Sustainability

19 pages, 1317 KiB

Open AccessEditor’s ChoiceArticle

Conventional and Conservation Seedbed Preparation Systems for Wheat Planting in Silty-Clay Soil

by Roberto Fanigliulo, Daniele Pochi and Pieranna Servadio

Sustainability 2021, 13(11), 6506; https://doi.org/10.3390/su13116506 - 7 Jun 2021

Cited by 11 | Viewed by 4030

Conventional seedbed preparation is based on deep ploughing followed by lighter and finer secondary tillage of the superficial layer, normally performed by machines powered by the tractor’s Power Take-Off (PTO), which prepares the seedbed in a single pass. Conservation methods are based on [...] Read more.

Conventional seedbed preparation is based on deep ploughing followed by lighter and finer secondary tillage of the superficial layer, normally performed by machines powered by the tractor’s Power Take-Off (PTO), which prepares the seedbed in a single pass. Conservation methods are based on a wide range of interventions, such as minimum or no-tillage, by means of machines with passive action working tools which require two or more passes The aim of this study was to assess both the power-energy requirements of conventional (power harrows and rotary tillers with different working width) and conservation implements (disks harrow and combined cultivator) and the soil tillage quality parameters, with reference to the capability of preparing an optimal seedbed for wheat planting. Field tests were carried out on flat, silty-clay soil, using instrumented tractors. The test results showed significant differences among the operative performances of the two typologies of machines powered by the tractor’s PTO: the fuel consumption, the power and the energy requirements of the rotary tillers are strongly higher than power harrows. However, the results also showed a decrease of these parameters proceeding from conventional to more conservation tillage implements. The better quality of seedbed was provided by the rotary tillers. Full article

(This article belongs to the Special Issue Soil Tillage Systems and Wheat Yield under Climate Change)

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19 pages, 4081 KiB

Open AccessEditor’s ChoiceArticle

Dwelling Is a Key Idea in Traditional Residential Architecture’s Sustainability: A Case Study at Yangwan Village in Suzhou, China

by Fengyi Ji and Shangyi Zhou

Sustainability 2021, 13(11), 6492; https://doi.org/10.3390/su13116492 - 7 Jun 2021

Cited by 7 | Viewed by 3321

Abstract

Previous studies have failed to grasp the essence of traditional building habits responding to natural challenges. Therefore, contradictions arise between unified regulations protecting traditional residential architecture proposed by experts and the diverse construction transformation performed by locals. To resolve these contradictions, fieldwork was [...] Read more.

Previous studies have failed to grasp the essence of traditional building habits responding to natural challenges. Therefore, contradictions arise between unified regulations protecting traditional residential architecture proposed by experts and the diverse construction transformation performed by locals. To resolve these contradictions, fieldwork was conducted in Yangwan, a famous village in South China. The traditional residential architectural characteristics in three periods were obtained and compared. Peirce’s interpretation of the three natures of habit and Heidegger’s dwelling help determine the essence of building habits. The logic in traditional residential architecture is analysed through the “four-layer integrated into one” framework (including the natural environment, livelihood form, institution and ideology), yielding the following results. (1) The characteristics of the residential architectural form change with local livelihood form, institution and ideology. Nevertheless, the process by which local residents think, judge and respond to natural challenges remains unchanged (Thirdness of Habit), forming the core of dwelling. (2) The characteristics of the architectural form are determined by the causal chain of “four-layer integrated into one”. Stable causal chains are formed by the Thirdness of Habit, which represents people’s initiative in addressing natural challenges. Therefore, the protection of traditional residential architecture should centre on dwelling and people’s agency in response to the natural environment rather than on maintaining a unified physical form. Full article

(This article belongs to the Section Sustainable Urban and Rural Development)

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17 pages, 3459 KiB

Open AccessEditor’s ChoiceArticle

The Post-Pandemic Recovery of Transport Activity: Emerging Mobility Patterns and Repercussions on Future Evolution

by Panayotis Christidis, Aris Christodoulou, Elena Navajas-Cawood and Biagio Ciuffo

Sustainability 2021, 13(11), 6359; https://doi.org/10.3390/su13116359 - 3 Jun 2021

Cited by 53 | Viewed by 6472

Abstract

The expectations for post-COVID recovery of transport activity point towards a gradual return to normality, once the pandemic is under control and mobility restrictions end. The shock to society and economy has, however, caused a number of behavioural changes that can influence the [...] Read more.

The expectations for post-COVID recovery of transport activity point towards a gradual return to normality, once the pandemic is under control and mobility restrictions end. The shock to society and economy has, however, caused a number of behavioural changes that can influence the evolution of the transport sector. We analyse the main factors that can influence future supply and demand and explore how they may affect trip generation, distribution and modal split in passenger transport. We combine several conventional and innovative data sources with a detailed strategic transport model at the EU level, in order to present quantitative estimates under various scenarios. New remote work patterns or personal risk avoidance attitudes can lead to increased levels of car ownership and use. Public policy priorities in the aftermath of the pandemic would need to address the emerging challenges and adopt measures that can sustain the shift to active travel, support public transport, railways and aviation and stimulate innovation in transport technologies and services. Full article

(This article belongs to the Special Issue Ensuring Sustainable Development at the Light of New Mobility Trends and Challenges)

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24 pages, 3590 KiB

Open AccessEditor’s ChoiceArticle

Data-Driven Analysis on Inter-City Commuting Decisions in Germany

by Hui Chen, Sven Voigt and Xiaoming Fu

Sustainability 2021, 13(11), 6320; https://doi.org/10.3390/su13116320 - 2 Jun 2021

Cited by 8 | Viewed by 3726

Abstract

Understanding commuters’ behavior and influencing factors becomes more and more important every day. With the steady increase of the number of commuters, commuter traffic becomes a major bottleneck for many cities. Commuter behavior consequently plays an increasingly important role in city and transport [...] Read more.

Understanding commuters’ behavior and influencing factors becomes more and more important every day. With the steady increase of the number of commuters, commuter traffic becomes a major bottleneck for many cities. Commuter behavior consequently plays an increasingly important role in city and transport planning and policy making. Although prior studies investigated a variety of potential factors influencing commuting decisions, most of them are constrained by the data scale in terms of limited time duration, space and number of commuters under investigation, largely owing to their dependence on questionnaires or survey panel data; as such only small sets of features can be explored and no predictions of commuter numbers have been made, to the best of our knowledge. To fill this gap, we collected inter-city commuting data in Germany between 1994 and 2018, and, along with other data sources, analyzed the influence of GDP, housing and the labor market on the decision to commute. Our analysis suggests that the access to employment opportunities, housing price, income and the distribution of the location’s industry sectors are important factors in commuting decisions. In addition, different age, gender and income groups have different commuting patterns. We employed several machine learning algorithms to predict the commuter number using the identified related features with reasonably good accuracy. Full article

(This article belongs to the Special Issue Reviews and Perspectives on Smart and Sustainable Metropolitan and Regional Cities)

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19 pages, 1279 KiB

Open AccessEditor’s ChoiceReview

Resource Assessment of Renewable Energy Systems—A Review

by Kim Maya Yavor, Vanessa Bach and Matthias Finkbeiner

Sustainability 2021, 13(11), 6107; https://doi.org/10.3390/su13116107 - 28 May 2021

Cited by 17 | Viewed by 4212

Abstract

The reduction of greenhouse gas emissions by the energy transition may lead to trade-offs with other impacts on the environment, society, and economy. One challenge is resource use impacts due to increasing demand for high-tech metals and minerals. A review of the current [...] Read more.

The reduction of greenhouse gas emissions by the energy transition may lead to trade-offs with other impacts on the environment, society, and economy. One challenge is resource use impacts due to increasing demand for high-tech metals and minerals. A review of the current state of the art resource assessment of energy systems was conducted to identify gaps in research and application. Publications covering complete energy systems and supplying a detailed resource assessment were the focus of the evaluation. Overall, 92 publications were identified and categorized by the type of system covered and the applied abiotic resource assessment methods. A total of 78 out of 92 publications covered sub-systems of renewable energy systems, and nine considered complete energy systems and conducted a detailed resource use assessment. Most of the publications in the group “complete energy system and detailed resource assessment” were found in grey literature. Several different aspects were covered to assess resource use. Thirty publications focused on similar aspects including criticality and supply risks, but technology-specific aspects are rarely assessed in the resource assessment of renewable energy systems. Few publications included sector coupling technologies, and among the publications most relevant to the aim of this paper one third did not conduct an indicator-driven assessment. Full article

(This article belongs to the Section Energy Sustainability)

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19 pages, 7791 KiB

Open AccessEditor’s ChoiceArticle

A Method for the Automated Construction of 3D Models of Cities and Neighborhoods from Official Cadaster Data for Solar Analysis

by Carlos Beltran-Velamazan, Marta Monzón-Chavarrías and Belinda López-Mesa

Sustainability 2021, 13(11), 6028; https://doi.org/10.3390/su13116028 - 27 May 2021

Cited by 6 | Viewed by 3287

Abstract

3D city models are a useful tool to analyze the solar potential of neighborhoods and cities. These models are built from buildings footprints and elevation measurements. Footprints are widely available, but elevation datasets remain expensive and time-consuming to acquire. Our hypothesis is that [...] Read more.

3D city models are a useful tool to analyze the solar potential of neighborhoods and cities. These models are built from buildings footprints and elevation measurements. Footprints are widely available, but elevation datasets remain expensive and time-consuming to acquire. Our hypothesis is that the GIS cadastral data can be used to build a 3D model automatically, so that generating complete cities 3D models can be done in a short time with already available data. We propose a method for the automatic construction of 3D models of cities and neighborhoods from 2D cadastral data and study their usefulness for solar analysis by comparing the results with those from a hand-built model. The results show that the accuracy in evaluating solar access on pedestrian areas and solar potential on rooftops with the automatic method is close to that from the hand-built model with slight differences of 3.4% and 2.2%, respectively. On the other hand, time saving with the automatic models is significant. A neighborhood of 400,000 m² can be built up in 30 min, 50 times faster than by hand, and an entire city of 967 km² can be built in 8.5 h. Full article

(This article belongs to the Section Sustainable Urban and Rural Development)

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16 pages, 7315 KiB

Open AccessEditor’s ChoiceArticle

Hydrogen vs. Battery-Based Propulsion Systems in Unipersonal Vehicles—Developing Solutions to Improve the Sustainability of Urban Mobility

by F. Isorna Llerena, E. López González, J. J. Caparrós Mancera, F. Segura Manzano and J. M. Andújar

Sustainability 2021, 13(10), 5721; https://doi.org/10.3390/su13105721 - 20 May 2021

Cited by 4 | Viewed by 2944

Abstract

The percentage of the population in urban areas has increased by ten points from 2000 (46%) to 2020 (56%); it is expected to reach up to 70% by 2050. This undoubtedly will encourage society to use alternative transports. On the other hand, the [...] Read more.

