1. Introduction

2. Analytical approach

3. Climate change, urban heat island impact, nature-based solution in built environment

3.1. Climate change and urban heat island impact

In recent decades, urban areas have experienced remarkable growth, with over four hundred cities having populations exceeding one million. This trend is expected to continue, with approximately 70% of the world population projected to live in urban areas by 2050 [14]. The rapid urbanization process, characterized by the construction of buildings and pavements that absorb and store solar radiation, limited airflow due to constrained roads, and low wind speeds within urban canyons, has led to elevated temperatures in cities compared to surrounding rural areas. A horizontal temperature gradient of up to 4°C per kilometre at the urban-rural boundary has been observed [15]. Although the urban heat island phenomenon was first identified 170 years ago, it continues to be the subject of intensive research. For example, Athens experiences an average intensity of over 10°C [16-18], while London reaches 8.9 ˚C [19-21]. Urban heat islands are not limited to large cities, even small cities exhibit temperature differences of over 5°C during the summer [22]. The consequences of these urban microclimate changes include chemical weathering of building materials, environmental degradation, increased discomfort, elevated mortality rates during the summer [23], and increased demand for cooling energy and electricity generation, leading to higher levels of pollutants and GHG emissions.

The severity of urban heat island (UHI) increases due to global and urban climate change. UHI interacts with climate change and the urban environment is being affected, especially by the production of heatwaves during high heat events in summertime and magnification of the city temperature. Therefore, the thermal urban conditions are enhanced, and heat stress affects human health, especially of the most vulnerable groups [24].

Furthermore, the UHI effect significantly contributes to increased electricity demand for air-conditioning in various climatic conditions (Table 1). The heat island effect doubles the energy required for cooling buildings in Athens and triples the peak electricity load for cooling [16]. In London, the cooling load in urban areas can be 25% higher compared to rural environments [19]. The average increase of cooling energy needs globally due to UHI is 6.63 kWh/m2/y/°C and 3.81 kWh/m2/y/°C, for residential and office use, respectively [25]. Consequently, a substantial amount of electricity is needed for a short period during the summer, primally generated from fossil fuels. Moreover, the increased indoor heat caused by the UHI effect is transferred outdoors through air conditioning, further exacerbating the urban heat generated by air-conditioning, contributing to the UHI effect [26].

Among building envelope components, the glazing ratio or wall insulation has minimal impact on the change in energy demand resulting from the UHI effect [27]. Roofs are the most exposed building elements to solar radiation, leading to excessive heat flow indoors. In arid and hot areas, nearly 50% of the building’s heat load comes from the roof [28, 29]. Roof temperatures during summer can reach up to 70°C, turning surfaces into radiators and disrupting indoor thermal comfort. Additionally, day and night temperature variations cause high expansion-contraction oscillations, leading to cracks. Roofs account for more than 20% of urban accessible areas [30], and mitigation measures for the urban heat island effect can directly impact cooling loads on the top floor and throughout the entire building [31]. Therefore, applying new and innovative responsive and dynamic technologies, even for well-insulated building roofs with significant temperature attenuation, can further enhance energy efficiency and reduce cooling loads.

Due to the significance of the UHI issue and the increased energy consumption in buildings, there has been a strong impetus for research and innovation to develop appropriate methods and solutions that can mitigate the severe consequences associated with these challenges, particularly during the summer.

Table 1. Studies on the effect of urban heat island effect in building’s energy consumption.

Table 1. Studies on the effect of urban heat island effect in building’s energy consumption.

City, country	Koppen Geiger climate classification; mean annual temperature (°C)	Global horizontal irradiation (kWh/m2/y) (BIPV zone)	Urban heat island intensity (°C)	Effect on building energy consumption	Reference
Manchester, UK	Cfb (Marine West Coast Climate) 9.4	949 (1)	3°C	9.4–12.2% increase in cooling energy needs	[32]
London, UK	Cfb (Temperate) 11.3	1001 (2)	6°C	Up to 25% increase in cooling and up to 22% decrease in heating energy needs	[33]
London, UK	Cfb (Temperate) 11.3	1001 (2)	Mean daily intensity of 2°C; the mean night-time 3.2°C	Cooling energy consumption is 32–42% higher than cooling energy required for the same building based outside the urban heat island	[34]
Reading, UK	Cfb (Oceanic) 10.5	1077 (2)	0.73 °C	0.9–10.8% reduction of heating needs	[35]
Berlin, DE	Cfb (Oceanic) 10.1	1113 (2)	2.2 °C	10% reduction of energy consumption	[36]
Antwerp, BE	Cfb (oceanic) 10.6	1107 (2)	2.4–3.3 °C	60.8–90% (res); 17.3–30.6% (off) increase in cooling energy needs	[37]
Munich, DE	Cfb (Marine West Coast Climate) 8.8	1194 (2)	17% increase in heating degree hours for 1982	17% lower heating loads in the city centre than rural site	[38]
Basel, CH	Cfb (Oceanic) 9.6	1240 (2)	1.7 °C (max)	43% in demand	[39]
Toulouse, FR	Cfa (Oceanic) 13.8	1428 (2)	5.3 °C (night winter)	A 5% increase in cooling energy demand per 1 K increase in the maximum UHI effect at night.	[27]
Modena, IT	Cfa (Humid subtropical climate) 13.8	1482 (3)	1.4 °C	10% increase in cooling and 16% decrease in heating energy needs	[40]
Rome, IT	Csa (Mediterranean) 15.2	1592 (3)	8 °C	12–46% increase in cooling energy needs	[41]
Rome, IT	Csa (Mediterranean) 15.2	1592 (3)	1.4 °C	30% increase in cooling and 16% decrease in heating energy needs	[42]
Barcelona, ES	Csa (Mediterranean) 17.7	1663 (3)	4.3 °C	18–28% increase in cooling energy needs	[43]
Agrinio, GR	Csa (Mediterranean); 17.2	1727 (3)	Mean hourly UHI intensities up to 6 °C; mean intensity of 3.8 °C during nocturnal hours of August	36.3% (max) higher cooling energy needs in the city centre than the rural areasxc. (CDD: 27 °C - HDD: 18 °C)	[22]
Athens, GR	Csa (Mediterranean); 18.3	1833 (3)	10 °C	120% increase in cooling load; 27% decrease in heating needs	[16]
Western Athens, GR	Csa (Mediterranean); 18.3	1833 (3)	6 °C	66% (in 1997) and 33% (in 1998) increase of cooling energy needs	[44]
Delhi, IN	BSh (Mid-Latitude Steppe and Desert) 25.2	1921 (4)	5.9 °C	6.2% to 15.7% increase in electricity consumption	[45]
Lusail, QA	BWh (Desert) 27.2	2125 (4)	NA	5.1 to 15.6% increase of cooling energy needs	[46]

4. Solar energy technologies for urban environments

4.1. BIPV and climate mitigation

4.1.1. Building integrated photovoltaics for European cities

The construction of environmentally friendly, energy-efficient, and carbon-neutral buildings has become a focal point, emphasizing the importance of incorporating efficient energy management systems to reduce emissions significantly. In this context, Building Integrated Photovoltaics (BIPV) systems have garnered increased interest as a promising solution for decarbonizing urban environments [13]. They can be utilized either as a building's envelope material or as a retrofit for facades, enabling them to generate electricity while fulfilling architectural requirements [100]. In the literature, several BIPV studies focus on its technology [101], environmental impact [102], economic viability [103], policy support [104], and real-world case studies [105]. By examining the opportunities and challenges of BIPV, we can understand its role in creating sustainable and low-carbon cities.

Evidently, rooftop integration should be prioritized since it provides the best annual solar energy harvesting (no matter the climate zone). At the same time, combining PV systems with different azimuth and tilt angles contributes to better load-matching, reducing storage needs [106]. This particularly applies to rooftop PV systems, commonly utilized in residential buildings, and offers greater flexibility than facade systems. However, it should be noted that facade PV systems are available in various configurations that can impact energy performance and indoor comfort [107]. An excellent demonstration of a rooftop BIPV installation corresponds to Umwelt Arena [108]. This remarkable structure features an octagonal design with 33 distinct surfaces, highlighting the limitless possibilities of architectural spaces. Remarkably, the BIPV system implemented in this facility achieves a zero CO₂ balance while generating twice the energy required to power the building [109].

However, the limited roof area, aesthetic considerations, and passive energy strategies highlighted façade-integrated photovoltaic systems as promising solutions for zero-energy buildings in different European countries. Such systems can be particularly advantageous in regions with higher latitudes and cold climates, where sunlight exposure is comparable to tilted roof integration during the cold season (when energy demand is high). The suggested practical values for implementing BIPV on facades and roofs range from 800 kWh/m²/year to 1000 kWh/m²/year [110]. Nevertheless, lower values of 600 kWh/m² can be justified considering the cost reduction and advancements in the PV industry [111]. This has been successfully demonstrated in North Europe's public (Copenhagen International School), commercial (Solsmaragden, Oslo), and residential (Frodeparken, Uppsala) buildings [112]. Although, additional energy sources (wind, biodiesel) are needed to meet heating needs and achieve the zero-energy target.

