Fleet Energy Research Articles

Scenario analysis of lightweight and electric-drive vehicle market penetration in the long-term and impact on the light-duty vehicle fleet

Electric-drive vehicles, including hybrid electric vehicles, plug-in hybrid electric vehicles, battery electric vehicles, fuel cell electric vehicles and fuel cell hybrid electric vehicles, are emerging as less polluting alternatives to internal combustion engine vehicles. Therefore, it is important to assess their penetration in the vehicle market in the future. A ‘two-step’ approach is used to estimate the optimum market penetration of lightweight and electric-drive vehicles in the long-term and the impact on the light-duty vehicle fleet, focusing on Japan. First, an optimization model is used to estimate the vehicle market composition in 2050. Then, a vehicle stock turnover model is used to estimate light-duty vehicle fleet energy and material consumption, CO2 emissions and cost. Internal combustion engine vehicles and hybrid electric vehicles dominate in the Base scenario. Fuel cell hybrid electric vehicles dominate when low cost is prioritized. Shift to battery electric vehicles occurs when low CO2 emissions are prioritized. CO2 emissions are reduced 56.9% between 2012 and 2050 in the Base scenario. Lightweight mini-sized battery electric vehicle diffusion has the largest CO2 emissions reductions, 87.3% compared to the 2050 baseline value; with the net cash flow peaking at 10.2 billion USD/year in 2035 and becoming negative after 2044.

Energy, environmental and economic impact of mini-sized and zero-emission vehicle diffusion on a light-duty vehicle fleet

Diffusion of battery electric vehicles and fuel cell hybrid electric vehicles can contribute to reduce passenger light-duty vehicle fleet CO2 emissions. However, barriers such as higher vehicle capital cost and lack of electricity and hydrogen infrastructure prevent their deployment. A vehicle stock turnover model was used to assess the impact of mini-sized and zero-emission vehicle diffusion on passenger light-duty vehicle fleet energy and material consumption, CO2 emissions and cost, focusing on Japan. 2050 passenger light-duty vehicle fleet energy consumption and tank-to-wheel CO2 emissions in the base scenario are 48.7 and 51.9% lower than the 2012 values. Diffusion of mini-sized and battery electric vehicles provides the largest energy consumption and CO2 emissions reductions, 64.7, and 87.8% compared with the 2050 baseline values. Incremental cost of zero emission vehicles is reduced through downsizing. The 2050 net cash flow for battery electric vehicles diffusion is reduced from 15.9 to −16.7billion USD/year if downsizing is applied; while in the case of fuel cell hybrid electric vehicle diffusion, downsizing reduces the 2050 net cash flow from −12.5 to −47.8billion USD/year. Thus, shifting to mini-sized zero emission vehicles provides the quadruple benefit of reducing energy and material consumption, CO2 emissions and cost.

Quantifying the role of vehicle size, powertrain technology, activity and consumer behaviour on new UK passenger vehicle fleet energy use and emissions under different policy objectives

This paper quantifies the impacts of policy objectives on the composition of an optimum new passenger vehicle fleet. The objectives are to reduce individually absolute energy use and associated emissions of CO2, NOx and PM2.5. This work combines a top down, diversity-led approach to fleet composition with bottom-up models of 23 powertrain variants across nine vehicle segments. Changing the annual distance travelled only led to the smallest change in fleet composition because driving less mitigated the need to shift to smaller vehicles or more efficient powertrains. Instead, managing activity led to a ‘re-petrolisation’ of the fleet which yielded the largest reductions in emissions of NOx and PM2.5. The hybrid approach of changing annual distance travelled and increasing willingness to accept longer payback times incorporates management of vehicle activity with consumers’ demand for novel vehicle powertrains. Combining these changes in behaviour, without feebates, allowed the hybrid approach to return the largest reductions in energy use and CO2 emissions. Introducing feebates makes low-emitting vehicles more affordable and represents a supply side push for novel powertrains. The largest reductions in energy use and associated emissions occurred without any consumer behaviour change, but required large fees (£79–99 per g CO2/km) on high-emitting vehicles and were achieved using the most specialised fleets. However, such fleets may not present consumers with sufficient choice to be attractive. The fleet with best diversity by vehicle size and powertrain type was achieved with both the external incentive of the feebate and consumers modifying their activity. This work has a number of potential audiences: governments and policy makers may use the framework to understand how to accommodate the growth in vehicle use with pledged reductions in emissions; and original equipment manufacturers may take advantage of the bottom-up, vehicle powertrain inputs to understand the role their technology can play in a fleet under the influence of consumer behaviour change, external incentives and policy objectives.

