Robert C. Hendricks

Glenn Research Center, Cleveland, Ohio

David L. Daggett and Peter Anast

The Boeing Commercial Airplane Group, Seattle, Washington

Nathan Lowery

Princeton University, Princeton, New Jersey

Future Fuel Scenarios and Their Potential 

Impact to Aviation

NASA/TM—2011-214042

May 2011

139–ISROMAC–11
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Robert C. Hendricks

Glenn Research Center, Cleveland, Ohio

David L. Daggett and Peter Anast

The Boeing Commercial Airplane Group, Seattle, Washington

Nathan Lowery

Princeton University, Princeton, New Jersey

Future Fuel Scenarios and Their Potential 

Impact to Aviation

NASA/TM—2011-214042

May 2011

139–ISROMAC–11

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135

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NASA/TM—2011-214042 1 

Future Fuel Scenarios and Their Potential Impact to Aviation 

Robert C. Hendricks 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

David L. Daggett and Peter Anast 

The Boeing Commercial Airplane Group 

Seattle, Washington 98124 

Nathan Lowery 

Princeton University 

Princeton, New Jersey 08544 

Abstract 

In recent years fuel prices have been growing at a rapid 

pace. Current conservative projections predict that this is only a 

function of the natural volatility of oil prices, similar to the oil 

price spikes experienced in the 1970s. However, there is 

growing concern among analysts that the current price 

increases may not only be permanent, but that prices may 

continue to increase into the future before settling down at a 

much higher level than today. At high enough fuel prices, the 

aircraft industry would become very sensitive to fuel price. In 

this paper, the likelihood of fuel price increase is considered in 

three different price increase scenarios: “low,” “medium,” and 

“high.” The impact of these scenarios on the aviation industry 

and alternatives are also addressed. 

Introduction 

According to the Boeing Current Market Outlook, air travel 

is projected to continue expanding at an average growth rate of 

about 5 percent per year. Underlying this projection of 

continued growth is an assumption that the industry will not be 

constrained by petroleum-based fuel availability. The purpose 

of the present discussion is to assess the validity of this 

assumption. If fuel is not available from various energy sources 

[1–4] in quantities required for such growth, alternative 

technologies for fuel and improved aircraft efficiency will need 

to be considered. 

Over the past 40 years, airplane fuel efficiency has improved 

dramatically (Fig. 1). 

However, the current rate of gains in efficiency will be 

outpaced by the projected growth in traffic, and the aircraft 

industry will thus require an increasing amount of fuel. This is 

true not only of the aviation industry, but of worldwide 

transportation energy uses in general (Fig. 2). 

Existing markets for energy use will not be the only source 

of increased demand for petroleum-based fuels. Growing 

economies in emerging nations—especially in Asia, Africa, and 

Latin America—will put an even tighter constraint on 

worldwide fuel supply (Fig. 3). 

With a growing gap between the growth rate of petroleum 

energy production and demand, it is imperative that the aircraft 

industry investigate issues related to fuel availability and 

possible technologies for alternative fuels and improved 

aircraft efficiency to offset the potentially devastating effects 

that would be encountered by a future scenario in which jet fuel 

availability is not sufficient to meet demand and prices 

skyrocket. 

Discussion 

When dealing on a global scale the word speculation takes 

root. While analysts may not agree when we will run out of 

“cheap-oil,” they all agree that we eventually will run out. 

Crises and fuel prices have fluctuated over several years (e.g., 

1970s), but in the past few years there are trends that indicate a 

different scenario. The projected energy demands of India, 

Russia, and China—especially China and India—for fuel are 

acute. Resources are being gobbled up, and deals for future 

fuels are being consummated amid concerns of foreign debt. 

Future Fossil-Oil Fuel Availability 

Before proceeding, a distinction needs to be made between 

fuel, an energy-storage medium, and petroleum energy sources 

(derived from oil). As inexpensive petroleum energy sources 
NASA/TM—2011-214042 2 
NASA/TM—2011-214042 3 

are exhausted, alternate energy sources will change the type of 

fuels available in the future, which in turn will impact the 

aircraft platform. A design using hydrogen will be very 

different from one using gas-to-liquid (GTL) derived fuels. 

These GTL fuels are usually environmentally cleaner—some 

can mimic Jet-A—and will enable new engine and aircraft 

technologies, yet will require major investments. 

