Mass- and power-related efficiency trade-offs and CO2 emissions of compact passenger cars.

Passenger cars in Europe have become both heavier and more powerful over the past decades. This trend has increased vehicle utility but it might have also offset technical improvements in powertrain efficiency. Here, we analyze efficiency trade-offs and CO2 emissions for three popular compact cars in Germany. We find that mass, power, and front area of model variants has increased by 66%, 147%, and 22%, respectively between 1980 and 2018. In the same period, fuel consumption decreased 14% for gasoline models but it increased 9% for diesel models. However, if vehicle mass, power, and front area had remained at 1980 levels, technical efficiency improvements would have decreased the fuel consumption of gasoline and diesel models by 23% and 24%, respectively. The related efficiency trade-offs amount to 24 g CO2/km or 13% of the current fuel consumption for gasoline models and 40 g CO2/km or 25% of the current fuel consumption for diesel models. These findings suggest that about half of the technical efficiency improvements in gasoline models and all of the technical efficiency improvements in diesel models are offset through other vehicle attributes. By accounting for the observed efficiency trade-offs, climate policy could become more effective.

Fully electric and plug-in hybrid cars - An analysis of learning rates, user costs, and costs for mitigating CO2 and air pollutant emissions.

This article presents experience curves and cost-benefit analyses for electric and plug-in hybrid cars sold in Germany. We find that between 2010 and 2016, the prices and price differentials relative to conventional cars declined at learning rates of 23 ±â€¯2% and 32 ±â€¯2% for electric cars and 6 ±â€¯1% and 37 ±â€¯2% for plug-in hybrids. If trends persist, price beak-even with conventional cars may be reached after another 7 ±â€¯1 million electric cars and 5 ±â€¯1 million plug-in hybrids are produced. The user costs of electric and plug-in hybrid cars relative to their conventional counterparts are declining annually by 14% and 26%. Also the costs for mitigating CO2 and air pollutant emissions through the deployment of electrified cars tend to decline. However, at current levels, NOX and particle emissions are still mitigated at lower costs by state-of-the-art after-treatment systems than through the electrification of powertrains. Overall, the observation of robust technological learning suggests policy makers should focus their support on non-cost market barriers for the electrification of road transport, addressing specifically the availability of recharging infrastructure.

Development of a freeze-drying protocol for the long-term storage of S9-fraction at ambient temperatures.

The purpose of this study was to investigate the long-term stabilization of the liver S9-fraction that is widely used in genotoxicity assays in order to mimic bio-activating processes of xenobiotics in vitro. A successful long-term stabilization of the S9-fraction meets the growing demand for the construction of a lab independent device for the detection of genotoxic compounds in field studies with an integrated module for the metabolic activation of pre-genotoxic compounds. The carbohydrates sucrose, trehalose and raffinose were tested in different concentrations or mixtures in order to increase the product stability of the S9-fraction during and after freeze-drying. The activity of the freeze-dried S9-samples was evaluated by means of their potential to activate pre-genotoxic compounds. The successful long-term stabilization of enzymes of the rodent liver S9-fraction for 6 weeks at room temperature by freeze-drying in the presence of 250 mM trehalose is presented.