David Paul Jenkins

Peer-reviewed paper 8-096-26 The International Energy Agency highlights that buildings are critical for climate action, yet the sector is not on track for net zero by 2050. Achieving full decarbonisation presents major challenges, requiring bold approaches to reduce and offset emissions. Biochar, a carbon-rich by-product of biomass pyrolysis, can be used in building applications due to its carbon sequestration potential. Although awareness of biochar has grown, it is still not used at scale, and its potential remains underexploited. This research investigates the use of biochar in buildings through an interdisciplinary approach integrating social science, civil engineering, and building modelling. The aim is to deepen understanding of the physical and mechanical properties of biochar-cementitious composites, quantify their energy and carbon-saving potential across different building archetypes, and integrate multistakeholder insights. The paper presents results from the first stakeholder workshop, which identified biochar feedstocks suitable for buildings and opportunities for integrating biochar into construction materials and building elements. These insights informed the initial biochar–concrete characterisation for non-structural elements using forestry waste feedstocks. In parallel, building simulations were conducted to evaluate potential energy savings. Material characterisation showed a 14% drop in compressive strength of biochar-concrete when 10% biochar was incorporated, and at 50% offers modest operational energy and carbon savings. These results inform the second stakeholder consultation, where the Delphi method is being used to confirm the key properties required to optimise biochar-concrete. The paper sets out how interdisciplinary methods can deliver meaningful insight into technology performance and a holistic understanding of biochar’s challenges and opportunities in buildings.

Energy Performance Certificates (EPCs) are indicators of building energy efficiency and carbon emissions across Europe, following the EU Energy Performance of Buildings Directive (EPBD). Assumptions behind EPC design differ significantly across Europe, despite emanating from a common starting point. Next Generation EPCs (NGEPC) relate to recently proposed updates to the EPBD, suggesting new functions and features that EPCs could adopt to be more useful for supporting decisions on zero carbon buildings. However, faced with such variation in approaches across Europe, this paper illustrates that a single pathway for upgrading EPCs will be difficult to achieve. Faced with this challenge, the paper presents methods of EPC categorisation to identify differences across European EPC approaches in a systematic way, directly addressing the consequences of a lack of harmonisation on the design of NGEPCs. By accounting for this variation, a framework is proposed for evolving specific EPC approaches to NGEPC status, captured in a way that is replicable to other EPC methods across Europe. Whilst the paper is informed by approaches across a selection of European countries, the situation in the UK is used as a more focussed case-study, with recommendations provided for how this approach may evolve in light of NGEPC progress. Practical application: The presented work provides guidance and decision-support for implementing changes to EPC frameworks as they incorporate next-generation EPC recommendations. The work particularly reflects on EPC practice in the UK but in context of many other European countries; in effect, learning from those countries (and the wider EPBD) but also potentially having impact on the implementation challenges in multiple countries.

Using a sample of buildings across chosen European countries, this study compares different EPC frameworks in terms of their published methodologies and generated outputs. The work demonstrates that, despite all emanating from a common central point of the Energy Performance of Buildings Directive, EPC frameworks across Europe exhibit clear differences in their methodologies, use of inputs/outputs, assessment processes, and assessor protocols. A process is proposed for comparing EPCs of a building when utilising EPC frameworks from different countries, whilst noting that direct comparisons of fundamentally different processes can be challenging and itself requires a designed methodology. When applying this process, EPC ratings can appear similar (when comparing EPCs designed for similar climate zones) in many buildings, but this can underestimate the differences in generating those EPC ratings in the first place. As further innovations are designed for EPCs at the EU level, this study demonstrates why incorporating a bottom-up understanding of country-specific EPCs will be necessary for successful implementation.

