The global shift towards sustainable urban environments necessitates a thorough understanding of how renewable energy technologies impact thermal comfort in public spaces. This study consolidates findings from three previous works to examine the effects of building-integrated active solar energy systems in Mediterranean and Arctic coastal cities—Limassol, Naples, Thessaloniki, and Luleå. Using the Physiological Equivalent Temperature (PET) as an indicator and the ENVI-met microscale climate model, we analyzed pre- and post-integration scenarios of photovoltaic (PV) systems on building facades. Results indicate that in Mediterranean cities, PET variations ranged from 0.5 to 2.0 °C, showing a negligible impact on thermal comfort, while in Luleå, PET increases between 3.0 and 4.5 °C suggest a more noticeable influence due to solar reflections. Urban morphology and density were found to modulate these effects, with denser environments amplifying temperature fluctuations. These insights highlight the importance of integrating BIPV systems within a holistic urban design framework that balances energy efficiency with thermal comfort considerations. The study provides guidance for policymakers and urban designers on the optimal placement and design of solar-integrated buildings to enhance both energy performance and livability across diverse climates.

The global shift towards low-carbon energy systems requires targeted strategies to support the sustainable transformation of communities, particularly at local and regional levels. This special issue presents a collection of original research focused on innovative approaches to the design, optimization, and management of community energy systems based on renewable resources. The contributions address a wide range of topics, including hybrid renewable energy systems, microgrid operation, machine learning-based forecasting, photovoltaic integration, hydrogen technologies, power-to-X planning, energy storage optimization, and the role of digital platforms in smart asset control. Several papers highlight the importance of user engagement, energy justice, and the inclusion of vulnerable consumers in energy transition strategies. By combining modelling techniques with real-world case studies and practical tools, the articles in this issue offer valuable insights into the technical, economic, and social dimensions of energy transition. Overall, the special issue underscores the urgency of implementing integrated, resilient, and inclusive energy solutions to accelerate decarbonization and build sustainable communities worldwide.

Europe, including Poland, is undergoing an energy transition. The use of renewable energy sources (RES) in the national energy sector is increasing significantly, and previously unused areas are increasingly developed for photovoltaic power plants. A specific type of housing common in Eastern European countries opens an additional opportunity for photovoltaic installations without occupying usable ground area. This article aims to analyze the potential for utilizing balconies and loggias in large-panel buildings, which are characteristic of major cities in Poland. Approximately 30% of the population resides in such housing. This presents significant potential for direct use of renewable energy by apartment residents. The article also explores the legal framework for such installations, both as individual investments by apartment owners and as collective initiatives managed by building administrators. The authors analyzed the potential performance of photovoltaic installations under varying azimuths and tilt angles, considering solar irradiation potential. The analyses also encompassed different photovoltaic module technologies, covering a spectrum of photovoltaic technologies, from commonly used monocrystalline panels to advanced transparent BIPV (Building-Integrated Photovoltaics) solutions. Furthermore, the study quantified the energy potential of such installations and compared the results with existing photovoltaic capacities and electricity demand in Poland.

Access to clean cooking energy remains a significant challenge globally, particularly in regions such as Sub-Saharan Africa, the Pacific Islands, and South Asia, where urban and rural disparities are most pronounced. In the Pacific Islands, rural areas continue to rely heavily on traditional biomass, exacerbating health and environmental issues. This study reviews trends in clean cooking energy access in the Pacific, emphasizing the stark differences between urban and rural regions. Through a comprehensive analysis of regional data, policy frameworks, and case studies, we identify barriers including limited infrastructure, high costs, and lack of awareness, which hinder the adoption of clean cooking technologies. To address these challenges, we examine the potential of biogas digesters as a renewable and sustainable solution. Biogas digesters not only provide clean energy but also offer significant benefits for public health, environmental conservation, and economic development. However, their successful deployment requires comprehensive policy interventions. This study proposes actionable recommendations: introducing targeted subsidies for rural households to reduce the high upfront costs of biogas systems, leveraging public-private partnerships to develop local supply chains, integrating clean cooking technologies into national energy strategies, and using community-based education programs to raise awareness about the health and economic benefits of clean energy. Furthermore, examples of successful policy frameworks, such as Fiji’s National Energy Policy 2023 and Tuvalu’s biogas pilot projects, illustrate the importance of aligning national plans with regional clean energy goals. By aligning with Sustainable Development Goal 7 (SDG 7), which advocates for universal access to affordable and clean energy, this study underscores the broader impact of clean cooking energy solutions on agriculture, business, education, healthcare, and transportation. Bridging the clean cooking energy gap is critical for advancing public health, fostering inclusive economic growth, and achieving sustainable development in the Pacific Islands.

This chapter interrogates the often-overlooked thermal consequences of building-integrated photovoltaic systems in Mediterranean coastal cities, where the pursuit of urban sustainability collides with the persistent challenge of outdoor thermal discomfort. Through advanced microscale climate simulations using the ENVI-met model, the study evaluates the influence of building-integrated photovoltaic installations on pedestrian-level thermal comfort in Limassol, Thessaloniki, and Naples. Despite the well-documented energy benefits of photovoltaic technologies, their capacity to reshape urban microclimates remains largely unsubstantiated in these southern European contexts. The findings demonstrate that building-integrated photovoltaic systems induce only minor thermal shifts, typically between 0.5 °C and 2.0 °C, that fall short of substantially improving thermal comfort or mitigating the urban heat island effect. Notably, these effects are geographically and morphologically contingent, with east–west street canyons exhibiting the most pronounced, albeit limited, variations. The research underscores that photovoltaic integration, while essential for energy transition, cannot singularly address the complexities of urban liveability in heat-stressed environments. Effective thermal resilience in Mediterranean cities demands integrated strategies combining energy technologies with vegetative, reflective, and shading interventions. By foregrounding this critical nuance, the chapter advances a more context-sensitive, human-centred approach to sustainable urban design. 