At lower latitudes and cities with moderate climate conditions, the integration approach starts with roof PV installations, followed by facade and shading structures. This sequential approach has demonstrated significant energy reduction and overall building efficiency advantages. An illustrative instance of this is the utilization of fixed or adjustable PV shading systems, which generate electricity and offer sun protection while ensuring minimal interference with winter solar gains in buildings. In this regard, the idea of a folded façade (zig-zag geometry) has been implemented for the ENERGY base office in Vienna [113]. Opaque PV modules are optimally oriented to receive the maximum solar radiation while providing shade, and the tilted glass panes (70% WWR) deliver daylight indoors. With a specific yield comparable to a rooftop PV system, up to 77% of the produced electricity is self-consumed, contributing 34% to the building energy demand (ranging between 18-22 kWh/m²) [113]. In another BIPV configuration, vertical blinds along the facade have been installed on a laboratory building in Petten, Netherlands. Electricity generation from the rooftop and façade integrated PVs was relatively high corresponding to 90% of the electricity demand. In addition, the proposed PV louver system optimized solar gains on the PV modules provided adequate shading during summer (no cooling is needed) and diffused/distributed daylight indoors [114]. Finally, BIPV elements as fixed external devices (vertical fins) were used to complement the rooftop PV system in the City Hall building in Freiburg (almost all around the façade), controlling the daylight and solar gains to the interior [115]. Results after the first year of monitoring indicated that even though it only contributed to approx. 18% of the total solar gain, in addition to the PV installation of the roof, façade BIPV is indispensable to reach the net plus-energy objective in such a building [116].

In warm-climate cities of Southern Europe (such as Lisbon), integrating BIPVs can transform buildings into net zero or even Positive Energy Buildings [117]. While incorporating PV systems on rooftops already has a positive effect on the thermal needs of buildings, traditional horizontal PV mounting often demands significant space. To address this challenge, both established and innovative BIPV technologies can be utilized as integral components of the building envelope, optimizing self-sufficiency and self-consumption. However, careful design is needed to cope with the overheating of the modules. An example of such an installation with a high level of detail was provided by Martín-Chivelet et al. (2018) [118] for a case study building in Madrid. This study presented an affordable and uncomplicated architectural approach for renovating buildings by incorporating standard PV modules into a newly designed ventilated façade. In addition, PV shading devices (PVSD) have shown favourable results in reducing cooling loads and increasing electricity generation potential in low latitudes [94, 119].

Similarly, semi-transparent PV (STPV) glazing [120] is unsuitable for cold climates due to overcooling in winter but has been proven to be beneficial for reducing solar gains and achieving energy savings, as documented by several experimental and simulation investigations for different Mediterranean cities. For instance, STPV windows were found to reduce heat gains by 30%, leading to a temperature drop of up to 2.5°C for an office room in Western Greece [121]. Their passive benefits were also confirmed by Cannavale et al. (2017) [122] for real case building in Southern Italy. The authors found that PV glass integrated as window and horizontal overhangs can lead to up to 22% net energy reduction with notable visual comfort benefits.

Hence, based on the preceding paragraphs, it becomes evident that the integration of photovoltaics into buildings surpasses the narrow scope of electricity generation, as observed in standalone PV systems. When addressing BIPV installations, it becomes imperative to consider their adaptability, which pertains to the capacity of the PV power system to modulate its electricity production in response to load variations. Other factors, such as aesthetics, shading from neighbouring structures, and existing support systems, also contribute to the need for flexible PV installations in densely populated areas. In this context, the characterization of BIPV technologies and their integration flexibility within specific building components becomes a multifaceted process. This review elucidates that local climate is significant in determining the optimal PV technology solution for building integration and enhancing energy flexibility. A compilation of real case buildings featuring integrated photovoltaic systems, along with their key findings pertaining to different European climates, is presented in Table 3.

4.1.2. BIPV and urban heat island

The urban environment requires further investigation in terms of building photovoltaics thermal or cooling effect and mostly studies have been focused on rooftop photovoltaics (RTPV) deployment. The rate of absorption of solar energy fluctuates according to the different spectral ranges and is not always higher with PV than the albedo rate, therefore, releasing the excess difference to the environment as heat, daily, diurnal, or seasonally. The latter develops thermal potential in local and even large, scaled impacts in urban islands. Therefore, using highly efficient PV panels reduces the heat waste in the environment and the risk of urban heating. The higher the photon-to-charge efficiency the lower the heat waste to the environment and the probability of the risk events. The interactions around the RTPV are well documented by modelling but lacks experimental evidence and remains at the top of the research due to the multi impacts in the energy and built environment and different climates. The solar flux exchanges and the balance in every layer are continuously changing both the irradiation parameters, the heat transfer characteristics and an interplay between the cooling and heating fluxes within a broad spectrum of incoming solar irradiation is of paramount importance to the sustainable energy transition.

In a daily operation with standard RTPV installations and built materials, the corresponding electricity production is accompanied by shading effects which in turn reduce the radiation and the emissivity downwards and upwards, while parameters as local temperature, wind speed and humidity interfere as disturbances in addition to evaporation and condensation phenomena.

On the other hand, during the diurnal operation, as the longwave radiation emission is blocked, it interferes with external and internal conditions, building upon the occurred difference. Internal and external comfort is positively and negatively affected, and this is a complicated process with contradicting parameters. The simulation results are not always accurate since the longwave radiation and other local effects need validation with experimental data to approach the performance behaviour better. Consequently, the above-mentioned results are integrated into the urban scale effects.

Another aspect worth investigating is the climate diversity effects, which characterize the building and the urban built environment, on a large scale. Indeed, in our previous works [13], where we distinguished the worldwide effects in four zones, depending on their discrete global horizontal irradiation, we addressed different effects of the BIPV or RTPV across these zones. Therefore, further analysis regarding the urban heat diffusion effects is expected to differentiate respectively and reveal the associated processes.

The wide installation of RTPVs in roof spaces must always be considered in alignment with the localized conditions and accompanied by a careful study of the heat waves on the urban scale. Besides the RTPVs, the appropriate design of mixed configurations, minimize the harmful effects of the urban islands or turn it in positive (for example, cool materials and PV with tuneable reflectance, depending on the climatic zone, could manage the sensible heat upwards or the longwave radiation). The positive effect against urban island is further increased when the latter surfaces are combined with open green spaces.

Several studies have been conducted to define the effect of PV deployment on the UHI in urban environments. Taha (2013) [127] stated that the effective albedo, equals to the reflectivity corresponding to the annual mean value of diurnal hours plus the solar conversion efficiency, is the main surface characteristic that changes due to the PV panels deployment. The surface radiation balance and the local interactions between the PV panels and the back and bare surrounding surfaces albedo need appropriate modification strategies to vanish the negative impacts of the heat waves. Furthermore, the analysis showed that, in Europe, considering mean values, the increase of solar energy conversion more than 20% would induce an ambient cooling effect under certain climate conditions, back and bare surfaces integration and PV potential deployment within the urban matrix [92]. The potential of the localized impact is a more complicated process, including climate parameters, heat transfer dynamics, discrete and sudden events, architecture, and technical parameters influence and spatial to name some. Furthermore, due to possible synergetic effect of thermal waves and urban heat island, thermal stresses in cities become stronger during the respective periods and increase the vulnerability and thermal risks in urban areas, requiring more detailed analysis of the balancing model to reveal the effects [128,129].

The solar energy harvesting optimization turns into a difficult task due to the contradicting effects in urban spaces modelling. The dark surfaces of PV modules and building glasses suffer from low reflectivity of solar energy which together with high incident angles of irradiance, both reduce the efficiency and the output and make vertical surfaces to demand enhanced optimization strategies tasks. The RTPV modules impact the PV induced heat island by increasing the ambient temperature where the vegetation and cool roofs reduce the temperature, depending on the hour and the PV efficiency [130,131]. The compromise between the maximization of open of green areas, RTPV modules, cool roofs and façade placed PV needs a comprehensive analysis considering the aforementioned UHI effects [132].

Table 4. Studies on the RTPV interactions with urban heat island.

Table 4. Studies on the RTPV interactions with urban heat island.

