Post-pandemic trends in urban mobility

The Covid-19 pandemic triggered significant changes in lifestyles and mobility patterns which are still evident at the end of 2022 and may still raise challenges for transport policy in the short to medium term. While changes in lifestyles -mainly as regards work patterns- have decreased total urban transport activity, the gradual return to pre-pandemic levels suggests that traffic and congestion levels may soon exceed their 2019 levels. Apart from the question of total transport activity, the trends identified in this report can influence modal choice and trip distances, with possible negative repercussions in terms of transport costs, congestion and emissions. The analysis combines a range of data sources and methodologies. Changes in mobility patterns are identified using the JRC Travel Survey 2021. The evolution of traffic congestion levels is monitored through daily TomTom data from 178 cities in the EU. The evolution of public transport activity is measured with up-to-date statistics from national and local sources. The role of active mobility is discussed using a model to estimate the potential uptake and benefits in terms of external costs. Information provided by the candidates for the EU Mission on Climate-Neutral and Smart Cities allows an extensive review of transport policy measures adopted at city level. Finally, a case study for 40 European cities using multiple data sources provides an empirical confirmation of the main findings.JRC.C.6 - Economics of Climate Change, Energy and Transpor

Expanding the applicability of daytime radiative cooling: Technological developments and limitations

Daytime radiative cooling is regarded as the gold promise of future sustainable building energy systems and a breakthrough in the fight against local climate change. Despite the fervid research interest, most literature reports exceptional theoretical performances under ideal, desert-like conditions, but overlooks the cooling impairment that occurs under low atmospheric transparency (cloudy, humid, polluted conditions) and reduced sky access (packed urban contexts). Power recovery and stabilization call for decoupling of incoming and outgoing radiation at equal wavelengths. Enhanced directionality and high-contrast, broadband asymmetric transmission have been recently proposed to expand the applicability of radiative coolers over a wider spectrum of climates, weathers and terrains. This review offers itself as a first, timely synthesis of the current technological arena. Physical principles, materials and designs, collected from a variety of applicative fields, are detailed and discussed in terms of performance and feasibility, to inspire the transition into sustainable building cooling, worldwide. Major grey areas and serious concerns on potential violations of the 2nd law of thermodynamics reinforce the need for experimental demonstrations in future research

Covenant of Mayors: 2022 assessment

Cities and local authorities are key players in addressing climate change. Since 2008, the European Commission endorses and supports their efforts through the Covenant of Mayors for Climate and Energy (CoM) and notably through the provision of capacity building, technical assistance, sharing of best practices and peer learning opportunities. The initiative helps consolidate practices to monitor and report on energy consumption and GHG emissions as well as on risks and vulnerabilities at the local level, allowing decision makers to identify priority sectors, set emission reduction targets and adaptation goals and plan relevant measures. This report provides a scientific assessment of the CoM pillars of climate change mitigation and adaptation, based on data reported through the MyCovenant reporting platform. It describes the Covenant community, the plans submitted by signatories, examines actions and measures and gives an overview on the progress made. On mitigation, looking only at 412 action plans with at least one monitoring report, a 30.9% reduction by 2030 is forecasted, while the targeted mean reduction is 44.6%. On adaptation, several vulnerable population groups including the elderly, persons living with chronic diseases, low-income households, and persons living in sub-standard housing, are exposed to climate hazards. Signatories report high-risk hazards (such as extreme heat, droughts & water scarcity, heavy precipitation and floods & sea level rise) that affect 33.3 million people.JRC.C.2 - Energy Efficiency and Renewable

Elastocaloric cooling: roadmap towards successful implementation in the built environment

In the pursuit of ever more efficient built environments, able to resiliently respond to the many implications of climate change, near room-temperature caloric cooling could be a game changer from multiple standpoints. In this paper, perspectives and challenges of successful implementation of elastocaloric devices in the built environment are explored by contrasting the current readiness level with the envisaged potentiality. Material-level and device-level criticalities are identified and potential solutions are discussed. The roadmap towards an informed and efficient use of this environmentally friendly technology is eventually proposed aiming at an increase of building’s energy efficiency, but also at counteracting the urban heat island effect