The percentage of the population in urban areas has increased by ten points from 2000 (46%) to 2020 (56%); it is expected to reach up to 70% by 2050. This undoubtedly will encourage society to use alternative transports. On the other hand, the widespread fear of pandemics seems to be here to stay, and it is causing most people to leave public transport to use private cars, and a few have chosen unipersonal electric vehicles. As a consequence, the decision of using private cars negatively affects the air quality, and consequently urban population health. This paper aims to demonstrate a sustainable solution for urban mobility based on a hydrogen powered unipersonal electric vehicle, which, as shown, provides great advantages over the conventional battery powered unipersonal electric vehicle. To show this, the authors have developed both vehicles in comparable versions, using the same platform, and ensuring that the total weight of the unipersonal electric vehicle was the same in both cases. They have been subjected to experimental tests that support the features of the hydrogen-based configuration versus the battery-based one, including higher specific energy, more autonomy, and shorter recharge time. Full article

(This article belongs to the Section Energy Sustainability)

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12 pages, 2707 KiB

Open AccessEditor’s ChoiceArticle

Urban Structure in Troubled Times: The Evolution of Principal and Secondary Core/Periphery Gaps through the Prism of Residential Land Values

by Erez Buda, Dani Broitman and Daniel Czamanski

Sustainability 2021, 13(10), 5722; https://doi.org/10.3390/su13105722 - 20 May 2021

Cited by 4 | Viewed by 2285

Abstract

The structure of modern cities is characterized by the uneven spatial distribution of people and activities. Contrary to economic theory, it is neither evenly distributed nor entirely monocentric. The observed reality is the result of various feedbacks in the context of the interactions [...] Read more.

The structure of modern cities is characterized by the uneven spatial distribution of people and activities. Contrary to economic theory, it is neither evenly distributed nor entirely monocentric. The observed reality is the result of various feedbacks in the context of the interactions of attraction and repulsion. Heretofore, there is no agreement concerning the means to measuring the dimensions of these interactions, nor the framework for explaining them. We propose a simple model and an associated method for testing the interactions using residential land values. We claim that land values reflect the attractiveness of each location, including its observable and unobservable characteristics. We extract land values from prices of residences by applying a dedicated hedonic model to extensive residential real estate transaction data at a detailed spatial level. The resulting land values reflect the attractiveness of each urban location and are an ideal candidate to measure the degree of centrality or peripherality of each location. Moreover, assessment of land values over time indicates ongoing centralization and peripheralization processes. Using the urban structure of a small and highly urbanized country as a test case, this paper illustrates how the dynamics of the gap between central and peripheral urban areas can be assessed. Full article

(This article belongs to the Special Issue Social Capital, Infrastructural Capital and Resilience Capacity in Urban Systems)

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17 pages, 2797 KiB

Open AccessEditor’s ChoiceArticle

Spatial Heterogeneity and Complexity of the Impact of Extreme Climate on Vegetation in China

by Shuang Li, Feili Wei, Zheng Wang, Jiashu Shen, Ze Liang, Huan Wang and Shuangcheng Li

Sustainability 2021, 13(10), 5748; https://doi.org/10.3390/su13105748 - 20 May 2021

Cited by 16 | Viewed by 2555

Abstract

The impact of extreme climate on natural ecosystems and socioeconomic systems is more serious than that of the climate’s mean state. Based on the data of 1698 meteorological stations in China from 2001 to 2018, this study calculated the 27 extreme climate indices [...] Read more.

The impact of extreme climate on natural ecosystems and socioeconomic systems is more serious than that of the climate’s mean state. Based on the data of 1698 meteorological stations in China from 2001 to 2018, this study calculated the 27 extreme climate indices of the Expert Team on Climate Change Detection and Indices (ETCCDI). Through correlation analysis and collinearity diagnostics, we selected two representative extreme temperature indices and three extreme precipitation indices. The spatial scale of the impact of extreme climate on Normalized Difference Vegetation Index (NDVI) in China during the growing season from 2001 to 2018 was quantitatively analyzed, and the complexity of the dominant factors in different regions was discussed via clustering analysis. The research results show that extreme climate indices have a scale effect on vegetation. There are spatial heterogeneities in the impacts of different extreme climate indices on vegetation, and these impacts varied between the local, regional and national scales. The relationship between the maximum length of a dry spell (CDD) and NDVI was the most spatially nonstationary, and mostly occurred on the local scale, while the effect of annual total precipitation when the daily precipitation amount was more than the 95th percentile (R95pTOT) showed the greatest spatial stability, and mainly manifested at the national scale. Under the current extreme climate conditions, extreme precipitation promotes vegetation growth, while the influence of extreme temperature is more complicated. As regards intensity and range, the impact of extreme climate on NDVI in China over the past 18 years can be categorized into five types: the humidity-promoting type, the cold-promoting and drought-inhibiting compound type, the drought-inhibiting type, the heat-promoting and drought-inhibiting compound type, and the heat-promoting and humidity-promoting compound type. Drought is the greatest threat to vegetation associated with extreme climate in China. Full article

(This article belongs to the Section Air, Climate Change and Sustainability)

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27 pages, 1468 KiB

Open AccessEditor’s ChoiceArticle

Circular Cities: What Are the Benefits of Circular Development?

by Jo Williams

Sustainability 2021, 13(10), 5725; https://doi.org/10.3390/su13105725 - 20 May 2021

Cited by 36 | Viewed by 10402

Abstract

If cities could become regenerative and adaptive urban ecosystems, in which resource loops were closed and waste was obsolete, their ecological footprint would diminish. In addition, urban resource security would increase, the health of urban populations would improve and urban greenhouse gas emissions [...] Read more.

If cities could become regenerative and adaptive urban ecosystems, in which resource loops were closed and waste was obsolete, their ecological footprint would diminish. In addition, urban resource security would increase, the health of urban populations would improve and urban greenhouse gas emissions would be reduced. These are the principle goals under-pinning the circular city. Circular cities emerge through the process of circular development. Circular development alters cities’ systems of provision to enable circular practices of inhabitants to develop. This manifests as circular food systems and construction, water and nutrient recycling; adaptive reuse of spaces and pop-up activities; bioremediation of contaminated sites and integration of blue-green infrastructure throughout cities. To transform our cities will require significant investment, political support and public engagement. If the benefits of adopting such an approach can be identified, this will begin to make the case for support. The research presented in this paper draws on an inductive and deductive content analysis of relevant literature and interviews with those implementing circular projects in European cities (London, Paris, Amsterdam and Stockholm). It provides a clear definition of the normative concept of circular development. It creates a framework of benefits which are likely to accrue from adopting this approach. It points to the synergistic benefits emerging from circular development. It also highlights problems around valuation of those benefits, the unintended consequences of circular development and the inequalities in accessing benefits across society. Full article

(This article belongs to the Section Sustainable Urban and Rural Development)

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17 pages, 365 KiB

Open AccessEditor’s ChoiceArticle

Stochastic Expansion Planning of Various Energy Storage Technologies in Active Power Distribution Networks

by Reza Sabzehgar, Diba Zia Amirhosseini, Saeed D. Manshadi and Poria Fajri

Sustainability 2021, 13(10), 5752; https://doi.org/10.3390/su13105752 - 20 May 2021

Cited by 2 | Viewed by 1941

Abstract

This work aims to minimize the cost of installing renewable energy resources (photovoltaic systems) as well as energy storage systems (batteries), in addition to the cost of operation over a period of 20 years, which will include the cost of operating the power [...] Read more.

This work aims to minimize the cost of installing renewable energy resources (photovoltaic systems) as well as energy storage systems (batteries), in addition to the cost of operation over a period of 20 years, which will include the cost of operating the power grid and the charging and discharging of the batteries. To this end, we propose a long-term planning optimization and expansion framework for a smart distribution network. A second order cone programming (SOCP) algorithm is utilized in this work to model the power flow equations. The minimization is computed in accordance to the years (y), seasons (s), days of the week (d), time of the day (t), and different scenarios based on the usage of energy and its production (c). An IEEE 33-bus balanced distribution test bench is utilized to evaluate the performance, effectiveness, and reliability of the proposed optimization and forecasting model. The numerical studies are conducted on two of the highest performing batteries in the current market, i.e., Lithium-ion (Li-ion) and redox flow batteries (RFBs). In addition, the pros and cons of distributed Li-ion batteries are compared with centralized RFBs. The results are presented to showcase the economic profits of utilizing these battery technologies. Full article

(This article belongs to the Special Issue Energy Management of Multi-Energy Storage Systems)

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34 pages, 1664 KiB

Open AccessEditor’s ChoiceReview

The Role of Biochar in Regulating the Carbon, Phosphorus, and Nitrogen Cycles Exemplified by Soil Systems

by Shu-Yuan Pan, Cheng-Di Dong, Jenn-Fang Su, Po-Yen Wang, Chiu-Wen Chen, Jo-Shu Chang, Hyunook Kim, Chin-Pao Huang and Chang-Mao Hung

Sustainability 2021, 13(10), 5612; https://doi.org/10.3390/su13105612 - 18 May 2021

Cited by 54 | Viewed by 6644

Abstract

Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions. Recently, biochar drew great attention due to its promising potential in climate change mitigation, soil amendment, and environmental control. Obviously, biochar can be a beneficial soil amendment in several [...] Read more.

Biochar is a carbon-rich material prepared from the pyrolysis of biomass under various conditions. Recently, biochar drew great attention due to its promising potential in climate change mitigation, soil amendment, and environmental control. Obviously, biochar can be a beneficial soil amendment in several ways including preventing nutrients loss due to leaching, increasing N and P mineralization, and enabling the microbial mediation of N₂O and CO₂ emissions. However, there are also conflicting reports on biochar effects, such as water logging and weathering induced change of surface properties that ultimately affects microbial growth and soil fertility. Despite the voluminous reports on soil and biochar properties, few studies have systematically addressed the effects of biochar on the sequestration of carbon, nitrogen, and phosphorus in soils. Information on microbially-mediated transformation of carbon (C), nitrogen (N), and phosphorus (P) species in the soil environment remains relatively uncertain. A systematic documentation of how biochar influences the fate and transport of carbon, phosphorus, and nitrogen in soil is crucial to promoting biochar applications toward environmental sustainability. This report first provides an overview on the adsorption of carbon, phosphorus, and nitrogen species on biochar, particularly in soil systems. Then, the biochar-mediated transformation of organic species, and the transport of carbon, nitrogen, and phosphorus in soil systems are discussed. This review also reports on the weathering process of biochar and implications in the soil environment. Lastly, the current knowledge gaps and priority research directions for the biochar-amended systems in the future are assessed. This review focuses on literatures published in the past decade (2009–2021) on the adsorption, degradation, transport, weathering, and transformation of C, N, and P species in soil systems with respect to biochar applications. Full article

(This article belongs to the Collection Soil and Water Management Challenges & Solutions for Sustainable Agriculture under Climate Change)

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25 pages, 705 KiB

Open AccessEditor’s ChoiceReview

Rooftop PV and the Renewable Energy Transition; a Review of Driving Forces and Analytical Frameworks

by Sam Wilkinson, Michele John and Gregory M. Morrison

Sustainability 2021, 13(10), 5613; https://doi.org/10.3390/su13105613 - 18 May 2021

Cited by 17 | Viewed by 2929

Abstract

Rooftop solar photovoltaics (PV) are accelerating the transition towards low carbon electricity systems in many countries, particularly in Australia. This review paper provides an overview of the (1) technical, (2) economic, (3) socio-political, and (4) regulatory and institutional aspects that should be considered [...] Read more.