City/country	Variables and simulations	Remarks on UHI effects	Reference
Europe	Effective and modified albedo, absorptivity, potential of PV deployment	0.05 effective albedo increase, and solar conversion efficiency increase from 10% to 20% is equivalent Cooling effect to the surroundings is expected at solar conversion efficiency values more than 20%, in Europe	[127]
France	Energy plus modelling, Surface Energy Balance	Reduces the effect on UHI in summer due to radiative and convection fluxes. Reduces the air condition demand by reducing the cooling needs. Slightly increase the heating demand in winter	[133]
Toronto	Urban Temperature Comfort Index, UHI mitigation scenarios under trees coverage and RTPV, Simplified analysis, convection effects lacking	Thermal stress is stronger in places perpendicular to the south – east wind directions. PV roofs with shortwave radiation larger than that of bare surfaces seemed cooler and offered less sensible heat to the air. The PV interventions in air temperature limited about 5m below the roof. Humidity, mean radiant temperature and wind speed are also affect the outdoor thermal comfort	[128]
Paris Strasbourg Marseille	Passive cooling assessment with two key performance indicators Cool roof, natural ventilation and RTPV comparison for UHI mitigation	RTPV as a shading device depicts a slight increase of the nearby environment heat. Cool Roofs mitigate the rejected heat to the environment up to 50% in all three cities with temperate climates due to increased albedo. Nocturnal night ventilation has no or low impact in the outdoor cooling potential	[134]
Roma	Energy plus simulation with Open Studio plug in coupled with Urban Weather Generator, UHI free and UHI influenced comparison are examined. PV model based on Energy plus is used	Both energy demand and supply optimization are needed to be integrated with urban climatic conditions and radiation UHI increased the building energy demand for air conditioning while the PV electricity supply declined by 0.33% In Net Zero Energy Building Districts (NZEB) the 60% façade PV covering reduced the modules productivity by 11% and more RTPV are needed to fill the gap.	[132]

4.1.3. The effect of BIPV on the built and urban environment of Europe

Building integration of photovoltaics affect their surrounding environment with a variable effect, influenced by many parameters and processes as the local global horizontal irradiation, PV geometries, PV-solar interaction properties (efficiency, albedo, thermal storage capacity, heat transfer and radiative loss), surface conditions underneath the photovoltaic panels (before and after panel deployment), wind direction and speed, heat balance of the surrounding environment (e.g., presence of water bodies with increased evaporation), sky-view factor and prevailing atmospheric conditions as temperature, humidity, precipitation and snow. Due to the large and wide variability of these parameters and the approximations used in modelling, conflicted conclusions have been reported in the scientific literature with both positive and negative effects of BIPV on the built environment.

In high-latitude climate, the literature review revealed that urban studies in the European cities are mainly concentrated on PV building integration and their effect on building energy performance or indoor environment. Outdoor effects are less studied especially in the high-latitude climate with a significant research gap in the studies on solar accessibility for the built environment and in agreement with the recent study of Formolli et al. 2023 [135].

In the warm urban microclimate of a strong heatwave at European mid-latitudes (or typical climate conditions of low latitude cities as in South Europe) with maximum summertime temperatures of 36°C and minimum of 27°C, Zonato et al., 2021 [136] found that rooftop photovoltaics have a positive effect on the building energy consumption (up to 210%) for all the studied urban configurations due to the electricity produced by the installed photovoltaics. In their study, a very low roof reflectance of 0.11 was used which combined with 0.19 PV efficiency attributes the largest remaining fraction of the incoming radiation to be converted in sensible heat and be transferred by convection in the surrounding environment. Therefore, air temperature at 2m in the PV environment increases during daytime with a peak of 1.5°C early in the morning and decreases at night up to 0.5°C due to the reduced heat stored in the building and emitted at night-time. In contrast, cool and green roofs were found to be more effective in reducing the 2m air temperature. Same results were also recently observed by Tan et al. (2023) [137] in the city-scale of the climate of Chicago (GHI: 1440 kWh/m²/y and considering a heatwave of 35°C) by applying a regional scale model of high resolution coupled with a building energy model and PV with albedo, efficiency, and emissivity of 0.2, 0.19, 0.90, respectively in parallel and unattached to the roof, parametrization. The model was validated by measuring 2m air temperatures with a good agreement but underestimated the 10m wind speed (and probably the daytime convective warming during the day due to the heat transferred from PV panels). In this work, the rooftop PV panels decreased the daytime temperature up to 0.6°C, a value lower than the corresponding of green roofs (1.2°C) and cool roofs (1.5°C). The daily average air-conditioning needs were reduced by 7.6 %, 14% and 16.6 % for RTPVs, green and cool roofs, respectively [137]. However, energy savings due to photovoltaics were increased to 46.7% by also summing electricity production.

In addition, the positive PV effect in the reduction of energy consumption is even higher if a higher reflectance is used. 17.8% reduction of the building cooling needs was determined with the RTPV deployment for a roof reflectance of 0.45 by Kapsalis et al., 2015 [138]. The reduction can take even higher values for several climatic zones if a white roof is considered underneath the photovoltaics panels [139] or these are installed on top of green roofs [136]. In these cases, the potential PV heat effect in increasing air-temperature is counterbalanced either directly by white roofs beneath the PVs or indirectly by the green roof for all the diurnal cycle with a positive additional effect in the night-time and wintertime. However, PV panels over a cool or a green roof increase the heat flux in the built environment, especially in warm and hot climate, compared to each solution [139]. Therefore, the excess heat generated in the PV environment can be dissipated by the use of phase change materials or thermal systems in PV/T combinations or with the installation of green walls. According to the results assessed in this review, the deployment of rooftop PV for electricity production and radiation shading combined with green walls as shadings and reducing both sensible and latent heat can be synergistically beneficial for the warm and hot climatic zones. Since green space is the most effective greenery mitigation strategy for the street-level UHI air temperature reduction during the summertime in almost all climatic zones of Europe with high sensible heat, the rooftop PV deployment should be ad hoc accompanied with the increase of trees and canopy cover in the urban environment. Towards sufficiency in energy production and a healthy urban environment, the potential air temperature increase per deployed PVs in hot climate should be balanced by an effective equivalent air temperature decrease per surface area of added vegetation. This first approximation in energy budget assumes a normalized equivalence between the two effects and a linear cooling from urban greenery. Since the research field of the synergistic effects of NBS and solar technologies in the urban energy budget is complex with the absence of large-scale experimental measurements, it needs particular attention and beyond integrated simplifications and approximated modelling.

It should also be noted that air temperature is an important factor to control in the urban environment and appropriate to start urban planning. However, all the parameters affecting indoor and outdoor thermal comfort like urban geometry, humidity, radiant load, and ventilation should be subsequently integrated in the thermal comfort design of urban neighbourhoods with the strategic goal of a sustainable planning with protection and enhancement of ecological systems and processes and reduction of GHG emission and use of resources. In this context, the co-function of different UHI and climate change mitigation methods in the strategic management of urban spaces will be maximized and succeed in making cities resilient to heat stresses, sustainable and liveable.

In the warm and hot climatic zones of the cities above and below Mediterranean Sea, the severity of microclimate change with UHI is high and will be further exacerbated from climate change with intense heatwaves, health effects and lives threats. In these urban areas, water bodies are the most effective UHI mitigation method in temperature reduction due to the transformation of the largest part of environmentally sensible heat in evaporated water vapor. However, the increase of humidity partially counterbalances the high improvement of urban thermal comfort. Therefore, the effectiveness of green spaces in the latter is higher due to the shading effect of trees and partially (around 0.3) reflection of incoming irradiation back to the atmosphere in addition to the heat reduction through evaporation and transpiration. The effect has been quantitively characterized by ENVI-met modelling in the hot climate of Beirut, Lebanon by comparing “green” and “blue” models [140]. In the same study, a “white” model with cool materials was found to positively affect only main roads and places with high sky-view factors during the daytime compared to shaded areas. Therefore, urban parks with greenery and water bodies, cool materials for roads and pervious pavements are essential means to regulate the heat released in the built environment while BIPV deployment is required for deep decarbonization and sustainability of the urban landscape.

Moreover, sufficiency at different scales (neighbourhood, district, city) may require additional technological solutions to overcome the intermittent nature of solar energy, especially in the mid- and high-latitude cities. In this case, energy storage can be used at the corresponding scale of PV deployment. On the building and neighbourhood scale, the interconnection of building energy to electric vehicles storage system can provide a mitigating solution to the diurnal lack of solar electricity accessibility and at all climatic conditions. In the district level, heating and cooling storage at a seasonal level have been successfully combined with RTPVs in the mid- and high- latitudes cities for positive energy districts. Use of NBS based on water bodies and grey urban infrastructure as a storage medium is another opportunity to merge solar technological to natural solutions. Ultimately, carbon neutrality at the city level can be attained by full decarbonization from fossil fuels and electrification with additional utility-scale solar energy applications, if needed, and large-scale storage by hydro-pumps.