Transport energy demand in Andorra. Assessing private car futures through sensitivity and scenario analysis

This paper presents a model which estimates current car fleet energy consumption in Andorra and forecasts such consumption as a reference scenario. The base-year model is built through a bottom-up methodology using vehicle registration and technical inspection data. The model forecasts energy consumption up to 2050, taking into account the fleet structure, the car survival profile, trends in activity of the various car categories, and the fuel price and income elasticities that affect car stock and total fleet activity. It provides an initial estimate of private car energy demand in Andorra and charts a baseline scenario that describes a hypothetical future based on historical trends. A local sensitivity analysis is conducted to determine the most sensitive input parameters and study the effect of its variability. In addition, the scenario analysis explores the most uncertain future aspects which can cause important variability in the results with respect to the Reference scenario and provides a broad estimate of potential energy savings related to different policy strategies.

Transitions and Impacts of Passenger Car Powertrain Technologies in European Member States

In this paper we seek to understand the relative impacts that policies and incentives focused on e-mobility may have on the technology market shares for passenger cars, and the associated fleet energy requirements and greenhouse gas emissions. We have a European Union (EU) wide focus, and from this deduce what recommendations could be provided for countries intending to encourage e-mobility in the near future. For this task we integrate two in-house models of the vehicle fleet and market developed by the European Commission Joint Research Centre. Our main policy conclusion is that although ambitious policy may lead to great improvements in specific efficiency and emissions, second order effects could lead to increased passenger car activity, limiting the overall emission improvement achieved. Therefore, any policy portfolio requires not only technological policies (aimed at both users and manufacturers), but also would need to address wider mobility patterns in an integrated approach. As such not only do we present findings relevant for policy decision making but also contribute to methodological approaches regarding the use and integration of modelling tools in support to policy design.

Impact of powertrain electrification, vehicle size reduction and lightweight materials substitution on energy use, CO2 emissions and cost of a passenger light-duty vehicle fleet

Electric-drive and lightweight vehicles can reduce CO2 emissions in road passenger transportation. However, maximum reductions are limited by the extent of their diffusion. A vehicle fleet stock turnover model was developed to study the impact of powertrain electrification, vehicle size reduction and lightweight materials substitution on light-duty vehicle fleet energy consumption, CO2 emissions and cost; and used in the case of Japan. Vehicle types included internal combustion engine vehicles, hybrid electric vehicles, battery electric vehicles, and fuel cell hybrid electric vehicles; using two glider types, conventional and lightweight; available in three vehicle size classes, normal, compact and mini-sized vehicles. Diffusion of mini-sized lightweight battery electric vehicles has the largest potential for tank-to-wheel energy consumption and CO2 emissions reductions, 70.6 and 92.2%, compared to the 2050 baseline values; with a net cash flow larger than zero until 2045. In contrast, diffusion of mini-sized lightweight fuel cell hybrid electric vehicles has the lowest net cash flow by 2050, with negative values from 2033 and potential tank-to-wheel energy consumption and CO2 emissions reductions of 55.4 and 82.9% compared to the 2050 baseline values. Lightweighting reduces significantly the capital cost of battery electric vehicles and fuel cell hybrid electric vehicles, favoring their deployment.

Analysis of impacts of alternative policies aimed at increasing US energy independence and reducing GHG emissions

The primary objectives of recent energy initiatives have been: (1) lowering greenhouse gas (GHG) emissions; and (2) increasing US energy security by reducing oil imports for the purposes of making the US less vulnerable to the actions of other countries. The concern is that relying on sometimes adversarial, sometimes unstable countries for a quarter of our oil carries certain risks. For that reason, reducing the external oil dependence has been of interest to policy makers. This paper examines the impacts and costs of transportation-based policies on light-duty vehicle fleet energy usage and emissions. Using the 2010 elastic version of the US Environmental Protection Agency's Market Allocation (MARKAL) model, recent increases in US Corporate Average Fuel Economy (CAFE) Standards are compared to what some economists suggest would be a much more “efficient” alternative-asystem-wide oil tax internalizing a number of environmental externalities. We discover that our series of oil taxes produce larger and more cost-effective reductions in economy-wide emissions than CAFE. The same cannot be said in regards to net oil imports. Stricter fuel economy regulations result in much larger cutbacks in imports than the oil tax. In fact, we found that in 2040 import demands are roughly 250 million BOE (barrels of oil equivalent) higher with our oil tax regime than they are with CAFE. The additional import reductions achieved with stricter CAFE Standards do come, however, at a much larger cost to society. A great deal of these additional economic costs stems from greater usage of more energy-efficient automobiles and the higher initial capital costs associated with their adoption. In our supplementary analysis, we find that even if the costs of these types of vehicles are lowered by as much as 75%, oil taxes would still be able to maintain their competitive edge over CAFE standards in regards to cost-effectiveness.