“Peak Oil” is a term that comes from the work of geologist 

M. King Hubbert, who correctly predicted the peak of U.S. oil 

production 15 years in advance. In the 1960’s, Hubbert 

predicted world oil production to reach a maximum around the 

year 2000. Ken Deffeys reworked Hubbert’s calculations with 

updated data and places this peak somewhere around the end of 

2005 or 2006 [5]. Still more experts [6] have done analyses of 

their own and made widely varying predictions of the timing of 

peak oil production. Colin J. Campbell of the Uppsala 

Hydrocarbon Depletion Study Group places the peak in oil at 

around 2008, and this study includes unconventional oil such 

as tar sands, deepwater oil, and natural gas liquids (see color 

bands of Fig. 4) [7]. Almost all experts in the field agree that 

petroleum is a non-renewable resource, and as such cannot be 

produced indefinitely. So the issue is not whether this peak will 

occur, but when? Many analysts think this peak will occur 

very soon. 

As shown in Fig. 5, this peak in oil production will mean 

that, as demand continues to grow, the gap between production 

and demand will also continue to grow. If the region on the 

chart marked “required new demand” is not able to be met 

through increased production of alternative fuels, the price of 

all petroleum products worldwide will naturally increase 

as well. 

The quantity of world oil that has been produced throughout 

the world as of 2005 has been estimated by Laherrere [8] to be 

just over 1 trillion barrels of conventional oil worldwide, with 

about 1 trillion more to be recovered. Cambridge Energy 

Research Associates (CERA) claims that the capacity of oil 

production will outpace demand until at least 2010 and that the 

peak in oil production will occur no sooner than 2020 [9]. 

CERA, like the Department of Energy Energy Information 

Administration (DOE–EIA) forecast “assumes that OPEC will 

pursue policies intended to increase production, that sufficient 

resources exist, and that access and capital will be available to 

expand production.” [10]. However, respected energy industry 

analyst Matthew Simmons indicates that at least for the 

claims made by the Saudi Arabian government—the largest 

producer of oil worldwide with 2/3 of the world proven 
NASA/TM—2011-214042 4 

 reserves—oil reserves have been significantly exaggerated for 

political reasons, and Saudi Arabia is not in fact capable of 

stepping up production to meet future demands like its 

government has repeatedly claimed; a fact recently 

corroborated by the Saudis [11–13]. Based on current oil 

industry practices, Boone Pickens, a retired geologist from 

Mesa Petroleum, sets global oil production at 84 Mbbl/day 

(million barrels per day) and does not expect increased 

production. This is based on the fact that we are currently 

consuming more than we are producing and are not 

replenishing our reserves [14]. With the peak of oil production 

imminent, it is useful to consider the possible effects of fuel 

availability on the cost of jet fuel, and, in turn, the effects of 

fuel costs on the aviation industry. 

Cost Scenarios 

Projections have been made for the cost to industry to 

enhance production of conventional and unconventional fuels, 

as well as for the impact on the aviation industry and airline 

consumers, while indirectly considering the effects of 

greenhouse gases and the need for nonfossil fuels. 

Projected Industry Costs.—With the dwindling supply of 

oil, it has been argued that unconventional oil sources such as 

shale oil and Canadian tar sands will be able to compensate. 

Even CERA, who conservatively places the peak in oil 

production in 2020, forecasts it will cost the energy industry $4 

to $6 trillion to bring production of unconventional oil up to 

these levels [15]. A similar number ($3 trillion) is cited by 

Klare [13] to enhance conventional oil production. In 2004, 

major oil companies spent about $64 billion on new capital 

projects. Over 15—even 30—years this investment gap could 

be covered by governments worldwide, but the current U.S. 

Energy Bill includes only $8 billion to encourage more energy 

research in all fields—nuclear, renewable and crude oil [16], 

and other governments worldwide cannot be relied upon to 

make up this deficit. International Energy Agency (IEA) 

estimates a total annual energy investment of about 

$530 billion per year is required with 40 percent ($200 billion 

per year) required by the gas and oil industry. Placing these 

figures into perspective, the Gross Domestic Product of 

Norway is less than $200 billion, and $530 billion is greater 

than the 2004 U.S. defense budget [15]. 

Future Fuel Price Scenarios.—Historical jet fuel prices are 

very closely correlated with the price of crude oil. With 

production restraints and “peaking” imminent, it is 

prudent to consider different cost scenarios for use in analyses 

of future technologies. The focus of this discussion is to 

consider three cases in which fuel prices rise over the long 

term, simply named the “low,” “medium,” and “high” fuel price 

scenarios, as shown in Fig. 6. 

Low-Price Scenario: Data from The U.S. Bureau of 

Transportation Statistics (BTS) Airline Fuel Cost and 

Consumption (1977 to 2005) data tables (available from 

http://www.bts.gov/) were fitted from 1995 to 2003 and 

extrapolated to year 2020 giving the low-price scenario of 

$1.33/gal. This assumes the recent upswing in price reverses 

and settles back down to the average growth trend experienced 

since approximately 1995 (after the Gulf War), as shown by the 

lower solid arrow on the chart. The DOE–EIA [10] provides 

several potential scenarios using data from 2003, yet greatly 

underestimates the prices that are being experienced in 2005. 