Rooftop solar photovoltaics (PV) are accelerating the transition towards low carbon electricity systems in many countries, particularly in Australia. This review paper provides an overview of the (1) technical, (2) economic, (3) socio-political, and (4) regulatory and institutional aspects that should be considered concurrently when navigating the transition towards a rooftop PV-dominated electricity system. We consider the suitability of two prominent long-range transitions theories for understanding the importance and interaction of elements within these four aspects during the transition. The multi-level perspective (MLP) of transitions theory is considered best suited for this task as it addresses fundamental shifts in the socio-technical systems, rather than being weighted towards technological and/or economic solutions. We find that relatively little research has been undertaken where the renewable energy transition is being driven by the uptake of rooftop PV within the distribution network of established islanded electricity systems. These islanded electricity systems will be the first to experience system impacts from high levels of rooftop PV. This review provides further analysis of important gaps in understanding the rooftop-PV-led energy transition and the implications for policy makers in maintaining stable electricity supplies during the transition. Full article

(This article belongs to the Section Energy Sustainability)

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20 pages, 3278 KiB

Open AccessEditor’s ChoiceArticle

Urban Planning Policies to the Renewal of Riverfront Areas: The Lisbon Metropolis Case

by Eduardo Medeiros, Ana Brandão, Paulo Tormenta Pinto and Sara Silva Lopes

Sustainability 2021, 13(10), 5665; https://doi.org/10.3390/su13105665 - 18 May 2021

Cited by 8 | Viewed by 5390

Abstract

Urban planning offers various design possibilities to solve fundamental challenges faced in urban areas. These include the need to physically renew old industrial and harbour riverside areas into liveable, inclusive and sustainable living spaces. This paper investigates the way urban planning policies have [...] Read more.

Urban planning offers various design possibilities to solve fundamental challenges faced in urban areas. These include the need to physically renew old industrial and harbour riverside areas into liveable, inclusive and sustainable living spaces. This paper investigates the way urban planning policies have helped to renew the waterfront areas in the Lisbon metropolis in the past decades. For this purpose, the contribution of the European Union (EU) and national urban development plans over the past decades are analysed. The results demonstrate an intense renewal of the waterfront areas in the Lisbon metropolitan area (LMA), particularly in Lisbon over the past three decades into leisure, ecologic and touristic areas, vis-à-vis the previous industrial and harbour vocation. Full article

(This article belongs to the Special Issue Urban Legacies of the Late 20th Century)

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14 pages, 1156 KiB

Open AccessEditor’s ChoiceArticle

Towns, High Streets and Resilience in Scotland: A Question for Policy?

by Leigh Sparks

Sustainability 2021, 13(10), 5631; https://doi.org/10.3390/su13105631 - 18 May 2021

Cited by 13 | Viewed by 4169

Abstract

The “death of the high street” has become a common refrain, particularly in the United Kingdom, often accompanied by calls for action and demands for improved resilience in town centres and high streets. This paper considers the policy context for towns and town [...] Read more.

The “death of the high street” has become a common refrain, particularly in the United Kingdom, often accompanied by calls for action and demands for improved resilience in town centres and high streets. This paper considers the policy context for towns and town centres in Scotland and the recent review of the country’s approach to towns, town centres and places. With the adoption of National Outcomes linked to the United Nations Sustainable Development Goals and the declaration of a Climate Emergency, the conclusion is drawn that a more fundamental and radical shift in policy is needed, if the resilience of town centres is to have any meaning, and that a clearer and more widely understood conceptualisation of resilience needs to be developed. Full article

(This article belongs to the Special Issue Urban Retail Systems: Vulnerability, Resilience and Sustainability)

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15 pages, 1562 KiB

Open AccessEditor’s ChoiceArticle

Stakeholder Expectations of Future Policy Implementation Compared to Formal Policy Trajectories: Scenarios for Agricultural Food Systems in the Mekong Delta

by Craig W. Hutton, Oliver Hensengerth, Tristan Berchoux, Van P. D. Tri, Thi Tong, Nghia Hung, Hal Voepel, Stephen E. Darby, Duong Bui, Thi N. Bui, Nguyen Huy and Daniel Parsons

Sustainability 2021, 13(10), 5534; https://doi.org/10.3390/su13105534 - 15 May 2021

Cited by 9 | Viewed by 4207

Abstract

The development of a coherent and coordinated policy for the management of large socio-agricultural systems, such as the Mekong delta in southern Vietnam, is reliant on aligning the development, delivery, and implementation of policy on national to local scales. Effective decision making is [...] Read more.

The development of a coherent and coordinated policy for the management of large socio-agricultural systems, such as the Mekong delta in southern Vietnam, is reliant on aligning the development, delivery, and implementation of policy on national to local scales. Effective decision making is linked to a coherent, broadly-shared vision of the strategic management of socio-agricultural systems. However, when policies are ambiguous, and at worst contradictory, long-term management and planning can consequently suffer. These potential adverse impacts may be compounded if stakeholders have divergent visions of the current and future states of socio-agricultural systems. Herein we used a transferable, scenario-based methodology which uses a standard quadrant matrix in order to explore both anticipated and idealized future states. Our case study was the Mekong delta. The scenario matrix was based upon two key strategic choices (axis) for the delta, derived from analysis of policy documents, literature, stakeholder engagement, and land use models. These are: (i) who will run agriculture in the future, agri-business or the established commune system; and (ii) to what degree sustainability will be incorporated into production. During a workshop meeting, stakeholders identified that agri-business will dominate future agricultural production in the delta but showed a clear concern that sustainability might consequently be undermined despite policy claims of the contrary. As such, our study highlights an important gap between national expectations and regional perspectives. Our results suggest that the new development plans for the Mekong delta (which comprise a new Master Plan and a new 5-year socio-economic development plan), which emphasize agro-business development, should adopt approaches that address concerns of sustainability as well as a more streamlined policy formulation and implementation that accounts for stakeholder concerns at both provincial and national levels. Full article

(This article belongs to the Special Issue Understanding the Society-Environmental Policy-Practice Nexus and Its Implications for Sustainability Transformations under Uncertain Futures)

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18 pages, 7157 KiB

Open AccessEditor’s ChoiceArticle

Geo-Crowdsourced Sound Level Data in Support of the Community Facilities Planning. A Methodological Proposal

by Gabriella Graziuso, Simona Mancini, Antonella Bianca Francavilla, Michele Grimaldi and Claudio Guarnaccia

Sustainability 2021, 13(10), 5486; https://doi.org/10.3390/su13105486 - 14 May 2021

Cited by 18 | Viewed by 2753

Abstract

To reduce environmental noise pollution and to safeguard people’s well-being, it is urgently necessary to move towards sustainable urban development and reconcile demographic and economic growth with the protection and restoration of the environment and the improvement of the quality of human lives. [...] Read more.

To reduce environmental noise pollution and to safeguard people’s well-being, it is urgently necessary to move towards sustainable urban development and reconcile demographic and economic growth with the protection and restoration of the environment and the improvement of the quality of human lives. This challenge should be a concern to policymakers, who must issue regulations and define the appropriate actions for noise monitoring and management, and citizens, who must be sensitive to the problem and act accordingly. Starting from an analysis of several crowdsourcing noise data collection tools, this paper focuses on the definition of a methodology for data analysis and mapping. The sound sensing system, indeed, enables mobile devices, such as smartphones and tablets, to become a low-cost data collection for monitoring environmental noise. For this study, the “NoiseCapture” application developed in France by CNRS and IFSTTAR has been utilized. The measurements acquired in 2018 and 2019 at the Fisciano Campus at the University of Salerno were integrated with the kernel density estimation. This is a spatial analysis technique that allows for the elaboration of sound level density maps, defined spatially and temporally. These maps, overlaid on a campus facilities map, can become tools to support the appropriate mitigation actions. Full article

(This article belongs to the Special Issue Urban Planning for Sustainable Development of Cities in the Geospatial (Big) Data ERA)

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22 pages, 3120 KiB

Open AccessEditor’s ChoiceArticle

Analysis of District Heating and Cooling Energy Systems in Spain: Resources, Technology and Management

by Beatriz María Paredes-Sánchez, José Pablo Paredes, Natalia Caparrini and Elena Rivo-López

Sustainability 2021, 13(10), 5442; https://doi.org/10.3390/su13105442 - 13 May 2021

Cited by 10 | Viewed by 4358

Abstract

District heating and cooling (DHC) systems play an important role under the new European Union (EU) energy transition strategy. Thermal energy networks are helping to stimulate the development of alternative technologies based on a broad range of renewable energy sources. The present study [...] Read more.

District heating and cooling (DHC) systems play an important role under the new European Union (EU) energy transition strategy. Thermal energy networks are helping to stimulate the development of alternative technologies based on a broad range of renewable energy sources. The present study analysed the current situation of DHC systems in Spain and provides an overview of the challenges and future opportunities that their use will entail. Its objective is to assess thermal energy conversion and management from a holistic perspective, including a study of existing energy infrastructures. The focus of this study lies on Spain given the country’s abundance of natural resources such as renewable energy sources including solar energy, biomass and geothermal energy, among others, as well as its strategic location on the map of the EU. Based on the analysis of the three factors for energy conversion in a district heating system, namely resources, technology, and management, the methodology provided an assessment of the different factors involved in running a DHC system. The results show an estimated total production for DHC networks of 1448 MW_th, of which 72% is supplied purely by renewable energy sources. Full article

(This article belongs to the Special Issue Biomass for Sustainability: Resource, Technology Conversion and Energy Management)

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19 pages, 15181 KiB

Open AccessEditor’s ChoiceArticle

Perceived Sensory Dimensions of Green Areas: An Experimental Study on Stress Recovery

by Sanaz Memari, Mahdieh Pazhouhanfar and Patrik Grahn

Sustainability 2021, 13(10), 5419; https://doi.org/10.3390/su13105419 - 12 May 2021

Cited by 24 | Viewed by 5247

Abstract

Natural environments have been shown to promote health, and are, therefore, important for achieving social sustainability in cities. As cities grow and become denser, it is important to develop knowledge about the characteristics of natural environments that work to promote health. Perceived Sensory [...] Read more.