The built environment is not a neutral backdrop to the energy transition; it is one of its most active battlegrounds. Buildings shape how energy is produced, consumed, valued, and contested, embedding within their walls the logics of markets, the rhythms of daily life, and the fractures of socio-e conomic access. Traversing within the Mediterranean city, where dense fabrics, climatic pressures, and architectural heritage collide with the urgency of sustainability, this work unravels the messy, interdependent dynamics that link energy policy, technological innovation, homeowner decision-making, valuation systems, and real estate markets. Far from offering a seamless pathway to low-carbon futures, the energy transition within the built environment is revealed as fragmented, hesitant, and socially uneven. Photovoltaic-integrated façades, bioclimatic designs, multi-storey innovations, and energy-efficient certifications circulate as promises, yet their materialization is conditioned by broken metrics, contested valuations, and persistent adoption barriers. Certification tools misrepresent performance, markets discount energy efficiency, and sustainable architecture is often reserved for the few who can afford to access it. Through a close engagement with case studies, valuation 2practices, homeowner agency, and urban design responses, a deeply situated understanding of sustainability is attempted, one that moves beyond technological prescriptions and confronts the social life of buildings. Arguing that sustainability cannot be certified into existence; it must be built, valued, negotiated, and ultimately lived. Challenging the notion of inevitable progress, while offering a narrative of entanglements, ruptures, and the everyday negotiations through which the energy transition is contested, materialized, and sometimes deferred. 

This volume reimagines the built environment not as a passive backdrop, but as a contested site where architecture, engineering, climate extremes, energy imperatives, and socio-economic inequalities converge. Sustainability is shown not as a universal mandate, but as a condition continually negotiated across uneven terrains of policy, design, and everyday inhabitation.Through contributions from leading scholars, the book examines Mediterranean cities to reveal the fractured foundations of the energy transition: fragmented regulations, misaligned certification systems, undervaluation of thermal performance, and urban fabrics that both resist and demand reinvention. Rejecting linear narratives and technocratic reductionism, the volume emphasizes the tensions between techno-optimism and the economic, infrastructural, and cultural inertias that delay transformation. Rather than offering prescriptive closure, it invites readers to grapple with contradictions that render the Mediterranean city both a site of impasse and a laboratory of renewal in the shadow of climate crisis.

This study examines the energy performance of residential buildings in Cyprus, focusing on the accuracy of the iSBEM-Cy Energy Performance Certification (EPC) system. Cyprus presents a unique context due to its Mediterranean climate and aging building stock, constructed mostly between 1980 and 2000 without energy efficiency regulations. This research investigates the discrepancies between simulated and actual energy consumption in typical Cypriot homes. Previous studies have highlighted the limitations of current EPC models, often showing significant variances between predicted and real-world energy usage. Using a comparative analysis, this study collects data from 15 residential units, examining heating, cooling, lighting, and hot water energy use. The results reveal notable differences, particularly in cooling loads, suggesting the need for improved modelling of user behaviour and local climate conditions. This research underscores the importance of accurate EPCs for effective policy-making and sustainable building practices, contributing to enhanced energy efficiency and reduced greenhouse gas emissions in the building sector. Future endeavours should prioritize integrating granular behavioural and climate-specific data to refine energy certification models further.

The imperative for energy-efficient buildings has never been more pronounced, particularly in regions where outdated infrastructure continues to undermine sustainability efforts. This chapter scrutinizes the precision of energy certification models. Despite their widespread use in certifying energy performance, their predictive reliability remains an open question. Through a comparative analysis of real-world energy consumption versus simulated estimates across common residential typologies, this research unveils critical discrepancies that call into question the accuracy of existing methodologies. Findings reveal that while heating load predictions align moderately well with actual usage, cooling and lighting consumption estimates exhibit substantial inaccuracies, raising concerns about the tool’s ability to account for climate-specific conditions and occupant behaviour, bearing broader implications. This work, indeed, serves as a clarion call for policymakers, industry professionals, and sustainability advocates to re-evaluate the efficacy of current regulatory frameworks. If energy performance certification is to fulfil its role as a driver of meaningful efficiency improvements, it must evolve beyond static models to embrace a more nuanced, data-driven approach. This work lays the groundwork for a new era in building energy evaluation – one that is rigorous, reflective of real-world conditions, and genuinely instrumental in shaping sustainable urban futures. 

This chapter investigates the socio-economic barriers hindering the adoption of bioclimatic design in the building sector, focusing on Cyprus as a representative Mediterranean case study. Utilizing a structured quantitative methodology, the study assesses the perceptions, motivations, and obstacles faced by residents in embracing sustainable construction practices. Results reveal that despite high awareness of energy efficiency benefits, financial constraints, insufficient incentives, and limited public understanding remain significant deterrents. The findings highlight critical predictors, such as gender, housing type, and the implementation of specific energy-saving measures, including photovoltaic systems and thermal insulation. Statistical analyses demonstrate the pivotal role of tailored financial policies and public engagement in overcoming these barriers. Bioclimatic design emerges as a transformative solution, integrating passive strategies like optimized building orientation, natural ventilation, and shading to reduce energy demand and enhance indoor environmental quality. However, its adoption is hindered by initial costs and regulatory challenges. The study underscores the need for integrated efforts from policymakers, practitioners, and educators to promote bioclimatic principles. It concludes by emphasizing the environmental and economic potential of sustainable architecture, offering actionable insights for advancing energy-efficient construction in resource-constrained regions. This work contributes to the ongoing discourse on climate-resilient urban development and the imperative of aligning architectural practices with ecological imperatives.