The news has recently been packed with items about airlines worldwide that have been conducting flights to test an interesting assortment of biofuel blends. Virgin Airlines, for example, last year flew a 747 powered by a blend of coconut oil and jet fuel, while New Zealand Air tested a jatropha-based fuel. This January, Continental Airlines made headlines with its test of a fuel derived from pond scum, jatropha, and jet fuel. It was followed by a much-covered flight by Japan Airlines, which successfully circled around in the Pacific Ocean using a blend of camelina, jatropha, and algae oil in one engine. According to reports, pilots aboard that flight said the biofuel blend surpassed the traditional 100% Jet-A fuel in efficiency.

Like the airline industry, power generators all over the world have been seeking alternative fuels with which to produce electricity, and the blends are bound to get stranger. One company is looking to make liquid fuels from chicken fat, beef tallow, and pork lard, for example. Here’s a list of innovative fuels that generators could use in the near future.

Jatropha Oil. Jatropha curcas, a plant that thrives anywhere — even in the crevices of rocks and in sandy and saline soils — produces a nonedible but high-energy seed (Figure 2). When crushed, the seeds’ oil can be processed to produce a high-quality biodiesel. The plant yields more than four times as much fuel per acre as soybean and more than 10 times that of corn.

2.    Bellyache bush. When crushed, the Jatropha curcas plant’s poisonous seeds produce a crude oil that can be used for power generation or processed into high-quality biodiesel. Courtesy: Thenergo

Raw jatropha oil is being used in small-scale power generation projects in villages across Asia and Africa, but it is a feasible fuel source for larger-scale projects as well, according to the Centre for Management and Technology and host of the JatrophaWorld conference.

In August, the world’s first engine-driven combined heat and power (CHP) plant to run on crude jatropha oil will come online. The grid-connected plant, which will be located in an agricultural area in Merkplas, Belgium, will be owned by Greenpower NV, a joint venture between Thenergo and four agricultural companies. Finnish company Wärtsilä will supply a 9-MW Wärtsilä 20V32 engine for the project (Figure 3). The power plant is expected to have a gross electrical efficiency of 44.2%.

3.    New oil power. The first combined heat and power plant to use crude jatropha oil as fuel will come online in August this year in Merkplas, Belgium. Finnish company Wärtsilä will supply a 9-MW Wärtsilä 20V32 engine to Greenpower NV, owner of the plant. Courtesy: Wärtsilä

Whiskey By-products. This January, the Scottish government said "aye" to the Rothes renewable energy project, a 7.2-MW biomass CHP plant that will use a combination of wood chips and by-products from the distilling of whiskey. The £24 ($35.5) million project, a joint venture between Helius Energy and the Combination of Rothes Distillers (which includes the Edrington Group and Chivas Brothers), will specifically use draff, or the solid grain product removed from the mash tun, and pot ale, the high-protein residues remaining in the wash at the end of the first distillation. The CHP plant, first announced in March 2008, is expected to be operational in about two years.

Glycerin. Glycerin, that odorless and viscous liquid used widely in pharmaceutical formulations, is a natural by-product of biodiesel production: For every 9 gallons of biodiesel produced, 1 gallon of crude glycerin is produced. According to UK renewable power technology company Aquafuel, glycerin’s density and high oxygen content offer the potential of exceptionally clean combustion, with much lower emissions than diesel, though the company admits on its web site that glycerin has a lower calorific value than diesel or biodiesel. Aquafuel, along with biofuel supplier Greenenergy, has developed a new technology for the combustion of crude glycerin in a standard diesel-engine CHP generator. That technology will be tested in early 2009.