Natural environments have been shown to promote health, and are, therefore, important for achieving social sustainability in cities. As cities grow and become denser, it is important to develop knowledge about the characteristics of natural environments that work to promote health. Perceived Sensory Dimensions (PSDs) is a tool that defines eight different cultural ecosystem services. They correspond to different human needs (rest, exercise, socialising, pleasure, or security) resulting in rehabilitation and health and well-being promotion. An experiment was conducted to study the potential of PSDs to restore people who experienced stressful accidents. One hundred and fifty-seven participants were recruited and asked first to watch a film clip of serious accidents, then to look at the pictures, depicting one particular type of PSDs, while listening to its respective audio recording. Their stress levels were measured before exposure to the stressor (baseline), after exposure to the stressor (pre-test), and after exposure to a particular type of PSDs (post-test). The results show that all eight PSDs effectively provide mental recovery, but there are statistical differences in their potentials. As such, it is proposed that the combined potential of the PSDs is needed, and should be used to increase the capacity and supply of health-promoting urban green areas. Full article

(This article belongs to the Special Issue Landscape Architecture Design to Promote Well-Being)

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17 pages, 4410 KiB

Open AccessEditor’s ChoiceArticle

Transport Airships for Scheduled Supply and Emergency Response in the Arctic

by Barry E. Prentice, Yui-Yip Lau and Adolf K. Y. Ng

Sustainability 2021, 13(9), 5301; https://doi.org/10.3390/su13095301 - 10 May 2021

Cited by 6 | Viewed by 4077

Abstract

As climate change progresses, the Arctic Ocean creates opportunities for new resource development and navigation routes. Such economic opportunities are attractive, but carry with them an increased risk of accidents and oil spills. Existing methods of emergency response face enormous challenges in the [...] Read more.

As climate change progresses, the Arctic Ocean creates opportunities for new resource development and navigation routes. Such economic opportunities are attractive, but carry with them an increased risk of accidents and oil spills. Existing methods of emergency response face enormous challenges in the Arctic because of its lack of transportation infrastructure and support services. Cargo airships offer a practical solution. Many airship designs are proposed that can carry over 30 tons, travel long distances at 150 km per hour, and land close to the emergency site. However, it is difficult to justify the economics of having enough capacity waiting and available to be marshaled in response to infrequent events. One solution is to develop a synergy with a new civilian cargo airship industry that can serve the regular transport needs of remote communities and mining operations. Through contingency contracts with these civilian operations, the Government of Canada could stretch its budgets and have access to the latest airship models and trained crews at locations across the Arctic. This paper gives valuable insight into the development of cargo airships. Advances in technology that make cargo airships a practical option in the 21st century are reviewed, and five competing airship designs are discussed. A case study of an existing rare earth mine proposal is used to illustrate the cost comparison of roads versus airships that could provide contingency services. Full article

(This article belongs to the Special Issue Towards Sustainable Development of the Arctic: Consequences of Pollutant in the Arctic)

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22 pages, 3145 KiB

Open AccessEditor’s ChoiceArticle

Life Cycle Assessment (LCA) of an Innovative Compact Hybrid Electrical-Thermal Storage System for Residential Buildings in Mediterranean Climate

by Gabriel Zsembinszki, Noelia Llantoy, Valeria Palomba, Andrea Frazzica, Mattia Dallapiccola, Federico Trentin and Luisa F. Cabeza

Sustainability 2021, 13(9), 5322; https://doi.org/10.3390/su13095322 - 10 May 2021

Cited by 6 | Viewed by 4529

Abstract

The buildings sector is one of the least sustainable activities in the world, accounting for around 40% of the total global energy demand. With the aim to reduce the environmental impact of this sector, the use of renewable energy sources coupled with energy [...] Read more.

The buildings sector is one of the least sustainable activities in the world, accounting for around 40% of the total global energy demand. With the aim to reduce the environmental impact of this sector, the use of renewable energy sources coupled with energy storage systems in buildings has been investigated in recent years. Innovative solutions for cooling, heating, and domestic hot water in buildings can contribute to the buildings’ decarbonization by achieving a reduction of building electrical consumption needed to keep comfortable conditions. However, the environmental impact of a new system is not only related to its electrical consumption from the grid, but also to the environmental load produced in the manufacturing and disposal stages of system components. This study investigates the environmental impact of an innovative system proposed for residential buildings in Mediterranean climate through a life cycle assessment. The results show that, due to the complexity of the system, the manufacturing and disposal stages have a high environmental impact, which is not compensated by the reduction of the impact during the operational stage. A parametric study was also performed to investigate the effect of the design of the storage system on the overall system impact. Full article

(This article belongs to the Special Issue Life-Cycle Assessment of Energy Storage in Building Applications)

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15 pages, 1960 KiB

Open AccessEditor’s ChoiceArticle

Automatic Detection of Photovoltaic Farms Using Satellite Imagery and Convolutional Neural Networks

by Konstantinos Ioannou and Dimitrios Myronidis

Sustainability 2021, 13(9), 5323; https://doi.org/10.3390/su13095323 - 10 May 2021

Cited by 11 | Viewed by 2910

Abstract

The number of solar photovoltaic (PV) arrays in Greece has increased rapidly during the recent years. As a result, there is an increasing need for high quality updated information regarding the status of PV farms. This information includes the number of PV farms, [...] Read more.

The number of solar photovoltaic (PV) arrays in Greece has increased rapidly during the recent years. As a result, there is an increasing need for high quality updated information regarding the status of PV farms. This information includes the number of PV farms, power capacity and the energy generated. However, access to this data is obsolete, mainly due to the fact that there is a difficulty tracking PV investment status (from licensing to investment completion and energy production). This article presents a novel approach, which uses free access high resolution satellite imagery and a deep learning algorithm (a convolutional neural network—CNN) for the automatic detection of PV farms. Furthermore, in an effort to create an algorithm capable of generalizing better, all the current locations with installed PV farms (data provided from the Greek Energy Regulator Authority) in the Greek Territory (131,957 km²) were used. According to our knowledge this is the first time such an algorithm is used in order to determine the existence of PV farms and the results showed satisfying accuracy. Full article

(This article belongs to the Special Issue Energy Transition and Climate Change in Decision-making Processes)

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16 pages, 1259 KiB

Open AccessEditor’s ChoiceArticle

How to Sustain Sustainability Monitoring in Cities: Lessons from 49 Community Indicator Initiatives across 10 Latin American Countries

by Ludger Niemann and Thomas Hoppe

Sustainability 2021, 13(9), 5133; https://doi.org/10.3390/su13095133 - 4 May 2021

Cited by 4 | Viewed by 2526

Abstract

Since the 1990s, many countries have witnessed the emergence of organizations publishing environmental, social, and quality-of-life indicators at a city level in order to promote public awareness, democratic participation, and sustainability policies. Many such initiatives are short-lived, however, and reasons for their success [...] Read more.

Since the 1990s, many countries have witnessed the emergence of organizations publishing environmental, social, and quality-of-life indicators at a city level in order to promote public awareness, democratic participation, and sustainability policies. Many such initiatives are short-lived, however, and reasons for their success and failure under-researched. Using interviews, surveys, and documental data, we explored the survival rates, obstacles, and achievements of 49 initiatives in 10 Latin American countries. Contrary to those in other world regions, most initiatives have civil society stakeholders (notably universities, media, and businesses), excluding governments. Implementing citizen perception surveys proved effective to gain public attention. Several initiatives obtained name recognition and policy influence, which are significant achievements in megacities such as Bogotá, São Paulo, and Lima, where numerous NGOs vie for attention. Frequent obstacles include a lack of finances. After a seven-year period (2014–2021), 55% of the sampled initiatives remained active, ranging from 90% in Colombia to none in other countries. Organizational continuity appeared to be associated with network membership and discontinuity with diverging obstacles, including political pressures in some countries (e.g., Mexico), data scarcity in poorer ones (e.g., Bolivia), and a lack of sustained interest in relatively richer ones (e.g., Chile). Recent increases in socio-economic inequalities are strengthening the potential of community indicators. Full article

(This article belongs to the Special Issue State of the Art and Future Perspectives in Smart and Sustainable Urban Development)

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22 pages, 756 KiB

Open AccessEditor’s ChoiceArticle

Nature-Based Solutions and Sustainable Urban Planning in the European Environmental Policy Framework: Analysis of the State of the Art and Recommendations for Future Development

by Claudia de Luca, Sandra Naumann, McKenna Davis and Simona Tondelli

Sustainability 2021, 13(9), 5021; https://doi.org/10.3390/su13095021 - 29 Apr 2021

Cited by 8 | Viewed by 4088

Abstract

Sustainable urban planning (SUP) is crucial in the development of sustainable cities, as also underlined by the New Urban Agenda. Nature-based solutions (NBS) are increasingly being recognized for their potential to offer multiple benefits that are necessary in order to cope with present [...] Read more.

Sustainable urban planning (SUP) is crucial in the development of sustainable cities, as also underlined by the New Urban Agenda. Nature-based solutions (NBS) are increasingly being recognized for their potential to offer multiple benefits that are necessary in order to cope with present and future urban challenges. The European policy framework, including the recently released European Green Deal, could strongly boost the role and recognition of NBS and SUP as drivers of sustainable and inclusive urban transition. Through a content analysis of current environmental European policies, strategies and agreements, this paper provides (i) an overview of the state of the art of the environmental European policy framework and the recognized role of NBS and SUP in reaching defined objectives, and (ii) insights on where NBS and SUP could play a larger role within this framework. On this basis, the paper identifies gaps and develops recommendations for a better integration of such concepts into the current framework. Full article

(This article belongs to the Special Issue Towards a Sustainable Urban Planning for the Green Deal Era)

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13 pages, 4494 KiB

Open AccessEditor’s ChoiceArticle

Environmental Sustainability of Building Retrofit through Vertical Greening Systems: A Life-Cycle Approach

by Katia Perini, Fabio Magrassi, Andrea Giachetta, Luca Moreschi, Michela Gallo and Adriana Del Borghi

Sustainability 2021, 13(9), 4886; https://doi.org/10.3390/su13094886 - 27 Apr 2021

Cited by 16 | Viewed by 3812

Abstract

Urban greening provides a wide range of ecosystem services to address the main challenges of urban areas, e.g., carbon sequestration, evapotranspiration and shade, thermal insulation, and pollution control. This study evaluates the environmental sustainability of a vertical greening system (VGS) built in 2014 [...] Read more.

Urban greening provides a wide range of ecosystem services to address the main challenges of urban areas, e.g., carbon sequestration, evapotranspiration and shade, thermal insulation, and pollution control. This study evaluates the environmental sustainability of a vertical greening system (VGS) built in 2014 in Italy, for which extensive monitoring activities were implemented. The life-cycle assessment methodology was applied to quantify the water–energy–climate nexus of the VGS for 1 m² of the building’s wall surface. Six different scenarios were modelled according to three different end-of-life scenarios and two different useful lifetime scenarios (10 and 25 years). The environmental impact of global-warming potential and generated energy consumption during the use phase in the VGS scenarios were reduced by 56% in relation to the baseline scenario (wall without VGS), and showed improved environmental performance throughout the complete life cycle. However, the water-scarcity index (WSI) of the VGS scenarios increased by 42%. This study confirms that the installation of VGSs offers a relevant environmental benefit in terms of greenhouse-gas emissions and energy consumption; however, increased water consumption in the use phase may limit the large-scale application of VGSs. Full article

(This article belongs to the Special Issue Climate Adaptation and Mitigation through Sustainable Energy Solutions)

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18 pages, 726 KiB

Open AccessEditor’s ChoiceArticle

Local and Application-Specific Geodemographics for Data-Led Urban Decision Making

by Amanda Otley, Michelle Morris, Andy Newing and Mark Birkin

Sustainability 2021, 13(9), 4873; https://doi.org/10.3390/su13094873 - 26 Apr 2021

Viewed by 2323

Abstract

This work seeks to introduce improvements to the traditional variable selection procedures employed in the development of geodemographic classifications. It presents a proposal for shifting from a traditional approach for generating general-purpose one-size-fits-all geodemographic classifications to application-specific classifications. This proposal addresses the recent [...] Read more.

