Saturday, December 02, 2006

Bioplastics. A potential carbon sink?

Bioplastics, thats an interesting idea.

I think I might have mentioned this idea before but now there is a blog called biooutput with more on this and many other ideas.

I`m interested in what others think about biodegradable plastics from bio-feedstocks. My comment on the referenced post:

I`m curious as to why we want bioplastics to be bio-degradable.

It just seems to tempting to have non-biodegradable plastics from biological materials.

This would effectively be a co2 pump out of the atmosphere and into landfill. I guess i`d rather see tonnes of solid and but inert waste in dumps or in curculation than in the atmosphere.
I think that in the end we will have to develop significant industries that utilise atmospheric 
co2 and fix it in a solid form. We seem to be moving past the stage where reductions in emissions
 will prevent rapid climatic destabilisation but I think that at some point govornments will really 
start to act, if this does ever happen then bioplastics may play some role in bringing down co2 concentrations..

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At 4:50 AM, Blogger C. Scott Miller said...

Thanks for commenting on my blog. My BIOoutput Blog is meant to focus attention on the issues surrounding carbon sequestration and emissions.

To answer your questions...

1 - By making plastics biodegradable we don't need to constantly retrieve and actively recycle them - saving manpower and transport costs. They can be used to add nutrients (including carbon) back into the soil.

2 - When plastics are non-biodegradable, they wreak havoc to ecosystems they inevitably pollute. One big problem is the amount of plastic that ends up in the oceans. They kill brine and small fish which effects every level above them, including birds.

3 - In California, we consider landfills to be a major problem. First, we are quickly running out of acceptable space for them. Second, they emit CO2 and, worse, methane (which is 22 times more toxic a greenhouse gas than CO2). Our utilities have committed to a 20-year plan (RENEW L.A.) to convert our trash into ethanol and electricity without toxic emissions - drastically reducing our need for landfills.

Keep up the good work, Calvin.

At 11:32 AM, Blogger Calvin Jones said...

Hi Scott,

Thanks for the reply. I must say arguing against biodegradable products does make me wonder about my sanity. However, I think that I should give my thoughts there clearest representation so here are some comments on your comments.

1. ii) Interesting point about not havving to recover plastics to recycle, but I beleive this is done largely to recover large amounts of internalised energy...where will we get the energy for bioplastic production from? I imagine bioplastics are less energy intensive to produce...perhaps this tips the energy ballance.
ii)Good point. On the topic of carbon more later.

2. When you say polloute, do you mean leach chemicals? I imagine bioplastics could be designed not to leach toxic chemicals. Plastics are a problem for many reasons, perhaps it is worth distinguising between certain uses.

3.i) If you don't have space then I guess a biodegradable plastic is just what you are after.
ii)Not biodegradable plastics don't emitt methane or co2...biodegradable ones might. The methane is largely from food isn't it? I think most the methane is usually captured for the UK atleast. I guess the bioplastic concept as you see it goes along with incineration.

Finally: I'm still unsure of this idea, I think I could argue either side. The space for waste problem could be solved by increased recycling of bioplastics. My idea of sequestering carbon in landfill certainly dosent sound like an option in California...but perhaps elsewhere and perhaps bioplastics as building materials.

At 2:49 AM, Anonymous Anonymous said...

Scott's points are all well made.

We want to create marginal impacts on the natural environment in which we live. To minimise the "environmental impacts" over the complete "lifecycle" of a process. Academically - the study of these systems - and the chemistry/science - inputs/outputs involved is what is known as "LCA - "lifecycle analysis".

You (Calvin) seem to think "bioplastics" would be a good method of carbon sequestration/fixation? Scott rightly indicates the other problems caused by certain chemicals that in the bigger picture would make this unwise. It's unlikely that doing this would have the impact on atmospheric CO2 you desire anyway.

But to make a case that a single change like plastics, would make the real difference is not really the way. Since there is as much a feedstock supply issue here that really can only be changed through the use of renewable resources, and hence mitigate the CO2 generated from the inital production stage of fuels for instance. Therefore the need for bioplastics made from biomass is one of sustainability.

The only real solution is improvements in energy efficiencies coupled with partial reductions in consumption (as a consequence of new technology where possible).

My professional interest is in microwave-assisted chemistries that use less energy in the production stage. Intelligent design from the outset of "bioplastics" for instance to make them degrade naturally in the environment with negligable effects is the goal of "Green Chemistry". This sort of product the microwave-technology would ideally be used on - so the benefits of both work in tandem!

You could say I work at the intercept of Green Chemistry / Clean Technology / Sustainable Resourcing

You may wish to check out my site on the technology I refer to:




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