5. Harnessing solar energy and nature-based solutions

6. Conclusions

References

1. Smith, R. COP26 diary: making health central to tackling climate change. BMJ 2021, 375, n2728. [Google Scholar] [CrossRef]
2. IEA - Empowering cities for a net zero future. Available online: www.iea.org/reports/empowering-cities-for-a-net-zero-future (accessed on 5 June 2023).
3. Grafakos, S.; Viero, G.; Reckien, D.; et al. Integration of mitigation and adaptation in urban climate change action plans in Europe: A systematic assessment. Renew. Sustain. Energ. Rev. 2020, 121, 109623. [Google Scholar] [CrossRef]
4. EEA - Urban Europe - statistics on cities, towns and suburbs. Available online: https://www.eea.europa.eu/data-and-maps/daviz/urban-europe-statistics-on-cities-2 (accessed on 5 June 2023).
5. EC - NBS for Cities: NBS for Climate Change Mitigation and Adaptation in Urban Areas - Action 10a. Available online: https://ec.europa.eu/environment/nature/ecosystems/pdf/NBS_leaflet_web.pdf (accessed on 6 June 2023).
6. (IEA - Global CO2 emissions in 2019. Available online: https://www.iea.org/articles/global-co2-emissions-in-2019 (accessed on 6 June 2023).
7. IPCC, 2022: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [P.R. Shukla, J. Skea, R. Slade, A. Al Khourdajie, R. van Diemen, D. McCollum, M. Pathak, S. Some, P. Vyas, R. Fradera, M. Belkacemi, A. Hasija, G. Lisboa, S. Luz, J. Malley, (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA. [CrossRef]
8. Shi, X.; Abel, T. ; Wang, L Influence of two motion types on solar transmittance and daylight performance of dynamic façades. Solar Energy 2020, 201, 561–580. [Google Scholar] [CrossRef]
9. Chan, HY.; Riffat, SB. , Zhu J. Review of passive solar heating and cooling technologies. Renew. Sustain. Energ. Rev. 2010, 14, 781–789. [Google Scholar] [CrossRef]
10. Orosa, JA.; Oliveira, A. Energy saving with passive climate control methods in Spanish office buildings. Ener. Build. 2009, 41, 823–828. [Google Scholar] [CrossRef]
11. Liu, H.-Y.; Jay, M.; Chen, X. The Role of NBS for Improving Environmental Quality, Health and Well-Being. Sustainability 2021, 13, 10950. [Google Scholar] [CrossRef]
12. Aalmo, G.O.; Gioli, B.; Rodriguez, D.G.P.; et al. Development of a Novel Framework for the Assessment and Improvement of Climate Adaptation and Mitigation Actions in Europe. Front. Sustain. Cities. 2022, 4, 1–12. [Google Scholar] [CrossRef]
13. Skandalos, N.; Wang, M.; Kapsalis, V.; et al. Building PV integration according to regional climate conditions: BIPV regional adaptability extending Köppen-Geiger climate classification against urban and climate-related temperature increases. Renew. sustain. Energy. rev. 2022, 2022. 169, 112950. [Google Scholar] [CrossRef]
14. UN - 68% of the world population projected to live in urban areas by 2050. Available online: https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html (accessed on 8 June 2023).
15. Oke, R. Boundary Layer Climates, 2nd ed.; Rontledge: London, UK, 1987; p. 289. [Google Scholar]
16. Santamouris, M.; Papanikolaou, N.; Livada, I.; Koronakis, I.; Georgakis, C.; Argiriou, A.; Assimakopoulos, D.N. On the impact of urban climate on the energy consumption of buildings. Sol. Ener. 2001, 70, 201–216. [Google Scholar] [CrossRef]
17. Santamouris, M. Cooling the Cities: A Review of Reflective and Green Roof Mitigation Technologies to Fight Heat Island and Improve Comfort in Urban Environments. Sol. Ener. 2007, 81(6), 755–769. [Google Scholar] [CrossRef]
18. Santamouris, M.; Ding, L.; Fiorito, F.; et al. Passive and active cooling for the outdoor built environment – Analysis and assessment of the cooling potential of mitigation technologies using performance data from 220 large scale projects. Sol. Ener. 2017, 154: 14-33. [CrossRef]
19. Kolokotroni, M.; Zhang, Y.; Watkins, R. The London Heat Island and building cooling design Sol. Energy 2007, 81, 102–110. [Google Scholar]
20. Kolokotroni, M.; Giridharan, R. Urban heat island intensity in London: An investigation of the impact of physical characteristics on changes in outdoor air temperature during summer. Sol. Ener. 2008, 82, 986–998. [Google Scholar] [CrossRef]
21. Kolokotroni, M.; Davies, M.; Croxford, B.; Bhuiyan, S.; Mavrogianni, A. A validated methodology for the prediction of heating and cooling energy demand for buildings within the Urban Heat Island: Case-study of London. Sol. Ener. 2010, 84, 2246–2255. [Google Scholar] [CrossRef]
22. Vardoulakis, E.; Karamanis, D.; Fotiadi, A.; Mihalakakou, G. The urban heat island effect in a small Mediterranean city of high summer temperatures and cooling energy demands. Sol. Ener. 2013, 94, 128–144. [Google Scholar] [CrossRef]
23. Wong, KV.; Paddon, A.; Jimenez, A. Review of world urban heat islands: many linked to increased mortality. J. Ener. Resour. Tech. 2013, 135, 022101–12. [Google Scholar] [CrossRef]
24. Luber, G.; McGeehin, M. Climate change and extreme heat events. Am. J. Prev. Med. 2008, 35, 429–435. [Google Scholar] [CrossRef] [PubMed]
25. López-Guerrero, RE.; Verichev, K.; Moncada-Morales, GA.; Carpio, M. How do urban heat islands affect the thermo-energy performance of buildings? J. Clean. Prod. 2022, 373, 133713. [Google Scholar] [CrossRef]
26. De Munck, C.; Pigeon, G.; Masson, V.; Meunier, F.; Bousquet, P.; Tremeac, B.; Merchat, M.; Poeuf, P.; Marchadier, C. How much can air conditioning increase air temperatures for a city like Paris, France? Int. J. Climatol. 2013, 33, 210–227. [Google Scholar] [CrossRef]
27. Bueno, B.; Norford, L.; Pigeon, G.; Brittera, R. A resistance-capacitance network model for the analysis of the interactions between the energy performance of buildings and the urban climate. Build. Environ. 2012, 54, 116–125. [Google Scholar] [CrossRef]
28. Nahar, NM.; Sharma, P.; Purohit, MM. Studies on solar passive cooling techniques for arid areas. Ener. Conver. Manag. 1999, 40, 89–95. [Google Scholar] [CrossRef]
29. Florides, GA.; Tassou, SA.; Kalogirou, SA.; Wrobel, LC. Review of solar and low energy cooling technologies for buildings. Renew. Sustain. Ener. Rev. 2002, 6, 557–572. [Google Scholar] [CrossRef]
30. Akbari, H.; Rose, SL.; Taha, H. Analyzing the land cover of an urban environment using high-resolution orthophotos. Land Urban Plan 2003, 63, 1–14. [Google Scholar] [CrossRef]
31. Spala, A.; Bagiorgas, HS.; Assimakopoulos, MN.; Kalavrouziotis, J.; Matthopoulos, D.; Mihalakakou, G. On the green roof system. Selection, state of the art and energy potential investigation of a system installed in an office building in Athens, Greece. Renew Ener 2008, 33, 173–177.
32. Skelhorn, CP.; Levermore, G.; Lindley, SJ. Impacts on cooling energy consumption due to the UHI and vegetation changes in Manchester, UK. Ener. Build. 2016, 122, 150–159. [Google Scholar] [CrossRef]
33. Kolokotroni, M.; Zhang, Y.; Watkins, R. The London Heat Island and building cooling design Sol. Energy 2007, 81, 102–110. [Google Scholar]
34. Kolokotroni, M.; Davies, M.; Croxford, B.; Bhuiyan, S.; Mavrogianni, A. A validated methodology for the prediction of heating and cooling energy demand for buildings within the Urban Heat Island: Case-study of London. Sol. Ener. 2010, 84, 2246–2255. [Google Scholar] [CrossRef]
35. Xie, X.; Sahin, O.; Luo, Z.; Yao, R. Impact of neighbourhood-scale climate characteristics on building heating demand and night ventilation cooling potential. Renew. Energy 2020, 150, 943–956. [Google Scholar] [CrossRef]
36. Jin, L.; Schubert, S.; Fenner, D.; Meier, F.; Schneider, C. Integration of a building energy model in an urban climate model and its application. Boundary-Layer Meteorol. 2021, 178, 249-281. [CrossRef]
37. Toparlar, Y.; Blocken, B.; Maiheu, B.; Van Heijst, G.J.F. Impact of urban microclimate on summertime building cooling demand: a parametric analysis for Antwerp, Belgium. Appl. Energy 2018, 228, 852–872. [Google Scholar] [CrossRef]
38. Briindl, W.; Hoppe, P. Advantages and disadvantages of the urban heat island – an evaluation according to the hygro-thermic effects. Arch. Meteo. Geophys. Bioclim. B 1984, 35, 55–66. [Google Scholar] [CrossRef]