This work seeks to introduce improvements to the traditional variable selection procedures employed in the development of geodemographic classifications. It presents a proposal for shifting from a traditional approach for generating general-purpose one-size-fits-all geodemographic classifications to application-specific classifications. This proposal addresses the recent scepticism towards the utility of general-purpose applications by employing supervised machine learning techniques in order to identify contextually relevant input variables from which to develop geodemographic classifications with increased discriminatory power. A framework introducing such techniques in the variable selection phase of geodemographic classification development is presented via a practical use-case that is focused on generating a geodemographic classification with an increased capacity for discriminating the propensity for Library use in the UK city of Leeds. Two local classifications are generated for the city, one a general-purpose classification, and the other, an application-specific classification incorporating supervised Feature Selection methods in the selection of input variables. The discriminatory power of each classification is evaluated and compared, with the result successfully demonstrating the capacity for the application-specific approach to generate a more contextually relevant result, and thus underpins increasingly targeted public policy decision making, particularly in the context of urban planning. Full article

(This article belongs to the Special Issue Advanced Modelling Tools to Support Urban and Regional Planning)

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25 pages, 392 KiB

Open AccessEditor’s ChoiceArticle

Cycling in the Era of COVID-19: Lessons Learnt and Best Practice Policy Recommendations for a More Bike-Centric Future

by Alexandros Nikitas, Stefanos Tsigdinos, Christos Karolemeas, Efthymia Kourmpa and Efthimios Bakogiannis

Sustainability 2021, 13(9), 4620; https://doi.org/10.3390/su13094620 - 21 Apr 2021

Cited by 115 | Viewed by 22956

Abstract

The COVID-19 pandemic has affected our cities in monumental ways with no sector likely being more severely impacted than transport. Lockdowns, physical spacing, transport restrictions and stay-at-home guidelines have transformed personal mobility and highlighted the mistakes of an unbalanced pro-car culture that defined [...] Read more.

The COVID-19 pandemic has affected our cities in monumental ways with no sector likely being more severely impacted than transport. Lockdowns, physical spacing, transport restrictions and stay-at-home guidelines have transformed personal mobility and highlighted the mistakes of an unbalanced pro-car culture that defined a century of urban planning. One immediate effect of the virus in relation to travel demand and supply was the emergence of active travel modes because of their unique ability to provide a socially distanced way of transport. Cycling is one of the modes that has enjoyed significant attention. Numerous cities have reallocated street and public space to cyclists and introduced pro-bike interventions like pop-up cycle lanes, e-bike subsidies, free bike-share use and traffic calming measures. This newly found outbreak-induced momentum creates an opportunity to establish a new ethos that allows the promotion of potentially permanent strategies that may help cycling to be (re-)established as a robust, mainstream and resilient travel mode for inner city trips and not as a second-class alternative operating under the automobile’s giant shadow. This paper provides a state-of-the-art description of the anti-COVID cycling-friendly initiatives that have been introduced globally, the successes and failures of these initiatives, the lessons learnt that can help us redefine the bicycle’s role in local societies today and a best cycling practice policy guide for planning a more bike-centric future. Full article

(This article belongs to the Collection Bicycling Today: Establishing and Learning from the State of the Art)

21 pages, 4443 KiB

Open AccessEditor’s ChoiceArticle

How the SP System May Promote Sustainability in Energy Consumption in IT Systems

by J. Gerard Wolff

Sustainability 2021, 13(8), 4565; https://doi.org/10.3390/su13084565 - 20 Apr 2021

Cited by 2 | Viewed by 1651

Abstract

The SP System (SPS), referring to the SP Theory of Intelligence and its realisation as the SP Computer Model, has the potential to reduce demands for energy from IT, especially in AI applications and in the processing of big data, in addition [...] Read more.

The SP System (SPS), referring to the SP Theory of Intelligence and its realisation as the SP Computer Model, has the potential to reduce demands for energy from IT, especially in AI applications and in the processing of big data, in addition to reductions in CO₂ emissions when the energy comes from the burning of fossil fuels. The biological foundations of the SPS suggest that with further development, the SPS may approach the extraordinarily low (20 W)energy demands of the human brain. Some of these savings may arise in the SPS because, like people, the SPS may learn usable knowledge from a single exposure or experience. As a comparison, deep neural networks (DNNs) need many repetitions, with much consumption of energy, for the learning of one concept. Another potential saving with the SPS is that like people, it can incorporate old learning in new. This contrasts with DNNs where new learning wipes out old learning (‘catastrophic forgetting’). Other ways in which the mature SPS is likely to prove relatively parsimonious in its demands for energy arise from the central role of information compression (IC) in the organisation and workings of the system: by making data smaller, there is less to process; because the efficiency of searching for matches between patterns can be improved by exploiting probabilities that arise from the intimate connection between IC and probabilities; and because, with SPS-derived ’Model-Based Codings’ of data, there can be substantial reductions in the demand for energy in transmitting data from one place to another. Full article

(This article belongs to the Collection Smart Energy for a Sustainable Future. Experiences in Photovoltaic System Monitoring)

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17 pages, 5046 KiB

Open AccessEditor’s ChoiceArticle

Particulate Matter Short-Term Exposition, Mobility Trips and COVID-19 Diffusion: A Correlation Analyses for the Italian Case Study at Urban Scale

by Armando Cartenì, Furio Cascetta, Luigi Di Francesco and Felisia Palermo

Sustainability 2021, 13(8), 4553; https://doi.org/10.3390/su13084553 - 20 Apr 2021

Cited by 11 | Viewed by 3095

Abstract

The conjecture discussed in this paper was that the daily number of certified cases of COVID-19 is direct correlated to the average particular matter (PM) concentrations observed several days before when the contagions occurred (short-term effect), and this correlation is higher for areas [...] Read more.

The conjecture discussed in this paper was that the daily number of certified cases of COVID-19 is direct correlated to the average particular matter (PM) concentrations observed several days before when the contagions occurred (short-term effect), and this correlation is higher for areas with a higher average seasonal PM concentration, as a measure of prolonged exposure to a polluted environment (long-term effect). Furthermore, the correlations between the daily COVID-19 new cases and the mobility trips and those between the daily PM concentrations and mobility trips were also investigated. Correlation analyses were performed for the application case study consisting in 13 of the main Italian cities, through the national air quality and mobility monitoring systems. Data analyses showed that the mobility restrictions performed during the lockdown produced a significant improvement in air quality with an average PM concentrations reduction of about 15%, with maximum variations ranging between 25% and 42%. Estimation results showed a positive correlation (stronger for the more highly polluted cities) between the daily COVID-19 cases and both the daily PM concentrations and mobility trips measured about three weeks before, when probably the contagion occurred. The obtained results are original, and if confirmed in other studies, it would lay the groundwork for the definition of the main context variables which influenced the COVID-19 spread. The findings highlighted in this research also supported by the evidence in the literature and allow concluding that PM concentrations and mobility habits could be considered as potential early indicators of COVID-19 circulation in outdoor environments. However, the obtained results pose significant ethical questions about the proper urban and transportation planning; the most polluted cities have not only worst welfare for their citizens but, as highlighted in this research, could lead to a likely greater spread of current and future respiratory and/or pulmonary health emergencies. The lesson to be learned by this global pandemic will help planners to better preserve the air quality of our cities in the post-COVID-19 era. Full article

(This article belongs to the Special Issue Transportation Planning, Mobility Habits and Sustainable Development in the Era of COVID-19 Pandemic)

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13 pages, 11638 KiB

Open AccessEditor’s ChoiceArticle

A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants

by Daniele Fiaschi, Giampaolo Manfrida, Barbara Mendecka, Lorenzo Tosti and Maria Laura Parisi

Sustainability 2021, 13(8), 4527; https://doi.org/10.3390/su13084527 - 19 Apr 2021

Cited by 8 | Viewed by 2247

Abstract

In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are [...] Read more.

In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies. Full article

(This article belongs to the Special Issue Sustainable Geothermal Energy)

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17 pages, 1694 KiB

Open AccessEditor’s ChoiceArticle

Adaptive Volt-Var Control Algorithm to Grid Strength and PV Inverter Characteristics

by Toni Cantero Gubert, Alba Colet, Lluc Canals Casals, Cristina Corchero, José Luís Domínguez-García, Amelia Alvarez de Sotomayor, William Martin, Yves Stauffer and Pierre-Jean Alet

Sustainability 2021, 13(8), 4459; https://doi.org/10.3390/su13084459 - 16 Apr 2021

Cited by 8 | Viewed by 2477

Abstract

The high-penetration of Distributed Energy Resources (DER) in low voltage distribution grids, mainly photovoltaics (PV), might lead to overvoltage in the point of common coupling, thus, limiting the entrance of renewable sources to fulfill the requirements from the network operator. Volt-var is a [...] Read more.

The high-penetration of Distributed Energy Resources (DER) in low voltage distribution grids, mainly photovoltaics (PV), might lead to overvoltage in the point of common coupling, thus, limiting the entrance of renewable sources to fulfill the requirements from the network operator. Volt-var is a common control function for DER power converters that is used to enhance the stability and reliability of the voltage in the distribution system. In this study, a centralized algorithm provides local volt-var control parameters to each PV inverter, which are based on the electrical grid characteristics. Because accurate information of grid characteristics is typically not available, the parametrization of the electrical grid is done using a local power meter data and a voltage sensitivity matrix. The algorithm has different optimization modes that take into account the minimization of voltage deviation and line current. To validate the effectiveness of the algorithm and its deployment in a real infrastructure, the solution has been tested in an experimental setup with PV emulators under laboratory conditions. The volt-var control algorithm successfully adapted its parameters based on grid topology and PV inverter characteristics, achieving a voltage reduction of up to 25% of the allowed voltage deviation. Full article

(This article belongs to the Special Issue Integration and Control of Renewable Energy and Power Electronics for Future Power Systems)

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25 pages, 351 KiB

Open AccessEditor’s ChoiceArticle

Public Norms in Practices of Transitional Planning—The Case of Energy Transition in The Netherlands

by Willem Salet

Sustainability 2021, 13(8), 4454; https://doi.org/10.3390/su13084454 - 16 Apr 2021

Cited by 9 | Viewed by 2769

Abstract

The fallibility of intervening in complex realities is widely recognized in planning theory. The prevailing planning approaches of the last two decades may be summarized as attempts to make planning more responsive, corrective, and resilient, and also more sociocratic vis à vis the [...] Read more.

