the Air Vent

Because the world needs another opinion

Super Algae Bio-Diesel Energy

Posted by Jeff Id on November 25, 2008

I received an interesting link from Richard M part of his comment is below the rest is HERE.

Richard M Says:
November 24, 2008 at 10:35 pm e

I believe there is some hope for one bio-feul ā€¦ algae. It has significantly better output than does corn, soy, etc. There is a new tecnology currently being test marketed that uses a vertical arrangement to get more output. They claim 33,000 gals/acre/year.

The great thing about comments on a small blog like mine is that I read each and every one. Along with my natural lack of political correctness I also am unafraid of being wrong. I do it quite often as my wife will happily tell you. Check out the link above, it is pretty interesting.

They claim 33,000 gallons per acre of vegetable oil created using a cool structure which stacks the algae in tubes. This is a huge claim considering that corn produces like 50 gallons per acre or something. Pond algae was the previous best at an inflated 900 gallons of oil per acre. Pretty exciting stuff if it’s true really.

Well we know that bio is a form of solar. Typically there is a very low conversion rate for sunlight into the oil, a bunch of light energy is wasted and a bunch more is put into plant proteins and other things not related to the final product – oil. So the first thing I did was check on how much sunlight energy per acre we can count on. These are just estimates- back of the napkin calcs – but they will give us a smell test.

Direct high noon sunlight is about 1000 Watts/m^2 on a clear day.

If we have 12 hours of top quality sunlight

1000 Watts/m^2* 12 hr/day * 365days/yr* 3600 sec/hour = 15,768,000,000 Watt-s /m^2

Then we assume a cosine distribution for daylight intensity of 63% of peak energy (an optics thing, the approximate average of the cos function)

Assume again that most places will only receive 70% of this amount of light. (also high estimate)

15,768,000,000 Watt-s /m^2* .63 * .7 = 6,953,688,000 Watt-Sec/m^2

1 acre = 4047 sq meters

28,141,575,000,000 Watt-Sec/acre or — Joules per acre in proper units.

How many Joules per acre are there in 33,000 gallons of vegetable oil. Well my 5 minute search didn’t reveal any value for algae veggie oil but it did reveal that wikipedia was using my guesstimated value of 1 gal veggie oil to 1 gal gasoline. They are both hydrocarbons after all. Ripping hydrogen off a carbon chain (oils are to my knowledge all carbon chain based) and combining with oxygen produces the nearly the same energy from nearly every oil type fuel. In college grad school I taught a fuels and lubes lab to keep shoes on my feet.

Well gas is about 121,000,000 joules per gallon so we get 33,000*121,000,000 = 3,993,000,000,000 Joules per acre.

This means that 3,993,000,000,000/28,141,575,000,000 * 100 =14.1% of the total sunlight is converted into oil. This is a huge number.

Look at the system they used.


It looks pretty cool, vertical arrays of poly-something tubes with pretty green stuff. But the total sunlight absorbed is the question here. I am an optical engineer so there are definite issues with the structure as to actual use of the light. Note the glare off the plastic in top right corner of the above picture. This is lost light. A substantial percentage of light will be reflected from the surfaces of these bags. In this greenhouse configuration it is especially true for directly overhead sunlight.

Now in the shots below you see a diffuse layer applied to the top of the greenhouse. I am no greenhouse expert but diffuse polymers is something I am familiar with. This material likely reflects, scatters or absorbs 20-50% of the sunlight striking the greenhouse although there are materials which can do better. I suppose it is designed to make sure that plants don’t burn from too much light, but I am not an expert in botany. If you see the shadow inside the greenhouse created by the roof material you can get a feel that more than 50% of the light is absorbed, scattered or reflected. There is definitely a significant reduction in the light striking the algae.


What happens to the numbers if we apply a few more losses?

From before 14.1% of the light is required to convert into oil to meet 33,000 gallons/acre.

