Results 1 - 10 of 10
Results 1 - 10 of 10. Search took: 0.018 seconds
|Sort by: date | relevance|
[en] Various alternative fuels and improved engine and vehicle systems have been proposed in order to reduce emissions and energy use associated with heavy vehicles (predominantly trucks). For example, oil companies have proposed improved methods for converting natural gas to zero-aromatics, zero-sulfur diesel fuel via the Fischer-Tropsch process. Major heavy-duty diesel engine companies are working on ways to simultaneously reduce particulate-matter and NOX emissions. The trend in heavy vehicles is toward use of lightweight materials, tires with lower rolling resistance, and treatments to reduce aerodynamic drag. In this paper, we compare the Mecycle energy use and emissions from trucks using selected alternatives, such as Fisher-Tropsch diesel fuel and advanced fuel-efficient engines. We consider heavy-duty, Class 8 tractor-semitrailer combinations for this analysis. The total life cycle includes production and recycling of the vehicle itself, extraction, processing, and transportation of the fuel itself, and vehicle operation and maintenance. Energy use is considered in toto, as well as those portions that are imported, domestic, and renewable. Emissions of interest include greenhouse gases and criteria pollutants. Angonne's Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is used to generate per-vehicle fuel cycle impacts. Energy use and emissions for materials manufacturing and vehicle disposal are estimated by means of materials information from Argonne studies. We conclude that there are trade-offs among impacts. For example, the lowest fossil energy use does not necessarily result in lowest total energy use, and lower tailpipe emissions may not necessarily result in lower lifecycle emissions of all criteria pollutants
[en] Electric vehicle batteries use energy and generate environmental residuals when they are produced and recycled. This study estimates, for 4 selected battery types (advanced lead-acid, sodium-sulfur, nickel-cadmium, and nickel-metal hydride), the impacts of production and recycling of the materials used in electric vehicle batteries. These impacts are compared, with special attention to the locations of the emissions. It is found that the choice among batteries for electric vehicles involves tradeoffs among impacts. For example, although the nickel-cadmium and nickel-metal hydride batteries are similar, energy requirements for production of the cadmium electrodes may be higher than those for the metal hydride electrodes, but the latter may be more difficult to recycle
[en] Long-haul trucks idling overnight consume more than 838 million gallons (20 million barrels) of fuel annually. Idling also emits pollutants. Truck drivers idle their engines primarily to (1) heat or cool the cab and/or sleeper, (2) keep the fuel warm in winter, and (3) keep the engine warm in the winter so that the engine is easier to start. Alternatives to overnight idling could save much of this fuel, reduce emissions, and cut operating costs. Several fuel-efficient alternatives to idling are available to provide heating and cooling: (1) direct-fired heater for cab/sleeper heating, with or without storage cooling; (2) auxiliary power units; and (3) truck stop electrification. Many of these technologies have drawbacks that limit market acceptance. Options that supply electricity are economically viable for trucks that are idled for 1,000-3,000 or more hours a year, while heater units could be used across the board. Payback times for fleets, which would receive quantity discounts on the prices, would be somewhat shorter
[en] In 1994, Ford produced a small demonstration fleet of Mercury Sables with aluminum bodies. Argonne National Laboratory obtained one of these vehicles on a lease so that Laboratory staff could observe the wear characteristics of the body under normal operating conditions. The vehicle was placed in the transportation pool, parked outdoors, and used by staff members for both local and longer trips. The vehicle performed normally, except for having particularly good acceleration because of its light weight and highpower SHO engine. No significant problems were encountered that related to the Al body or engine. No special driving protocols were observed, but a log was kept of trip lengths and fuel purchases. Fuel economy was observed to be improved, compared with that of a similar conventional steel-bodied vehicle that was available for one year of the lease period. The vehicle was tested on a chassis dynamometer to obtain emissions and fuel economy over the federal test cycle. The impacts of further mass reduction were also simulated. At the end of the lease, the body was in excellent condition, which we documented with a set of detailed photographs before the vehicle was returned to Ford. There were minor imperfections in the painted surface, probably resulting from the omission of an E-coat during the painting process. We also examined three similar conventional vehicles for comparison; these exhibited varying degrees of rust
[en] Using the 'total energy cycle' methodology, we compare U.S. near term (to ∼2015) alternative pathways for converting energy to light-duty vehicle kilometers of travel (VKT) in plug-in hybrids (PHEVs), hybrids (HEVs), and conventional vehicles (CVs). For PHEVs, we present total energy-per-unit-of-VKT information two ways (1) energy from the grid during charge depletion (CD); (2) energy from stored on-board fossil fuel when charge sustaining (CS). We examine 'incremental sources of supply of liquid fuel such as (a) oil sands from Canada, (b) Fischer-Tropsch diesel via natural gas imported by LNG tanker, and (c) ethanol from cellulosic biomass. We compare such fuel pathways to various possible power converters producing electricity, including (i) new coal boilers, (ii) new integrated, gasified coal combined cycle (IGCC), (iii) existing natural gas fueled combined cycle (NGCC), (iv) existing natural gas combustion turbines, (v) wood-to-electricity, and (vi) wind/solar. We simulate a fuel cell HEV and also consider the possibility of a plug-in hybrid fuel cell vehicle (FCV). For the simulated FCV our results address the merits of converting some fuels to hydrogen to power the fuel cell vs. conversion of those same fuels to electricity to charge the PHEV battery. The investigation is confined to a U.S. compact sized car (i.e. a world passenger car). Where most other studies have focused on emissions (greenhouse gases and conventional air pollutants), this study focuses on identification of the pathway providing the most vehicle kilometers from each of five feedstocks examined. The GREET 1.7 fuel cycle model and the new GREET 2.7 vehicle cycle model were used as the foundation for this study. Total energy, energy by fuel type, total greenhouse gases (GHGs), volatile organic compounds (VOC), carbon monoxide (CO), nitrogen oxides (NOx), fine particulate (PM2.5) and sulfur oxides (SOx) values are presented. We also isolate the PHEV emissions contribution from varying kWh storage capability of battery packs in HEVs and PHEVs from ∼16 to 64 km of charge depleting distance. Sensitivity analysis is conducted with respect to the effect of replacing the battery once during the vehicle's life. The paper includes one appendix that examines several recent studies of interactions of PHEVs with patterns of electric generation and one that provides definitions, acronyms, and fuel consumption estimation steps.