39. Allegrini, J.; Dorer, V.; Carmeliet, J. Influence of the urban microclimate in street canyons on the energy demand for space cooling and heating of buildings. Energy Build. 2012, 55, 823–832. [Google Scholar] [CrossRef]
40. Magli, S.; Lodi, C.; Lombroso, L.; Muscio, A.; Teggi, S. Analysis of the urban heat island effects on building energy consumption. Int. J. Ener. Environ. Eng. 2015, 6, 91–99. [Google Scholar] [CrossRef]
41. Zinzi, M.; Carnielo, E. Impact of urban temperatures on energy performance and thermal comfort in residential buildings. The case of Rome, Italy. Ener. Build. 2017, 157, 20-29. [CrossRef]
42. Guattari, C.; Evangelisti, L.; Balaras, C.A. On the assessment of urban heat island phenomenon and its effects on building energy performance: a case study of Rome (Italy). Energy Build 2018, 158(2018), 605–615. [Google Scholar] [CrossRef]
43. Salvati, A.; Roura, HC.; Cecere, C. Assessing the urban heat island and its energy impact on residential buildings in Mediterranean climate: Barcelona case study. Ener. Build. 2017, 146, 38–54. [Google Scholar] [CrossRef]
44. Hassid, S.; Santamouris, M.; Papanikolaou, N.; Linardi, A.; Klitsikas, N.; Georgakis, C.; Assimakopoulos, D.N. The effect of the Athens heat island on air conditioning load. Ener. Build. 2000, 32(2), 131–141. [Google Scholar] [CrossRef]
45. Kumari, P.; Kapur, S.; Garg, V.; Kumar, K. Effect of surface temperature on energy consumption in a calibrated building: a case study of Delhi. Climate 2020, 8, 2–15. [Google Scholar] [CrossRef]
46. Kamal, A.; Abidi, SMH.; Mahfouz, A.; Kadam, S.; Rahman, A.; Hassan, IG.; Wang, LL. Impact of urban morphology on urban microclimate and building energy loads. Ener. Build. 2021, 253, 111499. [Google Scholar] [CrossRef]
47. Kabisch, N.; Qureshi, S.; Haase, D. Human-environment interactions in urban green spaces — A systematic review of contemporary issues and prospects for future research. Environmental Impact Assessment Review, 2016, 58, 1–14. [Google Scholar] [CrossRef]
48. Hyde, R.; Woods, P. Climate Responsive Design: A Study of Buildings in Moderate and Cold Climates, 1^st ed.; Taylor & Francis Ltd, 2000, pp. 256.
49. EC - Building on EU nature laws – biodiversity proofing urban projects. Available online: https://ec.europa.eu/environment/nature/ecosystems/index_en.htm (accessed on 7 June 2023).
50. Berndtsson, J.C. Green Roof Performance Towards Management of Runoff Water Quantity and Quality: A Review. Ecological Engineering 2010, 36(4), 351–360. [Google Scholar] [CrossRef]
51. Getter, K. L.; Rowe, D. B. The Role of Extensive Green Roofs in Sustainable Development. HortScience 2006, 41(5), 1276–1285. [Google Scholar] [CrossRef]
52. Browning, W. D.; Ryan, C. O.; Clancy, J. O. 14 Patterns of Biophilic Design: Improving Health and Well-Being in the Built Environment. Terrapin Bright Green LLC: New York, USA, 2014, pp. 64.
53. Kellert, S. R.; Heerwagen, J. H.; Mador, M. L. Biophilic Design: The Theory, Science and Practice of Bringing Buildings to Life, 1^st ed.; Wiley, 2008, pp. 432.
54. Specht, K.; Siebert, R.; Hartmann, I.; Freisinger, U. B.; Sawicka, M.; Werner, A.; Thomaier, S. Urban Agriculture of the Future: An Overview of Sustainability Aspects of Food Production in and on Buildings. Agriculture and Human Values, 2014, 31(1), 33-51.
55. Orsini, F.; Gasperi, D.; Marchetti, L.; Piovene, C.; Draghetti, S.; Ramazzotti, S.; Bazzocchi, G.; Gianquinto, G. Exploring the Production Capacity of Rooftop Gardens (RTGs) in Urban Agriculture: The Potential Impact on Food and Nutrition Security, Biodiversity and Other Ecosystem Services in the City of Bologna. Food Security, 2014, 6(6), 781-792.
56. Givoni, B. Passive and Low Energy Cooling of Buildings. Wiley, 1994, pp. 272.
57. Benyus, J. M. Biomimicry: Innovation Inspired by Nature. Harper Perennial, 2002, pp. 308.
58. Pawlyn, M. Biomimicry in Architecture. RIBA Publishing, 2016, pp. 176.
59. Thaicharoen, A.; Chirarattananon, S. Energy Management System for Green Buildings Based on Internet of Things (IoT) and Computational Intelligence. Sustainable Cities and Society, 2018, 38, 709-718.
60. Zhang, Y.; Wu, J.; Jiang, B.; Zhou, C. Smart Green Building: An Implementation of Sustainable Development Goals. Journal of Cleaner Production, 2018, 192, 26-35.
61. Baudron, F.; Delaporte, A.; Corbeels, M.; Herrera, J. M. How climate and socioeconomic factors determine the sustainability of NBS for watershed services. Environmental Research Letters, 2019, 14(3), 034038. [CrossRef]
62. UNEP - Making peace with nature: A scientific blueprint to tackle the climate, biodiversity and pollution emergencies. Available online: https://www.unep.org/resources/making-peace-nature (accessed on 8 June 2023).
63. World Bank - NBS for sustainable development. Available online: https://www.worldbank.org/en/topic/environment/brief/nature-based-solutions (accessed on 8 June 2023).
64. Makhzoumi, J.; Pungetti, G. Green roofs in semi-arid and arid climates: Research and design possibilities. Urban Ecosystems, 2013, 16(2), 241-251. [CrossRef]
65. Yahdjian, L.; Ghermandi, L.; Chertcoff, M.; van Renterghem, T.; Monteverdi, M.; Renison, D. Designing green roofs for arid and semi-arid environments: A review. Journal of Arid Environments, 2020, 179, 104160. [CrossRef]
66. Raimondo, F.; Domina, G.; Spadaro, V. Native plant species for extensive green roofs in Mediterranean climates. Ecological Engineering, 2018, 118, 87-94. [CrossRef]
67. Lundholm, J. T. Plant species and functional group combinations affect green roof ecosystem functions. PLOS ONE 2015, 10(6), e0128001. [Google Scholar] [CrossRef]
68. Stovin, V.; Vesuviano, G.; Kasmin, H. Green roof vegetation for enhanced rainwater retention: The importance of plant species choice. Ecological Engineering 2017, 98, 123–124. [Google Scholar] [CrossRef]
69. Smolders, S.; Keuckelaere, M. D.; Van Eetvelde, V. Reconnecting the Blue and Green Heart of Antwerp: Collaborative Water System Planning and Design of Blue-Green Infrastructure. Sustainability, 2021, 13(4), 1937. [CrossRef]
70. Gaterell, M.; Ashley, R.; Tucker, G. Waterways as green infrastructure: Demonstration projects in Thamesmead, UK. Urban Water Journal 2016, 13(4), 422–433. [Google Scholar] [CrossRef]
71. Frantzeskaki, N.; Tillie, N. Urban nature development and climate adaptation: A transformative perspective on green space development in Rotterdam. Environmental Science & Policy 2017, 77, 15-24. [CrossRef]
72. Massetti, L.; Mattioli, W.; & Paletto, A. Urban forest and city resilience: A comprehensive assessment framework. Urban Forestry & Urban Greening 2018, 32, 120-132. [CrossRef]
73. Getter, KL.; Rowe, DB.; Robertson, GP.; Cregg, BM.; Andresen, JA. Carbon sequestration potential of extensive green roofs. Environ Sci Technol 2009, 43, 7564–7570. [Google Scholar] [CrossRef] [PubMed]
74. Nguyen, P. A.; van Bokel, R.; van den Dobbelsteen, A. Effects of a Vertical Green Façade on the Thermal Performance and Cooling Demand: A Case Study of a Tube House in Vietnam. Journal of Facade Design and Engineering 2019, 7(2), 45–64. [Google Scholar] [CrossRef]
75. CABERNET - NBS and Re-Naturing Cities. Available online: https://www.renaturecities.eu/media/1905/nbs-and-re-naturing-cities-summary-brief.pdf (accessed on 9 June 2023).
76. PBL Netherlands Environmental Assessment Agency. Enhancing urban nature provision in the Netherlands. PBL Netherlands Environmental Assessment Agency: The Hague, Netherlands, 2023, pp. 87. T: Environmental Assessment Agency.
77. The Rotterdam Climate Change Adaptation Strategy. Available online: https://prospectcv2030.com/wp-content/uploads/2019/12/Bass-Amelung-2.pdf (accessed on 8 June 2023).
78. The benefits of living walls. Available online: https://www.livingroofs.org/living-walls/the-benefits (accessed on 8 June 2023).
79. Gholami, M.; Barbaresi, A.; Tassinari, P.; Bovo, M.; Torreggiani, D. A Comparison of Energy and Thermal Performance of Rooftop Greenhouses and Green Roofs in Mediterranean Climate: A Hygrothermal Assessment in WUFI. Energies 2020, 13, 2030. [Google Scholar] [CrossRef]