If we say the light is reduced by 50% due to the roof. We have 28.2% required to convert into oil.

If we have a loss of 15% due to the plastic bags we get 33.1% of the light energy must turn into oil. Plants photosynthesis has a maximum of 6% efficiency in the link here. A substantial portion of that energy is used to keep the cells alive and not for oil – say half at the very least. So at my original number of 14% these Algae are running 4X higher efficiency than is physically possible. With the other numbers included for 33.1% of the light energy required we achieved an efficiency of 11X the maximum allowed by reality.

My numbers are heavily biased in favor of the company!

Well like many things in the green world, this one has claims that exceed reality. What does this mean?

1 – Will algae from this process exceed the production from a pond style algae farm?

I am not sure, I think a well mixed and fed clean water pond will capture more light energy and may produce the same amount of oil. No proof here though.

2 – Is this a good energy solution?

The numbers provided cannot be trusted. Pond based algae energy doesn’t work because of the massive area required, I suspect this will also have the same problem. There isn’t enough sunlight striking the earth to make this work.

3 – Even if they’re several times off in efficiency isn’t this the best solution?

Yes, if they are only several times off. What I don’t like is that they have presented physically impossible numbers to support their company position and by the numbers my guess is 30 times off. Before I accuse anyone of pulling a Michael Mann, there is one case (besides my inability to multiply or bad numbers) I can think of where I might be wrong (Just because I’m often wrong doesn’t mean I give up easy).

If you remember the water powered car’s that crop up from time to time. People use special fuel cells which convert water into electricity by splitting H20 into hydrogen and oxygen. Well the reality was that a coating is applied to the fuel cell which actually contains the energy, not the water. This coating’s energy is used in the same fashion as gasoline and when it is consumed the car stops running.

The food given to the Algae wasn’t disclosed on the website. If the food contains high energy materials (not a botanist) this could drastically change the energy balance giving falsely high results to an otherwise energy wasting process. If the food was made from scrap such as corn husks or stalks it still might be a good process but the disclosure on the website wasn’t sufficient.

Therefore, if there are high energy foods used (previously stored sunlight) this process has a chance.

If not. — Another myth busted.

Either way, it is easy to believe in these companies, I want them to be true more than I can say. A good comment by Richard made me question my other results and run through them again. I hope my readers understand that I will be thrilled to find other reasonable answers to energy. If other cost effective solutions become available, this engineer will immediately become their biggest supporter. You can see my tone when I started this post, I hadn’t done the calcs yet. Anyway, I’m not buying any stock in this one until they disclose more.

25 Responses to “Super Algae Bio-Diesel Energy”

  1. Richard M said

    Here’s a few more links that may help. I haven’t had the time to investigate them in any detail:

  2. Richard M said

    I should add that my own interest in algae is not based on producing lots of gas. If power plants can produce whatever (feed, fertilizer, plastics, etc) to sequester all of their current carbon output, this would eliminate the cost of future carbon taxes on the electrical grid. This would pave the way for pluggable hybrid technology to be based on zero carbon. I read recently where 78% of the miles could be moved from oil to the grid with todays hybrid technolgy. I don’t know if this is true, and we won’t see everyone coverted immediately. However, I believe this is one way to energy independence (my primary motivation). New jobs, reduced imports, etc.

  3. Richard M said

    There are a few other questions that need to be answered if this is ever going to work. How many acres of algae would be needed to sequester the carbon from an average coal plant (or NG)? What is the cost of transporting the carbon? How much carbon is lost in the process of this transport and feeding the algae?

    There’s probably a few more but the impact of this technology is potentially huge. I believe many skeptics would be happy to have much of the carbon sequestered in this manner. Like many others I’m concerned the impacts of cap&trade or other carbon taxes is worse than the impact of warming.

  4. Jeff Id said


    There are a bunch of readers for this post. Not too many comments yet though.

