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5 Sustainable Alternative Jet Fuels
Pages 71-87

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From page 71...
... This chapter addresses those challenges and related research projects. It is not feasible for the aviation industry to switch from conventional jet fuel to a different fuel type, nor are BOX 5.1 Drop-in Jet Fuel Drop-in jet fuels have aggregate properties that are essentially equivalent to those of conventional (petroleum-based)
From page 72...
... To be successful over the long term, alternate fuels will need to be sustainable both in terms of their ability to reduce net life-cycle carbon emissions relative to conventional jet fuel and in terms of environmental, societal, and economic factors. Not all alternative fuels will result in a net reduction in life cycle carbon depending, for example, on their source materials.
From page 73...
... Operators of aircraft powered by gas turbines will continue to demand the use of hydrocarbon jet fuel for the foreseeable future. While burning SAJF will produce nearly the same amount of CO2 per unit of fuel as conventional jet fuel, the use of SAJF reduces net life-cycle carbon emissions because SAJF enable reusing or recycling carbon that is already in the biosphere to create the fuel.
From page 74...
... As discussed in Chapter 4, neither fuel cells nor batteries will advance enough to power large commercial aircraft within the 30-year time frame addressed by this report. Liquefied natural gas and liquid hydrogen both have higher energy content per unit mass than conventional jet fuel, but they require two to four times as much volume to hold the same amount of energy as jet fuel.
From page 75...
... In the future some alternative fuels may qualify as drop-in fuels without blending, but that has not been the case to date. SAJF State of Development Although SAJF have been produced, the oil and transportation fuel industry is very competitive, increasingly so given low crude oil prices, making it very difficult for producers of SAJF to be economically competitive, especially given the capital costs of building large production facilities, the difficulty of establishing new supply chains, and the projected operating costs associated with proven feedstocks and conversion processes.
From page 76...
... , as well as aircraft emissions. Biomass-derived alternative jet fuels have the potential to reduce life-cycle emissions compared to conventional jet fuel, since biomass-based hydrocarbons 2  IATA, "Alternative Fuels," http://www.iata.org/whatwedo/environment/Pages/alternative-fuels.aspx, accessed May 14, 2016.
From page 77...
... For SAJF (that is, for alternative fuels derived entirely from biomass) , depending upon the feedstock and conversion process, reductions in CO2 emissions relative to conventional jet fuel range from 41 to 89 percent.
From page 78...
... greenhouse gas emissions for alternative jet fuels compared to petroleum-based jet fuels. CB20TL, coal/biomass-to-liquid with 20 percent biomass in total inputs (by mass)
From page 79...
... the inability to capture sufficient value from the primary attribute of the new product, which is the inherent reduction in net carbon emissions resulting from the use of SAJF. The challenges associated with cost-competitiveness are illustrated in Figure 5.3, which shows that even with optimistic estimates of capital and operating expenses, SAJF costs more than conventional jet fuel, especially in the face of low crude oil prices.
From page 80...
... Energy Information Administration projects that the spot price of crude oil in 2040 will be 2 to 7 times as much as current prices.20 Economic Challenges The economic challenges to widespread use of SAJF are spread across the business model: high capital expense, high operating expense (including feedstock cost) , and the relative immaturity of the systems, machinery, and processes required to enable robust supply chains for these processes.
From page 81...
... Large producers of conventional jet fuel, who are perhaps in the best position to address this challenge, currently seem to have little motivation to do so, given that SAJF by design is interchangeable with their current products, but its production comes with uncertain margins, higher investment, and higher risk. Technoeconomic Factors Lack of technoeconomic assessments and comparative understanding of various approaches impedes the ability of industry and the researchers and agencies that support SAJF R&D to make practical decisions about the prioritization of R&D and demonstration and deployment efforts.
From page 82...
... The engagement of large, well-respected commercial engineering and construction companies who could provide turnkey project development and performance guarantees would help to alleviate such concerns, but unresolved risks have likewise dissuaded these companies from taking on such a role, implying that demonstration and deployment efforts executed to date have not been successful enough to move to the next step. Funding for SAJF Capital Investments Uncertainty about economic viability of SAJF production has impeded engagement from the petroleum industry or other large industrial entities that could bring appropriate resources to bear on addressing economic challenges.
From page 83...
... Fuel qualification and certification processes are costly, fuels required for testing are difficult to produce in sufficient quantities in reasonable amounts of time, and the entities pursuing qualification are typically small, underfunded start-up organizations that will also need to deal with the many other technical and economic challenges that a start-up company usually encounters. An industry process has been established through the use of standard ASTM practices and specifications, and it is being used to qualify production pathways for alternative jet fuels.
From page 84...
... For example, both the U.S. Renewable Fuel Standard and the independent Roundtable on Sustainable Biomaterials have established the need for advanced fuels to achieve at least a 50 percent reduction in life-cycle CO2 emissions.22 This disincentivizes the potential of some synthetic fuel production pathways that could produce lesser but still substantial reductions in life-cycle carbon emissions.
From page 85...
... RATIONALE FOR SUSTAINABLE ALTERNATIVE JET FUELS Finding. Rationale for Sustainable Alternative Jet Fuels.
From page 86...
... -- nstitute a process to periodically refresh technoeconomic assessments and to evaluate new SAJF I production pathways of interest as they are identified, for example, through interactions with organizations such as the ASTM International Committee on Petroleum Products, Liquid Fuels, and Lubricants, the Coordinating Research Council, the Commercial Aviation Alternative Fuels Initiative, and the Federal Aviation Administration's Center of Excellence for Alternative Jet Fuels and Environment. • Enhance system modeling and analysis capabilities for microscale (individual projects)
From page 87...
... of potential SAJF pathways. • Develop a database, made broadly available to the members of the SAJF community, of fuel feedstocks, processes, fuel properties, and combustion emission characteristics to facilitate utilization of alternative jet fuels.


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