Energy Performance Certificates (EPC) are used across Europe to communicate the energy performance of buildings to a range of different end users. However, as new approaches are introduced and guided at the European level via the Energy Performance Buildings Directive (EPBD), the ability of assessment methodologies and assessors to accommodate these new forms is likely to differ due to the significantly different frameworks in each country. The Horizon-funded crossCert project investigates this by identifying how EPC methodologies differ across countries, highlighting the implications of these differences on the performance gap and what that means for future innovations. Results indicate that methodologies vary considerably regarding general approaches, from highly standardised to highly tailored and assessor qualifications. This paper will look at such differences and investigate how these differences can affect future efforts towards improving EPCs. Practical application: With the recent recast of the Energy Performance of Buildings Directive (EPBD) emphasising the need for future innovations of EPCs across Europe and encouraging next-generation EPCs, it is important to study country-specific calculation methodologies. In particular, the lack of harmonisation in different approaches can make top-down innovations difficult to implement and raise questions about how an individual country can or should respond to those guidelines. This paper explores the variations in different aspects of EPC assessment methodologies across 10 European countries and how these differences impact the EPC performance gap and future metrics.

With rapid global economic growth and a rise in disposable household income, particularly within a progressively warming planet, the escalating demand for energy to achieve thermal comfort has become a salient concern in the Global South, notably in emerging economies like India. This burgeoning need for cooling solutions has not only underscored the vital role of energy consumption but has also accentuated the imperative of comprehending the ensuing implications for electricity policy and strategic planning, particularly within the ambit of the Global South. This study explored the nuanced landscape of active cooling within an intentional community, Auroville, in southern India, aiming to discern the factors underpinning household preferences and practices in the pursuit of thermal comfort. Employing a mixed-methods approach, this study contributed empirically and methodologically to the interdisciplinary discourse by analysing residential electricity consumption patterns and cooling practices within selected households in the specified community. The study unfolded in three methodological stages: firstly, an analysis of climatic data coupled with an environmental stress index (ESI) assessment; secondly, the monitoring of end-user electricity consumption followed by rigorous data analysis; and lastly, the utilisation of qualitative in-depth interviews and observational techniques. This study’s outcome yielded empirical insights into the unprecedented shifts in the ESI for Auroville since 2014. Furthermore, the study unravelled the intricate complexities inherent in occupant behaviour within residential structures, thereby offering valuable insights into the practices that shape householders’ cooling preferences. This research enriched the understanding of the dynamics of energy consumption in the pursuit of thermal comfort and contributes to the broader discourse on sustainable development and energy policy in the context of climate change.

Of the 33 global megacities, 10 were situated in South Asia. Extreme heat waves have become an annual phenomenon due to climate change in South Asian megacities, causing severe health issues and even deaths. In this study, we evaluated 29 years (1990–2019) of historical data on heat stress in ten selected megacities (existing and prospective)—New Delhi, Dhaka, Mumbai, Kolkata, Ahmedabad, Chennai, Bengaluru, Hyderabad, Chittagong, and Pune—in India and Bangladesh. We used heat index (HI) and environmental stress index (ESI) analyses to evaluate stress and vulnerability. Our results showed New Delhi, Mumbai, Kolkata, Ahmedabad, and Chennai in India; Dhaka and Chittagong in Bangladesh were already experiencing an elevated number of hours of “danger” levels of heat stress, which may lead to heat cramps, exhaustion, stroke, and even death. Furthermore, the frequency of “danger” levels of heat stress and vulnerable levels of ESI has increased significantly since 2011 in the selected megacities, which elevated the heat-related vulnerability among the millions of inhabitants in terms of work hours lost for light, moderate, and heavy work due to heat stress. The vulnerable population in the studied megacities might have to reduce annual work hours by 0.25–860.6 h (light work), 43–1595.9 h (moderate work), and 291–2402 h (heavy work) due to extreme heat in 1990–2019. We also discussed the implication of the work-hour loss on productivity, income, gross domestic product, and sustainable development goal progress because of heat stress and its causes and suggested recommendations to reduce its impact.