    If your read the second link you provided in #1, the power or energy/time in engineer speak collected by algae is really about 3 W/m^2. This number is substantially lower than my calculations above and is more in line with 900 gallons/acre (an ideal number). This makes the whole process of algae biofuel non-practical. That doesn’t mean that it can’t be used for some purposes but it does mean that this is not a good method for creating and storing energy.

    The cost balance for wind works somewhat but the fact that wind stops and starts creates enormous problems with our current energy storage technology. Solar is way out and biofuels are even farther behind. Creating a false industry will simply lead to higher energy costs all in the name of CO2 reduction. Jobs are created when the most cost effective solutions are used not when government subsidizes over priced industries.

    Pluggable hybrid is also a problem. I have personally participated in the construction of a hybrid vehicle. My job was the creation and integration of a complete computer controlled electronic system for a hybrid vehicle so I have some experience with these. Hybrid can give better fuel economy but the batteries are not ready yet. The entire advantage of Hybrid occurs simply because gas engines have a peak efficiency at about 60% load and the engine is kept near as that limit as possible.

    Pluggable hybrid only makes sense if the energy comes from a high efficiency on site generation due to high power transmission line losses (again solar won’t do it). People don’t realize that a huge percentage of our electricity generated is wasted on power lines. Otherwise we just consume even more energy to get the same job done. I may do a post on that in the future.

    Moving the miles to the grid would unfortunately be a huge energy waste.

    These are some of the myths presented by the green crowd. It’s pretty frustrating for me because engineers typically know these solutions won’t work and several of them don’t have much of a future. What’s worse is that we have a solution that does work now and in about 20 to 50 years we will have the batteries and storage solutions to make some of these other things work. I fully believe oil as a power source will be replaced quite naturally by technological advances and the less government tries to legislate it the better.

    My least favorite answer to the problem is “all of the green solar technologies above” because ten bad technologies (wind, bio, solar cell, solar steam, etc.) cannot replace one good one.

    What works you might ask? — Nuclear. It’s cheaper, there’s plenty of it and the new plant designs are much safer than the original behemoths. A free market would naturally retire the old designs and replace them with hundreds of massive new reactors. There are plenty of options for storing spent fuel as well. Nuclear electricity is so cheap that when batteries come around electric grid powered cars will be low cost options.

    Really it’s that simple, burn coal, natural gas, gasoline and oil. If we’re really worried about CO2 get the government out of the way for massive expansion of nuclear plants. These plants will run for the next 70 years when they are replaced by fusion or better solar power. Homes will naturally switch to solar by individual choice when storage systems improve and solar-electric conversion becomes cost effective. Cars need more energy than homes so perhaps a massive nuclear electrical grid will be the answer.

    Algae is unfortunately a low efficiency form of solar power. If you really need vegetable oil for food or an improved protein generator it might be a good use but after this post I don’t believe in it for energy.

  5. The Diatribe Guy said

    Alternative energy is in its infancy. All these experiments in biofuels, solar, wind, and everything else should be looked at as experiments that someday lead to a better solution. But this ill-informed angst over carbon in all its forms has pushed governments to try and create a market that should not exist. I applaud and encourage all these different kinds of research, but only inasmuch as they are taken for what they are: inefficient precursors to a better solution down the road. All these things have value as a stepping stone to a future solution, but simply are not a reasonable solution now. They are inefficient and expensive and make no sense at all. Biofuels are an interesting exercise in trying to understand how we can someday create fuel from other resources, if nexessary. But today, it’s truly ridiculous that we actually believe that using food for fuel in mass quantity is in any way a good idea.

    Experimenting with biofuels isn’t maddening. Rolling biofuels to market and convincing the public that it’s actually a “green” solution is maddening. It’s simply a lie. We know that it not only gains us nothing from a “carbon footprint” standpoint, but it additionally acts to use valuable land for a stupid purpose, reducing total food supply, and inreasing cost.

    It makes me want to hit something.