The DOE expects oil demand to jump from 77 Mbbl/day in 

2001 to 121 Mbbl/day by 2025, a net increase of 44 Mbbl/day. 

Over 1/4 of this additional oil—some 12.3 Mbbl/day—is 

expected to come from Saudi Arabia, the only country that may 

be capable of increasing its output by this amount. Take away 

Saudi Arabia's added 12.3 Mbbl/day, and there is no possibility 

of satisfying anticipated world demand in 2025, which is the 

reality of Figs. 1 to 5. One could, of course, suggest that some 

other oil producers will step in to provide the additional 

supplies needed, notably Iraq, Nigeria, and Russia; although 

these countries together would have to increase their own 

output by more than 100 percent simply to play their already 

assigned part in the DOE's anticipated global supply gain over 

the next two decades. This in itself may exceed their production 

capacities. To suggest that they could also make up for the 

shortfall in Saudi production is questionable. The DOE–EIA 
NASA/TM—2011-214042 5 

report tacitly assumes OPEC and the non-Gulf 81

 can and will 

meet energy demands. It was already noted though, that oil 

producing countries are too often mired in political strife and 

remain without sufficient infrastructure in place or plans to 

meet those demands [12–13]. 

CERA argues that alternative energy sources, especially 

unconventional oil will play a large role in allaying troubles 

arising from the depleting oil supply, making up almost 

35 percent of world oil supply by 2020. The report claims that 

there are about 20-30 new major projects coming online before 

2010, and these projects, combined with the increased capacity 

of current oil production sites, will produce about 

17.7 Mbbl/day of new capacity. This is an increase of about 

20 percent over current oil productivity. Assuming a demand 

growth of 2.2 percent per annum (which CERA claims is rather 

strong), this amount of new productivity would still be well 

above demand and thus prices should re-stabilize in the short 

term and resume moderate historical growth trends. 

This report paints an optimistic picture in the short to 

medium term and further asserts that when oil does peak, other 

conventional oil sources will have matured sufficiently such 

that there will not be a peak in oil, but more of a plateau that 

will be sustained until alternative energy (renewable, nuclear, 

unconventional oil, etc.) can replace oil almost entirely. 

So, while the CERA report probably means good news for 

the short term—with more than 20 new large-scale projects 

coming online in the next 5 years—the need for investment in 

unconventional oil remains a large question in the long term. 

Because of this, the low-fuel price scenario seems to be a 

decidedly optimistic projection; in 10 to 15 years, the price will 

likely be much higher. 

Medium-Price Scenario: The choice of the medium price, 

$2.67/gal (twice the low price) in year 2020, also corresponds 

quite well to the historical maximum crude oil price at the 

height of the oil crisis following the war between Iran and Iraq 

in the 1970s. In this case, it is assumed that rate of current price 

increases will diminish and will eventually flatten out to about 

the same as the slope of increase since 1991; the low-price 

scenario plus a constant. 

The price reflects unconventional oil sources being online, 

but due to practical constraints such as limited capital and the 

inherent time required to build new facilities, production from 

these sources is not able to keep up with the demand as well as 

CERA projects that it will. As a result, fuel prices rise 

appreciably in the long term. Because of the uncertainty in 

trying to predict how quickly these relatively immature 

technologies will be developed, this seems to be the most 

reasonable prediction. 

The DOE projection is predicated on technological advances 

and new energy sources. Hybrid- and diesel-powered 

automobiles are projected to enjoy an 11 percent market share 

by 2012, up from 4.8 percent in 2005 [18], and several fuel cell 

vehicles are currently in development. Cleaner synthetic fuels, 

such as gas-to-liquids (GTL) fuels, will also help alleviate the 

 

1

This group comprises Mexico, Venezuela, Colombia, Russia, Azerbaijan, 

Kazakhstan, Nigeria, and Angola. 

strain of dwindling oil supply and could reach 1.5 Mbbl/day by 

2020 (Jeroen van der Veer, CEO of Shell) that represent 

roughly 1 percent of projected worldwide oil demand at that 

time. These alternative energy sources may be able to stabilize 

the energy market in the very long term; however, it is the short 

and medium terms that are uncertain. 

Political factors are likely to manifest in the form of some 

type of rationing or nationalization of the industry. As supplies 

dwindle, and prices skyrocket, there will be more pressure on 

politicians and governments (domestically and internationally) 

to intervene and bring prices down. For example, the British 

Government in July 2005 began to discuss the idea of 

“Domestic Tradeable Quotas” of carbon, a type of personal 

carbon allowance [19]. Such a measure would ostensibly be 

implemented to manage carbon emissions, but would ultimately 

amount to a type of gas rationing, with low energy users selling 

part of their quotas to high energy users. 