The fallibility of intervening in complex realities is widely recognized in planning theory. The prevailing planning approaches of the last two decades may be summarized as attempts to make planning more responsive, corrective, and resilient, and also more sociocratic vis à vis the traditional government-centric rationalization of planning. These adaptations make sense, yet keep planning within the pragmatic scope of purposive aspirations and pragmatic problem solving. The pivotal statement of the article is that purposive systems run down in complex societies when not adequately sustained by institutionalizing sets of public norms. Public norms fulfil a different function than goal orientation. They provide a normative compass in times of uncertainty and set conditions to social interaction rather than organizing the performance of objectives or solving problems. The article aims to highlight the interrelationships of public norms and pragmatic strategies of planning. Empirically, the article addresses the major turning points of Dutch climate policy concerning the transitions of the electricity market, the major municipal–entrepreneurial initiatives of city-heating, and the decentralization of climate policies. The method of analysis is based on policy analysis of legislation, policy documents, and published contributions to public debates. The results of the analysis highlight the differences between the high policy aspirations and the outcomes. The results give evidence of the wicked problems in the complex energy transition. The discussion questions the mischievousness of ‘good’ planning intentions in complex social figurations, and critically examines the institutionalization of the material norms and the norms of politico-ordinance. The conclusions suggest that the social normalization of public norms in Dutch climate policies is not yet adequately materialized to effectively cope with wicked problems. Full article

(This article belongs to the Special Issue Cultural, Legal and Political Dimensions of Public Norms in Sustainable Metropolitan Spaces)

16 pages, 5248 KiB

Open AccessEditor’s ChoiceArticle

Flood Hazard Assessment Mapping in Burned and Urban Areas

by Hariklia D. Skilodimou, George D. Bathrellos and Dimitrios E. Alexakis

Sustainability 2021, 13(8), 4455; https://doi.org/10.3390/su13084455 - 16 Apr 2021

Cited by 39 | Viewed by 3838

Abstract

This study proposes a simple method to produce a flood hazard assessment map in burned and urban areas, where primary data are scarce. The study area is a municipal unit of Nea Makri, a coastal part of the eastern Attica peninsula (central Greece), [...] Read more.

This study proposes a simple method to produce a flood hazard assessment map in burned and urban areas, where primary data are scarce. The study area is a municipal unit of Nea Makri, a coastal part of the eastern Attica peninsula (central Greece), which has been strongly urbanized and suffered damage from urban fires in 2018. Six factors were considered as the parameters most controlling runoff when it overdraws the drainage system’s capacity. The analytical hierarchy process (AHP) method and a geographical information system (GIS) were utilized to create the flood hazard assessment map. The outcome revealed that the areas with highest flood hazard are distributed in the eastern and southern parts of the study area, as a result of the combination of lowlands with gentle slopes, torrential behavior of the streams, streams covered by construction, increasing urbanization and burned areas. The uncertainty and the verification analyses demonstrate a robust behavior for the model predictions, as well as reliability and accuracy of the map. Comparing the existing urban fabric and road network to the potential flood hazard areas showed that 80% of the urban areas and 50% of the road network were situated within areas prone to flood. The method may be applied to land use planning projects, flood hazard mitigation and post-fire management. Full article

(This article belongs to the Special Issue Natural and Technological Hazards in Urban Areas: Assessment, Planning and Solutions)

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25 pages, 1519 KiB

Open AccessEditor’s ChoiceArticle

Improving Energy Efficiency in Buildings Using an Interactive Mathematical Programming Approach

by Christina Diakaki and Evangelos Grigoroudis

Sustainability 2021, 13(8), 4436; https://doi.org/10.3390/su13084436 - 15 Apr 2021

Cited by 2 | Viewed by 1656

Abstract

Improving energy efficiency in buildings is a major priority and challenge worldwide. The employed measures vary in nature, and the decision analyst, who is typically the architect, the engineer, or the building expert that has undertaken the task to suggest energy efficient solutions, [...] Read more.

Improving energy efficiency in buildings is a major priority and challenge worldwide. The employed measures vary in nature, and the decision analyst, who is typically the architect, the engineer, or the building expert that has undertaken the task to suggest energy efficient solutions, faces a complex decision problem comprising numerous decision variables and multiple, usually competitive objectives. The solution of such multi-objective problems typically involves some sort of objectives aggregation, which reflects the preferences of the involved final decision maker that is the building’s user, occupant, and/or owner. The preferences elicitation, however, is a difficult task, and this paper aims to provide an interactive framework that will allow their consideration in a relatively easy manner. More specifically, a mathematical programming approach is proposed herein, which allows the elicitation and incorporation of the decision maker’s preferences in the decision model via the assessment of his/her utility function with the assistance of the multicriteria decision aid method UTASTAR. To study the feasibility and efficiency of the proposed approach, the case of a simple building is examined as an application example. The study results suggest that the proposed approach is capable of helping the decision analyst to suggest energy measures that satisfy, as much as possible, the decision maker’s preferences, without having to precisely prescribe them beforehand. Full article

(This article belongs to the Special Issue Energy Transition and Climate Change in Decision-making Processes)

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21 pages, 6623 KiB

Open AccessEditor’s ChoiceArticle

An Approach to the Operation Modes and Strategies for Integrated Hybrid Parabolic Trough and Photovoltaic Solar Systems

by José A. López-Álvarez, Miguel Larrañeta, Elena Pérez-Aparicio, Manuel A. Silva-Pérez and Isidoro Lillo-Bravo

Sustainability 2021, 13(8), 4402; https://doi.org/10.3390/su13084402 - 15 Apr 2021

Cited by 4 | Viewed by 2179

Abstract

Concentrated solar power (CSP) and photovoltaic (PV) solar systems can be hybridized, creating synergies: on one hand procuring dispatchability by storing thermal energy, and on the other hand generating electricity at a highly competitive prize. In this paper, we present an approach to [...] Read more.

Concentrated solar power (CSP) and photovoltaic (PV) solar systems can be hybridized, creating synergies: on one hand procuring dispatchability by storing thermal energy, and on the other hand generating electricity at a highly competitive prize. In this paper, we present an approach to the operation strategies and modes for integrated hybrid CSP + PV systems. We focus on parabolic trough (PT) solar plants, especially those operating in the south of Spain. Our study consists in the definition of suitable states for each of the subsystems that constitute a hybrid solar plant. We then propose modes from the combination of suitable states and establish the conditions for the transition between modes depending on the operation strategy. We propose two operation strategies: demand coverage and base load production. The results of this paper can be used in decision making for hybrid solar system simulation programs. Full article

(This article belongs to the Special Issue Solar Power System and Sustainability)

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22 pages, 2527 KiB

Open AccessEditor’s ChoiceArticle

Aerodynamic Characteristics of Airfoil and Vertical Axis Wind Turbine Employed with Gurney Flaps

by Yosra Chakroun and Galih Bangga

Sustainability 2021, 13(8), 4284; https://doi.org/10.3390/su13084284 - 12 Apr 2021

Cited by 13 | Viewed by 3229

Abstract

In the present studies, the effects of Gurney flaps on aerodynamic characteristics of a static airfoil and a rotating vertical axis wind turbine are investigated by means of numerical approaches. First, mesh and time step studies are conducted and the results are validated [...] Read more.

In the present studies, the effects of Gurney flaps on aerodynamic characteristics of a static airfoil and a rotating vertical axis wind turbine are investigated by means of numerical approaches. First, mesh and time step studies are conducted and the results are validated with experimental data in good agreement. The numerical solutions demonstrate that the usage of Gurney flap increases the airfoil lift coefficient

C_{L}

with a slight increase in drag coefficient

C_{D}

. Furthermore, mounting a Gurney flap at the trailing edge of the blade increases the power production of the turbine considerably. Increasing the Gurney flap height further increases the power production. The best performance found is obtained for the maximum height used in this study at 6% relative to the chord. This is in contrast to the static airfoil case, which shows no further improvement for a flap height greater than

0.5 % c

. Increasing the angle of the flap decreases the power production of the turbine slightly but the load fluctuations could be reduced for the small value of the flap height. The present paper demonstrates that the Gurney flap height for high solidity turbines is allowed to be larger than the classical limit of around 2% for lower solidity turbines. Full article

(This article belongs to the Special Issue Consistent Computational Approaches for Wind Energy Applications)

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16 pages, 2449 KiB

Open AccessEditor’s ChoiceArticle

Energy Transition toward Cleaner Energy Resources in Nepal

by Tika Ram Pokharel and Hom Bahadur Rijal

Sustainability 2021, 13(8), 4243; https://doi.org/10.3390/su13084243 - 11 Apr 2021

Cited by 14 | Viewed by 6863

Abstract

Energy is an important input for socioeconomic development and human well-being. The rationality of energy transitions toward cleaner energy resources is not only to improve individual living conditions, but also to enhance the economic growth of a nation. Nepal is considered to be [...] Read more.

Energy is an important input for socioeconomic development and human well-being. The rationality of energy transitions toward cleaner energy resources is not only to improve individual living conditions, but also to enhance the economic growth of a nation. Nepal is considered to be one of the countries with a low per-capita electricity use, heavily relying on traditional energy resources such as firewood and agricultural residues. The country is rich in hydropower resources. However, various economic and socioeconomic constraints have left the significant potential for hydroelectricity untapped. This study describes the energy transition patterns in Nepal based on a literature review and field survey of household energy use in the winter. We collected data from 516 households in the Solukhumbu, Panchthar, and Jhapa districts of Nepal. The rate of per-capita electricity consumption was 330 kWh/capita/year, which is significantly lower than that of other contemporary global societies such as India 1000 and China 4900 kWh/capita/year. The increasing trend in hydroelectricity production has optimistically transformed the energy sector toward cleaner resources; this correlates with the GDP per capita. Solar home systems, mini- and micro-hydropower plants, biogas technology, and improved cook stoves have been widely used, which has lowered the health and environmental burdens in rural areas. By analysing the survey data, we found that 25% of the households only relied on traditional cooking fuel, while 67% and 8% of the households relied on mixed and commercial cooking fuels, respectively. Moreover, 77% and 48% of traditional and mixed-fuel-using households were unhappy with current cooking fuels while 40% and 66% of these households preferred to use clean cooking fuels. The share of traditional energy resources decreased from 78% to 68%, while that of commercial energy resources increased from 20% to 28% from 2014/15 to 2019/20. This study suggests that future energy policies and programs should acknowledge the reality of energy transition to achieve sustainability by establishing reliable and clean sources of energy. Full article

(This article belongs to the Special Issue Sustainable Integration of Renewable Power Generation Systems)

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38 pages, 651 KiB

Open AccessEditor’s ChoiceArticle

Economizing the Uneconomic: Markets for Reliable, Sustainable, and Price Efficient Electricity

by Mohammad Rasouli and Demosthenis Teneketzis

Sustainability 2021, 13(8), 4197; https://doi.org/10.3390/su13084197 - 9 Apr 2021

Viewed by 2021

Abstract

Current electricity markets do not efficiently achieve policy targets i.e., sustainability, reliability, and price efficiency. Thus, there are debates on how to achieve these targets by using either market mechanisms e.g., carbon and capacity markets, or non-market mechanisms such as offer-caps, price-caps, and [...] Read more.

