Carbon dioxide emissions transportation

Forsberg, C. (2008a), Nuclear Energy for a Low-carbon-dioxide Emission Transportation System with Liquid Fuels , Nuclear Technology, Vol. 164, pp. 348-367, December. 

Transportation is also the emissions leader. About 75 percent of carbon dioxide emissions and 45 percent of nitrogen oxide emissions come from the transportation sector. If rising levels of CO, are found to be responsible for global warming, and measures are put in place to severely curtail CO, emissions, the measures will have the greatest impact on the transportation sector. 

Transportation accounts for about one-fourth of the primary energy consumption in the United States. And unlike other sectors of the economy that can easily switch to cleaner natural gas or electricity, automobiles, trucks, nonroad vehicles, and buses are powered by internal-combustion engines burning petroleum products that produce carbon dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons. Efforts are under way to accelerate the introduction of electric, fuel-cell, and hybrid (electric and fuel) vehicles to replace sonic of these vehicles in both the retail marketplace and in commercial, government, public transit, and private fleets. These vehicles dramatically reduce harmful pollutants and reduce carbon dioxide emissions by as much as 50 percent or more compared to gasoline-powered vehicles. 

The use of coal for electricity generation is responsible for about 32% of anthropogenic carbon dioxide emissions in the U S. 11 As shown by France, it is possible to displace virtually all the coal used in electricity generation. Thus, France in 1997 obtained about 78% of its electricity from nuclear power and only about 5% from coal. Further reductions in carbon dioxide emissions could be made by the electrification of other sectors of the energy economy, including buildings, and eventually perhaps much of transportation. 

Iceland uses its renewable energy for power generation and heating, so these sectors are nearly carbon-free. Carbon dioxide emissions are produced by the transportation, fishing, and industrial sectors, each of these contributes about one million tons of carbon dioxide (C02) per year. 

Biofuels offer a number of technical and enviromnental benefits over conventional fossil fuels, which make them attractive as alternatives for the transport sector. The benefits include greenhouse gas reductions including reduced carbon dioxide emissions, which will contribute to domestic and international targets, the diversification of the fuel sector, biodegradability, sustainability, and an additional market for agricultural products. Biofuels help to protect and create jobs. Table 3.1 shows the major benefits of biofuels. 

Also, all parts of society contribute to the problem. For instance, carbon dioxide emissions to the atmosphere due to fossil fuel combustion is caused 50% by industry the other parts are domestics and transport (the electric power contribution is divided between industry and domestics) (6,7). 

The use of fossil fuels to meet variable electrical demands may be limited in the future because of concerns about the price of natural gas and climate change. With any deep reduction in greenhouse gas emissions, carbon dioxide emissions will likely be limited to transportation, consumer products and other mobile applications - not stationary applications such as peak power production. While carbon dioxide from fossil power plants may be sequestered underground, such fossil power plants are likely to be uneconomic for the production of intermediate and peak electricity because of their high capital costs (MIT, 2007) and the difficulties in operating such plants with variable output. 

The conventional way to compare the efficiency of vehicles is by the distance they can travel per unit of fuel (e.g., kilometer per liter, miles per gallon). However, in Toyota s efforts to commercialize a fuel cell vehicle, two important factors must be considered first, the vehicle s efficiency jtank-to-wheel), and secondly, how efficiently energy is obtained and transported to the vehicle s tank well-to-tank). This new overall measure of efficiency, called "well-to-wheel," is important since Toyota s goals are to both reduce carbon dioxide emissions and consumption energy. 

The current ethanol supply is, in the large part, derived from starch. Nevertheless, vast amounts of agricultural residues and other lignocellulosic biomass can serve as the feedstock for ethanol production. Theoretically, enough ethanol can be produced from cellulosic biomass to meet most of the liquid fuel requirements in the US. The expanded utilization of lignocellulosic biomass for ethanol production can also free starchy crops for food and other uses. In addition, less carbon dioxide emission can be realized if more ethanol can be produced from lignocellulosic biomass and if the market for ethanol as a transportation fuel can be expanded beyond the current level. 

The introduction of biomass-derived components or even substitution fuels may help to alleviate the dependency on oil and to control fossil carbon dioxide emissions from transport, provided some conditions are respected ... 

The transportation sector accounts for 68 percent of all of the petroleum used and one-third of the anthropogenic carbon dioxide emissions in the United States. In addition, the utilization of internal combustion engines for transportation results in a significant amount of nitrogen oxides and particulate emissions. 

This latest survey by BiE included an additional section covering environmental performance. Companies were asked whether they measure and set targets for their performance in five areas, namely, energy, transport, carbon dioxide emissions, waste and water. 

The OECD transport sector produced nearly three times as much carbon dioxide in 1990 as it did in 1960 (lEA, 1993). There is a growing concern that these increasing carbon dioxide emissions will create a greenhouse effect on our planet (Boer et al., 1990). One way of reducing the emissions of CO2 would be to introduce renewable fuels, such as alcohol fuels or biogas. Carbon dioxide, which is produced by combustion of biomass-derived fuels, is naturally recycled and consumed in the photosynthesis. This means that there will be no net increase of COj in the atmosphere when using, for example, ethanol produced from biomass. This is valid if biomass-derived fuels or chemicals are used in all parts of the production chain. 

In the developed world, especially in North America, Western Europe, and Japan, we love to buy cut flowers for our homes, work places, as gifts or for special occasions. Over 50 million roses are given worldwide on Valentine s Day alone. Many of these cut flowers are transported long distances by air to reach the flower markets as swiftly as possible, and contribute to the problem of increased carbon dioxide emissions. 

The main greenhouse gas is carbon dioxide, which is responsible for 49% of the effect. The emissions result chiefly of burning of fossil fuels in the electricity generation, transports and industry (5 Gton of C per year), and deforestation (0.5 to 2 Gton of C per year) [1]. Figure 1 shows the percentage contribution to carbon dioxide emissions from human activities between 1980-85 [4]. 

Olsthoorn, X., 2001, Carbon dioxide emissions from international aviation 1950-2050, Journal of Air Transport Management 7, 87-93. 

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