Unfortunately, the complexities of this issue make 

speculation about its specific effects a futile effort. One can 

expect though, that if governments intervene, it will be only in 

the case that prices are rising rapidly with no sign of coming 

down, and such policies will be used to force fuel prices to 

settle at a reasonable, midrange price. 

The expectation of drastic price increases being slowed 

either by forces of the market or politics is the reasoning 

behind the “medium price” for U.S. Jet-A fuel being placed at 

about $2.67/gal, which is the current domestic price in India. 

This price represents a relatively modest 5 percent increase 

compounded annually over each of the next 15 years. In this 

scenario, it is expected that either other technologies will come 

online just fast enough to keep oil prices from skyrocketing 

without bound, or if they do not, governments will intervene to 

keep prices down. Airlines and engine and aircraft 

manufacturers would have even greater incentive to improve 

fuel efficiency. 

High-Price Scenario: The choice for the high-price scenario 

represents a projection based on BTS tabulated 2002 to 2005 

fuel cost data and represents nearly a quadrupling of current 

fuel prices by 2020 to $5.51/gal. Fig. 6 shows this would occur 

in the event that recent growth trends continue for several years 

and only slow gradually and asserts that global oil production 

has or is about to peak. 

Pickens (Mesa Petroleum) claims that global production has 

already peaked [14], Deffeys (updating of Hubbert’s work) 

cites 2005, Simmons places the peak sometime in the next 

3 years [12], and Campbell (Uppsala Hydrocarbon Depletion 

Group) places the peak in oil at around 2008. Campbell’s work 

includes unconventional oil such as tar sands, deepwater oil, 

and natural gas liquids [7]. This is in contrast to the CERA 

report which argues that unconventional oil sources will 

constitute 35 percent of the world’s energy supply by 2020 and 

delay the peak of oil until long into the future. 

If it is indeed true that oil production will peak within the 

next couple years, and that unconventional oil will do little to 

improve the situation, we can expect drastic increases in the 

price of oil until nuclear, alternate, and/or renewable energy is 

producing in large enough capacities to replace demand for oil. 
NASA/TM—2011-214042 6 

The EIA foresees these technologies growing only 

marginally by 2020: according to their numbers, nuclear power 

production will increase by 9 percent, hydropower by 

17 percent and other renewables by 28 percent [20]. However, 

it should be noted that these power sources currently represent 

only about 15 percent of domestic power production, and even 

after these increases they will actually represent only 

14 percent of the projected power demand in 2020, or a 

reduction in the overall contribution of these alternative power 

sources. This means that if—as Simmons writes in his book—

the production of oil does not grow at the rate the EIA predicts, 

these other sources will have to increase at a much higher rate 

than current data suggests, or there will be a significant energy 

shortage, and prices will skyrocket. 

Assuming that this actually happens, and that governments 

do not intervene to keep prices down, it is very difficult to 

determine a realistic oil price. 

For example, what if oil prices continue to rise dramatically 

and Jet-A becomes $5.51/gal, which is about four times current 

jet fuel prices? For the price to quadruple in 15 years, an 

annual increase of about 9.7 percent is required. This is a rather 

strong increase to sustain over such a long period, but it is 

much less than the current rate at which prices are growing. 

The average price in 2003 was 20 percent higher than in 2002. 

In 2004 the price increased another 36 percent, and the year-todate average price as of July 2005 is another 28 percent 

increase over 2004 [20]. Thus, as a theoretical “high price” 

scenario, $5.51/gal is not completely out of the question and in 

line with some 2005 European petrol consumer prices near 

$5/gal. In a world where oil production has peaked and there 

are limited alternatives, the price of oil will increase without 

bound until alternatives are sufficient to slow its pace. 

These projected scenarios are based on analysts views and 

speculation; it is true that any projection, be it scientific or 

otherwise, is speculation and often an analysts opinionated 

position for an ideology. There are very few absolutes. But 

these projections are, presently, the best that we can achieve 

while indirectly addressing the greenhouse gases (GHG) 

challenge of our planet with the acute need for nonfossil energy 

supplements. 

So why investigate the high, medium, and low fuel price 

scenarios? First, these factors illustrate the vulnerability of 

nations and industry to fuel prices and second, aircraft 

operation and design is greatly influenced by fuel costs. The 

aircraft design for the low-price fuel would be similar to that 

which is being designed and fielded today. However, the high 

fuel price would necessitate a new aircraft design philosophy 

and would be different than what is on the boards today. 

