• Energy Research
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This thesis aims to examine the causal mechanisms of living environments on leisure mobilities and verify whether their inclusion is actually able to challenge the compact city as a sustainable urban form. The research focuses on the Swiss case and in particular the cities of Geneva and Zurich. The empirical approach is based on three types of additional analysis carried out in these areas: contextual analysis, quantitative analyzes based on data from the Mobility and Transport Microcensus 2010 and qualitative analysis through interviews. The main results are the following: â ¢ We find the existence of two opposing logics of association between land density and distance traveled: a decreasing link to daily mobility, but a positive correlation for occasional mobility (day trips and overnight trips). The denser is the living environment, the greater is the distance for this mobility. â ¢ Adding the two types of mobility to obtain a total average, we find that the inner city dwellers displayed, ultimately, much higher totals than would suggest the analysis of their daily mobility alone which therefore represent an invitation to invalidate the link compact city=short distances. â ¢ By transforming these distances into environmental impact, however, our calculations show that even while taking into account the many trips of urban dwellers, the negative relationship between total energy consumption and land density of the territory remains. â ¢ By examining in detail the share of leisure in daily and occasional mobility, we see that the logic of compensation is not what structures the links with urban environnements. In everyday life, the logic of proximity prevails: to live in the centre is rather correlated to more compactophile leisure and residing in the periphery to more leisure oriented towards the attributes of nature. â ¢ For occasional trips, we show firstly that compactophile mobilities represent a large part of these practices among all respondents, and secondly, that even in the case of very important and high energy consuming naturophile mobility, the relationship with the density of the living environment is not established. The central Genevans and are much less consumers of this type of leisure than people in the centre of Zurich even though their city is much more airy and green. Moreover, we also highlight, in peri-urban dwellers, a very intense mobility or this purpose. â ¢ The interpretation that we propose refers to lifestyles and residential choice of city dwellers which takes into account their leisure aspirations. These tastes are then translated into specific leisure activities and travel. In everyday life, they rely on proximity and functional, social and sensitive attributes of their living environment that they have chosen largely also for this. When it comes to breaking the routines during holidays and vacations, the same lifestyles result in significant occasional mobility whose motives can register in continuity of their daily lifestyle (loving the same things elsewhere) or by contrast (appreciate the diversity of spaces). In both cases, these motivations echo the valorisation of the diversity inherent in urbanity without questioning the urban residential location quality itself. Our results lead us ultimately to reject the compensation effect hypothesis and reaffirm, against the defenders of the sprawl-city, the virtues of the compact city, which remains a sustainable urban form, including for our leisure mobility.

The factsheets describe 13 electricity supply alternatives that could contribute to the Swiss electricity mix in 2035: (1) three hydropower types, including large dams, large run-of-river, and small hydropower; (2) five new renewable technologies—solar cells (photovoltaics), wind, deep geothermal, woody biomass, and biogas; (3) nuclear power; (4) waste incineration and large natural gas power; (5) net electricity import from abroad (net on the annual basis); and (6) electricity savings and efficiency improvements to reduce the electricity demand. Each technology, its current status, resource potential, and environmental, health, and economic impacts were described qualitatively and quantitatively. The impacts included climate change (CO2equiv); local air pollution (PM10equiv; SOx and NOx); water, landscape, and land use (m2 of land use); flora and fauna; accidental impacts, resource use, and waste (kWh of nonrenewable energy used for 1 kWh of electricity); electricity costs (rappen (Rp.) per kWh); and electricity supply reliability. The impacts were assessed using data from literature, prioritizing the Swiss-specific data as much as possible and including qualitative explanations for non-experts. The factsheets are accompanied by a glossary and a supplementary overview table that applied a five-color indicator system to reflect the severity of impacts across technologies. The factsheets were developed for an informed citizen panel study in July 2017 in Switzerland, described in the following publication: Volken, S.; Xexakis, G.; Trutnevyte, E. Perspectives of Informed Citizen Panel on Low-Carbon Electricity Portfolios in Switzerland and Longer-Term Evaluation of Informational Materials. Environmental Science & Technology 2018 52 (20), 11478-11489, DOI: 10.1021/acs.est.8b01265

So far in the Twenty-first century the field of people transportation has had numerous setbacks, of these some are related to air pollution and some to the rarefaction of petroleum sources. Studies have been undertaken within this domain for many years now. Hybrid vehicles in which the conventional energy source is kept and an on-board energy source is added are showing themselves to be a potentially good solution in the short term. In these hybrids the vehicle autonomy is assumed by the first energy source and the power constraints are taken upon by the second. Moreover, the storage element adds the possibility to recuperate the braking energy in an optimal way. During the last decade, an important development has come about in the field of energy storage elements. The supercapacitors newly appearing on the scene are power components well suited for an application in transportation domain: their lifetime is over 500,000 cycles and their power density (W/kg) is much higher than for batteries. The present work is concerned with air pollution and energy storage elements and presents the details of using a power assistance system for vehicles. In this case, the auxiliary power energy storage element is on board and is made of supercapacitors. The decreased energy consumption of the vehicle is directly dependant on the vehicle's type, the route driven and the size of the storage element within the vehicle. An optimal method of sizing the energy storage element is developed. An application of the principles is presented in three different categories of vehicle: a transportation network fed by catenaries, a diesel-electric vehicle and a light electrical vehicle. In all three cases, the size of the storage elements, the on-board energy control system and the reduction of the vehicle consumption are defined. Following the different methods developed here, it is possible to define the conditions for when a power assistance system can give a real decrease in the vehicle's energy consumption. When an on-board storage element is added in a vehicle, a static converter has to be used. Its main role is to adapt the voltage level between the storage element and the other vehicle propulsion equipment and to control the energy flow on board the vehicle. An interleaved mutichannel continuous-continuous converter operating in a discontinuous conduction mode is especially dedicated to mobile applications. This type of converter is lighter and smaller in volume, yet its efficiency is greater.