80. Sanyé-Mengual, E.; Specht, K.; Krikser, T.; Vanni, C.; Pennisi, G.; Orsini, F.; Gianquinto, G.P. Social acceptance and perceived ecosystem services of urban agriculture in Southern Europe: The case of Bologna, Italy. PLoS ONE 2018, 13(9), e0200993. [Google Scholar] [CrossRef] [PubMed]
81. Milan - NBS for urban regeneration. Available online: https://networknature.eu/casestudy/19446 (accessed on 9 June 2023).
82. Mariani, L.; Parisi, S.G.; Cola, G.; Lafortezza, R.; Colangelo, G.; Sanesi, G. Climatological analysis of the mitigating effect of vegetation on the urban heat island of Milan, Italy. Science of The Total Environment 2016, 569–570, 762-773.
83. Municipality of Milan - ForestaMi: The Forestation Project of the Municipality of Milan. Available online: https://www.comune.milano.it/forestami (accessed on 7 June 2023).
84. Elmes, A.; Rogan, J.; Williams, C.; Ratick, S.; Nowak, D.; Martin, D. Effects of urban tree canopy loss on land surface temperature magnitude and timing. ISPRS Journal of Photogrammetry and Remote Sensing 2017, 128, 338–353. [Google Scholar] [CrossRef]
85. Venter, Z.S.; Krog, N.H.; Barton, D.N. Linking green infrastructure to urban heat and human health risk mitigation in Oslo, Norway. Science of The Total Environment 2020, 709, 136193. [Google Scholar] [CrossRef]
86. Rahman, M.A.; Armson, D.; Ennos, A.R. A comparison of the growth and cooling effectiveness of five commonly planted urban tree species. Urban Ecosyst 2015, 18, 371–389. [Google Scholar] [CrossRef]
87. Žuvela-Aloise, M.; Koch, R.; Buchholz, S.; Früh, B. Modelling the potential of green and blue infrastructure to reduce urban heat load in the city of Vienna. Climatic Change 2016, 135, 425–438. [Google Scholar] [CrossRef]
88. Vienna unveils comprehensive Smart Climate Strategy for the next 20 years. Available online: https://www.themayor.eu/en/a/view/vienna-unveils-comprehensive-smart-climate-strategy-for-the-next-20-years-9813 (accessed on 8 June 2023).
89. Castleton, HF.; Stovin, V.; Beck, SBM.; Davison, JB. Green roofs; building energy savings and the potential for retrofit. Energy Build. 2010, 42, 1582-1591.
90. Virk, G.; Jansz, A.; Mavrogianni, A.; Mylona, A.; Stocker, J.; Davies, M. Microclimatic effects of green and cool roofs in London and their impacts on energy use for a typical office building. Ener. Build. 2015, 88, 214–228. [Google Scholar] [CrossRef]
91. Solcerova, A.; van de Ven, F.; Wang, M.; Rijsdijk, M.; Giesen, N. Do green roofs cool the air? Build Environ. 2017, 111, 249–255. [Google Scholar] [CrossRef]
92. Jaffal, I.; Ouldboukhitine, SE.; Belarbi, R. A comprehensive study of the impact of green roofs on building energy performance. Renew. Ener. 2012, 43, 157–164. [Google Scholar] [CrossRef]
93. Alcazar, SS.; Olivieri, F.; Neila, J. Green roofs: Experimental and analytical study of its potential for urban microclimate regulation in Mediterranean–continental climates. Urban Climate 2016, 17, 304–317. [Google Scholar] [CrossRef]
94. Susca, T.; Zanghirella, F.; Colasuonno, L.; Del Fatto, V. Effect of green wall installation on urban heat island and building energy use: A climate-informed systematic literature review. Renew. Sustain. Energy Rev. 2022, 159, 112100. [Google Scholar] [CrossRef]
95. Doick, KJ.; Peace, A.; Hutchings, TR. The role of one large greenspace in mitigating London's nocturnal urban heat island. Sci. Total Environ. 2014, 493, 662–671. [Google Scholar] [CrossRef]
96. Gunawardena, K.; Steemers, K. Assessing the influence of neighbourhood-scale vertical greening application. Build. Cities 2023, 4, 103–123. [Google Scholar] [CrossRef]
97. Vidrih, B.; Medved, S. Multiparametric model of urban park cooling island. Urban For. Urban Green. 2013, 12, 220–229. [Google Scholar] [CrossRef]
98. Mariani, L.; Parisi, SG.; Cola, G.; Lafortezza, R.; Colangelo, G.; Sanesi, G. Climatological analysis of the mitigating effect of vegetation on the urban heat island of Milan, Italy. Sci. Total Environ 2016, 569–570, 762-773.
99. Oliveira, S.; Andrade, H.; Vaz, T. The cooling effect of green spaces as a contribution to the mitigation of urban heat: a case study in Lisbon. Build. Environ. 2011, 46, 2186–2194. [Google Scholar] [CrossRef]
100. Attoye, D.E.; Aoul, K.A.T.; Hassan, A. A review on building integrated photovoltaic façade customization potentials. Sustainability (Switzerland), 2017. 9(12).
101. Kuhn, T.E., Erban, C.; Heinrich, M.; Eisenlohr, J.; Ensslen, F.; Neuhaus, D.H. Review of technological design options for building integrated photovoltaics (BIPV). Energy and Buildings 2021, 231, 110381. [CrossRef]
102. Lu, L.; H. Yang, Environmental payback time analysis of a roof-mounted building-integrated photovoltaic (BIPV) system in Hong Kong. Applied Energy 2010, 87(12), 3625-3631. 12.
103. Weerasinghe, R.P.N.P.; Yang, R.J.; Wakefield, R.; Too, E.; Le, T.; Corkish, R.; Chen, S.; Wang, C.. Economic viability of building integrated photovoltaics: A review of forty-five (45) non-domestic buildings in twelve (12) western countries. Renewable and Sustainable Energy Reviews 2021, 137, 110622. [CrossRef]
104. Lucchi, E., Dall'Orto, I.; Peluchetti, A.; Toledo, L.; Pelle, M.; López, C.P.; Guazzi, G. Photovoltaic technologies in historic buildings and protected areas: Comprehensive legislative framework in Italy and Switzerland. Energy Policy 2022, 161, 112772. [CrossRef]
105. IEA - Successful Building Integration of Photovoltaics - Collection of International Projects. Available online: https://iea-pvps.org/wp-content/uploads/2021/03/IEA-PVPS-Task-15-book-executive-summary.pdf (accessed on 8 June 2023).
106. Freitas, S.; Reinhart, C.; Brito, M. Minimizing storage needs for large scale photovoltaics in the urban environment. Solar Energy 2018, 159, 375–389. [Google Scholar] [CrossRef]
107. Skandalos, N.; Karamanis, D. An optimization approach to photovoltaic building integration towards low energy buildings in different climate zones. Applied Energy 2021, 295. [Google Scholar] [CrossRef]
108. Architekten, R.S. Umwelt Arena. Available online: https://archello.com/project/umwelt-arena (accessed on 9 June 2023).
109. Devetaković, M.; Djordjević, D.; Radojević, M.; Krstić-Furundžić, A.; Burduhos, B.-G.; Martinopoulos, G.; Neagoe, M.; Lobaccaro, G. Photovoltaics on Landmark Buildings with Distinctive Geometries. Appl. Sci. 2020, 10, 6696. [Google Scholar] [CrossRef]
110. Compagnon, R. Solar and daylight availability in the urban fabric. Energy and Buildings 2004, 36(4), 321–328. [Google Scholar] [CrossRef]
111. Aguacil, S.; Lufkin, S.; Rey, E. Active surfaces selection method for building-integrated photovoltaics (BIPV) in renovation projects based on self-consumption and self-sufficiency. Energy and Buildings 2019, 193, 15–28. [Google Scholar] [CrossRef]
112. SUPSI. Building Integrated Photovoltaics: A practical handbook for solar buildings' stakeholders. SUPSI-Becquerel Institute: Trevano, Switzerland, 2020, pp 54.
113. Selke, T.; Wiedermann, W. ENERGYbase office building: A reality check by seven years of monitored energy system performance. In Proceedings of the EuroSun 2016, Palma de Mallorca, Spain, 11-14 October 2016. [Google Scholar]
114. Kaan, H.F.; Reijenga, T. H. Retrofit & Architectural Integration of PV Modules in Façade and roof of an Office & Laboratory Building, Energy research Centre of the Netherlands ECN: Petten, Netherlands, 2002, pp 26.
115. Freiburg Town Hall. Available online: https://architizer.com/projects/freiburg-town-hall (accessed on 9 June 2023).
116. Réhault, N.; Engelmann, P.; Lämmle, M.; Munzinger, L. New town hall in Freiburg (D): concept, performance and energy balance after the first year of monitoring of a large net plus-energy building. In IOP Conference Series: Earth and Environmental Science, Volume 352, 1st Nordic conference on Zero Emission and Plus Energy Buildings, 6–7 November 2019, Trondheim, Norway. 6–7 November.
117. Aelenei, D.; Lopes, R.A.; Aelenei, L.; Gonçalves, H. Investigating the potential for energy flexibility in an office building with a vertical BIPV and a PV roof system. Renewable Energy 2019, 137, 189–197. [Google Scholar] [CrossRef]
