Transport fuel demand responses to fuel price and income projections: Comparison of integrated assessment models

Income and fuel price pathways are key determinants in projections of the energy system in integrated assessment models. In recent years, more details have been added to the transport sector representation in these models. To better understand the model dynamics, this manuscript analyses transport fuel demand elasticities to projected income and fuel price levels. Fuel price shocks were simulated under various scenario assumptions to isolate price effects on energy demand and create a transparent environment to compare fuel demand response. Interestingly, the models show very comparable oil price elasticity values for the projected first 10–20 years that are also close to the range described in the empirical literature. When looking at the very long term (30–40 years), demand elasticity values widely vary between models, between 0.4 and −1.9, showing either continuous demand or increased demand responses over time. The latter can be the result of long response time to fuel price shocks, availability of new technologies, and feedback effects on fuel prices. The projected transport service demand is more responsive to changes in income than fuel price pathways, corresponding with the literature. Calculating the models' inherent elasticities proved to be a suitable method to evaluate model behaviour and its application is also recommended for other models as well as other sectors represented in integrated assessment model

Modelisation moleculaire des phases organiques apres extraction de plutonium

International audienceDans le cadre des etudes menees sur les systemes de 4eme generation, des procedes hydrometallurgiques de separation sont en cours de developpement au CEA. La comprehension et l'amelioration des processus d'extraction selective peuvent etre realisees grace a l'etude plus fondamentale de la chimie de coordination des actinides, en phase aqueuse et organique. Plusieurs etudes experimentales ont ete realisees ces dernieres annees sur les ions An4+ dans le milieu aqueux et organique [1], cependant, elles restent toujours difficiles a interpreter. Les simulations a l'echelle moleculaire peuvent aider a mieux comprendre la coordination, la dynamique et la mobilite de ces elements en phase organique (ou/et aqueuse). Compte tenu de la taille du systeme, les simulations de dynamique moleculaire classique semblent etre l'outil le plus pertinent pour traiter le systeme complet sur des temps de simulation relativement longs. La dynamique moleculaire permet de simuler le comportement d'un systeme au cours du temps pour des conditions de pression et de temperature donnees et de prendre en compte explicitement les effets de solvatation.Cependant, ces simulations s'appuient sur l'utilisation d'un champ de force pour decrire les interactions entre tous les constituants des phases de solvant (cf.fig.1). Alors que le developpement de champs de force pour le Pu(IV) en phase aqueuse a deja ete initie [2] , en particulier pour simuler l'interaction entre l'ion et l'eau, il reste un important travail de developpement pour caracteriser les modifications de proprietes de la phase organique en presence du complexe metallique

Electrochemical Behavior of Ce(IV)/Ce(III) Couple in N,N‐Di(2‐ethylhexyl)‐n‐butanamide (DEHBA), N,N‐Di(2‐ethylhexyl)‐iso‐butanamide (DEHiBA), and N,N‐Di(2‐ethylhexyl)‐3,3‐dimethyl Butanamide (DEHDMBA)

International audienceIn this work we report on the electrochemical behavior of Ce(IV)/Ce(III) redox couple in pure N,N-dialkyl amides (N,N-DA), namely N,N-di(2-ethylhexyl)-n-butanamide (DEHBA), N,N-di(2-ethylhexyl)-iso-butanamide (DEHiBA), and N,Ndi(2-ethylhexyl)-3,3-dimethyl butanamide (DEHDMBA) equilibrated with nitric aqueous solutions as an entry to the direct electrochemical characterization of plutonium in these extractants. Ce(IV)/Ce(III) redox process was used as a model. Its potential (E 1/2 1.02 V/SCE) is not affected by the temperature and the nature of the N,N-DA and this clearly indicates that the functionalities of the these extractants produce the same relative effect on both +IV and +III oxidation states of the cerium cation. Linear variations of the current intensity of the reduction peak of Ce(IV) with the concentration of Ce(IV)/N,N-DAs/HNO 3 (5M) solutions were obtained from cyclic voltammograms recorded at 25°C and 40°C. Due to the poor definition of the voltammograms in DEHiBA and DEHDMBA, such characterization allows only the evaluation of the performances of the chemical extraction of Ce(IV) from aqueous nitric acid solution by the undiluted DEHBA. To our knowledge, the electrochemical behavior of Ce(IV)/Ce(III) in N,N-DAs was not previously studied and our findings will for sure open the door for further investigations in this field