Exploring Microalgae as Solutions to Global Fuel Issues

[OmCheeto]

Oilgae has links to all of the information that you could want. There are no simple answers, but many different approaches to each aspect of the process can be found.

We hit a bit of a delay with the company but hope to be back on track shortly.

Bio-engineering the algae seems like a good idea. I see that they have some that are 40% lipids by weight already. Sounds like you could almost pump it raw into an ICE and drive around town. Might smell like a dirty old pond instead of freedom fries running down the road, but what do I care. It's better than the smell of napalm. Unless of course you love that kind of thing...

 

[Dale]

Ivan can probably comment more, but I believe that the process of getting biodiesel from algae is essentially you compress it really hard and squeeze the oil out, then you do some minor processing like filtering and additives. No fermentation or distillation or anything like that required.

My understanding is that most of what is left is protein suitable for animal feed.

 

[baywax]

Ivan can probably comment more, but I believe that the process of getting biodiesel from algae is essentially you compress it really hard and squeeze the oil out, then you do some minor processing like filtering and additives. No fermentation or distillation or anything like that required.

My understanding is that most of what is left is protein suitable for animal feed.

Sounds like a win win arrangement. Unless you happen to be algae.-(

 

[Ivan Seeking]

Methods of extraction include but are not limited to:
1. Expeller/Press
2. Hexane solvent oil extraction
3. Supercritical Fluid extraction
4. Enzymatic extraction
5. Ozmotic shock
6. Ultrasonic assisted extraction

The residual mash is touted as a high quality feed.

A note from Zapper:

Algae could one day be major hydrogen fuel source

http://www.anl.gov/Media_Center/News/2008/news080401.html

 

[Ivan Seeking]

The algal oil is then reacted to make biodiesel through a low-energy process called transesterifcation.

What is transesterification?

The process of converting vegetable & plant oils into biodiesel fuel is called transesterification, and is fortunately much less complex than it sounds.

Transesterification refers to a reaction between an ester (Ester – from Wikipedia) of one alcohol and a second alcohol to form an ester of the second alcohol and an alcohol from the original ester, as that of methyl acetate and ethyl alcohol to form ethyl acetate and methyl alcohol ( see also interesterification – Interesterification – from Cyber Lipid) . Chemically, transesterification means taking a triglyceride molecule or a complex fatty acid, neutralizing the free fatty acids, removing the glycerin and creating an alcohol ester. This is accomplished by mixing methanol with sodium hydroxide to make sodium methoxide (Sodium Methoxide – from Great Vista Chemicals, Sodium Methoxide MSDS – JT Baker) . This liquid is then mixed into vegetable oil. The entire mixture then settles. Glycerin is left on the bottom and methyl esters, or biodiesel, is left on top. The glycerin can be used to make soap (or anyone of 1600 other products) and the methyl esters is washed and filtered.

Transesterification is not a new process. Scientists E. Duy and J. Patrick conducted it as early as 1853. One of the first uses of transesterified vegetable oil was powering heavy-duty vehicles in South Africa before World War II.

Transesterification of Algal Oil into Biodiesel

Transesterification of algal oil is normally done with ethanol and sodium ethanolate serving as the catalyst. Sodium ethanolate can be produced by reacting ethanol with sodium. Thus, with sodium ethanolate as the catalyst, ethanol is reacted with the algal oil ( the triglyceride) to produce bio-diesel & glycerol. The end products of this reaction are hence biodiesel, sodium ethanolate and glycerol.[continued]

http://www.oilgae.com/algae/oil/biod/prod/prod.html

 

[baywax]

This is from a resourceful website (no pun intended)

8. Talking practically, is it feasible to produce biodiesel from algae on a large scale?

Theoretically, biodiesel produced from algae appears to be the only feasible solution today for replacing petro-diesel completely. No other feedstock has the oil yield high enough for it to be in a position to produce such large volumes of oil. To elaborate, it has been calculated that in order for a crop such as soybean or palm to yield enough oil capable of replacing petro-diesel completely, a very large percentage of the current land available needs to be utilized only for biodiesel crop production, which is quite infeasible. For some small countries, in fact it implies that all land available in the country be dedicated to biodiesel crop production. However, if the feedstock were to be algae, owing to its very high yield of oil per acre of cultivation, it has been found that about 10 million acres of land would need to be used for biodiesel cultivation in the US in order to produce biodiesel to replace all the petrodiesel used currently in that country. This is just 1% of the total land used today for farming and grazing together in the US (about 1 billion acres). Clearly, algae are a superior alternative as a feedstock for large-scale biodiesel production.

