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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
