Can Microalgae Solve Global Fuel and Environmental Challenges?

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
Sign up Log in
566 replies · 249K views
Thank you for keeping on these developments Ivan!
 
Earth sciences news on Phys.org
According to the calculations by Dr. David JC MacKay in his book "Sustainable Energy – without the hot air", it looks like CO2 enriched algae is about 20 times better than corn based ethanol per square meter. The numbers were:

Bioethanol from corn: 0.2W/m2
Bioethanol from sugar cane: 1.2W/m2
CO2 Enriched Algae Biodiesal: 4W/m2

The calculations are on pages 284-285

You can download the whole book here:
http://www.withouthotair.com/download.html"
Or go straight to the html page here:
http://www.inference.phy.cam.ac.uk/withouthotair/cD/page_284.shtml"

The printed version actually says 0.02 for corn but there is a errata entry in the html version that says:

Page 284 Bioethanol section: "0.02 W/m**2" should be "0.2 W/m**2".

To make this section more informative I would rewrite
it thus:

1 acre produces 122 bushels of corn per year, which makes
122 x 2.6 US gallons of ethanol, which at 84000 BTU per gallon would
mean a power per unit area of {0.2 W/m^2}; however, the energy
inputs required to process the corn into ethanol amount to
83,000 BTU per gallon; so 99% of the energy produced is used up by
the processing, and the net power per unit area is about
{0.002 W/m^2}. The only way to get significant net power from the
corn-to-ethanol process is to ensure that all co-products are
exploited; including the energy in the co-products, the net power per
unit area is about 0.05 W/m^2.
 
Last edited by a moderator:
joelupchurch said:
1 acre produces 122 bushels of corn per year, which makes
122 x 2.6 US gallons of ethanol, which at 84000 BTU per gallon would
mean a power per unit area of {0.2 W/m^2}; however, the energy
inputs required to process the corn into ethanol amount to
83,000 BTU per gallon; so 99% of the energy produced is used up by
the processing, and the net power per unit area is about
{0.002 W/m^2}. The only way to get significant net power from the
corn-to-ethanol process is to ensure that all co-products are
exploited; including the energy in the co-products, the net power per
unit area is about 0.05 W/m^2.

The net-net yield of the corn-ethanol process is hotly debated. Many people argue that the efficiency of the complete process is zero or worse - meaning [as you know] that we derive no benefit whatsoever, or we are even losing energy! Most standard sources seem to place the processing efficiency at about 30%. But one has to be careful about which number is being cited. I tend to refer to the "net yield" as the yield after including energy for processing. Then there is what I tend to refer to as the net-net yield, which includes the fuel for tractors and land management, hidden energy costs in the fertilizers, soil supplements, pesticides, antifungals, or whatever else might be used, the energy for pumping water, etc.
 
When I applied MacKay's numbers of 60 grams of CO2 per square meter and multiplied by the 10,000 tons of CO2 per day produced by a 500MW coal plant and came up with 17SqKm of Algae. That comes out to a Algae field 4km on the side, which doesn't sound too bad, if you assume a sunny climate with cheap real estate.

Of course, sunny and cheap usually means a desert, so the water consumption situation needs to be analyzed.

Anybody want to calculate how much biodiesel 17 SqKm of algae would produce?

I find this interesting, since if the law starts requiring CCS for coal and natural gas plants, then the biodiesel would offset part of the capture cost and avoid the sequestration part entirely. There was a recent Harvard study, "Realistic Costs of Carbon Capture", that estimated $35 to $70 per ton of CO2 capture.

http://belfercenter.ksg.harvard.edu/publication/19185/realistic_costs_of_carbon_capture.html

Since the Algae only need 10% CO2, it isn't clear what you need to do to the output of the coal plant before you feed it to the algae if you have stack scrubbers. I should point out that the biodiesel produced isn't technically renewable, since it is produced using the carbon from the coal and not from the atmosphere.

I don't think CCS is practical, or that the continued use of coal is desirable, but I always like to check the math.
 