In practice however, biodiesel has not yet been produced on a wide scale from algae, though large scale algae cultivation and biodiesel production appear likely in the near future (4-5 years).

See also: Widescale Biodiesel Production from Algae – Michael Briggs, University of New Hampshire

http://www.castoroil.in/reference/plant_oils/uses/fuel/sources/algae/biodiesel_algae.html

The Engine Manufacturer's Association has put out some interesting information about what forms of Biodiesel will pass regulatory requirements. Here are the conclusions from the PDF on their site with regard to these hurtles.

Conclusions
· Depending on the biomass feedstock and the process used to produce the fuel,
B100 fuels should meet the requirements of either ASTM D 6751 or an approved
European specification.
· Biodiesel blends up to a maximum of B5 should not cause engine or fuel system
problems, provided the B100 used in the blend meets the requirements of ASTM
D 6751, DIN 51606, or EN 14214. Engine manufacturers should be consulted if
higher percentage blends are desired.
· Biodiesel blends may require additives to improve storage stability and allow use
in a wide range of temperatures. In addition, the conditions of seals, hoses,
gaskets, and wire coatings should be monitored regularly when biodiesel fuels
are used.
· Although the actual loss will vary depending on the percentage of biodiesel
blended in the fuel, the net effect of using B100 fuel is a loss of approximately 5-
7% in maximum power output.
Page 6 of 6
· Neat biodiesel and biodiesel blends reduce particulate, HC and CO emissions
and increase NOx emissions compared with petroleum-based diesel fuel used in
an unmodified diesel engine. Neither B100 nor biodiesel blends should be used
as a means to improve air quality in ozone non-attainment areas.
· Biodiesel fuels have generally been found to be nontoxic and are biodegradable,
which may promote their use in applications where biodegradability is desired.
· Individual engine manufacturers determine what implications, if any, the use of
biodiesel fuel has on the manufacturers’ commercial warranties.
· Although several factors affect the cost of biodiesel fuel, its average cost
exceeds that of petroleum-based diesel fuel. The relative cost of converting an
existing fleet to biodiesel blends, however, is much lower than the cost of
converting to other alternative fuel.
DATED: February 2003

http://www.enginemanufacturers.org/admin/library/upload/297.pdf

 

[Ivan Seeking]

Many of these issues have been or are being addressed daily. It depends on the company. For example, a buddy just bought a new Ford truck that is rated for B100. Synthetic materials make moot many of the concerns about seals and other soft components, but one certainly has to check with the manufacturer for any given engine before using strong mixes of biodiesel. Many people claim B20 as a safe limit.

Generally it is claimed that the superior lubrication provided by biodiesel as compared to petrodiesel offsets the slight reduction in the energy density [In either case, the paper is from 2003, and the price of fuel has gone up by 400% since then]. In support of this claim is the fact that using a B2 is as good as adding sulfur for lubrication, which is known to be true, but I have never checked to see if the mileage claim is supported by testing [late edit: I should say that I have never seen a comprehensive test]. Note that normally one doesn't run an engine at 100% of load capacity, so I don't think this reference rules out the claim that the fuel efficiency remains fairly constant in real applications.