  6. Richard M said

    I absolutely agree that nuclear is the way to resolve our energy problems … but … That was the idealist in me. The realist in me doubts we will see much in the way of nuclear development for many years to come. Many people fear nuclear.

    So, if the “best” solution is off the table where do we go? That is why I am interested in algae. If the technology is better than all the other bio-fuels and it can be located pretty much anywhere then it could act as a carbon sink while maintaining the low cost of fossil fuels. The by-products may make it cost effective even though the energy capacity is wanting.

    I also saw another algae idea recently. It was a portable filter that trapped emissions from cars. I suppose one would exchange it every time they filled the gas tank. I know, it does seem a little clunky.

    So, I’m not quite ready to give up on algae although I really need to see some results from the test sites before going off half cocked šŸ™‚

  7. BDAABAT said

    Richard M: I don’t think algae is an actual carbon sink. The algae eventually die, then decay, releasing CO2. Sort of a temporary carbon holder.

    RE: Nuclear; yes, more nuclear should be built in the US… just that it needs to be kept in the correct proportion (one shouldn’t assume that nuclear is going to provide 80+% of the power need).

    The problem with energy use is that demand changes over time… there are peaks and valleys every day. Nuclear doesn’t work that way… requires running full out or near full out all the time. What do you do with the electricity generated by nuclear when the demand isn’t there??? In France (where they overbuilt nuclear capacity), they’ve been able to sell their excess capacity to other countries nearby. That’s not the case in the US.


  8. Jeff Id said


    I will work on the Area calculations next, the required area will be quite large if I use true numbers. For the company above, I am now concerned that this might be fraud and I hope they find a way to cover their butts as they are part of a public company. This is a situation I didn’t expect to run into when I started this post. To be honest, I’m a bit nervous about catching it.

    Bruce has a good point also. I think there are some workarounds for the excess energy such as heating a man made lake. Having an extra sink would allow for 100% nuclear to become practical. I don’t mind coal myself but just to make the point that there are methods for dumping excess energy but it would need to be planned for.

  9. Richard M said


    I understand it is not really a sink. I’ve explained it to others as more of a double your money situation. You get twice the energy for the same amount of carbon which, in effect, reduces the carbon emissions by one-half (not an accurate number, I know, but something I can explain to non-technical folks).

    It would be interesting to know how the 33K number was computed for algae. Are they assuming algae has a better efficiency than the 5-10% number commonly used? It doesn’t seem like a fraud since they are running test sites as we speak. The fraud wouldn’t last long in this case (unless the results are altered) and wouldn’t last past the first real world installation.

  10. Jeff Id said

    I hope you’re right Richard but the numbers look pretty far off. My feel for the numbers is that the corrections are more in line with good algae ponds. I’ll do some more calcs tonight if I get time. Perhaps I made a mistake but I can’t find it yet. Also, high energy food (sugars or something) would give additional energy input to the system but that would also apply to ponds.

  11. Jeff Id said

    Ok, how far off are their numbers. I used Richards second link in comment #1.

    If we assume 3 W/m^2 of energy absorbed in Belgium by the best Algae – I get

    3W/m^2 *24 hr/day * 365days/yr* 3600 sec/hour = 94,608,000 Watt-s /m^2

    382,878,576,000 W-s/acre

    To make 33000 gallons of oil we need – from above
    3,993,000,000,000 W-s/acre.

    The claims exceed the maximum possible generation by 10 times. This assumes that all of the sunlight is actually used in photosynthesis by the greenhouses shown we know the sunlight is not reaching the algae efficiently. My guess is at least half is wasted but it is just a guess. So I suspect they are 20 times off from reality.

    There are about 390 million gallons of gas used each day in the US which is 142,350,000,000 gal/yr. If we assume an excellent production level of 3000 gallons per acre 47,450,000 acres are required which equates to 74,140 miles square to create all of our fuel according to today’s use. Since Nevada is 110,000 sq miles and the sunlight would be improved from Belgium calcs we probably could cover only half of Nevada and meet our needs, not that bad really.

