Proponents of achieving energy independence for the United States by expanding the use of alternative fuels recently won a victory that may have implications for the aviation industry, among others.
On June 24, ASTM International's Aviation Fuels Subcommittee approved a new fuel specification that will enable airlines to use synthetic jet fuel. The specification, labeled "D-7566," describes the fuel properties and criteria necessary to control the manufacture and quality of these fuels for aviation use. The aviation industry is interested in integrating synthetic jet fuel into its energy supply so that it can better protect itself against crude oil price volatility and reduce greenhouse gas emissions.
One Hurdle Down
"Obviously meeting the certification challenge has been key," said Richard Altman, Executive Director of the Commercial Aviation Fuels Initiative (CAAFI). CAAFI is a coalition of airlines, aircraft and engine manufacturers, refiners, government agencies, and others charged with developing and deploying alternative jet fuels for commercial aviation. Having crossed a fundamental hurdle, CAAFI's stakeholders now must confront a challenge that is more technical in nature: making synthetic jet fuel less costly to produce.
Altman, an engineer by training with more than four decades of aviation industry experience, admits that CAAFI participants still have a heady task before them. For instance, they need to develop a combination of advanced processes to produce synthetic fuels from specific feedstocks such as the renewable resources algae and biomass and the non-renewables coal and natural gas. "Such process developments correspond to factors such as algae water extraction, cooling water requirements, and reduced gasifier costs for Fischer-Tropsch (FT) plants," Altman explained. In FT, feedstocks such as biomass, natural gas, and coal are used to produce synthetic petroleum products. A synthetic jet fuel produced in this manner would serve as a blendstock under D-7566, which calls for combining the synthetic fuel with conventional Jet A fuel.
Initially, the specification will allow commercial aircraft to be powered by up to a 50/50 blend of conventional Jet A and an FT-produced blendstock. The synthetic fuel must exhibit the ability to "drop-in"; in other words, it needs to be fully compatible with existing pipelines, fuel tank farms, and all other distribution and storage channels. "No new equipment will be required," said Altman. He added that companies representing these interests are members of CAAFI and are working to ensure the desired high level of fuel flexibility within their infrastructure.
ASTM is expected to allow more exotic blendstocks, such as hydrotreated renewable jet (HRJ) fuel produced with animal fats and oils, into D-7566 by late-2010. Other blendstocks that are in earlier stages of development -- fuels produced with the fermentation or pyrolysis processes -- will need to overcome further technical hurdles before they can qualify for certification within the range of required fuel characteristics, Altman noted. The likelihood is low that fuels containing ethanol would be approved for this purpose because ethanol has proven incompatible with turbine engines.
CTL: The Best Approach?
Many see the FT process as the most immediate route to producing large volumes of synthetic jet fuels, and using coal as the feedstock offers compelling advantages. First, the fact that coal is fossil-based easily overcomes the "food vs. fuel" controversy that exists with certain biofuels; no land is farmed that would otherwise be used to grow food. In addition, proponents of using coal as the feedstock in FT contend that fuels produced in this "coal-to-liquids" (CTL) process are economically viable at current oil prices; they reason that the raw material, coal, is much cheaper than crude oil.
Although the economics may indeed appear attractive during the operations phase of a CTL plant, raising the capital to build such a plant is another matter – particularly when the facility would cater to an industry that commands a relatively small share of the refined products market. "Financing projects in the current investment environment and encouraging producers to provide feedstocks and dedicate resources to aviation so the fuel can be deployed first in a market with unique distribution channels -- but less than a 10% total market share -- is clearly the biggest challenge that remains," Altman said.
Altman said that studies from Princeton University and the Nobilis consulting firm, among others, have shown that FT plants achieve needed economies of scale at 30,000 barrels per day (b/d) of processing capacity. The present estimated cost of these facilities is $100,000 per barrel per day, so a 30,000-b/d plant might carry a price tag of $3 billion. This cost is relatively high when one considers that a new oil refinery with nearly five times the processing capacity was recently built in Vietnam for approximately the same amount of money.
According to Robert L. Freerks, Director of Product Development with California-based Rentech, Inc., it is important to consider that a truly reliable estimate of a synthetic fuel plant's cost will only be available after one is actually built. Rentech has developed a gasification/FT/upgrading technology that is designed to produce hydrocarbon fuels from any energy source that contains carbon. Freerks reasons that building a maiden CTL plant will enable the project's developer to optimize design and construction costs and hence reduce the overall cost of a CTL facility. "We really don't know what Plant 2 will cost until Plant 1 is up and running," he said.
Freerks added that analyses of CTL plant well to wheel emissions show that CTL facilities will emit no more CO2 than conventional fuel plants.
Considerable technological and economic challenges may impede the pathway to widespread production of synthetic jet fuel, but Altman is buoyed by the prospect of developing a fuel supply for the aviation industry that offers greater stability in terms of supply and cost. Given the federal government's oft-stated eagerness to achieve "energy independence" by developing significant volumes of alternative fuels, Altman maintains the widespread production of synthetic jet fuel should be at the forefront of this endeavor.
"(The) whole goal here is to not impact aircraft manufacture or use," said Altman. "So the question is largely if we can achieve 'first-mover' status among transportation modes, our overall competitiveness and environmental acceptability will improve." In a broader context, Altman believes that the aerospace industry – which produced the Apollo program that put man on the Moon – is a natural fit to perfect ways to produce synthetic jet fuel and other products that would advance the cause of energy independence.
"The creation of a whole new system of technology will require a massive and concerted systems engineering effort," he concluded, likening such an endeavor to an "Apollo-type" initiative. "If there is a national goal of this nature, why not start with the industry that has demonstrated the capability to execute such an effort?"
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