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What Are the Main Characteristics of Alternative Jet Fuels? 15 4) Municipal solid waste a) Sources/availability MSW includes a wide array of discarded materials such as residential and commercial garbage, plastics, textiles, wood, yard trimmings, and food scraps. In some areas, MSW can also include nonsolid materials such as sludge from wastewater treatment plants. Depending on the type of solid waste used as feedstock, different technologies can be used to produce liquid fuels. For example, wood and yard trimmings can be used with FT processing facilities, while waste oils can be used in HEFA processing facilities. b) Economics and logistics Once recyclables are removed, waste-to-energy providers and landfills compete for the remaining MSW. Depending on the locality, MSW generators may pay for its disposal. In some instances, however, depending on the market structure and scarcity value of the waste, MSW generators may receive payment for access to their waste. Because of MSW's bulk, an alternative jet fuel processing plant would need to be sited close to existing waste flows. MSW may need to be preprocessed to convert it into feedstock. While the preprocessing technology exists, it adds cost to the entire process. c) Environmental considerations The environmental effects of MSW-based fuels vary significantly based on the contents of the waste. Therefore, the environmental effects could be minimized by the removal of various items down the waste stream. For example, if an objective is to maximize life-cycle GHG footprint reduction, then plastics and tires can be left out of the feedstock. If an objective is to eliminate or reduce the use of landfills, plastics and tires can be included in the feedstock, although this would suboptimize the potential life-cycle GHG reduction. d) Advantages Municipalities may recapture some of their waste collection costs by selling MSW to refiners. In addition, using MSW can reduce the need for landfills and decrease methane and other greenhouse gasses typically associated with MSW in landfills. e) Disadvantages There are several challenges to using MSW as a feedstock, including consistency and reliabil- ity of supply, proximity of waste to the conversion facility, sorting, and preprocessing. The poten- tial perception that an MSW-based alternative jet fuel plant and the accompanying transporta- tion infrastructure degrade the local municipal environment must also be addressed. Furthermore, it needs to be noted that some may perceive use of MSW for fuel as competing with existing recycling programs by diverting waste that would otherwise be recycled to fuel production. 5) Summary comparison of feedstock characteristics Table 2 presents a summary of feedstock characteristics. 2.3 Technologies for Producing Alternative Jet Fuels What technologies can be used to produce drop-in alternative jet fuels? There are currently two main technologies for producing drop-in alternative jet fuels: the FT process and hydroprocessing. FT can be used to turn coal, natural gas, or biomass into liquid fuels, including alternative jet fuel and diesel. Hydroprocessing uses a process similar to conventional
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16 Guidelines for Integrating Alternative Jet Fuel into the Airport Setting Table 2. Summary comparison of feedstock characteristics. Feedstock Sources/Availability Economics and Logistics Environmental and GHG Benefits Supply Extraction and Cost Markets, Supply Chain Cultivation Pricing Logistics Mechanisms Fossil Coal Abundant; feedstock Well developed Low Well developed Well developed Without CCS, GHG fuels supply scalable to footprint may be match commercial greater than for conversion facility. conventional fuels. Natural gas Abundant; feedstock Well developed Low Well developed Well developed GHG footprint less supply scalable to than conventional match commercial fuels with CCS; conversion facility. similar or greater without CCS. Oils and Nonedible Current supplies are Developing Currently Not mature; Can use existing Potential for lower fats oils (e.g., tight and very quickly; on- high; expected to infrastructure for GHG carbon footprint Camelina, competitive. Need going research expected develop as commercial oils than conventional Jatropha, significant increase needed to to feedstock available today. fuels depending on pennycress, in acres cultivated to increase yields. decline availability land-use change algae) support commercial with yield increases. assumptions. conversion facility. improve- ments. Edible oils Tight and very Well developed High Well developed Well developed Potential for lower (e.g., competitive GHG carbon footprint soybean, than conventional canola) fuels depending on land-use change assumptions. Animal fats Steady but finite Well developed Medium Well developed Well developed Potential for lower (tallow), supply to low GHG carbon footprint frying oil, than conventional greases fuels. Biomass Energy Potentially abundant Still in research Still in Not mature; Low energy Potential for lower crops and develop- research expected to density of bulky GHG carbon footprint ment stage. and develop as biomass makes than conventional develop- feedstock logistics fuels depending on ment availability challenging to land-use change stage increases. support assumptions. commercial scale. Agricultural Abundant; type and Well developed Low Not mature; Low energy Potential for lower residues availability varies with research expected to density of bulky GHG carbon footprint considerably based ongoing to develop as biomass makes than conventional on geographic address bulk feedstock logistics fuels depending on region. density issues. availability challenging to land-use change increases. support assumptions. commercial scale. Woody Must compete with Well developed Medium Well developed Well developed Potential for lower biomass current uses in pulp to low GHG carbon footprint and paper industry. than conventional fuels depending on land-use change assumptions. MSW Steady but finite Well developed Medium Well developed Well developed Potential for lower supply for some types to low GHG carbon footprint.
