Transportation

Toyota Prius III, an gas-electric hybrid vehicle.

S 400 HYBRID

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 Alternative Fuels

 

  • Comparing Diesel to Gasoline Featured Article Comparing Diesel to Gasoline Comparing Diesel to Gasoline

    Diesel fuel is denser than gasoline (petrol) and contains about 11% more energy per volume, yet both fuels cost about the same per volume to extract and refine. Diesel engines... More »

  • Transportation and Energy Conservation Featured Article Transportation and Energy Conservation Transportation and Energy Conservation

    Light-duty (car or small truck) vehicles are only one of many modes of personal transportation. Greenhouse gas emissions from these modes vary widely. A person on a bicycle... More »

  • Mitigation from Transportation Featured Article Mitigation from Transportation Mitigation from Transportation

    Globalization of the world’s economy requires that humans and their goods move long distances. Consequently, passenger and freight travel are likely to double during the... More »

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Compatibility: Biofuels and Existing Transportation Infrastructure Last Updated on 2011-02-09 00:00:00 But Are They Compatible? New biofuels must be compatible with America's existing transportation infrastructure. The ultimate goal of ORNL's BioEnergy Science Center is, naturally, to produce biofuel—but not just any biofuel. To achieve the center's goal of helping to reverse the nation's dependence on oil imports, a successful biofuel will need to be a stepping stone that fits neatly into America's current fuel infrastructure as part of a path to a transportation system that rests far less heavily on petroleum products. The research performed by Distinguished Scientist Bruce Bunting and his colleagues at ORNL's Fuels, Engines and Emissions Research Center (FEERC) focuses on ensuring that new biofuels meet both requirements. The research, funded in large measure by the Department of Energy's Office of Energy Efficiency and Renewable... More »
Transportation and Energy Conservation Last Updated on 2010-12-19 00:00:00 Light-duty (car or small truck) vehicles are only one of many modes of personal transportation. Greenhouse gas emissions from these modes vary widely. A person on a bicycle emits about 2.3 grams of carbon per kilometer, and a person walking or running emits 6.3 grams per kilometer; these modes are the ultimate in biofuel conversion. At the other extreme, a commuter helicopter emits carbon at a rate of 180.5 grams per kilometer per passenger. A central factor in transportation efficiency is passenger occupancy. Except for cycling, walking, or running, the incremental energy required per additional passenger is small for most modes of transportation. Therefore, doubling passenger occupancy nearly halves the effective greenhouse gas emissions per distance traveled. Private and public modes of transportation. Travel (1012 passenger-km) in the United States and Europe via... More »
Mitigation from Transportation Last Updated on 2010-12-16 00:00:00 Globalization of the world’s economy requires that humans and their goods move long distances. Consequently, passenger and freight travel are likely to double during the next half century. This expanded travel derives both from human population growth and from everyone traveling a greater distance each year. In addition, more people possess their own light-duty vehicle (passenger car or small truck) and are using them for travel. Petroleum serves as the energy source for over 95% of transportation. The transportation sector consumes half of the world’s petroleum output, a proportion that is likely to increase in the future. A straightforward strategy for prolonging petroleum supplies is to invoke additional conservation measures in the transportation sector. The Middle East supplies most of the world’s petroleum and has the world’s largest proved oil... More »
Biofuels: A Greenhouse-Gas Free Energy Source? Last Updated on 2010-11-09 00:00:00 Most modern engines have the flexibility to combust mixtures containing biofuels. Biofuels are those produced from living materials and include bioethanol, biomethane, and biodiesel. The energy in biofuels originally derives from photosynthesis. Bioethanol is produced through the fermentation of a carbohydrate such as glucose (C6H12O6) into Ethanol, and combustion of ethanol yields chemical energy. Summing these reactions together yields the simple energy conversion: light (solar electromagnetic energy) --> chemical energy In theory, the chemical energy in bioethanol propels a vehicle without any net production of greenhouse gases.. Biomethane or biogas follows a similar series of reactions. Carbohydrates produced via photosynthesis are converted into methane (CH4), the main component of natural gas, and combustion of this “natural” natural gas (as... More »
Comparing Diesel to Gasoline Last Updated on 2010-11-09 00:00:00 Diesel fuel is denser than gasoline (petrol) and contains about 11% more energy per volume, yet both fuels cost about the same per volume to extract and refine. Diesel engines are also inherently more efficient than gasoline engines in converting the energy in the fuel into mechanical work because they operate at higher pressures (higher compression ratios) and temperatures. Altogether, diesel engines obtain roughly 40% higher fuel efficiency per volume of fuel than gasoline engines of the same power. [1] Large trucks and agricultural vehicles have diesel engines to take advantage of this higher efficiency. Many countries, in consideration of the role of such vehicles in their economy, do not tax diesel fuel as heavily as gasoline. Still, small diesel engines have been plagued with performance issues such as being noisier, generating more vibrations, being more difficult to... More »