Wool More Efficient to Produce Than Synthetic

September 29, 2006 - It's official. Merino wool has another positive marketing advantage to add to its arsenal. Not only is wool fabric less flammable and more 'natural' than nylon, polyester and acrylic, officially it has been shown to take much less energy to produce.

Results from the Merino Life Cycle Assessment project show that it takes only 46 megajoules (MJ) of energy to produce a kilogram of wool tops. This includes farming and shearing the sheep, sorting, blending and scouring the wool, producing the 'top' and ship transportation to Shanghai. 'Top' is the term for the continuous ribbon of wool produced from the combing machine.

Nylon takes five times as much energy to produce a similar fabric, acrylic 3.8 times and polyester 2.7 times. All these synthetic products are sourced from fossil fuels.

Even cotton and viscose (from wood pulp) take more energy to get to a fabric stage - although cotton is not far behind wool in terms of energy efficiency.

What Merino farmers have long suspected can now be shouted from the rooftops. Purchasing merino fiber over synthetic fiber is a far more environmentally friendly option in terms of energy use.

Wool processing makes up a whopping 47 percent of the final energy use figure, with the energy-hungry scouring process taking the lion's share. Scouring consumes almost 90 percent of the processing energy share, using 21,700MJ/ton of greasy wool.

A big surprise was the minimal contribution transportation to market makes to the overall energy figure. It only took 3 percent of the total energy use figure to get the wool top to Chinese shores. Energy to get the wool to market was based on a ship traveling 10,460 km from a South Island port to Shanghai. This is about 27 liters of fuel per ton of wool top.

The 'cradle to the grave' Life Cycle Assessment is a popular method of measuring inputs and outputs over the life of a product. It traditionally covers from the extraction of the raw materials right through to product disposal or recycling.

This Merino Life Cycle Assessment looks specifically at energy usage. This means others effects on the environment, like water use, nitrification and social effects, were not included.

While cotton has a comparable energy use figure to wool (49MJ versus 46) it could be said that cotton demand for irrigation, fertilizer and pesticide means it leaves a heavier 'footprint' on the environment.

There was not enough data on linen production to run a comparison.
Reprinted in part from Country-Wide, New Zealand

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