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What Are the Main Characteristics of Alternative Jet Fuels? 17 petroleum refining to turn plant oils or animal fats into liquid fuels. Alternative jet fuels obtained through hydroprocessing are also known as hydroprocessed esters and fatty acids or bio-SPK fuels. What are the main characteristics of FT and HEFA processes? Table 3 lists the main considerations of the FT and HEFA processes. Table 3. Main considerations of the FT and HEFA processes. Consideration Fischer-Tropsch SPK (FT SPK) Hydroprocessed Renewable Jet (HEFA or bio-SPK) Feedstock Biomass, coal, natural gas. Plant oils or animal fats. Cost of feedstock Very low for biomass. High for commercial plant oils Low for coal. (e.g., soybean) because of high Low to medium for natural gas. demand. High for plant oils not currently produced at commercial scales (e.g.,Camelina) but expected to decrease as scale is achieved. Medium to low for animal fats. Cost of feedstock High infrastructure and Medium to high for extracting gathering and logistics procurement costs for biomass plant oils, but low for transporting collection and transport. plant oils with existing Low for natural gas if connected infrastructure. to existing infrastructure. Medium to high for animal fats. Medium for coal if connected to existing infrastructure. Production costs Low marginal cost of production. Low to medium marginal cost of production. Scale Very large (300 million GPY Medium (7.5 million GPY minimum, 1-2 billion GPY minimum, 90150 million GPY typical). typical); production economics favor larger sizes. Product quality High (meets critical jet fuel High (meets critical jet fuel properties--such as freeze and properties--such as freeze and flash points--defined in the flash points--defined in the ASTM specification). ASTM specification). Approved by ASTM. Approved by ASTM. By-products Large quantities (60%80%) of Moderate quantities (30%50%) by-products: diesel, high of renewable diesel, LPG, and molecular waxes, naphtha, naphtha. liquefied petroleum gas (LPG). Capital requirements Existing FT plants are very Depends on scale. Smallest large--larger than typical crude practical scale is about 7.5 oil refineries. Small-scale FT million GPY for about $50 plants are being proposed, but million; larger scale of 70 million typical capital investments are GPY for about $250 million. about $500 million for small scale (75 million GPY) and running up to billions of dollars for large scale (750 million GPY). Plant area or physical Typical refinery size footprint is Large-scale refinery is about footprint 10 to 15 acres. one-tenth the size of a conventional refinery--roughly 1 to 5 acres. Can be integrated into a conventional refinery. Life-cycle GHG Medium with CCS. Low for land-based plant oils footprint Very large for coal gasification (ignoring land use). without carbon CCS. Very low for sea-based plant oils Medium for natural gas. (e.g., algae). Low for biomass (ignoring land- Medium for plant oils (including use change). land-use change). Medium for biomass (including land-use change).
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18 Guidelines for Integrating Alternative Jet Fuel into the Airport Setting What are the major factors affecting the economics of alternative jet fuel production? The major factors affecting the economics of alternative jet fuel production can be classified in three categories: market, technology, and policy factors. Market factors reflect the dynamics of a new industry having to compete with established industries for the same resources. For example, current availability of nonfood feedstocks for alternative jet fuel production, such as forest residues, oilseed crops, and algae, is rather limited because there has not been historically signifi- cant demand for these kinds of raw materials. However, it is expected that as alternative fuels start to expand, more quantities and types of feedstock will become available. As the supply chains for these feedstocks mature, their costs are projected to fall. At the same time, alternative jet fuel pro- duction will face competition from other alternative fuels (e.g., biodiesel) for the same nonfood feedstocks and other inputs (e.g., labor, land, water, industrial supply chains). Another important market factor is the cost of alternative jet fuel with respect to conventional fuel. If the price of crude oil and carbon increases as forecasted by some, alternative jet fuel will become more competitive. Technology factors are related to processes available for producing alternative jet fuels and how their costs are expected to change over time. The FT and HEFA technologies provide a near- term opportunity for commercial production of alternative jet fuel. As these technologies im- prove, become more efficient, and scale-up, processing costs are expected to decrease. Further- more, new facilities are expected to have lower operating costs due to the more efficient use of natural gas and other inputs. A similar cost-reduction progression is expected for new production processes that are still in research and development. Finally, policy and government action can have a significant impact on the costs of alternative jet fuels. In the United States there are a series of mandates, taxes, and tariffs on alternative fuels, including the Renewable Fuel Standard 2 (RFS-2) and other mechanisms discussed in Section 2.6. All of these mandates and regulations can greatly influence the economics of alternative jet fuels. Moreover, the military is considering various ways to support the development of alternative jet fuel supplies, including the provision of funding for facilities, long-term purchase agreements, and the possibility of fuel pricing that is not tied to that of petroleum-based fuel. Therefore, it is important for all stakeholders of alternative jet fuel projects to understand how government action can affect them, positively or negatively. It is important to point out that capital requirements and operating costs for any facility will be dependent on local conditions such as access to feedstocks and labor, site conditions, and what utilities are already in place. For example, space adjacent to an existing processing facility is advantageous due to utilities typically being in place and the advantage for creating a mixing point on-site. Are there other pathways for producing alternative jet fuels? Many research and development (R&D) sources are pursuing so-called "advanced process" pathways, with the goal of ASTM qualification in the 2013 to 2015 time period. While the qual- ification authorities are in the process of deciding how many independent pathways to pursue, as of this writing, there are three fundamental approaches under consideration: 1. Advanced fermentation to jet (FTJ), using biological organisms that turn feedstocks directly into finished products, 2. Catalytic to jet (CTJ), using nonbiological agents that produce alcohols, which can then be processed into alternative jet fuel, and 3. Pyrolysis oil to jet (PTJ), which converts cellulosic feedstocks into a bio-crude that can be used to produce alternative jet fuel. These processes are characterized by the fact that they can utilize a broad variety of bio-based feedstocks, including cellulosic materials. The potential for a large supply of possible feedstocks