The biggest problem that I know of is the production of NOxs, but I see this as a fairly minor technology challenge given the overall benefit of a conversion to biodiesel. Remember that we are talking about going from gasoline to diesel, not just diesel to biodiesel. A diesel engine is not only far more efficient - at least 20% to 30% more efficient - than gasoline engines, but again, biodiesel also has a higher energy density than does gasoline: 125,000 BTUs per gallon, as opposed to gasoline which has about 115,000 BTUs per gallon of available chemical energy. So regardless of whether one uses biodiesel or petrodiesel, there are significant energy savings as compared to using gasoline internal combustion. And, not only do you get higher efficiencies and more bang per gallon, but we also have fewer gallons to process and transport for the same energy requirement. So we see additional advantages in the supply chain. [late edit]This is especially true when we consider ethanol, which only has about 77,000 BTUs per gallon, or just over 60% of the energy density of biodiesel, which means that we have to transport 1.6 gallons of ethanol for every gallon of biodiesel in order to supply the same amount of energy to the market.

Or course the fact that we don't have to ship it half way around the world as crude helps a bit as well.

- Late edits -

 

[baywax]

Many of these issues have been or are being addressed daily. It depends on the company. For example, a buddy just bought a new Ford truck that is rated for B100. Synthetic materials make moot many of the concerns about seals and other soft components, but one certainly has to check with the manufacturer for any given engine before using strong mixes of biodiesel. Many people claim B20 as a safe limit.

Generally it is claimed that the superior lubrication provided by biodiesel as compared to petrodiesel offsets the slight reduction in the energy density. In either case, the paper is from 2003, and the price of fuel has gone up by 400% since then.

The biggest problem that I know of is the production of NOxs, but I see this as a fairly minor technology challenge given the overall benefit of a conversion to biodiesel. Remember that we are talking about going from gasoline to diesel, not just diesel to biodiesel. A diesel engine is not only far more efficient - at least 20% to 30% more efficient - than gasoline engines, but again, biodiesel also has a higher energy density than does gasoline: 125,000 BTUs per gallon, as opposed to gasoline which has about 115,000 BTUs per gallon of available chemical energy. So regardless of whether one uses biodiesel or petrodiesel, there are significant energy savings as compared to using gasoline internal combustion. And, not only do you get higher efficiencies and more bang per gallon, but we also have fewer gallons to process and transport for the same energy requirement. So we see additional advantages in the supply chain.

Or course the fact that we don't have to ship it half way around the world as crude helps a bit as well.

Thank you for all your work on this Ivan Seeking.

 

[joema]

New CNN article and video on biofuel from algae: http://www.cnn.com/2008/TECH/science/04/01/algae.oil/index.html#cnnSTCText

 

[baywax]

New CNN article and video on biofuel from algae: http://www.cnn.com/2008/TECH/science/04/01/algae.oil/index.html#cnnSTCText

That solves the containment challenge. I'm not as put off by bioengineering algae if they use that system. Texans and Canadians work well together! Just look at the space shuttle's robotic arm and Dexter™ :•]

 

[Dale]

Texans and Canadians work well together!

As we say at Texas A&M: "hullabaloo, canuk, canuk"

 

[Dale]

Remember that we are talking about going from gasoline to diesel, not just diesel to biodiesel.

I don't think that is very realistic in the next two decades or more. You can switch from diesel to biodiesel with replacement of some minor parts like seals, but the conversion from gasoline to biodiesel will require a whole new engine. All of the existing gasoline vehicles will have to finish out their "lifespan".

 

[OmCheeto]

I don't think that is very realistic in the next two decades or more. You can switch from diesel to biodiesel with replacement of some minor parts like seals, but the conversion from gasoline to biodiesel will require a whole new engine. All of the existing gasoline vehicles will have to finish out their "lifespan".

Americans spend 1/2 trillion dollars on new cars every year. I think today would be a good day to start selling multi-fuel capable cars. One's that will run on raw algae are starting to interest me.

 

[Dale]

I don't know of any multi-fuel engine that can do gasoline and diesel. The compression ratios are just too different. This isn't a trivial transition at all. I am not saying that it cannot happen, but it will take decades.

 

[baywax]

As we say at Texas A&M: "hullabaloo, canuk, canuk"

Cool. I was in College Station for a while and its a very different culture you guys have there. Mostly of the leatherhead variety. In BC we have the failing hockey team, The Canucks, (just got punted out of the playoffs... last year Dallas Stars took the Stanley Cup from us) and the slogan the Canuck management team came up with was...