Ivan Seeking said:
The net-net yield of the corn-ethanol process is hotly debated. Many people argue that the efficiency of the complete process is zero or worse - meaning [as you know] that we derive no benefit whatsoever, or we are even losing energy! Most standard sources seem to place the processing efficiency at about 30%. But one has to be careful about which number is being cited. I tend to refer to the "net yield" as the yield after including energy for processing. Then there is what I tend to refer to as the net-net yield, which includes the fuel for tractors and land management, hidden energy costs in the fertilizers, soil supplements, pesticides, antifungals, or whatever else might be used, the energy for pumping water, etc.

It seems to me MacKay's numbers are pretty close to 30%. He assume a gross of .2 w/m2 and a net of .05w/m2 which is a 25% net yield.

I would like to point out that from a climate perspective corn based ethanol makes little sense, even if the economics are better than break even. It can only offset the CO2 going into the corn, not the CO2 produced by the infrastructure to raise the corn. It seems to me that we would come out ahead on CO2 if we switched more of our vehicle fleet to compressed natural gas, since it produces much less CO2 per KWH.
 
joelupchurch said:
When I applied MacKay's numbers of 60 grams of CO2 per square meter and multiplied by the 10,000 tons of CO2 per day produced by a 500MW coal plant and came up with 17SqKm of Algae. That comes out to a Algae field 4km on the side, which doesn't sound too bad, if you assume a sunny climate with cheap real estate.

Of course, sunny and cheap usually means a desert, so the water consumption situation needs to be analyzed.

Anybody want to calculate how much biodiesel 17 SqKm of algae would produce?
See up thread per Ivan: conservatively 2000 GPAY . 17 sq km = 4200 acres, or 8.5 million gallons per year.

I find this interesting, since if the law starts requiring CCS for coal and natural gas plants, then the biodiesel would offset part of the capture cost and avoid the sequestration part entirely.
As you noted, many of those coal plants are located where there isn't good sun.
 
Maybe you could use some concentrators to get more sunlight for the algae.

Down here in Florida we have plenty of sun. Will algae work in saltwater? How about partially processed sewage?

Here is a new announcement from a company called Origin Oil about a method to "milk" the oil out of the algae without harvesting it.

http://www.originoil.com/company-news/originoil-announces-breakthrough-process-for-live-algae-oil-extraction.html"
 
Last edited by a moderator:
joelupchurch said:
Maybe you could use some concentrators to get more sunlight for the algae.

My impression is that this can be done in areas that are low on light. But more significant is the length of the day, and temperature. Keeping the algae cool in full light is one of the challenges for bioreactor designs. In the Aquatic Species Program, the winter temperatures are what killed the blooms [one example of why open systems can't work, imo]. There was plenty of light, but it was simply too cold.

As for the length of day, obviously the energy input to the system is reduced by having shorter days. IIRC from reading the literature current a couple of years ago, algae can be productive for up to about sixteen hours a day if light is available. Of course this led many of the fringe developers to provide artificial lighting, which is obviously a losing proposition!

Down here in Florida we have plenty of sun. Will algae work in saltwater?

Yes. There are many varieties of salt-water algae, and there are some known to be good producers of oil.

How about partially processed sewage?

Yes. Algae has the potential to treat many types of waste including industrial, municipal, and agricultural waste products. In the case of agriculture, the controlled growth of algae could be used to remediate runoff that creates dead zones in the ocean. The runoff is typically high in nitrogen, which algae love. In fact it is the uncontrolled growth of algae that depletes the oxygen needed for aquatic life. We could control this, solve the problem, and produce fuel as a consequence.
 
Last edited:
Looks like the algae phase may be entirely unnecessary.
http://www.cbsnews.com/stories/2009/07/27/tech/cnettechnews/main5190810.shtml
The Cambridge, Mass.-based company on Monday is disclosing its technology and business plans for making ethanol and other liquid fuels from genetically-manipulated microorganisms that have been fed only sunlight and carbon dioxide.
 
Skyhunter said:
Looks like the algae phase may be entirely unnecessary.
http://www.cbsnews.com/stories/2009/07/27/tech/cnettechnews/main5190810.shtml

Sounds great! We will have to see if the reality meets the hype. [a news release is a far cry from years of real testing, as we have with algae]

One issue that bothers me is that they make ethanol. When one considers the offset in energy and efficiency as compared to diesel, 25,000 gallons of ethanol is probably worth about 10,000 gallons of biodiesel. This means added distribution costs. There is also the problem of being incompatible with heavy trucks and aircraft. Recall that an algae-jatropha oil mix was recently tested in a 737. It passed with flying colors.
 