Impact on Airplane Operating Cost 

Airline operating costs are currently dominated by flight 

crew costs, which represent about 33 percent of the total, as 

shown in Fig. 7(a). If one now considers the tenuous position 

of fuel availability and the high-cost scenario from above, with 

all other costs inflated nearly 1 percent/year, fuel costs are 

projected to dominate with about a 50 percent share of the total 

cash airplane-related operating costs (CAROC) (Fig. 7(b)). 

If fuel costs become the most important operating expense 

for aircraft, alternate fuel sources might become more attractive 

to the aviation industry. Alternative fuels would require 

significant changes to the design of current aircraft. 

Alternate Energy Sources for Fuels 

As petroleum prices continue to increase, several alternative 

fuel sources will become price competitive with currently 

available energy sources. Synthetic fuels made from plentiful 

energy sources such as coal, natural gas, or other hydrocarbon 

feedstock show significant promise as fuels that could be easily 

integrated into today’s aircraft with little or no modification to 

current aircraft designs, yet may require additives. These synthetic 

fuels are most often referred to as “gas-to-liquid” or GTL fuels. 

The market for GTL fuels is rapidly emerging. The process 

used to produce this synthetic fuel, which is sometimes called 

“Fischer-Tropsch” or “FT” fuel after its inventors, was 

developed in 1923 and put into use by Germany during WWII. 

The actual Fischer-Tropsch process refers to the conversion of 

synthesis gas, or “syngas,” into any of a variety of synthetic 

fossil fuels. Syngas is the name for a mixture of hydrogen and 

carbon monoxide gases that can be obtained through 

reformation of a number of feedstocks including coal, natural 

gas, or biomass. 

Today, the most promising feedstock for use in this process 

is natural gas and coal because of the potential to make use of 

the large amounts of these energy sources available around the 

world. One potential source is the natural gas found in oil fields 

that is currently “flared” (burned) because no use can be found 
NASA/TM—2011-214042 7 

for it. According to one source, the energy content of the 

natural gas flared each day (10 billion cubic feet worldwide) 

could provide 17 percent of the daily power demand in the 

United States [21] More promising (yet less proven) energy 

sources in terms of the world’s organic carbon are found in 

remote locations around the world (Fig. 8). 

The so-called “stranded” natural gas reserves are reserves 

that have been located but are not economically exploitable 

because they are not located near a pipeline, and thus currently 

lay unused. Current figures place the total known amount of 

this stranded gas at about 14 quadrillion cubic feet. If this gas 

were able to be harvested and converted to synthetic fuel, it 

alone would supply the world’s energy needs for 25 years [22]. 

Looking even further into the future, in addition to these 

known stranded gas reserves, there are tremendous amounts of 

natural gas in the form of methane hydrates that are found in 

permafrost regions and below the ocean floor (Fig. 9). 

Until recently, there was no economically viable way of 

harvesting methane hydrates, but Syntroleum, Inc. (Tulsa, OK), 

received a patent in 1999 for a process that will allow them to 

recover this gas from the ocean floor. According to David 

Greene of the Oak Ridge National Laboratory, “worldwide 

estimates of the natural gas content of methane hydrates 

approach 400 quintillion cubic feet.” [23]. This is 30 000 times 

the amount of known stranded natural gas. Given that there is 

enough stranded natural gas to supply energy for the world for 

25 years, these methane hydrates represent the potential to 

supply the world’s energy needs for the next 750 000 years. 

They also represent an environmental problem because 

methane, as a GHG, is 20 times worse than CO2. 

There are several reasons GTL fuels are so attractive, not the 

least of which being the fact that current oil prices hover above 

$60/barrel. According to the chairman of Syntroleum, “these 

projects would have been profitable with oil at $25-30 a 

barrel” [24]. Since, according to Greene, GTL fuels cost about 

$15-20/barrel to produce, there is a good business opportunity 

with this technology. Perhaps more significant for consumers, 

GTL diesel burns very cleanly [25]. There are only 1 to 15 ppm 

sulfur [26] and negligible amounts of aromatics and metals in 

GTL diesel [27]. In a study conducted by Shell, when used 

with a catalyzed diesel particulate filter, emissions of 

particulate matter from heavy-duty trucks were reduced by 

97 percent. Better catalytic filters can be used with this fuel 

because of the low sulfur content of the fuel [24]. Finally, and 

most importantly for the short term, this fuel can be transported 

using current infrastructure and can be used in current diesel 

engines or mixed with “dirtier” diesel fuels with no 

modification to the engines. This means that with the tightening 

emissions regulations soon to go into place in Europe and 

eventually worldwide, GTL diesel can be used to improve the 

quality of current diesel inventories to bring them up to 

standards. 