"...we are all Canucks... "

but it boils down to saying we're all losers so... not the greatest marketing ploy. Then again... at least we're not algae.(snicker)

 

[joema]

I don't know of any multi-fuel engine that can do gasoline and diesel. The compression ratios are just too different. This isn't a trivial transition at all. I am not saying that it cannot happen, but it will take decades.

That is correct, however transition from gas to diesel uses already-existing technology.

That technology today can provide operational characteristics, range and performance familiar to most consumers.

IOW they can refuel it at a local station, accelerate briskly, and drive 300 miles.

The distribution chain (pipelines, tanker trucks, retail fuel pumps), etc already exists.

It's true despite all that it would take decades to transition the U.S. or world vehicle fleet to (say) 90% diesel engines fueled with algae-produced biodiesel.

However -- compare this to other alternative transportation technologies (hydrogen fuel cells, battery electric, etc) AND the energy sources associated with each of those.

Those typically require totally new vehicle technology, totally new distribution infrastructure, and often entail different operational characteristics. Can a safe, reliable fuel cell vehicle be economically produced in quantities of hundreds of millions? Nobody knows. We do know that's possible with diesel vehicles today, and the end-to-end energy efficiency is probably equal or better than fuel cell vehicles.

Of course hybrid battery/electric diesels are also possible with today's technology (think a diesel Prius), so that's an additional option for certain applications.

However long it would take for a major algae/biodiesel transition, it would take much longer for any other alternative.

Also it's unclear whether the energy sources for the other alternatives can be scaled upward to the titanic industrial levels required to make a meaningful difference. E.g, the world consumes about 100 quadrillion BTU (2.9E16 watt hours) of transportation energy per year. Providing a meaningful % of that from any alternative source is very difficult. Biodiesel from algae seems the only one with the theoretical yield/acre and net energy balance which could fulfill this within the next 20-30 years.

 

[Ivan Seeking]

However long it would take for a major algae/biodiesel transition, it would take much longer for any other alternative.

That is I believe the most important conclusion to recognize. However long it will take, which we can debate to no end, biodiesel-from-alage is the shortest and most direct path to a complete energy solution. Obviously many other alternatives do and will increasingly contribute to the energy supply, but it appears to me that algae is the only solution viable today that can scale-up to meet the demand for petro energy.

As for the time required to make such a conversion, we could have done this for the price of the Iraq war, which makes me want to cry... I think the time required for such a conversion is largely dependent on political will and the support that it gets publically. And when one considers the 1/2 trillion dollar annual contribution to the economy and the millions of jobs that such an effort would create, it seems self-evident that the project could be justified.

This is one concept that the dems have finally picked up: Going green means jobs!

There are two primary reasons why we don't drive diesel cars in the US today.

1). Diesel cars made in the 1970s were loud, smokey, and gutless. As result, they were very unpopular.

Diesel car technology has evolved a great deal since then and its use has continued and is common in many countries, if not most. Noteworthy is that a for the first time ever, a diesel car won at Le Mans. Auto racing is THE ultimate test of the latest automotive technologies: You win, or you lose. If you have an advantage, you win.

2). The sulfur that provided lubrication in diesel fuel systems was responsible in part for "acid rain" as well as other environmental contaminants. For that reason most diesel cars could not meet the revised EPA standards for emissions.

The new, "clean diesel engines", and the requirement to use ultra-low sulfur fuels makes the sale of diesel cars practical in the US once again. Most auto companies are planning to introduce diesel cars in the US over the next few years, but this will depend in part on demand, which gets back to political will and support. As for large trucks, the conversion to biodiesel is well under way, so from what I see that's basically a done deal. As long as we stay above the $3/gallon mark for petro it seems that biodiesel is competitive, which is in the end all that matters for a viable product.

Also it's unclear whether the energy sources for the other alternatives can be scaled upward to the titanic industrial levels required to make a meaningful difference. E.g, the world consumes about 100 quadrillion BTU (2.9E16 watt hours) of transportation energy per year. Providing a meaningful % of that from any alternative source is very difficult. Biodiesel from algae seems the only one with the theoretical yield/acre and net energy balance which could fulfill this within the next 20-30 years.