Current electricity markets do not efficiently achieve policy targets i.e., sustainability, reliability, and price efficiency. Thus, there are debates on how to achieve these targets by using either market mechanisms e.g., carbon and capacity markets, or non-market mechanisms such as offer-caps, price-caps, and market-monitoring. At the same time, major industry changes including demand response management technologies and large scale batteries bring more elasticity to demand; such changes will impact the methodology needed to achieve the above mentioned targets. This work provides market solutions that capture all three policy targets simultaneously and take into account the above-mentioned industry changes. The proposed solutions are based on: (i) a model of electricity markets that captures all the above mentioned electricity policy targets; (ii) mechanism design and the development of a framework for design of efficient auctions with constraints (individual, joint homogeneous, and joint non-homogeneous). The results show that, within the context of the proposed model, all policy targets can be achieved efficiently by separate capacity and carbon markets in addition to efficient spot markets. The results also highlight that all three policy targets can be achieved without any offer-cap, price-cap, or market monitoring. Thus, within the context of the proposed model, they provide clear answers to the above-mentioned policy debates. Full article

(This article belongs to the Special Issue Renewable Energy Technologies for Sustainable Development)

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24 pages, 47457 KiB

Open AccessEditor’s ChoiceArticle

Human Dimensions of Urban Blue and Green Infrastructure during a Pandemic. Case Study of Moscow (Russia) and Perth (Australia)

by Diana Dushkova, Maria Ignatieva, Michael Hughes, Anastasia Konstantinova, Viacheslav Vasenev and Elvira Dovletyarova

Sustainability 2021, 13(8), 4148; https://doi.org/10.3390/su13084148 - 8 Apr 2021

Cited by 48 | Viewed by 7764

Abstract

Significant challenges of the COVID-19 pandemic highlighted that features of a modern, sustainable and resilient city should not only relate to fulfilling economic and social urban strategies, but also to functional urban design, in particular, related to urban blue and green infrastructure (BGI). [...] Read more.

Significant challenges of the COVID-19 pandemic highlighted that features of a modern, sustainable and resilient city should not only relate to fulfilling economic and social urban strategies, but also to functional urban design, in particular, related to urban blue and green infrastructure (BGI). Using results from a web-based questionnaire survey conducted May–July 2020 in Moscow (Russia) and Perth (Australia), this paper provides insights regarding citizens’ needs for and values of urban BGI as well as their changes during and after the COVID-19 restrictions. Survey data collected during the lockdown period have captured information about people’s ability to access green and blue spaces within urban BGI, inequalities in access, feelings, and values as well as needs and perceived pathways of future development of urban natural environment. In both cities, lockdowns limited access of people to green spaces which affected their mental and physical health. Survey results revealed that the quality, functionality, and location of open green spaces illustrated a disparity in distribution, meaning that in many cases several communities from particular neighborhoods suffered from limited access to BGI. Furthermore, in addition to analyzing perceptions and values of urban nature during the COVID-19 pandemic, some suggestions for improvement of urban BGI based on the survey responses are provided. Full article

(This article belongs to the Section Sustainable Urban and Rural Development)

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17 pages, 2675 KiB

Open AccessEditor’s ChoiceArticle

Cogeneration Supporting the Energy Transition in the Italian Ceramic Tile Industry

by Lisa Branchini, Maria Chiara Bignozzi, Benedetta Ferrari, Barbara Mazzanti, Saverio Ottaviano, Marcello Salvio, Claudia Toro, Fabrizio Martini and Andrea Canetti

Sustainability 2021, 13(7), 4006; https://doi.org/10.3390/su13074006 - 3 Apr 2021

Cited by 11 | Viewed by 4128

Abstract

Ceramic tile production is an industrial process where energy efficiency management is crucial, given the high amount of energy (electrical and thermal) required by the production cycle. This study presents the preliminary results of a research project aimed at defining the benefits of [...] Read more.

Ceramic tile production is an industrial process where energy efficiency management is crucial, given the high amount of energy (electrical and thermal) required by the production cycle. This study presents the preliminary results of a research project aimed at defining the benefits of using combined heat and power (CHP) systems in the ceramic sector. Data collected from ten CHP installations allowed us to outline the average characteristics of prime movers, and to quantify the contribution of CHP thermal energy supporting the dryer process. The electric size of the installed CHP units resulted in being between 3.4 MW and 4.9 MW, with an average value of 4 MW. Data revealed that when the goal is to maximize the generation of electricity for self-consumption, internal combustion engines are the preferred choice due to higher conversion efficiency. In contrast, gas turbines allowed us to minimize the consumption of natural gas input to the spray dryer. Indeed, the fraction of the dryer thermal demand (between 600–950 kcal/kgH₂O), covered by CHP discharged heat, is strictly dependent on the type of prime mover installed: lower values, in the range of 30–45%, are characteristic of combustion engines, whereas the use of gas turbines can contribute up to 77% of the process’s total consumption. Full article

(This article belongs to the Special Issue Industrial Energy Management and Sustainability)

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22 pages, 9567 KiB

Open AccessEditor’s ChoiceArticle

The Importance of Stud Flanges Size and Shape on the Thermal Performance of Lightweight Steel Framed Walls

by Paulo Santos and Keerthan Poologanathan

Sustainability 2021, 13(7), 3970; https://doi.org/10.3390/su13073970 - 2 Apr 2021

Cited by 13 | Viewed by 2912

Abstract

Energy production still relies considerably on fossil fuels, and the building sector is a major player in the energy consumption market, mainly for space heating and cooling. Thermal bridges (TBs) in buildings are very relevant for the energy efficiency of buildings and may [...] Read more.

Energy production still relies considerably on fossil fuels, and the building sector is a major player in the energy consumption market, mainly for space heating and cooling. Thermal bridges (TBs) in buildings are very relevant for the energy efficiency of buildings and may have an impact on heating energy needs of up to 30%. Given the high thermal conductivity of steel, the relevance of TBs in lightweight steel framed (LSF) components could be even greater. No research was found in the literature for evaluating how important the size and shape of steel studs are on the thermal performance of LSF building elements, which is the main objective of this work. This assessment is performed for the internal partitions and exterior façade of load-bearing LSF walls. The accuracy of the numerical model used in the simulations was verified and validated by comparison experimental measurements. Three reference steel studs were considered, six stud flange lengths and four steel thicknesses were evaluated, and five flange indentation sizes and four indent filling materials were assessed, corresponding to a total of 246 modelled LSF walls. It was concluded that the

R

-value decreases when the flange length and the steel studs’ thickness increases, being that these variations are more significant for bigger flange sizes and for thicker steel studs. Additionally, it was found that a small indentation size (2.5 or 5 mm) is enough to provide a significant

R

-value increase and that it is preferable not to use any flange indentation filling material rather than using a poor performance one (recycled rubber). Full article

(This article belongs to the Special Issue Thermal Behavior and Energy Efficiency of Buildings)

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22 pages, 10136 KiB

Open AccessEditor’s ChoiceArticle

Aiming Strategy on a Prototype-Scale Solar Receiver: Coupling of Tabu Search, Ray-Tracing and Thermal Models

by Benjamin Grange and Gilles Flamant

Sustainability 2021, 13(7), 3920; https://doi.org/10.3390/su13073920 - 1 Apr 2021

Cited by 6 | Viewed by 2040

Abstract

An aiming point strategy applied to a prototype-scale power tower is analyzed in this paper to define the operation conditions and to preserve the lifetime of the solar receiver developed in the framework of the Next-commercial solar power (CSP) H2020 project. This innovative [...] Read more.

An aiming point strategy applied to a prototype-scale power tower is analyzed in this paper to define the operation conditions and to preserve the lifetime of the solar receiver developed in the framework of the Next-commercial solar power (CSP) H2020 project. This innovative solar receiver involves the fluidized particle-in-tube concept. The aiming solution is compared to the case without the aiming strategy. Due to the complex tubular geometry of the receiver, results of the Tabu search for the aiming point strategy are combined with a ray-tracing software, and these results are then coupled with a simplified thermal model of the receiver to evaluate its performance. Daily and hourly aiming strategies are compared, and different objective normalized flux distributions are applied to quantify their influence on the receiver wall temperature distribution, thermal efficiency and particle outlet temperature. A gradual increase in the solar incident power on the receiver is analyzed in order to keep a uniform outlet particle temperature during the start-up. Results show that a tradeoff must be respected between wall temperature and particle outlet temperature. Full article

(This article belongs to the Special Issue Advances in Solar Thermal Energy)

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24 pages, 3007 KiB

Open AccessEditor’s ChoiceArticle

Improvement of Self-Starting Capabilities of Vertical Axis Wind Turbines with New Design of Turbine Blades

by Samuel Mitchell, Iheanyichukwu Ogbonna and Konstantin Volkov

Sustainability 2021, 13(7), 3854; https://doi.org/10.3390/su13073854 - 31 Mar 2021

Cited by 21 | Viewed by 3242

Abstract

A lift-driven vertical axis wind turbine (VAWT) generates peak power when it is rotating at high tip-speed ratios (TSR), at which time the blades encounter angles of attack (AOA) over a small range from zero to 30 degrees. However, its ability to self-start [...] Read more.

A lift-driven vertical axis wind turbine (VAWT) generates peak power when it is rotating at high tip-speed ratios (TSR), at which time the blades encounter angles of attack (AOA) over a small range from zero to 30 degrees. However, its ability to self-start is dependent upon its performance at low TSRs, at which time the blades encounter a range of AOAs from zero to 180 degrees. A novel vented aerofoil is presented with the intention of improving the performance of a lift-driven VAWT at low TSRs without hampering the performance of the wind turbine at high TSRs. Computational fluid dynamics (CFD) simulation is used to predict the aerodynamic characteristics of a new vented aerofoil based on the well documented NACA0012 profile. Simulations are performed using the SST turbulence model. The results obtained show a reduction in the coefficient of tangential force (the force that generates torque on the wind turbine) at low AOAs (less than 90 degrees) of no more than 30%, while at high AOAs (more than 90 degrees) an improvement in the tangential force of over 100% is observed. Using a simple momentum based performance prediction model, these results suggest that this would lead to an increase in torque generation by a theoretical three-bladed VAWT of up to 20% at low TSRs and a minor reduction in coefficient of performance of up to 9% at TSR of 2 and closer to 1% at higher TSRs. Full article

(This article belongs to the Special Issue Design and Optimization of Renewable Energy Systems)

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34 pages, 2186 KiB

Open AccessEditor’s ChoiceReview

Survey on e-Powered Micro Personal Mobility Vehicles: Exploring Current Issues towards Future Developments

by Stefania Boglietti, Benedetto Barabino and Giulio Maternini

Sustainability 2021, 13(7), 3692; https://doi.org/10.3390/su13073692 - 26 Mar 2021

Cited by 69 | Viewed by 6954

Abstract

Nowadays, the diffusion of electric-powered micro Personal Mobility Vehicles (e-PMVs) worldwide—i.e., e-bikes, e-scooters, and self-balancing vehicles—has disrupted the urban transport sector. Furthermore, this topic has captured many scholars and practitioners’ interest due to multiple issues related to their use. Over the past five [...] Read more.

