Vocabulary

Decarbonisation, a term which echoes through the corridors of academia, politics, practical applications, and stands at the forefront of contemporary discussions on sustainability. Intricately intertwined with concepts such as net-zero and climate neutrality, it represents a pivotal shift in our approach to environmental sustainability. In its essence, decarbonisation signifies the systematic reduction of carbon dioxide intensity, a crucial endeavour in the battle against climate change (Zachmann et al., 2021). This overview delves into the multifaceted concept of decarbonisation within the context of the European Union. Beginning with a broad perspective, we examine its implications at the macro level before homing in on the complexities of decarbonisation within the realm of building structures. Finally, we explore the literature insights, presenting key strategies that pave the way toward achieving a decarbonised building sector. From a broad perspective, decarbonisation is an overarching concept that aims to achieve climate neutrality (Zachmann et al., 2021, p.13). Climate neutrality means achieving a state of equilibrium between greenhouse gas emissions and their removal from the atmosphere, preventing any net increase in atmospheric CO2 concentration (IEA, 2022). From an energy decarbonisation perspective, however, in a document provided by the Economic, Scientific and Quality of Life Policy Department at the request of the Industry, Research and Energy (ITRE) Committee, Zachmann et al. (2021) explain that energy systems require a fundamental shift in the way societies provide, transport and consume energy (Zachmann et al., 2021). In the construct of decarbonisation, as outlined by the Intergovernmental Panel on Climate Change (IPCC), the focus lies on strategic directives aimed at reducing the carbon content of energy sources, fuels, products and services (Arvizu et al., 2011; Edenhofer et al., 2011). This complex process involves the transition from carbon-intensive behaviours, such as fossil fuel use, to low-carbon or carbon-neutral alternatives. The main goal of decarbonisation, therefore, is to reduce emissions of greenhouse gases such as CO2 and methane, which are closely linked to the growing threats of climate change (Edenhofer et al., 2011). Hoeller et al. (2023) explain that decarbonisation efforts within the Organisation for Economic Co-operation and Development (OECD) focus on harmonising economic growth, energy production and consumption with climate objectives to mitigate the adverse effects of climate change while promoting sustainable development (Hoeller et al., 2023). From a pragmatic perspective, however, according to the OECD Policy Paper 31: A framework to decarbonise the economy, published in 2022,  progress on economic decarbonisation remains suboptimal. This raises the urgent need for a multi-dimensional framework that is not only cost-effective but also inclusive and comprehensive in its strategy for decarbonisation (D’Arcangelo et al., 2022). D’Arcangelo et al. (2023) add that such framework should include several steps such as setting clear climate targets, measuring progress and identifying areas for action, delineating policy frameworks, mapping existing policies, creating enabling conditions, facilitating a smooth transition for individuals, and actively engaging the public. From an academic perspective, Weller and Tierney (2018) provide an explanation of decarbonisation, defining it as a twofold concept. Firstly, it involves reducing the intensity of fossil fuel use for energy production. Secondly, it emphasises the role of policy in mitigating the negative externalities associated with such use. They argue that decarbonisation is a politically charged policy area that needs to be 'just', while also serving a means to revitalise local economies (Weller & Tierney, 2018). Kyriacou and Burke (2020) expand on this definition, highlighting decarbonisation as the transition from a high-carbon to a low-carbon energy system. This transition is driven by the need to mitigate climate change without compromising energy security. Boute (2021), on the other hand, emphasises the long-term structural reduction of CO2 emissions as the core strategy of decarbonisation. Boute adds that the effectiveness of decarbonisation must be measured in terms of a unit of energy consumed across all activities. In the economic context, the Oxford Institute for Energy Studies concludes that decarbonisation aims to reduce the carbon intensity of an economy. This reduction is quantified as the ratio of CO2 emissions to gross domestic product (Henderson & Sen, 2021). Addressing methodological concerns, Buettner (2022) added that decarbonisation is often misused as a generic term. Moreover, Buettner highlights the diverse levels at which decarbonisation occurs, ranging from carbon neutrality (focused on reducing CO2 emissions), to climate neutrality (aiming to reduce CO2, non-fluorinated greenhouse gases, and fluorinated greenhouse gases) and, finally, to environmental neutrality (which reduces all substances negatively impacting the environment and health) (Buettner, 2022). The debate on the decarbonisation of the construction sector revolves around similar issues. The report on Decarbonising Buildings in Cities and Regions, published by the OECD in 2022, defines the concept as reducing energy consumption by improving envelope insulation, installing high performance equipment, and scaling up the use of renewable sources to meet the energy demands (OECD, P24). Another definition comes from a working paper by the OECD Economics Department, Hoeller et al. (2023) contend, it is necessary to consider direct emissions from household fossil fuel combustion and indirect emissions from the generation of electricity and district heating used by households (Hoeller et al., 2023). The comprehensive study “Decarbonising Buildings” published by the Climate Action Tracker (CAT) in 2022, defines the term as transforming the building sector to achieve net zero emissions by 2050. Achieving this goal requires various technological solutions and behavioural changes to decarbonise heating and cooling, such as energy-efficient building envelopes, heat pumps and on-site renewables (CAT, 2022). Gratiot et al. (2023) consider decarbonisation as the process of reducing or eliminating CO2 emissions that contribute to climate change from a building’s energy sources. This involves systematically shifting buildings from carbon-intensive energy sources (e.g., gas, oil and coal) to low-carbon or carbon-neutral alternatives (e.g., solar, wind and geothermal). This process includes improving the energy efficiency of buildings through better insulation, lighting and appliances (Gratiot et al., 2023). Blanco et al. (2021) consider the decarbonisation of buildings and operation of buildings. This includes enhancing the energy efficiency of buildings and minimizing embodied carbon from building materials and construction activities of greenhouse gas emissions from the construction and operation of buildings. Achieving a decarbonised building sector is a multifaceted endeavour that demands extensive efforts in several key areas, such as energy sources, building envelope, building policy and transformation funds. The objective of the energy transition is to shift from reliance on fossil fuels to clean or renewable energy sources, primarily used for heating and cooling, such as heat pumps, district heating, hydrogen (Jones, 2021). Decarbonising the building envelope, on the other hand, involves improving the energy efficiency of buildings through better insulation, lighting and appliances. It also necessitates minimising embodied carbon from building materials and construction activities (CAT, 2022; D’Arcangelo et al., 2022). Incorporating effective policies into building construction is crucial. This includes adopting of performance standards and building codes that regulate the energy use and emissions of both new and existing buildings. These regulations directly impact the extent and pace of decarbonisation (CAT, 2022; Jones, 2021). Additionally, it is essential to establish a clear vision and climate targets for the buildings sector and operationalise them with a comprehensive policy mix that encompass emissions pricing, standards, regulations and complementary measures (Jones, 2021). The most significant challenge lies in financing the transition to a decarbonised sector. Therefore, it is imperative to mobilise finance on a large scale and collaborate with industry stakeholders. This collaboration is vital to facilitate the transition, overcome barriers, and manage the costs associated with deploying low- or zero-carbon technologies (D’Arcangelo et al., 2022). In summary, the overarching concept of decarbonisation primarily targets the reduction of carbon dioxide in economic and industrial activities, with a focus on energy production and distribution systems. At the building level, the emphasis lies in integrating low-carbon or carbon-neutral systems to minimise both direct and indirect emissions. Nevertheless, the literature examined indicates that other societal aspects, including social and behavioural factors, have not been thoroughly researched. This gap in knowledge could challenge the realisation of the goal of carbon neutrality by 2050 and underscores the need for further studies in these areas.