As you know, we have run these numbers many different ways and I don't see any other viable option at this time. In principle we could cover the deserts with solar panels, but the price per acre is astronomical as compared to algae, and we still have to convert the energy to a form useful for transportation.

 

[OmCheeto]

Noteworthy is that a for the first time ever, a diesel car won at Le Mans - auto racing is THE ultimate test of the latest automotive technologies: You win, or you lose. If you have an advantage, you win.

So when is a Tesla-esque auto going to enter the fray?
Change out the battery pack in the pits and whoooosh!
(you know where I'm going with this...)

As you know, we have run these numbers many different ways and I don't see any other viable option at this time. In principle we could cover the deserts with solar panels, but the price per acre is astronomical as compared to algae, and we still have to convert the energy to a form useful for transportation.

I got the new lower unit for my electric outboard conversion and finished the mating yesterday and completed several hours of data accrual and determined that my $10/day leisure trip will now cost 20 cents. Between rain showers, I searched for a 4 stroke 5 hp water cooled diesel engine. (I am an advocate of utilizing current technologies whilst we wait for the future). For some reason, only Chinese web sites popped up...

But I have digressed... as usual...
I have 40 gallons of unused ichthyological apparatii that are sitting idle. I really want to start growing some really slimy stuff. Which strain do you recommend?

 

[Ivan Seeking]

All of the existing gasoline vehicles will have to finish out their "lifespan".

True in principle, but signficant tax benefits could help to ensure that the change happens more quickly. These can be justified in the face of the wealth created by producing fuel domestically.

Also, we don't really know what will happen to the price of petroleum. It is possible that we will see spikes in the price; maybe even extreme spikes due to weather related events such as we saw with Katrina, and shortages resulting from our limited refining capacity generally, military conflicts, and perhaps due to political events. Any one of these scenarios could temporarily drive the price of petro based fuels to $10 per gallon or higher by some estimates. It wouldn't take much of this to drive the market to alternative fuels, which we see happening even now at $4 per gallon and less. And this would be especially true for the transportation industry as well as people who drive older cars and who have to be budget conscious. But most important of all, imagine the implications if we had an international crisis and the price of petro fuels hit $15 or $20 per gallon as is claimed to be possible? Whatever the worst-case number might be, this clearly becomes a matter of national security. So we might even justify dedicating some of the defense budget towards enabling algae-fuel production. We can certainly justify accelerating the entire conversion process with a focused political effort based on national security concerns as well as a campaign to create millions of new jobs. As an afterthought we might mention that it's carbon neutral.

 

[Dale]

As for the time required to make such a conversion, we could have done this for the price of the Iraq war, which makes me want to cry...

Or we could have done it several times over for the price of all of our various redistribution of wealth programs, which makes me want to scream.

 

[Ivan Seeking]

So when is a Tesla-esque auto going to enter the fray?
Change out the battery pack in the pits and whoooosh!
(you know where I'm going with this...)

Right now the batteries weigh 900 lbs and probably cost at least $50,000. The car itself sells for about $80-90k, so I would assume that the motor and drives aren't cheap.

A new diesel engine for a standard sized car probably costs about $5000 and weighs a few hundred pounds.

 

[Ivan Seeking]

The bottom line is that the algae option is now viable because the price of fuel is high enough. This has only happened over the last few years.

 

[mheslep]

Right now the batteries weigh 900 lbs and probably cost at least $50,000. The car itself sells for about $80-90k, so I would assume that the motor and drives aren't cheap.

A new diesel engine for a standard sized car probably costs about $5000 and weighs a few hundred pounds.

Well the Tesla is a limited production sports car. GM's Lutz says the Chevy Volt will be $30k. 120HP electric, batteries for 30-40 mile range. Electric (plug ins) are very close to practical now for around town driving. Cost is not really the problem for plugin electric cars. Its the range/re charge time that will be awhile yet before E plug-ins can compete w/ a 5 minute fill up on hydrocarbon fuels.
http://www.wired.com/cars/futuretransport/news/2008/01/lutz_volt_qa

ICE engine even less than that - $1-2k factory cost.

 

[joema]

...Cost is not really the problem for plugin electric cars. Its the range/re charge time that will be awhile yet before E plug-ins can compete w/ a 5 minute fill up on hydrocarbon fuels...

Even when that happens, plugin electric cars don't solve the transportation energy problem -- they merely push the problem elsewhere.

Battery electrics, hybrids and variants are a good idea from an efficiency standpoint in urban driving.

However those will not solve the transportation energy problem, no matter how widely deployed.

The energy they consume must come from somewhere. Nothing is free. A few thousand electric cars (out of 100s of millions of vehicles) won't cause much problem, nor contribute much benefit.

However scaled up to a level producing significant benefit (many millions of vehicles), it will demand new energy sources to supply them. E.g, supplying only 1/2 of world transportation energy via electric vehicles would require construction of 1,600 new one gigawatt power plants.

By contrast biodiesel from algae is a new renewable energy source, combined with an energy transport and storage system.

 

[mheslep]

Yes. Nice thing about E cars is the efficiency and zero distributed emissions.
https://www.physicsforums.com/showthread.php?t=210919"

..However scaled up to a level producing significant benefit (many millions of vehicles), it will demand new energy sources to supply them. E.g, supplying only 1/2 of world transportation energy via electric vehicles would require construction of 1,600 new one gigawatt power plants.

By contrast biodiesel from algae is a new renewable energy source, combined with an energy transport and storage system.

Not much contrast there in terms of energy. The system needs 1600 gigawatts either way: power plants or continuous fuel flow straight to vehicles. Biofuel industry expansion is well underway though, increasing production 300,000 barrels every day. Of course demand is increasing at 900,000 barrels a day, still 600k light.

 

[baywax]

Zapper Z mentioned that algae is a significant source of Hydrogen.

Is the process of collecting H2 from algae as inefficient as it is from electrolysis or other means of gathering it?

 

[Ivan Seeking]

Note that Zapper only forwarded the news release.

No, right now getting hydrogen from algae is about as efficient as getting cellulosic ethanol from wild grasses - single digit efficiencies.

 

[OmCheeto]

Note that Zapper only forwarded the news release.

No, right now getting hydrogen from algae is about as efficient as getting cellulosic ethanol from wild grasses - single digit efficiencies.

What was the name of that group of beings in Vonneguts book? Tramfalmagorians? I seem to remember them giggling during the movie.

This post about H2 producing algae looks like a script for a TV show that they might enjoy:

Earthlings genetically enhance algae to produce copious amounts of hydrogen. The enhanced algae escape and meet their oxygen producing siblings. Humans spend the next few hundred years running away from spontaneously combusting ponds...


http://en.wikipedia.org/wiki/Slaughterhouse-Five
Tralfamadorian

 

[baywax]

Note that Zapper only forwarded the news release.

No, right now getting hydrogen from algae is about as efficient as getting cellulosic ethanol from wild grasses - single digit efficiencies.

Thanks Ivan... hopefully wild grasses will be left out of the process then. I'm part owner in a 400 acre reserve of wild prairie grassland. The local township will annex it if it isn't developed soon. So even if it isn't used for ethanol, it will either be used to hide the sewage lines or it'll be wiped out by genetically-modified cross-pollination.

Kind of an "ice-nine" situation.

 

[Ivan Seeking]

On a related note:

The ability of corals to change the type of symbiotic algae they contain may allow them to adapt to rising seawater temperatures caused by global warming, scientists have found.

Madeleine van Oppen and Ray Berkelmans of the Australian Institute of Marine Science studied the Indo-Pacific SPS coral Acropora millepora and found that, in some circumstances, adult corals were capable of developing increased tolerance to higher water temperature through switching the type of symbiotic algae held in their tissues.

