It seems like there is no way to avoid a guilt-trip these days, particularly if you are trying to travel. Whether you choose to go by car, bus, train, ship, or airplane, someone out there is counting the carbon emissions created. Not to mention the nonrenewable fuel source that was consumed.
But perhaps a glimmer of hope is on the horizon for beleaguered jet-setters. After all, buying carbon offsets may soothe the conscience but it doesn’t address the underlying problem. A new experimental technology might help. In the US, Continental Airlines has just tested an algae-based biofuel.
A Boeing 737-800 completed a 90-minute flight using a combination of aviation fuel and biofuel. One engine used a 50-50 mixture, while the other used conventional fuel. The plane took off from Houston, circled over the Gulf of Mexico, and successfully completed a rigorous series of tests. Everything went smoothly, which is encouraging given that the aviation industry has a 5-year goal to start using biofuels. Within five to seven years, regular commercial flights could incorporate biofuels, responding to the need to reduce aviation carbon emissions.
The recent test flight used biofuel derived from plant oils, including algae and jatropha. Algae are plentiful, energy dense, and fast-growing – even causing problematic overpopulations (blooms) at times. A number of algae applications have been proposed, from biofuel to food source. The algal fuel was supplied by Sapphire Energy, after being rendered into oil and refined. Jatropha is a perennial shrub that can be grown on poor land.; it grows rapidly with little need for water or nutrients and yields large amounts of oil. Terra Sol Biofuel supplied the jatropha portion. The resulting biofuel combination was used without any engine modifications, making it an even more promising alternative.
In order to establish sustainable fuel sources, certain criteria have been set: the plants must not affect food crops, water resources, or forest ecosystems. In addition, the biofuels must be second generation forms, without ethanol, to allow use in airplane engines. From a technical standpoint, biofuel needs to meet certain standards for aviation use, including a low freezing point (to avoid freezing at high altitude), thermal and storage stability, energy density, and elastomeric compatibility (to ensure engine operation with biofuel blends).
With biofuel seen as an option for the future, designated flights have tested other options. Early in 2008, a Virgin 747 flew from London to Amsterdam using – in part – fuel blended from babassu nuts and coconuts. The passenger-free flight marked the first commercial aircraft test of biofuel alternatives. The fuel was created by Imperium Renewables, based in Seattle. Only last month, Air New Zealand used a combination of jatropha oil and jet fuel in a Boeing 747 flight.
Clearly, making a transition to biofuels must be undertaken cautiously – passengers will want iron-clad assurances about safety and efficiency before boarding. Initially, biofuel content is likely to be 10% or less, as the industry gains confidence and suppliers expand to fill the demand.
Photo credit: Eileen Flanagan