Halving energy demand from buildings: The impact of low consumption practices

Highlights

• The adoption of low energy consuming behaviors and technologies could halve buildings' energy demand in 2050 and 2100.

• Despite economic and demographic growth, global buildings' energy demand could fall below 2015 levels.

• Insulation, efficient space conditioning technologies and lower hot water usage have the largest potential.

Abstract

Limiting global warming below 1.5 °C requires rapid decarbonization of energy systems. Reductions of energy demand have an important role to play in a sustainable energy transition. Here we explore the extent to which the emergence of low energy consuming practices, encompassing new behaviors and the adoption of more efficient technologies, could contribute to lowering energy demand and thereby to reducing CO₂ emissions.

To this end, we design three detailed energy consumption profiles which could be adopted by individuals in current and future wealthy regions. To what extent does the setting of air conditioners to higher temperatures or the widespread use of efficient showerheads reduce the aggregate energy demand? We investigate the potential of new practices at the global level for 2050 and 2100.

The adoption of new, energy saving practices could reduce global energy demand from buildings by up to 47% in 2050 and 61% in 2100 compared to a scenario following current trends. This strong reduction is primarily accounted for by changes in hot water usage, insulation of buildings and consumer choices in air conditioners and heat pumps. New behaviors and efficient technologies could make a significant long-term contribution to reducing buildings' energy demand, and thus facilitate the achieval of stringent climate change mitigation targets while limiting the adverse sustainability impacts from the energy supply system.

Introduction

Limiting global warming in line with the Paris Climate Agreement poses a great challenge to socio-economic structures across the world. On the one hand, geophysical studies revealed a proportional relationship between cumulative CO₂ emissions and temperature increases (Matthews et al., 2009), which means that staying below 1.5 °C global warming requires cumulated emissions to remain within a tight carbon budget (Rogelj et al., 2016). Carbon neutrality must therefore be reached by mid-century (Rogelj et al., 2015). On the other hand, the pace of emission reductions necessary for remaining below 2 °C, and a fortiori below 1.5 °C global warming, resembles only few examples in history (Riahi et al., 2015) and is unprecedented on a global scale.

Energy consumption in buildings accounted for 23% of energy-related CO₂ emissions in 2014 (Rogelj et al., 2018). These emissions resulted from both direct emissions released by on-site combustion of fossil fuels and biomass (8%), as well as from indirect emissions attributed to electricity consumption in buildings and district heating (15%). Reducing energy demand in buildings therefore constitutes an important strategy to decrease GHG emissions.

Many studies appraised the global potential for reduction of the energy consumed in buildings. Overall, they found this potential to be substantial (Lucon et al., 2014). However, these studies usually assessed the potential as a result of technological changes, leaving aside the impact of behavioral changes (e.g. Chaturvedi et al., 2014; IEA, 2016; Teske et al., 2015). Some other studies investigated the energy demand reduction potential following changes in lifestyles, while excluding technological changes. Thereby, these studies implied a dichotomy between technological and behavioral solutions (e.g. van Sluisveld et al., 2016; Ven et al., 2017).

However, this dichotomy between technological solutions and behavioral solutions to climate change overlooks the co-evolution of technologies and behaviors identified in several social theory frameworks. For instance, Steg and Vlek (2009), in a review of psychological studies focusing on the determinants of individual behavior, delineate three factors determining environmental behavior: individual motivations, habitual behavior, and contextual factors. The last covers factors including physical infrastructure, technologies available on the markets and the characteristics of the technologies. Taking a more macro perspective, the socio-technical regime concept (Geels et al., 2017; Smith, 2007) underlines that technical arrangements include a social dimension and that new technologies cannot advance without changes in purchasing practices, daily rituals, professional skills, etc. Drawing upon these theories but giving more weight to the individual perspective, Stephenson et al. (2010) conceived the Energy Cultures framework which encompasses the different dimensions of energy behaviors. In this framework, consumer energy behavior can be understood through the interactions between cognitive norms, material culture (technologies) and energy practices (activities, processes). Each dimension interacts with the others to shape the energy consuming behavior. For instance, the presence of an insulation layer on the external walls of a building will influence how much people heat, in which rooms. Each dimension is influenced by different factors: education influences cognitive norms; energy prices affect energy practices, etc. By shifting one of these dimensions, it is possible to influence behaviors. The theory of practices (e.g. Shove and Walker, 2010) constitutes another perspective on energy behaviors which insists on the inter-connectedness of many elements playing on the adoption and evolution of practices. Within this theoretical framework, Gram-Hanssen (2014) proposes to classify elements holding practices together within four categories: embodied habits, institutional knowledge, engagement (the meaning to the people following such practices) and technologies. There is therefore a widespread agreement across these various theories that technologies and behaviors are interdependent. For our purpose, this means that energy demand reduction potentials should consider technological and behavioral aspects alike.

Some analyses exploring the potential for reduction of energy demand already considered technological and behavioral approaches together. Taking an individual perspective, Dietz et al. (2009) considered all the interventions that US households could take to reduce their emissions, and therefore their energy demand, covering changes in technology purchase patterns as well as usage habits. According to them, residential emissions could decrease by 20% within ten years if all these measures were implemented. Anable et al. (2011) started from the assumption that behaviors change over time and that deep cuts in energy demand will require changes at the social level, implying new norms and conventions. From this premise, they imagine scenarios where people, motivated by concerns about energy use and environmental issues, change their consumption patterns as well as their technological choices. They find that the UK energy demand could decrease by 50% until 2050. More recently, Grubler et al. (2018) designed a low energy demand scenario at the global level. Despite the growing income and population in developing countries, their scenario also envisions a halving of buildings' energy demand until 2050,

In this paper, we investigate more closely the potential of new practices for global energy demand from buildings. We first present the Energy Demand Generator model (EDGE) — a bottom-up energy demand model projecting buildings' energy demand at the global scale for five energy services (Levesque et al., 2018). We then design three individual energy consumption profiles which could prevail for individuals in current and future advanced economies. These profiles describe how people shower, heat or cool their homes and offices, insulate their buildings, etc. We hence focus on the question of how people consume energy, and not on the question of which factors drive them to change practices—like the influence of energy prices for instance. Two of these profiles display low energy consuming practices. With the EDGE model, we can then appraise the impact of these contrasted energy practices on buildings' energy demand in 2050 and 2100, and compare with scenarios from other studies, before concluding.