Analysis of Solar Energy Power Generation in Urban Environments

In today’s global energy and climate context, there’s an urgent need to shift towards renewable energy sources. This need is underscored by the increasing urbanization, coupled with the heightened frequency and severity of extreme weather events due to climate change. These factors have placed high pressure on our energy infrastructure, environment, economy, and society. Addressing this pressure requires a decisive shift from fossil fuel-based to renewable energy resources. Central to this transition are urban systems. High population density and increasing energy demand in cities position them at the center of the energy issue. Recent concepts such as Nearly Zero Energy Buildings (nZEB) and Districts (nZED) have brought forth discussions on energy efficiency, introducing the idea of on-site or nearby renewable energy production. In this context, solar energy is one of the most direct means of integration. Yet, a comprehensive understanding of the urban solar potential demands careful planning, design, and optimization for effective integration. This entails a comprehensive, interdisciplinary scientific approach that accounts for the complex interplay of geometric, physical, morphological, and climatic attributes within the urban environment. Challenges such as shading, inter-reflections, and microclimatic effects like the Urban Heat Island (UHI) reduce the effectiveness of solar systems and increase building energy needs. This thesis investigates this intricate subject, spanning solar engineering, building design, urban planning and climate studies. It presents a series of scientific publications, each addressing a distinct yet interconnected aspect. Initially, it focuses on the physical characterization of urban systems, with specific attention to the Urban Heat Island, emphasizing its pivotal role in urban planning and its impact on building energy simulation and performance. The research then shifts to studying solar radiation distribution in relation to urban morphological attributes. Following this, the performance of photovoltaic installations in urban settings is analysed, with a particular focus on local climatic conditions and mounting configurations. Finally, it addresses the application of concentrated solar systems, specifically Linear Fresnel Collectors (LFCs), offering a promising alternative for solar integration for industrial applications in peripheral urban areas. The key goal is to assess the challenges in implementing city-wide solar energy integration. This is mainly achieved through real-world case studies, proposing integrated workflows with diverse and coupled simulation tools. One of the key issues is to minimize the computational resources required for such large-scale analyses. Notably, these investigations encompass not only the city-scale but also extend to district-level and individual production system scales. Methodologically, a wide range of tools is employed, including analytical models and numerical simulations, tailored to each study’s specific scope and scale. These encompass simulations of urban microclimate, building energy performance, photovoltaic energy production, and ray-tracing techniques. Statistical methods also play a key role, particularly in Geographic Information System (GIS) data analyses. Data-driven techniques aid in aggregating and analyzing spatial data, enhancing understanding of urban morphologies and solar radiation distribution. Unsupervised machine learning techniques, like clustering, are deployed to unveil patterns within extensive datasets. The results of this thesis aim to prioritize the integration of solar systems in urban environments, highlighting the significance of climate mitigation strategies. Moreover, the research endeavors to provide practical urban planning guidelines for effectively addressing the requirements of energy-efficient urban development.