Next to hydroprocessing, an old technology exists — the Fischer-Tropsch process invented by Franz Fischer and Hans Tropsch in Germany in 1925. Who will win the race between Fischer-Tropsch and hydroprocessed aviation fuels? The Fischer-Tropsch process is a four-step synthesis that first involves gasifying bio­mass feedstock and reacting it with steam at moderate pressure and elevated temperatures in the absence of combustion. The resulting synthesis gas ("syn gas”) often contains impurities like sulfur and large amounts of carbon dioxide, which requires that it be scrubbed. The third step involves passing the syn gas over a catalyst (usually iron — or cobalt-based) to form a variety of hydrocarbons. Depending on the gasification process, one can alter the reaction conditions (pressure, temperature, time, or catalyst), resulting in changes to the molecular structure of the hydrocarbons. Using well-established refining methods, the hydrocarbon is upgraded to the subsequent liquid fuel.

Although both processes produce essentially the same end fuel, the differences between biomass and oil-seed-based aviation fuels are stark.

The idea of producing synthetic aviation fuel is hardly a new concept. Germany pioneered the production of Fischer-Tropsch synthetic fuels during World War II. Currently, the South African airline Sasol (www. sasol. com) produces approxi­mately 150 000 barrels per day at its coal-to-liquid facilities. (South Africa also used the Fischer-Tropsch process during the era of apartheid.)

A number of companies are currently exploring the utilization of the Fischer- Tropsch process to transform biomass into aviation fuel. Companies like Choren, Rentech, and the Solena Group have announced commercial projects that could result in hundreds of millions of gallons of production capacity coming online by 2014.

Synthetic aviation fuels created via a process known as biomass-to-liquids (BTL) have a number of benefits beyond the obvious one — that they are not petroleum — based! Fischer-Tropsch fuels have lower carbon and particulate matter emissions, thermal stability, and can be derived from any type ofbiomass, as well as from coal and natural gas.

In the race to the commercialization of aviation biofuel, hydroprocessing has a number of advantages over the Fischer-Tropsch process. First, in recent years, every major airline that has tested biofuels has used jet fuel derived from hydroprocessing. For example, when Virgin Atlantic became the first commer­cial airline to oversee a flight partly powered by biofuels, it used a 25% blend of biofuels in one of its engines that included hydroprocessed coconut oil and babassu oil. KLM, Air New Zealand, Qatar Airways, Continental Airlines, and Japan Airlines have also completed flights using biofuels like Jatropha, algae, and Camelina.

In 2014, 100 million gallons of Camdina-based jet fuel are expected to be delivered to 15 airlines by Sustainable Oils and AltAir. There are a number of commercial hydroprocessing plants being built, most notably by Neste Oil and ConocoPhilips.

For example, Neste Oil has built a facility in Singapore that has a production capacity of 58.2 million gallons per year at an upfront capital cost of $135 million. Another Neste refinery with the same concept was opened in the fall of 2011 in Rotterdam.

Given the strategic importance for the military of obtaining copious amounts of domestically sourced energy and the blank check the Department of Defense receives, it is clear that aviation biofuels are coming — whether from the Fischer — Tropsch process or hydroprocessing.