Skyhunter said:
Looks like the algae phase may be entirely unnecessary.
http://www.cbsnews.com/stories/2009/07/27/tech/cnettechnews/main5190810.shtml

The Cambridge, Mass.-based company on Monday is disclosing its technology and business plans for making ethanol and other liquid fuels from genetically-manipulated microorganisms that have been fed only sunlight and carbon dioxide.

Well fundamentally they've haven't changed anything in that statement, just the DNA. Algae is essentially "microorganisms that have been fed only sunlight and carbon dioxide". The issues of temperature, invasion by other strains in open systems, and in general the issues separation of the hydrocarbon product, large water requirments and a dedicated CO2 sources still remain. The only stand out part of the article to my mind is
The company estimates it can produce 20,000 gallons of fuel per acre per year, which is far more than existing processes or others under development.
As that is indeed far better (10 to 2X better) than processes with natural strains, if they can do it.
 
Ivan Seeking said:
...

One issue that bothers me is that they make ethanol. ...
Maybe not:
Cnet Tech News said:
...It claims that it can make its end product - ethanol or another hydrocarbon fuel - ...
 
mheslep said:
Maybe not:

To me, that is key. Ethanol makes no sense on so many levels that to me it hardly seems worth consideration in any case [including cellulosic ethanol], but if they can make biodiesel, that would be another matter. At the least, we will need biodiesel in addition to other options.

Key also is that the claim of quantities is based on ethanol. In order to judge fairly, we need to know the rates and costs of production for biodiesel feedstock.

I think most serious people who have looked at algae expect bioengineering to play a key role. While it may be possible to convert now using natural strains, the question is, at what cost? Whereas natural algae fuels and cellulosic ethanol are sometimes referred to as second generation fuels - corn-ethanol and soy-biodiesel are first generation fuels - this and other similar work may be examples of third generation fuel technologies.

The best news of all is that this is beginning to look like a horse race! I think we have seen at least a half dozen approaches to advanced fuel technolgies.
 
Last edited:
This just popped up:
Given that the US Marines burn through "h[PLAIN]http://www.guardian.co.uk/environment/2009/aug/13/us-marines-afghanistan-fuel-efficiency"[/URL] gallons of fuel a day in Afghanistan (alone), they are well motivated to find ways of reducing the logistics tale. Turns out one of the things they (the DoD) have been working on is algae, made in the battlefield no less:
http://www.independent.co.uk/news/b...powered-soldiers-in-the-pipeline-1766017.html
The Independent said:
Can Darpa now score another double success by changing how both the military and civilian worlds consume and produce energy?
...
With the expense of convoys and guards thrown in, the cost of a gallon of fuel used at the front can range from $15 to several hundred dollars, says the same report.
...
It now wants to develop inexpensive diesel and jet fuel from algae that could be produced in the battle zone. All three programmes include the aim of accelerating the manufacture of any new product by private companies, from whom the military could buy.
...
Others say Darpa's goals can be unrealistic. Darpa wants to reduce the current cost of algae-based fuel from $20-$30 per gallon down to $3. In January, Darpa awarded contracts worth up to $34.8m to two companies to produce aviation fuel at $3 a gallon from algae. The competitors are General Atomics, best known for its Predator drone, and Science Applications International. They have three years to do it. Some doubt these companies – or any company – can achieve that goal.

Anyone care to comment on The Independent's '$20-$30' per gallon figure? It seems inappropriate to call it the 'current' figure, and not the theoretical figure given no large scale production (yet).

I also see, however, that at least half of the fuel goes to running field generators at forward bases. Now that is a perfect case for one of these small portable nuclear designs running around, say a 15ton 25 MW design that could be flown in by C130, and not biofuel.
 
Last edited by a moderator:
mheslep said:
Anyone care to comment on The Independent's '$20-$30' per gallon figure?