The study, which used both transplantation and experimental manipulation, has been published today in the Proceedings of the Royal Society and found that the increased thermal tolerance was a direct result of a change in the type of zooxanthellae held in the host coral's tissues from Symbiodinium type C to type D. [continued]

http://www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=1054

 

[mheslep]

... So you'd need some 40-200 m² fuel production area per car. How far am I off? Is this feasible as prominent fuel source for the future?

Usually we consider the total measured energy demand based on gallons per year and BTU per gallon, but using your numbers:

At 200 sq meters per car and an estimated 243 million cars in the US, we find a total required area of about 19,000 sq miles - about 140 X 140 miles to completely replace gasoline.

No problem. That is about 0.5% of the total area of land and water in the US. [water area is about 10% of the land area, and both may be used to grow algae]. In fact we could do it by using only 10% of the water area.

Ethanol from corn would require almost the entire land area of the US [assuming that it's not really a net negative, which may be the case].

My goal is to replace not only gasoline, but also petro-diesel and coal. This basically doubles the requirement. Also, as a practical matter I would use a conversion efficiency of 5%, not 10%, but then again a good part of the US is farther south than 45 degrees latitude. Processing efficiency is likely about 70% and improving. The oil content of the algae by weight is typically between 30-60%. And a good part of what's not oil is sugar that can be used to make ethanol.

All of this ignores advancements from the biological side, so it will get even better.
...

Following up on Andre's feasibility question and Ivan's energy assumptions with Ethanol usage for comparison:

The US planned on having 90.5x10^6 acres of corn planned for 2007 (40% of world production BTW). Now according to http://www.ers.usda.gov/AmberWaves/April06/Features/charts/feature4_Basel.jpg" . That is 21K square miles of US farmland going right now into Ethanol. Convert that to Algae with the above assumptions and oil is done.

A question on algae production energy needs though: part of the oft cited problem w/ Ethanol is all of the energy that goes into producing it - land preparation, just driving tractors about is part of that hit. Its not clear if this is accounted for in the above 10% (5%) efficiency assumptions?

 

[mheslep]

Same subject run another way:
Up thread Ivan gives us a figure of 10^4 gal/acre-year of fuel from algae. Starting from that instead of solar and car counts:

US total Oil use: 20Mbbl/day or 307x10^9 gal/year. Thus 307x10^5, or 30.7 million acres required to cover all US oil use, not just cars. So that's about double the 2007 US ethanol corn crop acreage, still no problem. The other existing energy crops such as soybean diesel should be converted as well. Note that only half of that would be required to totally eliminate oil imports.

 

[Ivan Seeking]

Note again that the actual limit for production is widely disputed. Some sources argue that a theoretical limit of 5000 gallons per acre-year exists, while others argue that they have real data showing yields of 10,000 gpay and higher. One of the problems that I have found is that many times the authors get lazy about specifying which units they are using - gallons, liters, acres, hectares, sq meters, sq feet, per day, per year, etc. - which causes confusion.

 

[mheslep]

Note again that the actual limit for production is widely disputed. Some sources argue that a theoretical limit of 5000 gallons per acre-year exists, while others argue that they have real data showing yields of 10,000 gpay and higher. One of the problems that I have found is that many times the authors get lazy about specifying which units they are using - gallons, liters, acres, hectares, sq meters, sq feet, per day, per year, etc. - which causes confusion.

Are these figure given in terms of net energy produced or is that off the books? That is, some percentage of fuel has to be used to run the paddle wheels, pump CO2, etc. Is that typically included in these gpay figures? If not, what's a reasonable estimate of energy usage in production?

 

[Ivan Seeking]

That is one number bantered as a theoretical upper limit based solely on the solar energy input, so in that case the processing efficiency has to be applied to that number. Of course the big assumption made is the solar conversion efficiency of the algae itself...and the PAR - photosynthetically active radiation - for a given strain. In many cases I have been unable to find any empirical data except for the few most popular strains. The processing efficiency is also widely disputed in part because there are many different methods used. Normally I see the processing efficiency listed between 50% and 70%, but there are still practical issues such as plugged centrifuges, invasive strains, mutations, and other issues that reduce the yields or increase the labor or energy needed to produce the fuel.