Effects of longer heavy vehicles on traffic congestion

Two-lane, “microscopic” (vehicle-by-vehicle) simulations of motorway traffic are developed using existing models and validated using measured data from the M25 motorway. An energy consumption model is also built in, which takes the logged trajectories of simulated vehicles as drive-cycles. The simulations are used to investigate the effects on motorway congestion and fuel consumption if “longer and/or heavier vehicles” (LHVs) were to be permitted in the UK. Baseline scenarios are simulated with traffic composed of cars, light goods vehicles and standard heavy goods vehicles (HGVs). A proportion of conventional articulated HGVs is then replaced by a smaller number of LHVs carrying the same total payload mass and volume. Four LHV configurations are investigated: an 18.75 m, 46 t longer semi-trailer (LST); 25.25 m, 50 t and 60 t B-doubles and a 34 m, 82 t A-double. Metrics for congestion, freight fleet energy consumption and car energy consumption are defined for comparing the scenarios. Finally, variation of take-up level and LHV engine power for the LST and A-double are investigated. It is concluded that: (a) LHVs should reduce congestion particularly in dense traffic, however, a low mean proportion of freight traffic on UK roads and low take-up levels will limit this effect to be almost negligible; (b) LHVs can significantly improve the energy efficiency of freight fleets, giving up to a 23% reduction in fleet energy consumption at high take-up levels; (c) the small reduction in congestion caused by LHVs could improve the fuel consumption of other road users by up to 3% in dense traffic, however in free-flowing traffic an opposite effect occurs due to higher vehicle speeds and aerodynamic losses; and (d) underpowered LHVs have potential to generate severe congestion, however current manufacturers’ recommendations appear suitable.

Evaluation of vehicle fleet maintenance management indicators by application of DEMATEL and ANP

The paper refers to the importance of maintenance management to increase the vehicle fleet energy efficiency. The fleet maintenance management influences as the vehicle maintenance process itself as well as the primary transport process but also their environment. In order to increase fleet energy efficiency by means of a more efficient maintenance management, it is indispensable to observe maintenance process, transport process and the environment. Since the implementation effects of such measures can be measured by different indicators, this paper analyses the influence of indicators in all three mentioned areas on management decision-making. In this sense, appropriate indicators have been defined and subsequently used in fleet maintenance management. To determine levels and intensities of interdependence as well as relative weight of selected indicators two methods have been combined: Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Process (ANP). A model was proposed with indicators’ interdependence whose relative weights were calculated. The proposed model has been implemented in several companies with road vehicle fleets. Collected results show the perceived evaluation by company managers in view of maintenance management process influence onto their fleet energy efficiency. Besides, by proposed model implementation we have obtained equally managers’ evaluation upon effectiveness and efficiency of the maintenance management within studied companies.

Simulating the impact of policy, energy prices and technological progress on the passenger car fleet in Austria—A model based analysis 2010–2050

This paper investigates the effects of policy, fuel prices and technological progress on the Austrian passenger car fleet in terms of energy consumption and greenhouse gas (GHG) emissions. To analyse these effects a simulation model is used. We model the car fleet from a bottom-up perspective, with a detailed coverage of vehicle specifications and propulsion technologies. The model focuses on the technological trend toward electrified propulsion systems and their potential effects on the fleet's energy consumption and GHG emissions. To represent the impact of prices and income on the development of the fleet, we combine the fleet model with top-down demand models.We developed two scenarios for the time frame 2010–2050, using two different sets of assumptions for regulatory development and conditions of increasing fossil fuel prices and continuous technological progress in vehicle propulsion technologies.The results indicate that material cuts in energy consumption and GHG emissions can be achieved with changes to the political framework for passenger cars. Appropriate taxation of fuels and cars can stabilise demand for individual motorised transport and lead to an improvement in vehicle efficiency by fostering the adoption of efficient vehicle propulsion technologies and low carbon fuels.

