, Building and Environment (2007).

[20] Lollini, Barozzi, Fasano, Meroni, Zinzi, Optimisation of opaque com-ponents of the building envelope. Energy, economic and environmen-tal issues, Building and Environment (2005).

[21] T. Boermans, K. BettgenhÃďuser, S. Offermann, Markus Schimschar, Renovation Tracks for Europe up to 2050, Technical Report, Ecofys, 2012.

OY Edelenbosch et al.: Preprint submitted to Elsevier Page 10 of 11

82 Chapter 3 Long term, cross-country effects of buildings insulation policies

Long term, cross-regional effects of building insulation policies

[22] Exploring Experience Curves for the Building Envelope: An Investi-gation for Switzerland for 1970âĂŞ2020 (2003).

[23] E. Heiskanen, K. Matschoss, et al., D2.4. of WP2 of the Entranze Project; Working paper: Literature review of key stakeholders, users and investors, Technical Report, 2012.

[24] G. Haq, M. Weiss, Time preference and consumer discount rates-insights for accelerating the adoption of efficient energy and trans-port technologies, Technological Forecasting and Social Change 137 (2018) 76–88.

[25] T. Masui, K. Matsumoto, Y. Hijioka, T. Kinoshita, T. Nozawa, S. Ishi-watari, E. Kato, P. Shukla, Y. Yamagata, M. Kainuma, An emission pathway for stabilization at 6 wm- 2 radiative forcing, Climatic change 109 (2011) 59.

OY Edelenbosch et al.: Preprint submitted to Elsevier Page 11 of 11

3.7 References 83