Nowadays, the diffusion of electric-powered micro Personal Mobility Vehicles (e-PMVs) worldwide—i.e., e-bikes, e-scooters, and self-balancing vehicles—has disrupted the urban transport sector. Furthermore, this topic has captured many scholars and practitioners’ interest due to multiple issues related to their use. Over the past five years, there has been strong growth in the publication of e-PMV studies. This paper reviews the existing literature by identifying several issues on the impact that e-PMVs produce from different perspectives. More precisely, by using the PRIMA’s methodological approach and well-known scientific repositories (i.e., Scopus, Web of Science, and Google Scholar), 90 studies between 2014 and 2020 were retrieved and analyzed. An overview and classification into endogenous issues (e.g., impact on transport and urban planning) and exogenous issues (e.g., impact on safety and the environment) are provided. While several issues are deeply investigated, the findings suggest that some others need many improvements. Therefore, the status quo of these studies is being assessed to support possible future developments. Full article

(This article belongs to the Special Issue Service Quality in Public Transport Systems and Personal Mobility Vehicles)

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30 pages, 15746 KiB

Open AccessEditor’s ChoiceArticle

Applying PCA to Deep Learning Forecasting Models for Predicting PM_2.5

by Sang Won Choi and Brian H. S. Kim

Sustainability 2021, 13(7), 3726; https://doi.org/10.3390/su13073726 - 26 Mar 2021

Cited by 26 | Viewed by 4781

Abstract

Fine particulate matter (PM_2.5) is one of the main air pollution problems that occur in major cities around the world. A country’s PM_2.5 can be affected not only by country factors but also by the neighboring country’s air quality factors. [...] Read more.

Fine particulate matter (PM_2.5) is one of the main air pollution problems that occur in major cities around the world. A country’s PM_2.5 can be affected not only by country factors but also by the neighboring country’s air quality factors. Therefore, forecasting PM_2.5 requires collecting data from outside the country as well as from within which is necessary for policies and plans. The data set of many variables with a relatively small number of observations can cause a dimensionality problem and limit the performance of the deep learning model. This study used daily data for five years in predicting PM_2.5 concentrations in eight Korean cities through deep learning models. PM_2.5 data of China were collected and used as input variables to solve the dimensionality problem using principal components analysis (PCA). The deep learning models used were a recurrent neural network (RNN), long short-term memory (LSTM), and bidirectional LSTM (BiLSTM). The performance of the models with and without PCA was compared using root-mean-square error (RMSE) and mean absolute error (MAE). As a result, the application of PCA in LSTM and BiLSTM, excluding the RNN, showed better performance: decreases of up to 16.6% and 33.3% in RMSE and MAE values. The results indicated that applying PCA in deep learning time series prediction can contribute to practical performance improvements, even with a small number of observations. It also provides a more accurate basis for the establishment of PM_2.5 reduction policy in the country. Full article

(This article belongs to the Section Environmental Sustainability and Applications)

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20 pages, 40809 KiB

Open AccessEditor’s ChoiceArticle

Life Cycle Assessment (LCA) of a Concentrating Solar Power (CSP) Plant in Tower Configuration with and without Thermal Energy Storage (TES)

by Gemma Gasa, Anton Lopez-Roman, Cristina Prieto and Luisa F. Cabeza

Sustainability 2021, 13(7), 3672; https://doi.org/10.3390/su13073672 - 25 Mar 2021

Cited by 27 | Viewed by 8299

Abstract

Despite the big deployment of concentrating solar power (CSP) plants, their environmental evaluation is still a pending issue. In this paper, a detailed life cycle assessment (LCA) of a CSP tower plant with molten salts storage in a baseload configuration is carried out [...] Read more.

Despite the big deployment of concentrating solar power (CSP) plants, their environmental evaluation is still a pending issue. In this paper, a detailed life cycle assessment (LCA) of a CSP tower plant with molten salts storage in a baseload configuration is carried out and compared with a reference CSP plant without storage. Results show that the plant with storage has a lower environmental impact due to the lower operational impact. The dependence on grid electricity in a CSP tower plant without storage increases its operation stage impact. The impact of the manufacturing and disposal stage is similar in both plants. When analyzed in detail, the solar field system and the thermal energy storage (TES) and heat transfer fluid (HTF) systems are the ones with higher impact. Within the storage system, the molten salts are those with higher impact. Therefore, in this study the impact of the origin of the salts is evaluated, showing that when the salts come from mines their impact is lower than when they are synthetized. Results show that storage is a key element for CSP plants not only to ensure dispatchability but also to reduce their environmental impact. Full article

(This article belongs to the Special Issue Advances in Renewable Energy Technologies for Distributed Generation)

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18 pages, 1204 KiB

Open AccessEditor’s ChoiceReview

Mobility as a Service and Public Transport: A Rapid Literature Review and the Case of Moovit

by Georgina Santos and Nikolay Nikolaev

Sustainability 2021, 13(7), 3666; https://doi.org/10.3390/su13073666 - 25 Mar 2021

Cited by 21 | Viewed by 6513

Abstract

Mobility as a Service (MaaS) is often proposed as a tool for achieving sustainable mobility and, in particular, increasing the share of public transport trips in cities. In this paper we conduct a rapid review of the literature on MaaS and, using Moovit [...] Read more.

Mobility as a Service (MaaS) is often proposed as a tool for achieving sustainable mobility and, in particular, increasing the share of public transport trips in cities. In this paper we conduct a rapid review of the literature on MaaS and, using Moovit as a case study, we explore the association between the popularity of searches in Google using the term “Moovit” and the share of workers that commute by public transport. The exercise focuses on metropolitan areas in the United States over the period 2010 to 2019. We find a positive correlation, and we speculate that metropolitan areas with pre-existing higher shares of workers commuting by public transport tend to be metropolitan areas where use of Moovit is more likely. Full article

(This article belongs to the Collection Sustainability in Urban Transportation Planning)

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21 pages, 451 KiB

Open AccessEditor’s ChoiceReview

Vertically Integrated Supply Chain of Batteries, Electric Vehicles, and Charging Infrastructure: A Review of Three Milestone Projects from Theory of Constraints Perspective

by Michael Naor, Alex Coman and Anat Wiznizer

Sustainability 2021, 13(7), 3632; https://doi.org/10.3390/su13073632 - 24 Mar 2021

Cited by 12 | Viewed by 25265

Abstract

This research utilizes case study methodology based on longitudinal interviews over a decade coupled with secondary data sources to juxtapose Tesla with two high-profile past mega-projects in the electric transportation industry, EV-1 and Better Place. The theory of constraints serves as a lens [...] Read more.

This research utilizes case study methodology based on longitudinal interviews over a decade coupled with secondary data sources to juxtapose Tesla with two high-profile past mega-projects in the electric transportation industry, EV-1 and Better Place. The theory of constraints serves as a lens to identify production and market bottlenecks for the dissemination of electric vehicles. The valuable lessons learned from EV1 failure and Better Place bankruptcy paved the way for Tesla’s operations strategy to build gigafactories which bears a resemblance to Ford T mass production last century. Specifically, EV1 relied on external suppliers to develop batteries, while Better Place was dependent on a single manufacturer to build cars uniquely compatible with its charging infrastructure, whereas Tesla established a closed-loop, green, vertically integrated supply chain consisting of batteries, electric cars and charging infrastructure to meet its customers evolving needs. The analysis unveils several limitations of the Tesla business model which can impede its worldwide expansion, such as utility grid overload and a shortage of raw material, which Tesla strives to address by innovating advanced batteries and further extending its vertically integrated supply chain to the mining industry. The study concludes by sketching fruitful possible avenues for future research. Full article

(This article belongs to the Special Issue Innovative Business Transaction, Product Development or Service Design for Advancement of Sustainable Transportation in the 21st Century)

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20 pages, 700 KiB

Open AccessEditor’s ChoiceArticle

Different Levels of Smart and Sustainable Cities Construction Using e-Participation Tools in European and Central Asian Countries

by Laura Alcaide Muñoz and Manuel Pedro Rodríguez Bolívar

Sustainability 2021, 13(6), 3561; https://doi.org/10.3390/su13063561 - 23 Mar 2021

Cited by 26 | Viewed by 4376

Abstract

Cities are developing strategies to deal with the complex challenges of global change and sustainability. These initiatives have involved the implementation of Information and Communication Technologies (ICTs) as a good driver for achieving sustainability because digital transformation can boost sustainable development strategies, providing [...] Read more.

Cities are developing strategies to deal with the complex challenges of global change and sustainability. These initiatives have involved the implementation of Information and Communication Technologies (ICTs) as a good driver for achieving sustainability because digital transformation can boost sustainable development strategies, providing opportunities to accelerate transformation. Smart City (SC) models built on empowering people in making public decisions favor access to sustainable development solutions based on knowledge and innovation. Nonetheless, SC experiences around the world denote divergent conceptions of SCs which could lead to different SCs construction. It deserves a more thorough understanding of the nature of collaboration in different settings. Therefore, this paper contributes to the debate on the different uses of ICTs in SCs construction in developing vs. developed countries, by examining the use of ICTs for creating collaborative environments in a sample of SCs in different countries, depending on their economic level, and seeking to identify differences in the objectives pursued by city governments with the use of these technologies. To achieve this aim, e-participation platforms, apps or social media platforms (European and Central Asia SCs) are examined for identifying SCs construction differences between developed vs. developing countries. The findings of this paper put an emphasis on the need for taking into account the differences among SCs in developed vs. developing countries when raking or when performance measurement is designed, because the assessment should be tailored to the cities’ particular visions and priorities for achieving their objectives. Full article

(This article belongs to the Special Issue Building Smart and Sustainable Cities: Emerging Technologies and Innovation for Digital-Era Governance and Long-Term Impacts)

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17 pages, 3424 KiB

Open AccessEditor’s ChoiceArticle

Optimal Operation of a Hydrogen Storage and Fuel Cell Coupled Integrated Energy System

by Oscar Utomo, Muditha Abeysekera and Carlos E. Ugalde-Loo

Sustainability 2021, 13(6), 3525; https://doi.org/10.3390/su13063525 - 22 Mar 2021

Cited by 25 | Viewed by 4532

Abstract

Integrated energy systems have become an area of interest as with growing energy demand globally, means of producing sustainable energy from flexible sources is key to meet future energy demands while keeping carbon emissions low. Hydrogen is a potential solution for providing flexibility [...] Read more.

Integrated energy systems have become an area of interest as with growing energy demand globally, means of producing sustainable energy from flexible sources is key to meet future energy demands while keeping carbon emissions low. Hydrogen is a potential solution for providing flexibility in the future energy mix as it does not emit harmful gases when used as an energy source. In this paper, an integrated energy system including hydrogen as an energy vector and hydrogen storage is studied. The system is used to assess the behaviour of a hydrogen production and storage system under different renewable energy generation profiles. Two case studies are considered: a high renewable energy generation scenario and a low renewable energy generation scenario. These provide an understanding of how different levels of renewable penetration may affect the operation of an electrolyser and a fuel cell against an electricity import/export pricing regime. The mathematical model of the system under study is represented using the energy hub approach, with system optimisation through linear programming conducted via MATLAB to minimise the total operational cost. The work undertaken showcases the unique interactions the fuel cell has with the hydrogen storage system in terms of minimising grid electricity import and exporting stored hydrogen as electricity back to the grid when export prices are competitive. Full article

(This article belongs to the Special Issue Sustainable Hydrogen Energy Systems: Electric Applications)

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