Friday, March 07, 2008

Can biofuels help reduce greenhouse emissions?

The answer, from a recent CSIRO study (pdf), appears to be yes - unless it's from a plantation that was established by clearing forest.


The study compared total life-cycle emissions from biofuels from various sources with diesel. Fuel from canola has 49% lower emissions over its life cycle than diesel and, for a waste product such as used cooking oil, emissions can be 87% lower than diesel.


However, total life-cycle emissions from biofuels derived from palm oil plantations established by clearing rainforest or swamp forest are up to 21 times higher than diesel.


The problem is that some biofuels do indeed come from these sources.


The CSIRO report points to other studies that have estimated that a substantial proportion of international palm oil production is established by clearing - and often burning - these forests in Indonesia and Malaysia, which together supply 83% of the world's palm oil:
  • It has been estimated that in Malaysia nearly half of all new oil palm plantations involve deforestation, with 87% of deforestation between 1985 and 2000 due to oil palm expansion.
  • From 1982 to 1999, about 16,000 square miles of Indonesian tropical rainforest was converted to plantation. Oil palm plantations were responsible for at least 44 percent of that rainforest loss.

And although palm oil hasn't so far been a major source of biofuels, that may slowly change:

with growing demand for biodiesel, especially in Europe, with increasingly large suggested as well as mandatory targets, it has been observed that it is unlikely production will be able to meet future demand without the use of palm oil as a feedstock.

It seems that biofuels do have the capacity to lower greenhouse emissions from transport. But whether their contribution will be good, bad or ugly depends critically on where they come from.

It's true: oils ain't oils.

3 comments:

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wclevenger@gmail.com said...

Forgive me if I'm just reading the paper wrong. But it seems that to get to that 21 number you have to compare the one time cost of clearing forest with the yearly benefit of replacing fossil fuel use.

That same piece of land should be able to produce biofuels for years to come, eventually offsetting that
initial carbon cost.

Global warming is a long term problem and a solution that takes 10-20 years to reduce net carbon release seems reasonable in that context. Especially when compared with the multi-million year cycle of fossil fuel renewal.

Interested in your thoughts.

-Will

David Jeffery said...

Will, I think you are reading the paper wrong. To get that figure, they assumed that the palm plantation would produce palm oil for 50 years and spread the emissions from clearing over 50 years. Ie, the net benefit at the end of 50 years of getting palm oil is still hugely negative.

They have a chart with clearing emissions spread over different periods so, if you were interested, you could probably play around with their numbers and see how long it would take to make up for the clearing by the lower 'tailpipe' emissions from biofuels. My guesstimate: centuries.