Urban transport in the EU Mission on Climate Neutral and Smart Cities: preliminary data from applicants' expressions of interest

The EU Mission on Climate Neutral and Smart Cities is an ambitious initiative to involve a wide range of stakeholders and deliver 100 climate-neutral and smart cities by 2030. These cities will act as experimentation and innovation hubs to enable all European cities to follow suit by 2050. The results from the expressions of interest suggest that the Mission's objectives are shared by a significant number of cities: 314 EU cities (representing 18% of EU population) plus 48 non-EU cities declared their ambition and preparedness to become climate neutral. Transport is a key sector to address, with the overwhelming majority of applicant cities setting specific targets and policy measures. Electrification of urban transport appears as the main approach towards decarbonization. Nevertheless, the required investments and the repercussion on the citizens' costs for mobility are major concerns

On the energy modulation of daytime radiative coolers: A review on infrared emissivity dynamic switch against overcooling

Passive daytime radiative cooling represents one of the boldest answers to tackle the future cooling needs of the built environment and to mitigate urban heat island effects. Recent developments in the field targeted subambience with several successful examples. On the other side, heating demands may get exacerbated unless effective countermeasures against overcooling are identified, especially in wintertime or heating-dominated climates. This review aims at collecting state-of-the-art technologies and techniques to dynamically control the heat transfer to and from the radiative emitter and ultimately modulate its cooling capacity. Potential solutions are selected from different applicative fields, including spacecraft thermal control, thermal camouflage and electronics. Environmentally-responsive solutions are analyzed in depth given their perfect match with radiative cooling design requirements. Among them, VO2-tuned Fabry-Perot resonators are given particular emphasis, owing to their proven applicability. Active solutions are presented for completeness, but in less detail. Underlying principles, structural composition and experimental/simulated results are detailed and discussed to identify prominent pathways towards technically and economically effective integration in the built environment

Upscaling of SMA film-based elastocaloric cooling

A new concept of upscaling a shape memory alloy (SMA) film based elastocaloric cooling device is presented by arranging SMA films in parallel to increase the specific cooling capacity at low actuation force, while maintaining the large surface-to-volume ratio needed for rapid heat transfer. Selected materials are cold-rolled TiNiFe films that exhibit maximum adiabatic temperature changes of 27.3 and -18.1 K upon loading and unloading, respectively. Demonstrators are designed, fabricated and characterized consisting of five free-standing TiNiFe film bridges that are coupled antagonistically for work recovery. Thermomechanical cycling is performed by out-of-plane deflection of the SMA bridges, while heat transfer is established through mechanical contact with solid heat sink/source elements. The cooling capacity of the demonstrators scales with the number of active SMA films, which confirms the concept of parallelization for upscaling. Investigated demonstrators reach a maximum cooling capacity of about 900 mW compared to a maximum of about 200 mW achieved for reference devices consisting of a single TiNiFe film. The investigation also reveals a number of open issues related to narrow fabrication tolerances upon upscaling, which may cause different plastic straining and varying inhomogeneous stress accumulation among the individual SMA films

Covenant of Mayors: 2021 assessment

Cities and local authorities are key players in addressing climate change. Since 2008, the European Commission endorses and supports their efforts through the Covenant of Mayors for Climate and Energy (CoM) and notably through the provision of capacity building, technical assistance, sharing of best practices and peer learning opportunities. The initiative helps consolidate practices to monitor and report on energy consumption and GHG emissions as well as on risks and vulnerabilities at the local level, allowing decision makers to identify priority sectors, set emission reduction targets and adaptation goals and plan relevant measures. This report provides a scientific assessment of the CoM pillars of climate change mitigation and adaptation, based on data reported through the MyCovenant reporting platform. It describes the Covenant community, the plans submitted by signatories, examines actions and measures and gives an overview on the progress made. The key findings on mitigation show that the overall commitment to reducing GHG emissions by signatories is 25.7 % by 2020 and 44.5 % by 2030 compared to baseline emissions. On adaptation, while committed signatories and adaptation action plans are less numerous than mitigation ones, figures are constantly growing. For example, considering the reported adaptation actions by year (2010-2020), the numbers are increasing at an exponential rate, and the trend is projected to continue.JRC.C.2 - Energy Efficiency and Renewable