    It’s a little encouraging to me that it may actually be possible but we can’t trust the 33,000 gal/acre from this company so we can’t trust their cost. I am still intrigued by the closed system they just need to work on getting more of the light to the plants.

  12. BDAABAT said

    Roman: So what about carbon? As Jeff has shown, it isn’t REALLY the issue that many people claim. Am not saying developing alternative ways of producing energy is a bad thing. Just saying that doing so to avoid carbon production doesn’t make a lot of sense.


  13. Richard M said

    I agree it doesn’t make sense but the handwriting is on the wall. Obama and other leaders are headed down the path of carbon restrictions/taxes. We need low-carbon energy that is less expensive than some of the alternatives being considered today and algae allows carbon to “re-used”.

    Algae may meet this goal if the claims are true. However, if it’s just another wild goose chase we need to understand that before a new industry is created.

    I think one thing missing from Jeff’s analysis is that the vertical area receiving sunlight may be greater than one acre for a corresponding one acre of land. This may help increase the % of “usable” energy per acre. I don’t know how much this helps. OTOH, Jeff used 24 hours and I don’t think we can count on 24 hours of sunlight. So, these may cancel each other out.

  14. Jeff Id said


    Unfortunately the energy per acre of sunlight does not change with vertical area so there is no change there. For the 24 hours, I did it like that because the link didn’t describe if it was an average wattage for all the time in the year including nighttime so I erred on the side of the algae.

    This is a common method I have used through all the different energy methods I have explored because my intent was not to debunk these methods but rather to see how reasonable they are.

    The major things missing from my half of Nevada calc was that all of the solar energy was captured and all of it turned into oil. My understanding is the best algae is only half oil so it would be reasonable to magnify my acreage by two to four times which would cover the state of California with algae.

    Think of it like this, the algae system is 5% efficient, other solar solutions reach over 20% but the energy cannot be stored easily. In the next 15 years I think that will change.

  15. Richard M said

    Jeff, a couple of things.

    First, are there any energy gains from the biology? Or, is all net energy usage?

    Second, my comment about the vertical orientation was only meant to question the percent of energy available. Clearly, a pond scheme would be limited to direct sunlight where the vertical arrangement allows for reflection, etc. to facilitate growth.

    Thirdly, the carbon used to increase algae yields would allow coal and NG power plants to be lower carbon producers. So, an approach that averages the energy of burning these fossil fuels in with the algae energy product might be more appealing.

    Finally, there are “other” products provided by the algae system. The oil is only part of the equation. If the food byproduct replaced field corn for example, that would reduce oil consumption planting corn fields or increase food supply.

    I guess all I’m trying to assert is this a multi-dimensional situation. I understand the numbers you have posted and they need to be factored into the equation.

  16. Jeff Id said


    You make good points.

    I think most of the biology is a step up in energy level so if we could find a way to use it this energy wouldn’t be lost.

    The vertical might have some advantages over a pond surface if it was done correctly. The best part of it might be the cost but there aren’t any good numbers. If the cost works out this still might work. Let’s burn a little ocean or desert space for algae. The bottom line would be dependent more on cost of different systems. This seems like a very low effort way to capture and store energy, but it has low efficiency also.

    The third point has me a bit confused, this would be a very short term carbon sink so if that’s what the greens consider an offset then I would consider it another example of government over-regulation leading to waste.

    Other products are more interesting to me than energy but at least in the US food isn’t a problem yet.

    Thanks for the link, it got me thinking. BTW: I don’t mind spending money on research for new technologies but spending money to subsidize implementation of incomplete technologies is where I disagree with our government leaders.

  17. cmb said

    I wouldn’t spend too much time doing feasibity calcs on an inital test bed design, I’d expect this design – and algae – to go through a lot of improvement in the next few years.

