Friday, February 15, 2013

Is Biomass Green?

The Evidence is Mixed

Continuing the theme I started last week of looking at the unanticipated effects of technologies that most of us would assume are benign, I want to report today on several recent articles on biomass that also address some consequences that were not initially considered.  In this case, two of them point to issues I have heard about before (although not in the first flush of excitement about biomass), but the renewed coverage of the issues got my attention.  The third article, however, was new--at least to me.

The first of these articles carries the alarming headline "most biofuels are not green."  As always, the truth is more complicated.  The point of the article is that there are multiple interactions and several advantages and disadvantages of biofuels, depending on the circumstances.  It makes a difference to the net emissions savings whether the biofuels are grown on agricultural land (in which case, they can, of course, have a detrimental effect on food production) or whether forested land has to be cleared for biofuels production.  There can be other environmental effects as well, such as acidification of the soil, and pollution of lakes and rivers from runoff of fertilizer.  On the other hand, biomass production can, under some circumstances, help make desert land arable.

A related article delves more deeply into how to assess the availability of land for biomass production.  The article talks about the fact that proposals often talk about using "surplus land" for biomass production, yet, "We still have limited understanding of how much land is truly surplus and suitable for energy crop production,"according to Dr. Dauber, the lead author of the study.

The third article, however, was the one that really got my attention.  Increasing attention has been given recently to the use of algae as a source of biomass.  Some articles have speculated that algae-based biomass would avoid a lot of the agricultural concerns.  However, now concerns are being raised about algae-based biomass.  Again, there is an eye-catching title:  large-scale production of biomass made from algae poses sustainability concerns.  The concerns raised in this article include:  "the relatively large quantity of water required for algae cultivation; magnitude of nutrients, such as nitrogen, phosphorus, and CO2, needed for cultivation; amount of land area necessary to contain the ponds that grow the algae; and uncertainties in greenhouse gas emissions over the production life cycle." 

Once again, my guess is that we will find ways to increase biomass production, but we clearly must consider very carefully where and how we grow such crops.


1 comment:

  1. I had an interesting message from a friend regarding algae. Who knew I had someone who knew about this in my circle of friends! In his message to me, he named the relative, but since I can't be sure he'd want such information public, I've cut off the relative's name and am leaving his identity anonymous. He wrote that he had a relative who...

    "...was an algologist, though the profession has been changing its name to phycology, not sure why. His focus was on the taxonomy of Australian algaes, thus his special concern and knowledge of plant morphology. We had many discussions about the use of algae as an energy source and he always stressed to me the fact that algae is a very primitive form of plant life - so primitive that its reproductive system is far from the mature system of most all other living things.

    The point here is that algae does not reproduce true from generation to generation - the genetic structure of the plant is very fluid and changes rapidly over time. Therefore the scientific procedures which most folks are using to develop genetically identical strains of algae, the purpose of which, for example, might be to produce copious quantities of hydrocarbons as fuel, are bound to fail since the strain once it starts to reproduce in commercial quantities will naturally continually change and the desired trait will quickly be "diluted" away.

    Yet another fun dimension to "going green"."