That is the number that I see bantered about wrt some of the ridiculous designs for bioreactors out there. This is what I'm talking about when I say that the cost per unit area is so critical. We aren't growing tomatoes; we can't do this using high-end bioreactor designs or commercial greenhouses, and we don't need to.

The Aquatic Species Program estimated a cost of about $2 per gallon. If we factor in inflation, $3 is probably reasonable, and DARPA landed precisely where I did on price expectations. In the end I used a retail price of 3$ as a basis and tried to drive the production costs accordingly.
 
Last edited:
I never thought I'd see myself saying this...

¡¡¡GO ALGAE GO!
 
I'm not really familiar with all the processes needed to go from algae to a ready to use fuel. And most of what I've been reading speaks of getting processes that can be done on a large scale.

So, would it be possible to make small scale systems to use, say on, a farm?
 
dlgoff said:
I'm not really familiar with all the processes needed to go from algae to a ready to use fuel. And most of what I've been reading speaks of getting processes that can be done on a large scale.

So, would it be possible to make small scale systems to use, say on, a farm?

In principle, yes, but there are a number of issues. The existing methods of processing the algae, which includes dewatering with centrifuges, and oil extraction with presses or supercritical extraction methods, are problematic. While it is possible to make oil now this way, no one has been able to do it at a price that is competitive with petrodiesel [just last night I heard the price of $8 per gallon mentioned in this context]. However, there are a number of alternatives being pursued, not the least of which eliminate the need for the centrifuges and the presses altogether. It is just a matter of time until we have better options - these problems are more along the line of engineering problems, not fundamental. It is also likely that growers will license the use of bioengineered algae, rather than using naturally occurring strains.

In principle this could be done at any scale desired, but it wouldn't be cost effective.

One issue lurking in the background is the use of homemade fuels that do not meet the national fuel standards. If one is making less than about a million gallons of fuel a year, the price of testing and approval is cost prohibitive. Homemade fuels have been an issue esp since they gave biodiesel a bad name early on. Many people are running vegetable oil, which is not biodiesel and does not meet federal fuel standards. Biodiesel can be made from almost any vegetable oil, but it is chemically altered and the glycerin contained in the oil is eliminated as a precipitate. Properly made biodiesel does meet Federal fuel standards.

A bit of luck: Of all vegetable oils that could be used, it turns out that algae produce oils that, when converted to a fuel, produce a very clean fuel in terms of emissions. This is true because they are low in saturated fats.

Late edit: I would have to check my notes, but I probably should have said that in order for the required federal testing and approval to be cost effective, one needs a batch of a million gallons of fuel for each test. In any event, it is not cost effective for very small producers, and I suspect the EPA will eventually start pursuing those using illegal fuel.
 
Last edited:
Ah! Hahahaha! A car with Ivan's name all over it:

http://gas2.org/2009/09/01/150-mpg-algaeus-plug-in-prius-to-cruise-coast-to-coast-on-algae-fuel/"
September 1st, 2009

algaeus.jpg


In an effort to drum up attention and support for their algae-based biofuel, http://www.sapphireenergy.com/" has announced they will conduct a coast-to-coast journey in their “Algaeus” plug-in hybrid. Part electric hybrid, part biofuel vehicle, Sapphire claimes the Algaeus will get 150 miles per gallon from its hybrid/biofuel drivetrain.

The Algaeus will visit 10 cities, starting in San Francisco on September 8th and ending in New York City on the 18th.

:!)
 
Last edited by a moderator:
OmCheeto said:
Ah! Hahahaha! A car with Ivan's name all over it:



:!)
Hmm, they make gasoline from algae? Not BD or ethanol?
 
mheslep said:
Hmm, they make gasoline from algae? Not BD or ethanol?

I read Sapphire Energy's press releases and the information on their website and it isn't really clear what they are doing. They imply that have a product that can refined into gasoline. Here is an excerpt from the press release:

Sapphire Energy is providing the fuel that is a complete drop-in replacement containing a mixture of hydrocarbons refined directly from algae-based Green Crude, extracted through Sapphire’s proprietary process, and fossil fuels to afford a high octane gasoline.​

It sound like whatever fuel they are using is actually blended with regular gasoline, but it doesn't sound like ethanol.