Alternate Fuel Possibilities 

While our economy and security are currently dependent on 

inexpensive oil and other fossil-based fuels, there are 

alternatives, many of which have been discussed in the 1970s 

by Reed and Lerner [28], such as 

(1) GTL biomass: a renewable source and more 

environmentally friendly in most applications including 

• ethanol from corn, corn-stover, and grasses (e.g., 

switch grass) 

• biodiesel from soybeans 

• methanol from trees and wastes 

• synthesis gases in general 
NASA/TM—2011-214042 8 

(2) Solar and wind generation of electricity: also renewable 

and environmentally benign and can be used in fuels synthesis 

for transportation, see references 28 to 36, for example, and Fig. 9. 

(3) Hydrogen: Today most comes from reformation of coal; 

as such, for heat engine applications, gas or liquid, the life 

cycle is not environmentally friendly. Yet other energy sources 

as solar, wind, or nuclear-electric electrolysis can be used. 

Alternate Fuel Use in Aircraft 

There are aircraft challenges in implementing many of the 

alternate fuels (e.g. fuel freezing, thermal stability, 

sustainability, storage, safety, reliability, etc.). 

While using Jet A-GTL mixtures or synthetic jet fuel (SJetA) 

will require qualification testing, including crash fire safety for 

example, and unexpected complications may arise, these fuels 

should become acceptable. On the other hand, there are many 

issues that need to fall into place prior to using biomass fuels 

(some of which apply equally to SJetA or mixtures).2

 A few 

examples are listed here: 

(1) Assurance of supply and consistency of biofeedstocks 

(switchgrass, soybeans, rapeseed, stover, trees, wastes) 

(2) Need for new more efficient methods and cycles for 

biostock to fuel conversion and waste disposal. 

(3) Need to determine how current systems and components 

must be altered, such as fuel metering, fuel injection, storage, 

handling, and transfer systems; safety; anthropogenic emissions 

(combustion, production, propulsion, and flight); 

standardization of fuel heating values and constituents; 

thermophysical properties measurements and fundamental 

equation or equation of state predictors; long-term storage 

separation and stratification; long- and short-term corrosion 

and materials compatibility; fuel thermal stability for Bio-Jet 

(fails JFTOT test, ASTM D 3241 (Jet Fuel Thermal Oxidation 

Tester)), poor lubricity for GTL-Jet; heat of combustion content 

of the fuels (not too bad for Bio-Jet or GTL-Jet fuels); life 

cycle emissions impact; and fuel cost impact, to name a few. 

(4) For aviation applications, low temperatures at altitude 

engender fuel viscosity and freezing issues that require 

resolution. Standardization of the percentage fossil-fuel to biofuel blends becomes necessary and to determine if EJ15 is 

better suited for aviation than EJ10 or EJ50? Or could EJ100 

be used? Here EJ15 implies 15 percent ethanol + 85 percent 

Jet-A by volume. 

 

2

Typical heat content of Jet-A is 18,500 BTU/lb. The density varies but is 

around 6.74 lb/gal or 124,690 BTU/gal. Seattle to Washington DC is 2325 

statute miles. If the aircraft consumes 25,000 lbs of fuel, seats 162 passengers 

(737-800) with a passenger load factor of 80%, this will give a fuel mileage of 

81.5 passenger miles (pmi) per gallon, which provides for an energy 

requirement of 1,530 BTU/pmi. 

Note: Lufthansa (year 2003) fleet average 4.31liter/100 pkm (passenger 

kilometer) 

 = 4.31 liter/100 pkm 

3.78 liter gal

      x [1.60934 km/mi] 

= 1.846 gal/100 pmi or 54.2 pmi/gal or 2301 BTU/pmi

Assuming that these factors can be resolved, fuel type, cost, 

and availability could now drive design of the engine and 

airplane configuration (Figs. 10 and 11). 

Hydrogen bulk density is low, necessitating large storage 

volumes. Engine efficiency enhancements through intercooling 

of the compressor and recuperating heat from the turbine 

exhaust represent major design challenges. Unmanned 

ultrahigh altitude solar electric and fuel cell communications 

platforms present new opportunities for flight propulsion and 

aircraft integration [37]. 

Fuel savings of lower altitude and lower cruise Mach 

number may also become interim solutions to the high cost of 

fueling. For example, turboprop aircraft and ocean skimmers 

are envisioned, illustrated in Fig. 11 [38]. 

Preparing for the Future 

While hydrogen-fueled systems represent our nation’s longterm goal, this goal appears further into the future than 

anticipated. To alleviate potential shortages and enhance our 

ability to grow aviation, research and development needs to be 

done for all alternate fuels and not just hydrogen. 

Conclusions 

With rising fuel prices, improving airplane energy efficiency 

becomes an increasingly important driving factor in new 

aircraft design. If prices reach and sustain levels near the 

medium- or high-price scenarios discussed above, it will not be 

sufficient to continue with incremental improvements to 

aircraft efficiency. Instead, fundamental aircraft technologies 

will need to be reconfigured for more fuel-efficient designs. 

Another factor of rising fuel prices that will indirectly affect 

the aviation industry will be the introduction of alternative 
NASA/TM—2011-214042 9 

fuels into the market. The development of these fuels will be 

driven by the price of crude oil and will help to stabilize the 

long-term price of jet fuel. However, most experts agree that 

there will be a long and difficult transition period in which 

prices will remain high and place considerable constraint upon 

the aviation industry. 

Aside from helping to stabilize the price of fuel, alternative 

fuels offer other benefits to the aviation industry. Most of these 

alternative fuels, such as biodiesel and in the longer term, 

hydrogen, are best used in the ground transportation sector. 

With the increased use of these fuels, a greater portion of a 

barrel of crude oil can be used for producing jet fuel, because 

aircraft are not as fuel-flexible as ground vehicles. However, 

the aviation industry would of course have to pay a significant 

premium to increase its share in the overall consumption of 

petroleum. This provides further incentive to design more fuelefficient aircraft. 

Much work remains to be done to bring alternate fuels into 

more widespread use, both within the aviation industry and 

outside of it. Questions have been raised about the energy 

needed to produce some of these fuels compared to the energy 

that they provide. Further life-cycle analyses need to be 

performed to verify the practicality of using these fuels in the 

entire transportation sector. 

Finally, because of the ease with which it can be integrated 

into current aircraft, GTL fuels show significant promise to 

transition the aviation industry from traditional petroleumbased jet fuel to other sustainable fuels in the long term. 

References 

[1] Hydrocarbon start and growth http://www.mtholyoke.edu/ 

acad/intrel/oil1.htm

[2] U.S. energy use % hydrocarbon usage http://www.eia. 

doe.gov/oiaf/aeo/aeoref_tab.htm

[3] 85.9% world’s energy from hydrocarbon 

http://tonto.eia.doe.gov/FTPROOT/international/edexfiles/phie

ata.ppt#277,4,Slide 4 http://www.eia.doe.gov/emeu/

international/total.html#IntlConsumption

[4] 84-87 % US hydrocarbon use http://www.eia.doe.gov/

oiaf/aeo/aeoref_tab.html

[5] Deffeys, Kenneth. Beyond Oil: the View from Hubbert’s 

Peak, published by Farrar, Straus, and Giroux, 2005. 

[6] Hirsch, Robert L. Peaking of World Oil Production: 

Impacts, Mitigation, and Risk Management. Report for the 

Department of Energy. Written February, 2005, accessed July, 

2005 from http://hdl.handle.net/1813/692. 

[7] “Oil and Gas Liquids, 2004 Scenario,” Chart produced by 

Colin J. Campbell, accessed July 2005 from 

http://www.peakoil.net/uhdsg/Default.htm

[8] Laherrere, Jean. “Modelling future liquids production 

from extrapolation of the past and from ultimates.” Energy 

Exploration and Exploitation. vol. 20, no. 6, December 2002, 

pp. 457-479. 

[9] “Oil and Liquids Capacity to Outstrip Demand until At 

Least 2010: New CERA Report” Press Release on June 21, 

2005 from http://www.cera.com. 

[10] Annual Energy Outlook 2005, accessed from July, 2005 

from http://www.eia.doe.gov/oiaf/aeo/download.html. 

[11] “Saudis say OPEC will not meet projected oil demand in 

10-15 years.” Accessed July 2005 from 

http://www.finfacts.com/irelandbusinessnews/publish/printer_1

0002504.shtml. 

[12] Simmons, Matthew R., Twilight in the Desert: The 

Coming Saudi Oil Shock and the World Economy, John Wiley 

and Sons, Hoboken, NJ. 

[13] Klare, Michael T. Blood and Oil and “The Saudi Oil 

Bombshell” Asia Times Online, June 29, 2005. Accessed July, 

2005 from http://www.atimes.com/atimes/Middle_East/

GF29Ak01.html. 

[14] “Boone Pickens warns of petroleum production peak” 

Author unknown. Written May 3, 2005, accessed July 2005 

from http://www.peakoil.net/BoonPickens.html. 

[15] Dittrick, Paula. “CERA: SEC reporting system outdated” 

accessed July, 2005 from http://www.royaldutchshellplc.com/

weekseven/weekeight/oil__gas_journal25feb05.htm. 

[16] “Energy Bill won’t ease fuel prices quickly, Bush says.” 

Reuters, April 21, 2005. Accessed July 2005 from 

http://www.climateark.org/articles/reader.asp?linkid=41027. 