118. Martín-Chivelet, N.; Gutiérrez, J. C.; Alonso-Abella, M.; Chenlo, F.; Cuenca, J. Building retrofit with photovoltaics: Construction and performance of a BIPV ventilated façade. Energies 2018, 11(7), 1719. [Google Scholar] [CrossRef]
119. Mandalaki, M.; Zervas, K.; Tsoutsos, T.; Vazakas, A. Assessment of fixed shading devices with integrated PV for efficient energy use. Solar Energy 2012, 86(9), 2561–2575. [Google Scholar] [CrossRef]
120. Skandalos, N.; Karamanis, D. PV glazing technologies. Renewable and Sustainable Energy Reviews 2015, 49, 306–322. [Google Scholar] [CrossRef]
121. Skandalos, N.; Karamanis, D.; Peng, J.; Yang, H. Overall energy assessment and integration optimization process of semitransparent PV glazing technologies. Progress in Photovoltaics: Research and Applications 2018. 26(7), 473-490. [CrossRef]
122. Cannavale, A.; Ierardi, L.; Hörantner,M.; Eperon, G.F.; Snaith, H.J.; Ayr, U.; Martellotta, F. Improving energy and visual performance in offices using building integrated perovskite-based solar cells: A case study in Southern Italy. Applied Energy 2017, 205, 834-846. [CrossRef]
123. Gholami, H.; Røstvik, H.N.; Kumar, N.M.; Chopra, S.S. Lifecycle cost analysis (LCCA) of tailor-made building integrated photovoltaics (BIPV) façade: Solsmaragden case study in Norway. Solar Energy 2020, 211, 488–502. [Google Scholar] [CrossRef]
124. Nørgaard, P.; Poder, S.H. Perspectives on solar power in dense urban areas–with Copenhagen International School as case study. The Journal of Engineering 2019, 18, 5134–5137. [Google Scholar] [CrossRef]
125. Vasiliev, M.; Nur-E-Alam, M.; Alameh, K. Recent Developments in Solar Energy-Harvesting Technologies for Building Integration and Distributed Energy Generation. Energies 2019, 12(6), 1080. [Google Scholar] [CrossRef]
126. Theokli, C.; Elia, C.; Markou, M.; Vassiliades, C. Energy renovation of an existing building in Nicosia Cyprus and investigation of the passive contribution of a BIPV/T double façade system: A case-study. Energy Reports 2021, 7, 8522–8533. [Google Scholar] [CrossRef]
127. Taha, H. The potential for air-temperature impact from large-scale deployment of solar photovoltaic arrays in urban areas. Sol. Ener. 2013, 91, 358–367. [Google Scholar] [CrossRef]
128. Berardi, U.; Graham, J. Investigation of the impacts of microclimate on PV energy efficiency and outdoor thermal comfort. Sustain. Cities Soc. 2020, 62, 102402. [CrossRef]
129. Founda, D.; Santamouris, M. Synergies between Urban Heat Island and Heat Waves in Athens (Greece), during an extremely hot summer (2012). Sci. Rep. 2017, 7, 10973. [CrossRef]
130. Brito, MC. Assessing the Impact of Photovoltaics on Rooftops and Facades in the Urban Micro-Climate. Energies 2020, 13(11), 2717. [CrossRef]
131. Mandavgane, A.; Karve, S.; Kulkarni, P.; Dhamankar, N. The Impact of Solar Photovoltaic (PV) Rooftop Panels on Temperature Profiles of Surroundings and Urban Thermal Environment. In ICAER 2022: Advances in Clean Energy and Sustainability; Doolla, S., Rather, Z.H., Ramadesigan, V., Eds.; 2023 Springer: Singapore. pp. 409-419. [CrossRef]
132. Boccalatte, A.; Fossa, M.; Ménézo, C. Best arrangement of BIPV surfaces for future NZEB districts while considering urban heat island effects and the reduction of reflected radiation from solar façades. Renew. Ener. 2020, 160, 686–697. [Google Scholar] [CrossRef]
133. Masson, V.; Bonhomme, M.; Salagnac, J-L.; Briottet, X.; Lemonsu, A. Solar panels reduce both global warming and urban heat island. Frontiers Environ. Sci. 2014, 2. [CrossRef]
134. Kaboré, M.; Bozonnet, E.; Salagnac, P.; Abadie, M. Indexes for passive building design in urban context–indoor and outdoor cooling potentials. Ener. Build. 2018, 173, 315–25. [Google Scholar] [CrossRef]
135. Formolli, M.; Kleiven, T.; Lobaccaro, G. Assessing solar energy accessibility at high latitudes: A systematic review of urban spatial domains, metrics, and parameters. Renew. Sustain. Energy Rev. 2023, 177, 113231. [Google Scholar] [CrossRef]
136. Zonato, A.; Martilli, A.; Gutierrez, E.; Chen, F.; He, C.; Barlage, M.; Zardi, D.; Giovannini, L. Exploring the Effects of Rooftop Mitigation Strategies on Urban Temperatures and Energy Consumption. JGR Atmospheres 2021, 126. [Google Scholar] [CrossRef]
137. Tan, H.; Kotamarthi, R.; Wang, J.; Qian, Y.; Chakraborty, TC. Impact of different roofing mitigation strategies on near-surface temperature and energy consumption over the Chicago metropolitan area during a heatwave event. Sci Total Environ. 2023, 860, 160508. [Google Scholar] [CrossRef]
138. Kapsalis, V.; Karamanis, D. On the effect of roof added photovoltaics on building's energy demand. Ener. Build. 2015, 108, 195–204. [Google Scholar] [CrossRef]
139. Scherba, A.; Sailor, DJ.; Rosenstiel, TN.; Wamser, CC. Modeling impacts of roof reflectivity, integrated photovoltaic panels and green roof systems on sensible heat flux into the urban environment. Build. Environ. 2011, 46, 2542–2551. [Google Scholar] [CrossRef]
140. Fahed, J.; Kinab, E.; Ginestet, S.; Adolphe, L. Impact of urban heat island mitigation measures on microclimate and pedestrian comfort in a dense urban district of Lebanon. Sustain. Cities Soc. 2020, 61, 102375. [Google Scholar] [CrossRef]
141. Koirala, B.P.; Koliou, E.; Friege, J.; Hakvoort, R.A.; Herder, P.M. Energetic communities for community energy: A review of key issues and trends shaping integrated community energy systems. Renewable and Sustainable Energy Reviews 2016, 56, 722–744. [Google Scholar] [CrossRef]
142. Kloppenburg, S.; Smale, R.; Verkade, N. Technologies of engagement: how battery storage technologies shape householder participation in energy transitions. Energies 2019, 12(22), 4384. [Google Scholar] [CrossRef]
143. Becker, S.; Kunze, C.; Vancea, M. Community energy and social entrepreneurship: Addressing purpose, organisation and embeddedness of renewable energy projects. Journal of Cleaner Production 2017, 147, 25–36. [Google Scholar] [CrossRef]
144. Raina, G.; Sinha, S. Outlook on the Indian scenario of solar energy strategies: Policies and challenges. Energy Strategy Reviews 2019, 24, 331–341. [Google Scholar] [CrossRef]
145. Lee, J.; Shepley, M.M. Benefits of solar photovoltaic systems for low-income families in social housing of Korea: Renewable energy applications as solutions to energy poverty. Journal of Building Engineering 2020, 28, 101016. [Google Scholar] [CrossRef]
146. Amado, M.; Poggi, F.; Amado, A.R. Energy efficient city: A model for urban planning. Sustainable Cities and Society 2016, 26, 476–485. [Google Scholar] [CrossRef]
147. Parida, B.; Iniyan, S.; Goic, R. A review of solar photovoltaic technologies. Renewable and sustainable energy reviews 2011, 15(3), 1625–1636. [Google Scholar] [CrossRef]
148. Akrofi, M.M.; Okitasari, M. Integrating solar energy considerations into urban planning for low carbon cities: a systematic review of the state-of-the-art. Urban Governance, 2022, 2, 1, 157-172. [CrossRef]
149. Lange, M.; Page, G.; Cummins, V. Governance challenges of marine renewable energy developments in the US–Creating the enabling conditions for successful project development. Marine Policy 2018, 90, 37–46. [Google Scholar] [CrossRef]
150. Beatley, T. Envisioning solar cities: Urban futures powered by sustainable energy. Journal of Urban Technology 2007, 14(2), 31–46. [Google Scholar] [CrossRef]
151. Shahsavari, A.; Akbari, M. Potential of solar energy in developing countries for reducing energy-related emissions. Renewable and Sustainable Energy Reviews 2018, 90, 275–291. [Google Scholar] [CrossRef]
152. Lennon, B.; Dunphy, N.P.; Sanvicente, E. Community acceptability and the energy transition: A citizens’ perspective. Energy, Sustainability and Society 2019, 9(1), 1-18.
153. McCauley, S.M.; Stephens, J.C. Green energy clusters and socio-technical transitions: analysis of a sustainable energy cluster for regional economic development in Central Massachusetts, USA. Sustainability Science 2012, 7, 213–225. [Google Scholar] [CrossRef]
