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Algae + CO2 = Biofuel

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

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Written by Bentley on October 23rd, 2006 with 4 comments.
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4 comments

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Get your own gravatar by visiting gravatar.com Justin Lansford
#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.

Get your own gravatar by visiting gravatar.com sherpa2
#2. November 21st, 2006, at 4:39 PM.

Hi Justin,
Thanks for sharing your thoughts. I definitely understand what you are saying re: the “neutral” advantage of algal biofuel technologies. Obviously they would be much mure useful if we weren’t already in a heap of trouble.

That being said, I think this option (if it is indeed feasible on a large scale) provides a better alternative for producing biofuels, than say growing fields of corn – and burning biofuels for energy is obviously better than burning fossil fuels (neutral is better than increases).

Your idea for freezing the algae sounds interesting, so long as all that shipping didn’t result in massive CO2 emissions.

Anyway – thanks again for your thoughts. Its a very interesting topic for discussion!

B.

Get your own gravatar by visiting gravatar.com Justin Lansford
#3. January 24th, 2007, at 2:27 PM.

Thanks sherpa2 for your reply. The other concern I have about bio-fuels is that my current understanding is that it takes energy to convert the bio-source into a fuel-source and the CO2 release caused by the generation of that energy pretty much nullifies the advantages of using the bio-fuel. It does get us off the foreign oil dependency, so there are some political advantages. But speaking strictly from an environmental prospective, it doesn’t do a heck of a lot. Please correct me if my understanding is off base.

Get your own gravatar by visiting gravatar.com Bentley
#4. January 24th, 2007, at 5:57 PM.

Hi again Justin,
I think your ‘concern’ is certainly justified – obviously there isn’t too much point creating an alternative fuel source if it’s just going to end up using more energy than it creates. In my humble opinion the idea of growing agricultual crops for the purpose of producing biodiesel etc seems a little bit ‘off the mark’. Aside from all the fossil fuel etc needed to grow the crops, there is also the concern that such practices will have an impact on global food supplies (land being used for biofuel crops rather than food crops).

Although it’s still in it’s infancy, I think the algae biofuel concept is much more sound. You can create your algae farms on land that has no agricultural value, it is MUCH more space efficient (ie far higher productivity per unit area), uses far less water (in fact, typically seems to use salt water), among several other advantages.

If algae biofuel technology turns out to be as productive (on a large scale) as the preliminary trials seem to be showing, there would be a HUGE environmental advantage over petroleum. The algae are capturing carbon that already exists in the atmosphere and thus there would be no net increase in carbon when it is burned as fuel (unlike traditional oil which releases carbon that’s been locked up underground for millions of years. Of course there will be energy required to produce the algae biofuel but I can’t imagine it being even remotely as much as is required to pump and ship oil all over the world (not even considering the impact of the locked CO2 released when burning petroleum).

Anyway, thanks again for sharing your thoughts Justin. Hope my attempt at an explanation of my line of thinking makes some sense.

Cheers

Bentley

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