Algae + CO2 = Biofuel
This is turning out to be New Scientist day! I found very cool article in yet another recent issue (Vol 192; No.2572).
Just as an aside…you’ll notice I chat about articles from New Scientist every once in awhile. Just so you know, this is definitely a magazine subscription I would HIGHLY recommend! Aside from a decent number of environmentally-themed articles, it offers up a wide variety of interesting science features and tidbits in general. It’s also a weekly publication, so it really helps you stay current.
After spending all day reading off a computer screen, I have to admit its pretty nice to actually read a real magazine as well!
Anyway…
The article in question this time is called From Smokestack to Gas Tank (click the link for an online preview of the article), and discusses the idea of using tanks of algae to filter nasty emissions from power plants. Not only does this have the potential to reduce greenhouse gas emissions, but apparently the algae themselves can then be harvested and turned into copious amounts of biofuel!
GreenFuel Technologies (Cambridge Mass.) has been testing a pilot-scale application of this concept at Redhawk Power (in Arizona).
So how exactly does this all work?
Essentially, exhaust gas from the power plant is bubbled through cylindrical upright tanks full of algae-laden water. The algae extract the CO2 from the exhaust and convert it to sugars via photosynthesis. Via further metabolism these sugars are then converted to oils and proteins.
Portions of the algal soup are continually removed and dried into algae cakes (yummm!!). The cakes are then repeatedly washed with solvents to extract the ‘algal oil’. This oil is then converted to biodiesel via transesterification and the remaining biomass is treated with enzymes, thereby converting starches into simple sugars. Ethanol can then be produced via the fermentation of these simple sugars.
Pretty cool!!
So far GreenFuel technologies has secured more than $18 million USD in venture capital funding, and they are hoping to have a 1 km2 (or larger) algae-farm-bioreactor online by 2009 at the Redhawk site.
According to GreenFuel’s Chief Technology Officer Isaac Berzin, an algae farm large enough to absorb all the CO2 from a 1000 megawatt power plant (which would likely need to span 8-16km2), could potentially produce 150 million litres of biodiesel and 190 million litres of ethanol per year!
Another company with similar plans is Greenshift (based in New York).
They are hoping to remove CO2 from the exhaust of a bioethanol plant using similar technologies. Apparently by adding the algal technology into the mix they should be able to improve the conversion of corn to ethanol from 1/3 to 2/3!
Almost makes me wonder why anyone would grow crops for ethanol in the first place! According to the article, algae have major advantages in that they don’t need strong sunlight for photosynthesis and require far less space (eg. 33 times more land is needed to grow rapeseed than the fuel-equivalent amount of algae). As if that isn’t ENOUGH - algae also don’t require freshwater or valuable farm soil!
Very very interesting stuff!
Once again, be sure to check out GreenFuel Technologies & Greenshift to learn more about what they are doing.
If you want to preview the New Scientist article be sure to check out the link given above.
Related sherpa articles: Biofuel From Bacteria
Technorati Tags: algae, biofuel, ethanol, biodiesel, GreenFuel Technologies, Greenshift, CO2, global warming, power plant, transesterification, greenhouse gas emissions, New Scientist
Written by Bentley on October 23rd, 2006 with
4 comments.
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sherpa2
#1. November 21st, 2006, at 4:24 PM.
I have read similar articles about the use of algae as CO2 scrubbers and subsequent fuel source. However, I also believe that we cannot slow down the rate of emissions fast enough to get us to a balancing point. We must look at ways to pull carbon dioxide and other greenhouse gases out of the atmosphere if we are to keep levels below the 400ppm threshold.
One suggestion is to develop huge oceanic algae farms, then to harvest those farms and transport the processed algae sludge (water extracted) to a polar region for freezing. This would lock the CO2 into sheets of ice (providing there is any ice left).
Using the algae for fuel only releases the CO2 back into the atmosphere making it a CO2 neutral initiative. Locking the algae into sheets of ice would remove the CO2 from the atmosphere. However, there could be a dual purpose initiative with some polar storage and some fuel production.