154. Hoang, A.T.; Nguyen, X.P. Integrating renewable sources into energy system for smart city as a sagacious strategy towards clean and sustainable process. Journal of Cleaner Production 2021, 305, 127161. [Google Scholar] [CrossRef]
155. Wahlund, M.; Palm, J. The role of energy democracy and energy citizenship for participatory energy transitions: A comprehensive review. Energy Research & Social Science 2022, 87, 102482.
156. Lennon, B.; Dunphy, N.; Gaffney, C.; Revez, A.; Mullally, G.; O’Connor, P. Citizen or consumer? Reconsidering energy citizenship. Journal of Environmental Policy & Planning 2020, 22(2),184-197.
157. Kalkbrenner, B.J.; Roosen, J. Citizens’ willingness to participate in local renewable energy projects: The role of community and trust in Germany. Energy Research & Social Science 2016, 13, 60-70.
158. Danielsen, K. Gender equality, women’s rights and access to energy services. Available online: https://www.kit.nl/wp-content/uploads/2018/08/1975_Gender-Rights-and-Energy-Report-final.pdf (accessed on 9 June 2023).
159. Lowitzsch, J.; Hoicka, C.E.; van Tulder, F.J. Renewable energy communities under the 2019 European Clean Energy Package–Governance model for the energy clusters of the future? Renewable and Sustainable Energy Reviews 2020, 122, 109489. [Google Scholar] [CrossRef]
160. Feenstra, M.; Özerol, G. Energy justice as a search light for gender-energy nexus: Towards a conceptual framework. Renewable and Sustainable Energy Reviews 2021, 138, 110668. [Google Scholar] [CrossRef]
161. de Faria Jr, H.; Trigoso, F.B.; Cavalcanti, J.A. Review of distributed generation with photovoltaic grid connected systems in Brazil: Challenges and prospects. Renewable and Sustainable Energy Reviews 2017, 75, 469–475. [Google Scholar] [CrossRef]
162. Owusu, P.A.; Asumadu-Sarkodie, S. A review of renewable energy sources, sustainability issues and climate change mitigation. Cogent Engineering 2016, 3(1), 1167990. [Google Scholar] [CrossRef]
163. Catney, P.; MacGregor, S.; Dobson, A.; Hall, S.M.; Royston, S.; Robinson, Z.; Ormerod, M.; Ross, S. Big society, little justice? Community renewable energy and the politics of localism. Local Environment 2014, 19(7), 715–730. [Google Scholar] [CrossRef]
164. Shirazi, A.M.; Zomorodian, Z.S.; Tahsildoost, M. Techno-economic BIPV evaluation method in urban areas. Renewable Energy 2019, 143, 1235–1246. [Google Scholar] [CrossRef]
165. Mwasilu, F.; Justo, J.J.; Kim, E.K.; Do, T.D.; Jung, J.W. Electric vehicles and smart grid interaction: A review on vehicle to grid and renewable energy sources integration. Renewable and sustainable energy reviews 2014, 34, 501–516. [Google Scholar] [CrossRef]
166. Levesque, V.; Sivapalan, S.; Salvia, A.L.; Fritzen, B.; Deckert, R.; Kozlova, V.; LeVasseur, T.J.; Emblen-Perry, K.; Azeiteiro, U.M.; Paço, A.; Borsari, B. Social values and sustainable development: community experiences. Environmental Sciences Europe 2022, 34(67).
167. Palm, J. Household installation of solar panels–Motives and barriers in a 10-year perspective. Energy Policy 2018, 113, 1–8. [Google Scholar] [CrossRef]
168. Allen, J.; Sheate, W.R.; Diaz-Chavez, R. Community-based renewable energy in the Lake District National Park–local drivers, enablers, barriers and solutions. Local Environment 2012, 17(3), 261–280. [Google Scholar] [CrossRef]
169. Roebroek, CT.; Duveiller, G.; Seneviratne, SI.; Davin, EL.; Cescatti, A. Releasing global forests from human management: How much more carbon could be stored? Science 2023, 380, 749–75. [Google Scholar] [CrossRef]
170. Griscom, BW.; Lomax, G.; Kroeger,T.; Fargione, JE.; Adams, J.; Almond, L.; Bossio, D.; Cook-Patton, SC.; Ellis, PW.; Kennedy, CM.; Kiesecker, J. We need both natural and energy solutions to stabilize our climate. Change Biol. 2019, 25, 1889–2204.
171. Brilli, L.; Carotenuto, F.; Chiesi, M.; Fiorillo, E.; Genesio, L.; Magno, R.; Morabito, M.; Nardino, M.; Zaldei, A.; Gioli, B. An integrated approach to estimate how much urban afforestation can contribute to move towards carbon neutrality. Sci. Tot. Environ. 2022, 842, 156843. [Google Scholar] [CrossRef] [PubMed]
172. Sharon, H.; Reddy, K.S. A review of solar energy driven desalination technologies," Renewable and Sustainable Energy Reviews. Elsevier 2015, 41(C), 1080–1118. [Google Scholar]
173. UNEP Solar for All: Bringing Solar Power to Agriculture. Available online: https://www.unenvironment.org/resources/report/solar-all-bringing-solar-power-agriculture (accessed on 9 June 2023).
174. Schindler, BY.; Blaustein, L.; Lotan, R.; Shalom, H.; Kadas, GJ.; Seifan, M. Green roof and photovoltaic panel integration: Effects on plant and arthropod diversity and electricity production. J Environ Manage. 2018, 1, 225:288-299. 2: 1, 225. [CrossRef]
175. Solaripedia - Solar Trees and Urban Canopies. Available online: https://www.solaripedia.com/13/215/solar_trees_and_urban_canopies.html (accessed on 9 June 2023).
176. WHO - Solar powered disinfection of drinking water in the prevention of diarrhoeal diseases: field experiences in northern Bolivia. Available online: https://apps.who.int/iris/handle/10665/44520 (accessed on 9 June 2023).
177. Chen, Z. Wetland Artificial Floating Island Systems as a Potential Sustainable Solution for Nutrient Removal from Urban Runoff : A Pilot Study. Degree Master of Science, The Ohio State University, 2021.
178. BIQ House+SolarLeaf – the use of microalgae. Available online: https://pocacito.eu/sites/default/files/BIQhouse_Hamburg.pdf (accessed on 9 June 2023).
179. Rotating floating solar park for water utility Evides. Available online: https://www.dutchwatersector.com/news/rotating-floating-solar-park-for-water-utility-evides (accessed on 9 June 2023).
180. Solaripedia - Barcelona Solar Tree. Available online: https://www.solaripedia.com/13/285/barcelona_solar_tree.html (accessed on 9 June 2023).
181. Formolli, M.; Lobaccaro, G.; Kanters, J. Solar Energy in the Nordic Built Environment: Challenges, Opportunities and Barriers. Energies 2021, 14, 8410. [Google Scholar] [CrossRef]
182. Evans, J.; Strezov, V. Challenges and solutions for sustainable solar cities. Renewable and Sustainable Energy Reviews 2018, 81(Part 1), 855–863. [Google Scholar]
183. Ifaei, P.; Khiabani, H.; Piran, M.J.; Yoo, C.K. Techno-econo-environmental feasibility of retrofitting urban transportation system with optimal solar panels for climate change mitigation – A case study. Journal of Cleaner Production 2020, 251, 119639. [Google Scholar] [CrossRef]
184. Formolli, M.; Croce, S.; Vettorato, D.; Paparella, R.; Scognamiglio, A.; Mainini, A.G.; Lobaccaro, G. Solar Energy in Urban Planning: Lesson Learned and Recommendations from Six Italian Case Studies. Appl. Sci. 2022, 12, 2950. [Google Scholar] [CrossRef]
185. EU - Green infrastructure. Available online: https://environment.ec.europa.eu/topics/nature-and-biodiversity/green-infrastructure_en (accessed on 9 June 2023).
186. Horizon Europe Work Programme 2023-2024 - Climate, Energy and Mobility. Available online: https://ec.europa.eu/info/funding-tenders/opportunities/docs/2021-2027/horizon/wp-call/2023-2024/wp-8-climate-energy-and-mobility_horizon-2023-2024_en.pdf (accessed on 9 June 2023).
187. EU - Horizon Europe. Available online: https://research-and-innovation.ec.europa.eu/funding/funding-opportunities/funding-programmes-and-open-calls/horizon-europe_en (accessed on 9 June 2023).
188. EU - A European Green Deal, striving to be the first climate-neutral continent. Available online: https://commission.europa.eu/strategy-and-policy/priorities-2019-2024/european-green-deal_en (accessed on 9 June 2023).
189. EC - Energy Storage: The Role of Energy Storage in the Clean Energy Transition. Available online: https://ec.europa.eu/energy/sites/ener/files/energy_storage_2020.pdf (accessed on 9 June 2023).
190. EEA - NBS for urban areas: A potential approach to support urban adaptation to climate change. Available online: https://www.eea.europa.eu/publications/nature-based-solutions-for-urban-areas (accessed on 9 June 2023).