Carbon dioxide emissions reduction

One of the main drivers for the use of bioenergy and bioproducts is their potential environmental benefits (e.g. carbon dioxide emission reduction, biodegradability). It is thus essential that we assess the environmental impact of all the energy and chemical products we manufacture (across their life cycle) to make sure that they... 

Proponents of strong and early carbon dioxide emissions reductions act as if the potential impacts of climate change are comparable. But to obtain international agreement on measures that could entail substantial near-term costs, the dangers avoided must be more compelling than what a leading scientist advocate recently conceded were merely not implausible (Schellnhuber, 1999). 

Fuel switch. The choice of fuel used in furnaces and steam boilers has a major effect on the gaseous utility waste from products of combustion. For example, a switch from coal to natural gas in a steam boiler can lead to a reduction in carbon dioxide emissions of typically 40 percent for the same heat released. This results from the lower carbon content of natural gas. In addition, it is likely that a switch from coal to natural gas also will lead to a considerable reduction in both SO, and NO, emissions, as we shall discuss later. 

To comply with carbon reduction goals, some countries impose taxes on carbon dioxide emissions. Since biofuels have lower full-cycle carbon dioxide emissions than fossil fuels, biofuels are more cost-competitive with fossil fuels in regions where these taxes are imposed. 

One of the most straightforward methods to reduce carbon dioxide emissions is to enhance the fuel efficiency of engines. The three-way catalyst, although very successful at cleaning up automotive exhaust, dictates that engines operate at air-to-fuel ratios of around 14.7 1. Unfortunately, this is not the optimum ratio with respect to fuel efficiency, which is substantially higher under lean-burn conditions at A/F ratios of about 20 1, where the exhaust becomes rich in oxygen and NOx reduction is extremely difficult (Fig. 10.1). 

Chianese, D. S., Rotz, C. A., and Richard, T. L. (2009b). Simulation of carbon dioxide emissions from dairy farms to assess greenhouse gas reduction strategies. Trans. ASABE 52,1301-1312. 

It is relevant and, of course, not out of context to touch briefly on the technologies used for the reduction of carbon dioxide emissions from many origins, including several examples referred to in the present text. The up-swing in global temperature over the previous... 

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. 

Carbon dioxide emissions, 5 1-2 and coal gasification, 6 812 reduction, 5 23... 

Meeting the Kyoto goals could have a major impact on the electric power and auto industries and many believed the economy would suffer greatly. Developing countries like China and India would be exempt from the reduction of carbon dioxide emissions. China and India have plans to build over 600 coal-fired plants. The emissions of these plants would be 5 times the total saving of Kyoto. 

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. 

Utilization and Reduction of Carbon Dioxide Emissions at industrial Plants... 

Wang, L.K. Lee, S.L. Utilization and Reduction of Carbon Dioxide Emissions An Industrial Ecology Approach. The 2001 Annual Conference of Chinese American Academic and Professional Society (CAAPS), St. Johns University, New York, NY, USA, April 25, 2001. 

After some dramatic last-minute bargaining, a draft document was accepted by the conference and signed by all who attended. The hnal document called for reductions in carbon dioxide and other greenhouse gas emissions ranging from 6 percent below 1990 levels for Japan to 8 percent below those levels for members of the European Union. (The United States was assigned a 7 percent reduction.) The treaty was scheduled to go into effect when 55 nations accounting for at least 55 percent of all global carbon dioxide emissions had ratified the treaty. 

This master equation can then be used to calculate the increase in environmental impact for the population, or the increase in wealth with the same technology, or to calculate the required emission reduction per unit GDP by new technology. If, for instance, wealth worldwide reaches the same level as now in the industrialized world, then W increases by a factor of 4. If the population (P) does not increase and technology ( / ) stays the same, then El (e.g., carbon dioxide emissions to the atmosphere) would increase by a factor of 4. To keep El at the same level, the technology should be improved to give an emission reduction of a factor 4 per unit product or service. In reality this use of the expression is too simplistic ... 

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. 

As part of its systems analysis, the DOE should map out and evaluate a transition plan consistent with developing the infrastructure and hydrogen resources necessary to support the committee s hydrogen vehicle penetration scenario or another similar demand scenario. The DOE should estimate what levels of investment over time are required—and in which program and project areas—in order to achieve a significant reduction in carbon dioxide emissions from passenger vehicles by midcentury. 

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