How Weeds Can Be Used as Biofuel

Thlaspi arvensePhoto: Fornax

Pennycress is an invasive plant, neither wanted nor utilized, and being viewed as a new source of bio-fuel. It is also known as stinkweed. It is the oil from the plant’s massive supply of seeds that is utilized. Acid, and alcohol is used in the initial stages of treatment resulting in a bio-diesel and glycerol. However further refining is needed to analyze if the fuel can meet standards of the American Society for Testing and Materials.

In some countries biodiesel is less expensive than conventional diesel.Photo: Bob Tubbs

The Good and the Bad

It’s impressive to think of taking an ordinary roadway weed and acquiring such a complex material that can probably catapult the global world into the future. The pennycress grows quickly. However, the plant causes alarming ecological and economic problems in the western United States by obstructing river systems, ruining habitats for wildlife and livestock, limiting access for irrigation and diminishing water quality and quantity.

Filtered waste vegetable oilPhoto: knightmb

Critical Factors

Pennycress has demonstrated its use as a bio-fuel, particularly in cold climates. Its cloud point, which is the temperature at which crystals are visible in the fuel, is an important factor in both bio-diesel and petro-diesel production. Another important factor is its pour point, the temperature at which the fuel does not pour due to excessive solidification.

The Koenigsegg CCXR Edition at the 2008 Geneva Motor Show. This is an "environmentally friendly" version of the CCX, which can use E85 and E100.Photo: Fpm

Bio-fuels are being tested as jet-fuel also. The plant pennycress is mixed with regular JP-8 jet fuel.