[17] IEA: World Energy Investment Outlook 2003, November 

2003. http://www.eia.doe.gov/

[18] “Hybrid, Diesel Vehicle market share to hit 11% by 

2012” IHS Automotive July 6, 2005. Accessed July 2005 from 

http://auto.ihs.com/news-05Q3/jdpower-hybrid-diesel-vehiclemarket-share.jsp. 

[19] Clover, Charles. “Energy ration cards for everyone 

planned.” Telegraph, July 2, 2005. Available online from 

http://www.telegraph.co.uk. 

[20] Energy Information Administration http://eia.doe.gov/

Accessed Jan. 24, 2006. 

[21] “Syntroleum targets Small- to Mid-Sized Gas Fields for 

GTL” accessed July 2005 from Green Car Congress: Gas-ToLiquids (GTL), http://www.greencarcongress.com/

gastoliquids_gtl/. 
NASA/TM—2011-214042 10 

[22] “Why GTL?” accessed July 2005 from Conoco Gas 

Solutions, http://gassolutions.conoco.com/tech/why.asp. 

[23] Greene, David L. An Assessment of Energy and 

Environmental Issues Related to the Use of Gas-to-Liquid 

Fuels in Transportation. ORNL/TM-1999/258, November 

1999. (see also: http://www.sasolchevron.com/

conceptual_design.htm) 

[24] Parkinson, Gerald. “Gas to Liquids Technology Gains 

Momentum,” Chemical Engineering Progress, May 2005, Issue 

101, p. 6. 

[25] “GTL Outlook” accessed July 2005 from 

http://www.exxonmobil.com/corporate/files/corporate/GTL_ou

tlook.pdf. 

[26] “Synthetic Diesel: Step on the Gas,” The Engineer. 

London: Aug 6, 2004, p. 18. 

[27] Holmes, Jack B. and Jenkins, Greg. “GTL Technology 

just one step away from achieving its commercial potential” 

accessed July 2005 from Oil and Gas Financial Journal, 

http://ogj.pennnet.com/. 

[28] Reed, T.B, Lerner, R.M., Methanol: A Versatile Fuel for 

Immediate Use, Science, 28 Dec. 1973, vol. 182, pp. 1299-

1304. http://www.woodgs.com

[29] Swenson, Ron, Can Solar Energy Replace Oil? 

http://www.ecotopia.com/ISES/2005/Terawatts.ppt#277,1 

[30] Smalley, Richard http://www.sciscoop.com/story/2004/

11/3/20322/6497

[31] Thresher, Robert (2004) Wind Power Technology, GCEP 

Energy Workshops on Wind Power, April 26, 2004, 

http://gcep.stanford.edu/events/workshops_wind_04_04.html 

[32] Glaser, Peter E., Davidson, Frank P., and Csigi, Katinka, 

Solar Power Satellites, 1998, John Wiley & Sons 

[33] Hoffert, Marty (2004) Space Solar Power, GCEP Solar 

Energy Workshop, October 18-19, 2004. 

http://gcep.stanford.edu/events/workshops_solar_10_04.html

[34] Buckmeister Fuller http://www.bfi.org/

[35] Ausubel, Jesse H. (2004) Big Green Energy Machines, 

Millennium Technology Prize Symposium in Espoo, Finland 

June 14, The Industrial Physicist, vol. 10, no. 5, p. 20. 

http://www.aip.org/tip/INPHFA/vol-10/iss-5/p20.html

[36] http://www.wentworth.nsw.gov.au/solartower/

[37] Szodruch, Joachim (2005) [DLR, Germany] 

Technological Targets for Future Air Transportation in Europe, 

ISABE-2005-Pannel Discussion 3 

[38] Broichhausen, Klaus (2005) Engine Technology Prepared 

in Europe: Innovation by Successful Partnerships, Paper 

ISABE-2005-1001, 17th International Symposium on 

Airbreathing Engines, September 4-9, 2005, Munich Germany. 
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Future Fuel Scenarios and Their Potential Impact to Aviation 

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14. ABSTRACT

In recent years fuel prices have been growing at a rapid pace. Current conservative projections predict that this is only a function of the 

natural volatility of oil prices, similar to the oil price spikes experienced in the 1970s. However, there is growing concern among analysts 

that the current price increases may not only be permanent, but that prices may continue to increase into the future before settling down at a 

much higher level than today. At high enough fuel prices, the aircraft industry would become very sensitive to fuel price. In this paper, the 

likelihood of fuel price increase is considered in three different price increase scenarios: “low,” “medium,” and “high.” The impact of these 

scenarios on the aviation industry and alternatives are also addressed. 

15. SUBJECT TERMS

Fuels; GTL; Bio-fuels; Costs; Aircraft; Engines; Operations; Alternate fuels 

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