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How Can Alternative Jet Fuels Be Integrated into the Airport Setting? 39 In terms of targets for PM2.5 emission reductions, the focus should be that any reduction because of the introduction of alternative jet fuels is beneficial. This is especially true if the air- port is in a NAAQS non-attainment zone, although the benefits are important even if the airport is not in a non-attainment zone. What questions should be considered in this part of the evaluation? Questions to be considered in this part of the evaluation are: 1. What is the estimated reduction in PM2.5 emissions of the alternative jet fuels being considered in the option? 2. What is the overall PM2.5 intensity of the resulting mix of fuels at the airport, considering the expected percentage of total fuel that will be provided by the alternative fuel? 3. What is the range of uncertainty in the answer to (2)? These questions should be answered with the latest available official estimates of PM2.5 intensity. A sample calculation is as follows: Alternative fuel: coal and switchgrass to FT fuel, with GHG capture Estimated PM2.5 intensity: 0.250.5, relative to 1.0 conventional petroleum-based jet fuel (data from Figure 7 in section 5.1). Estimated mix of alternative and conventional fuels: 50/50 Resulting overall PM2.5 intensity of fuel mix, relative to 100% conventional case: relative footprint (low) = [(0.5 × 0.25) + (0.5 × 1.0)] / (1.0 × 1.0) = 0.63 relative footprint (high) = [(0.5 × 0.5) + (0.5 × 1.0)] / (1.0 × 1.0) = 0.75 Thus, the proposed alternative fuel at the proposed level of mixture with conventional jet fuel is estimated to reduce the overall PM2.5 intensity of the fuel being used by between 25% and 37%. How can local air quality benefits of alternative jet fuels be evaluated? Net environmental evaluation of the relative PM2.5 intensity effects may be done as follows: · Green--Use this rating if the alternative jet fuel is likely to achieve PM2.5 emissions reductions. · Yellow--Use this rating if the alternative jet fuel may achieve PM2.5 emissions reductions. · Red--Use this rating if the alternative jet fuel is not likely to achieve PM2.5 emissions reductions. After completing the grading, fill in the appropriate circle in the "Green," "Yellow," or "Red" column of "Worksheet 6: Evaluation Summary" in Section 5.2.6. 3.5.3 Logistical This section provides guidance regarding the evaluation of the main logistical elements for an alternative jet fuel project. What are the main logistical elements that should be considered in the evaluation of an alternative jet fuel project? There are two main logistical elements that should be considered in the evaluation of alterna- tive jet fuel projects: (1) the transportation and storage of feedstocks and (2) the transportation and storage of the alternative jet fuel. A simplified diagram of the supply chain of alternative jet fuels from feedstock extraction to the airport is shown in Figure 6.
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40 Guidelines for Integrating Alternative Jet Fuel into the Airport Setting Feedstock handling Alternative jet fuel handling Feedstock Intermediate Processing Intermediate Airport extraction storage plant storage Figure 6. Schematic of the alternative jet fuel supply chain. What are the options for transporting feedstocks to the processing plant? The options for transporting feedstocks to the processing plant depend to a large extent on the type of feedstock. The main options are: · Coal and natural gas: Coal is typically transported by rail, and natural gas is normally shipped by pipeline. Both transportation modes are well developed in the United States and offer the most cost-efficient ways for bulk transportation. However, given that building new rail lines or pipelines is very expensive, alternative jet fuel projects should be located close to existing infrastructure. More information on existing rail and pipeline infrastructure is available at the National Atlas of the United States (http://www.nationalatlas.gov/natlas/Natlasstart.asp) and the U.S. Department of Transportation's National Pipeline Mapping System (http://www.npms. phmsa.dot.gov/), respectively. · Plant oils: For traditional plant oils such as soybean and canola, existing transportation and logistics infrastructure can be used; however, similar to the case of coal and natural gas, the processing facility would have to be located within reach of the existing infrastructure to enjoy full benefits. For new types of plant oils, such as Camelina, it is possible that the existing trans- portation and logistics infrastructure may be used. If this is the case, the transportation of these plant oils would be much more economical than if new infrastructure were built. · Dedicated energy crops and other biomass: These materials are typically transported by truck; however, since they are bulky and not very dense, economics limit their transportation to a distance of about 50 miles from the processing facilities. For these feedstocks, intermediate storage may be required depending on the particular orga- nization of the supply chain. For example, the harvest of energy crops is seasonal and the timing of the harvest may vary depending on crop and region of the country; however, processing facil- ities need feedstock year round to maximize utilization. Therefore, if biomass were used as a feed- stock, storage at an intermediate location or at the processing facility should be considered. What are other logistical elements associated with agricultural feedstocks that need to be considered? In the case of agricultural feedstocks, an important element in the supply chain is a supply contract. Since the most common situation will be of one buyer and many suppliers, a single entity may be required to contract with many producers for a biomass. What are the options for transporting alternative jet fuel to the airport? The main options for transporting alternative jet fuel to the airport are: · Pipeline: This is the most cost-effective option for transporting the finished fuel, especially if the processing plant and the airport already have pipeline access. · Rail or barge: Rail or barges are the next most cost-effective options for transporting finished fuel. As in the case of pipelines, the maximum benefit is achieved if both the processing plant and the airport already have access to rail or barges. · Truck: This is the least cost-effective option for transporting the finished fuel; however, truck transportation provides the most flexibility because it does not require the existence of expen-