I found a longer article about Sapphire here:

http://www.xconomy.com/san-diego/2008/11/13/sapphire-energy-backed-by-bill-gates-tries-to-tone-down-the-hype-as-it-makes-gasoline-from-algae/"

One paragraph caught my eye:

After determining that their best prospect was to become a producer of gasoline and diesel fuels, Pyle says they set out to identify the best green technologies for making it. They found what they were looking for in the research of Stephen Mayfield, an algae biologist at The Scripps Research Institute in La Jolla, and Steven Briggs, a professor of cell and developmental biology at UC San Diego.​

I checked Mayfield's and Briggs' publications, but nothing seemed relevant at first glance.
 
Last edited by a moderator:
I was in contact with Briggs and I thought he was focused on the standard issues, but he also said that most of the information was proprietary. I also remember him saying that something should be hitting the market in two to three years - right about now.

He wouldn't be publishing papers for the work that was privately funded.
 
Darpa's looking to hand out some Algae money for those that can make JP-8 out of it.

BioFuels - Cellulosic and Algal Feedstocks
BAA
http://www.darpa.mil/STO/solicitations/baa08-07/index.html
 
Last edited by a moderator:
mheslep said:
Darpa's looking to hand out some Algae money for those that can make JP-8 out of it.

BioFuels - Cellulosic and Algal Feedstocks
BAA
http://www.darpa.mil/STO/solicitations/baa08-07/index.html

They are also looking at biodiesel:
http://blogs.wsj.com/environmentalcapital/2009/09/08/green-force-us-militarys-interest-in-algae-fuel-grows/"
The logistics for supplying troops in Afghanistan is so horrendous that even if biodiesel would cost them 20 dollars a gallon, it might be a bargain. They are also looking into portable nuclear power plants.

P.S. I wonder if we should request another forum for Climate Engineering and move topics like this and painting roofs white over there. A lot of topics like Wind Turbines, Solar Power, Biofuels, CCS and such are being done by commercial firms and the work never appears in peer reviewed literature.
 
Last edited by a moderator:
joelupchurch said:
They are also looking at biodiesel:
http://blogs.wsj.com/environmentalcapital/2009/09/08/green-force-us-militarys-interest-in-algae-fuel-grows/"
They being Darpa? I've not seen any solicitations from them other than the JP one.
They are also looking into portable nuclear power plants...
They should be, but I am not aware that they are. Do you have news on that? The Army had a program on portable nuclear decades ago and abandoned it.
 
Last edited by a moderator:
mheslep said:
They being Darpa? I've not seen any solicitations from them other than the JP one.

From your link they certainly appear to be planning on making diesel.

It now wants to develop inexpensive diesel and jet fuel from algae that could be produced in the battle zone. All three programmes include the aim of accelerating the manufacture of any new product by private companies, from whom the military could buy.

I am pretty sure the base oils for jet fuel is the same as that for biodiesel; the only difference should be the strain of algae grown. It was implied that in the Virgin airlines test with the 737 that they were running raw algae oil and not even fuel that had been transesterified, but that was never made clear in what I read.

There are some algal oils that cannot be transesterified that may be suitable as a fuel in raw form for that very reason. The glycerides cannot be reacted out because there are none.
 
Last edited:
Ivan Seeking said:
From your link they certainly appear to be planning on making diesel.
In the Darpa solicitation link the word diesel does not appear. The WSJ blog link from Joel mentions the US DoD is certainly looking at BD.
 
mheslep said:
They being Darpa? I've not seen any solicitations from them other than the JP one.
They should be, but I am not aware that they are. Do you have news on that? The Army had a program on portable nuclear decades ago and abandoned it.

Right now, they are just talking about it. There are no actual development programs that I know of. Obviously, they can't do any development without funding from Congress. I tried to watch the presentation by Col. Paul Roege "Nuclear Energy for Military Applications", but the quality of the video was poor.

http://www.aml.umd.edu/news/news_story.php?id=2832"

I actually looked at some papers from the old program you mentioned, since I was interested about the parts about using Ammonia as a vehicle fuel.
 
Last edited by a moderator: