Commercial Aircraft Propulsion and Energy Systems Research Reducing Global Carbon Emissions (2016) / Chapter Skim
Currently Skimming:
1 Introduction
1 Introduction
Pages 15-21
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 15... ...
Human activities also produce or release additional greenhouse gases other than CO2, most importantly methane, nitrous oxide, and fluorinated gases such as hydrofluorocarbons and perfluorocarbons. The physical mechanisms by which greenhouse gases cause climate change are well understood.1 Since 1750, CO2 has contributed more to global warming than any other greenhouse gas, and there is growing recognition of the need for aviation to reduce its CO2 emissions.2 One manifestation of this is the recent agreement at the International Civil Aviation Organization, a United Nations standards organization, on a fuel economy standard for new aircraft.
|
From page 16... ...
approximately 2.0 to 2.5 percent of total global annual CO2 emissions.4 In the United States, the aviation sector contributes about 11 percent of transportation greenhouse gases, with commercial aviation contributing 9 percent of total transportation emissions.5 As commercial aviation continues to grow in terms of revenue-passenger miles and cargo ton miles, CO2 emissions are expected to increase. To reduce the contribution of aviation to climate change, it is essential to improve the effectiveness of ongoing efforts to reduce emissions and initiate research into new approaches.
|
From page 17... ...
Decisions by airlines to invest in new aircraft -- and in which kind -- are driven by complex assessments involving many considerations, including nearand long-term projections of economic conditions; fuel costs; societal expectations regarding the environmental impact of aviation in terms of noise and emissions; the cost of retraining operational or maintenance personnel and of acquiring new facilities for maintenance and fuel distribution and other potential operational and capital costs; and national and international policies and regulations that impact aviation, and so on. These considerations are also important to aircraft and engine manufacturers as they try to anticipate the factors that will drive future purchase decisions by airlines.
|
From page 18... ...
, airframe improvements not related to advanced propulsion concepts, and nontechnology policy approaches such as the imposition of carbon taxes, the use of carbon offsets, or legislative limits on carbon emissions. 7 NASA uses technology readiness levels (TRLs)
|
From page 19... ...
• Turboelectric propulsion research.8 Turboelectric propulsion systems are likely the only approach for developing electric propulsion systems for a single-aisle passenger aircraft that is feasible in the time frame considered by this study. System studies indicate that turboelectric propulsion systems, in concert with distributed propulsion and boundary layer ingestion, have the potential to ultimately reduce fuel burn up to 20 percent or more compared to the current state of the art for large commercial aircraft.
|
From page 20... ...
The committee concluded, however, that batteries with the power capacity and specific power11 required by all-electric or hybrid-electric systems for aircraft at least as large as a regional jet are unlikely to be matured to the point that products satisfying FAA certification requirements can be developed within the 30-year time frame addressed by this report. The design of turboelectric electric propulsion systems, however, does not include high-power batteries, thereby eliminating a major technical risk.
|
From page 21... ...
Gas turbines dominate the current fleet of commercial aviation aircraft because their inherent characteristics, combined with decades of research, development, and operational experience, have resulted in very high levels of safety, reliability, performance, and efficiency. In addition, ongoing investments in gas turbine research have produced a steady trend of increasing efficiency, lower fuel consumption, and reduced emissions per passenger mile.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.