Tuesday, August 18, 2009

Algae Farming and it's Carbon

A few days ago, David Rush, @EcoEngineering over at Twitter, tweeted about Aquentium buying a New Mexico site for an Algae farm.

I responded with a comment about one line in the press release that looked funny to me. Here our conversation.

@EcoEngineering: Aquentium Announces 475 Acre Algae BioFuel Production Project - World Stock Wire (press release) http://bit.ly/mQWf1

Me: @EcoEngineering "Aquentium’s algae-based fuels will emit approximately two-thirds less CO2..." ??? shouldn't an algae system be GHG neutral?

Me: @EcoEngineering CO2 in at pond = CO2 out when it's burnt to product power/motion?

@EcoEngineering: Thx @gnoll110 So your saying more efficient algea system=more fuels to burn=more GHG. Good point!

Me: @EcoEngineering No, that if they don't feed the algae with coal/oil & make the setup using algae fuel, how can it not be GHG neutral?

Me: @EcoEngineering that is, as long as the setup is made using algae fuel, how could if be GHG positive? (all C from the air to start with)

Me: @EcoEngineering isn't the Atlantic Conveyor sinking and depositing huge amount of C (dead algae) of ocean floor how bioshere get ride of C?

Me: Carbon accounting strike me as simplistic, quantitative (at the expense of qualitative) and proven to creative accounting. Very spinable.

@EcoEngineering: Sorry @gnoll110 I think we're on different pages.

@EcoEngineering: @gnoll110 Send me a little more info so I can formulate a response please.

The above comments where made in reference to on-going operations. In a reply I've included the 'build' carbon too. I think a working Algae farm should be greenhouse gas (GHG) negative to start with and over time become slightly GHG positive once all fossils fuel usage (as a fuel) is replaced.

My reply to David and anyone who's interested.

Second attempt at a response. First one was turning into Ben-Hur.

Here is how I see it.

All the carbon in algae come from the atmosphere in the first place, so any burning process no matter how efficient or inefficient should be neutral at worst. Indeed an inefficient burn that produced an algae-char replacement for bio-char (charcoal) could make the process helpfully GHG negative.

Now lets switch to the energy front.

I going to assume that the total energy production over the life of the algae farm & associated processing chain is greater than the total energy consumption involved in building and operation said algae farm & processing chain. (if this is not true what we really got is most likely a coal to oil plant, and a different ball game).

Given the algae farm is a net energy producer, I'm going to assume these guys eat their own dog food and this means:
* they built the farm & chain using energy from the last one they built and
* that operational energy will be drawn from the farm & chain's previous operations

If the above is true, the carbon footprint is the physical carbon embedded in making the steel and other manufactures (ie coking coal needed to make the steel).

In reality this is likely not to be true. I.e. the bio-mass oil produced is likely to be used for transport, while the chain is operated by gas fired electricity (or some other non transport grade energy source). I'm not including this in my logic because this factor is highly situational.

Back to the carbon front.

Assuming that the net energy produced is going to replace the 'worst carbon energy source'. Isn't this what emission trading systems (ETSs) do? Act as a pricing mechanism to transfer resources between players. (I'm not including net changes to total human energy demand, that shouldn't effect the carbon & energy budget of individual artefacts).

Shouldn't any carbon cost of building and operating the farm & chain be far less than the carbon cost of building/continued operation of the low cost 'worst carbon energy source' that it replaces.

Granted the shut down of the low cost 'worst carbon energy source' won't happen on the day the algae farm & processing chain go operational. But the low cost high carbon alternative won't start either. Over time (and assuming governments don't corrupt the working of an international ETS system that includes an escalating carbon cost) the 'worst carbon energy source' will get replaced.

*** A working International Climate Change Agreement that a working International ETS system would be based on is a PRE-CONDITION to successfully fighting Global Warming (what the Australian Labor Party (ALP) is pushing atm does not meet these conditions and thus is a waste of current effort and may have big opportunity costs) ***

If the above happens, isn't an algae farm going to be GHG negative. The better the gross energy production:gross energy cost ratio (for the total life cycle), the more GHG negative the algae farm should be.

At some future date.

Repeating the no build/closures of 'worst carbon energy source' cycle over time would get you to the situation where the next algae farm itself becomes a 'worst carbon energy source'. One would hope that the base carbon cost is building an algae farm without the 'worst carbon energy source' offsets (offset = 0), is low enough that at that mythical future date when the human world as run by algae farm, the carbon load will be well within the Earth's ability to absorb (on an annual basis).

Update: If you get metal recycle percentages increasing, the net energy production would drop. but fossil fuel usage (as a feed stock, not a fuel) would drop too. This would close the introduction of fossil fuel (new) carbon into the carbon cycle down even more. More new carbon now (before the peak carbon), less new carbon later (at and after peak carbon): a good thing.

The end.

David, peer review to you hearts content. This in just a thought experiment on my part. Hope people find it helpful.