Development of a new tank-to-wheels methodology for energy use and green house gas emissions analysis based on vehicle fleet modeling

Tank-to-Wheels (TtW) makes the largest contribution to the total Well-to-Wheels (WtW) energy consumption and greenhouse gas (GHG) emissions from fossil-derived transportation fuels. The most commonly adopted TtW methodologies to obtain vehicle energy consumption, energy efficiency, and GHG emissions used to date all have significant limitations. A new TtW methodology, which combines micro-scale virtual vehicle simulation with macro-scale fleet modeling, is proposed in this paper. The models capabilities are demonstrated using a case study based on data from the passenger car sector in Great Britain. A simplified internal combustion engine model was developed in-house to simulate engine behaviors across a wide range of engine capacities and technologies. Vehicle simulation was then carried out using the efficiency map output by the simplified engine model for any given gasoline or diesel engine; the simulation was validated for 37 vehicles available on the UK market in terms of their vehicle-certification fuel consumption, with a discrepancy generally within 3%. Real-world fleet and driving data from the Great Britain’s car fleet was extracted from the Transport Statistics Great Britain (TSGB) database between 2001 and 2007TSGB 2001–2007. A virtual fleet was constructed with the validated virtual vehicles to represent the real-world passenger car fleet in terms of its composition and operating characteristics. This fleet model was shown to match the real-world fleet-averaged fuel consumption within 3% for the gasoline fleet and within 6% for the diesel fleet. Finally, several scenarios were analyzed using the validated fleet model, covering a projection for 2008, driving pattern, lubrication, and fuel. The vehicle-to-vehicle variation was found to be significant in some scenarios, indicating that a fleet-based methodology would be more rigorous and flexible. Energy consumption and CO2 emission figures from previous, well-recognized Europe-oriented studies (e.g., the 2008 JRC/EUCAR/CONCAWE study) were significantly lower than the TSGB real-world results based on the new TtW methodology. It is apparent that using a single vehicle to represent the whole fleet could be misleading; in particular, the relative energy efficiency and CO2 emission of diesel over gasoline cars might follow a different trend with time for the real-world fleet from that shown in previous studies. Future WtW studies can benefit from the modeling toolset and methodology reported herein in a number of ways: The virtual engine/vehicle/fleet model developed in this work can readily be expanded and upgraded in the future, in terms of model details, coverage, and data quality. The methodology itself is generically applicable to any defined fleet (passenger cars, commercial vehicles, etc.) with any operating characteristics at any given timeframe from any geographic region. Various subjects and their implications for fleet energy consumption and GHG emissions could be studied including, but not restricted to, the following:

Political Science and Prediction: What's Next for U.S. Climate Change Policy?

AbstractThis article analyzes how U.S. climate change politics and policy making are changing in the public, private and civil society sectors, and how such changes are likely to influence U.S. federal policies. It outlines the current status of U.S. climate change action and explores four overlapping pathways of policy change: (1) the strategic demonstration of the feasibility of climate change action; (2) the creation and expansion of markets; (3) policy diffusion and learning; and (4) the creation and promulgation of norms about the need for more aggressive climate change action. These four pathways seek to fruitfully draw from rationalist and constructivist approaches to policy analysis, without collapsing or confusing the different logics. Building on this analysis, it predicts that future federal U.S. climate policy will include six major components: (1) A national cap on GHG emissions; (2) A national market based cap‐and‐trade GHG emissions trading scheme; (3) Mandatory renewable energy portfolio standards; (4) Increased national product standards for energy efficiency; (5) Increased vehicle fleet energy efficiency standards; and (6) Increased federal incentives for research and development on energy efficiency issues and renewable energy development. In addition, expanding federal climate policy may bring about significant changes in U.S. foreign policy as U.S. international re‐engagement on climate change is likely to occur only after the development of more significant federal policy.

Future fuel cell and internal combustion engine automobile technologies: A 25-year life cycle and fleet impact assessment

Hydrogen fuel cell (FC) vehicles are receiving increasing attention as a potential powerful technology to reduce the transportation sector's dependence on petroleum and substantially decrease emissions of greenhouse gases (GHGs) at the same time. This paper projects energy use and GHG emissions from different FC vehicle configurations and compares these values to the projected characteristics of similarly sized and performing gasoline and diesel fueled automobiles on a life cycle, well to wheels and cradle to grave basis. Our analysis suggests that for the next 20 or more years, new internal combustion engine (ICE) hybrid drive train vehicles can achieve similar levels of reduction in energy use and GHG emissions compared to hydrogen FC vehicles, if the hydrogen is derived from natural gas. The fleet impact of more fuel-efficient vehicles depends on the time it takes for new technology to (i) become competitive, (ii) increase its share of the new vehicles produced, and finally (iii) penetrate significantly into the vehicle fleet. Since the lead times for bringing improved ICE vehicle technology into production are the shortest, its impact on vehicle fleet energy use and emissions could be significant in 20–30 years, about half the time required for hydrogen FC vehicles to have a similar impact. Full emission reduction potential of FC vehicles can only be achieved when hydrogen is derived from zero or very low-carbon releasing production processes on a large scale—an option that further increases the impact leadtime. Thus, a comprehensive short- and long-term strategy for reducing automobile energy use and emissions should include both the continuous improvement of ICE vehicles and simultaneous research and development of hydrogen FC cars.