[en] New US Environmental Protection Agency regulations are forcing locomotive manufacturers and railroads to reduce pollutant emissions from locomotive operation. All new locomotives must meet strict standards when they are built, and existing locomotives must comply when they are rebuilt. Emissions can be reduced either by adjusting combustion parameters, which incurs a fuel penalty, or by turning the diesel engine off when the train is not moving and would otherwise be idling. The latter reduces fuel consumption, but requires installation of a device-such as an auxiliary power unit (APU)-to ensure that the engine can be restarted in cold weather and to supply hotel loads for the crew. Without a financial incentive, capital-short railroads will opt to achieve compliance in the least costly way. However, if they have the option of selling emissions credits from reducing emissions below regulated levels, it would be in their best interest to install additional equipment to minimize emissions. These credits could be purchased by businesses with compliance costs greater than either the cost of the credits or the fines they would have had to pay for non-compliance. The result is a financial benefit for both parties, and a net reduction in emissions, because the seller is emitting below regulated levels, and the buyer is no longer non-compliant. This paper describes a railroad as the potential seller, unable to consummate trades because of uncertainty in the regulatory environment, and estimates financial benefits and reductions in emissions and energy use that could be achieved if the barrier could be removed
[en] In this paper, the energy savings of new technology offering significant improvements in fuel efficiency are tracked for over 20 years as vehicles incorporating that technology enter the fleet and replace conventional light-duty vehicles. Two separate analyses are discussed: a life-cycle analysis of aluminum-intensive vehicles and a fuel-cycle analysis of the energy and greenhouse gas emissions of double vs. triple fuel-economy vehicles. In both efforts, market-penetration modeling is used to simulate the rate at which new technology enters the new fleet, and stock-adjustment modeling is used to capture the inertia in turnover of new and existing current-technology vehicles. Together, these two effects--slowed market penetration and delayed vehicle replacement--increase the time lag between market introduction and the achievement of substantial energy savings. In both cases, 15-20 years elapse, before savings approach these levels
[en] Chromium, as Cr(VI), CrO42-, was found to be moderately toxic to several riverine algae, and less so to duckweeds. Accumulation of chromium by living and dead plant tissue was extensive and could have important effects on the river ecosystem. (author)
[en] Highlights: ► Cradle-to-gate (ctg) energy and emissions compared among five battery systems. ► Calculate material production values fall well within observed ranges. ► Values based on recycled materials in poor agreement with observed ranges. ► Material production data needed for recycled and some virgin battery materials. ► Battery manufacturing data range widely and hence also need updating. - Abstract: This study reviews existing life-cycle inventory (LCI) results for cradle-to-gate (ctg) environmental assessments of lead-acid (PbA), nickel–cadmium (NiCd), nickel-metal hydride (NiMH), sodium-sulfur (Na/S), and lithium-ion (Li-ion) batteries. LCI data are evaluated for the two stages of cradle-to-gate performance: battery material production and component fabrication and assembly into purchase ready batteries. Using existing production data on battery constituent materials, overall battery material production values were calculated and contrasted with published values for the five battery technologies. The comparison reveals a more prevalent absence of material production data for lithium ion batteries, though such data are also missing or dated for a few important constituent materials in nickel metal hydride, nickel cadmium, and sodium sulfur batteries (mischmetal hydrides, cadmium, β-alumina). Despite the overall availability of material production data for lead acid batteries, updated results for lead and lead peroxide are also needed. On the other hand, LCI data for the commodity materials common to most batteries (steel, aluminum, plastics) are up to date and of high quality, though there is a need for comparable quality data for copper. Further, there is an almost total absence of published LCI data on recycled battery materials, an unfortunate state of affairs given the potential benefit of battery recycling. Although battery manufacturing processes have occasionally been well described, detailed quantitative information on energy and material flows are missing. For each battery, a comparison of battery material production with its manufacturing and assembly counterpart is discussed. Combustion and process emissions for battery production have also been included in our assessment. In cases where emissions were not reported in the original literature, we estimated them using fuels data if reported. Whether on a per kilogram or per watt-hour capacity basis, lead-acid batteries have the lowest cradle-to-gate production energy, and fewest carbon dioxide and criteria pollutant emissions. The other batteries have higher values in all three categories.