    Another loss is the specular reflection from the overall plastic surface. The arrays are probably made so tall in order to minimize those losses, though.

  18. Jeff Id said


    It’s nice to get a more reasonable comment. The test bed results were pretty far out of reality which is what concerned me. From my optics background I can tell you that the height of the array does help a little in that surface reflections have an opportunity to be reabsorbed (it is a very small difference from a continuous horizontal sheet).

    The problem is twofold
    #1 The total incoming light energy just isn’t there.
    #2 The photosynthesis process is inherently inefficient.

    If they really did produce anywhere near 33,000gallons of oil per acre, unaccounted for chemical energy was introduced into the system through a food source.

  19. cmb said

    Jeff Id Says:

    If they really did produce anywhere near 33,000gallons of oil per acre, unaccounted for chemical energy was introduced into the system through a food source.

    – If it were my project, I’d assay the dead algae for complex carbohydrates and the like to use again in exactly that manner. =)

  20. Ecoeng said

    I hate to rain on your parade Jeff and I do agree with you that the algae-to-fuel industry is partly populated with dodgy venture companies which make outrageous claims.

    But you need to be aware that there is a very large literature on the subject of cyanobacterial energetics and solar (PAR) conversion efficiency, both in natural systems and in ‘unnatural’ man-made systems (both ecologically stable and unstable) some of it, ironically, involving excellent papers by Makarieva and Gorshkov.

    Unfortunately I am presently travelling in the US for my work (am Australian) and can’t respond in technical detail to your various points but may I recommend that you check some of the literature out and at least e.g. try to get a copy of the 10-year USDOE study on algae cultivation.

    Some points you may not be aware off:

    Cyanobacterial solar conversion efficiency of around 14% is achievable with certain bioreactor configurations.

    This is not necessarfily a critical issue anyway IF CO2 scrubbing of fossil fuel plant off gases is the goal as the key issue there is efficiency of CO2 uptake. In that case low light efficiency is tolerable.

    An associate of mine (a brilliant chemical engineer who designed one of the most efficient bioethanol plants in the world) has calculated that several structures similar to large city-style multi-level carparks would be adequate for producing counter-current scrubbing which would remove most CO2 from the exhaust gases of large coal fired power stations (>Gigawatt).

    There are also energy efficiencies to be gained in cyanobacterial energy conversion by mimicking natural systems where there are mixed consortia which use the ‘quorum sensing’ principle to optimize system energetics/biomass production. You may not be aware that many common oceanic cyanobacteria can survive up to ~100 days in the complete absence of light and can even grow under unusual conditions of apparent zero light in the flooded workings of underground coal mines i.e. they can switch to heterotrophic growth and/or use luminescent consorting bacteria e.g. Vibrio spp at will.

    This ‘algae story’ is by definitely no means energetically as facile as your simple calculations imply and the manufacture of biofuel from algae (= utilizing waste CO2 to make useful socially products efficiently) is by no means a scam, nor, I might add, is utilization of algae as high efficient bulk CO2 sequestors.

    This reality is why the whole AGW green movement hates (or ignores) algal cultivation so much – see e.g. their rabid opposition to oceanic iron fertilization trials which despite their lies, have largely been very successful at producing CO2 sequestration on a bulk scale.

    An emerging algae-based high technology strikes at the very heart of what they really want to do to our civilization. Think about it. Please.

  21. Jeff Id said

    I would be interested in seeing photosynthesis at 14 percent, let alone a conversion efficiency from solar of 14 percent. There is quite a bit of literature that claims the max theoretical efficiency is far lower than even that. The best paper I’ve read came in at 9% theoretical max. I very much doubt the 14 percent number but if you can produce a paper, I’ll read it.

  22. JimBrock said

    Any news on the ExxonMobil research on algae/oil? Privately financed, I presume.

  23. harry said

    15,768,000,000 Watt-s /m^2* .63 * .7 = 6,953,688 Watt-Sec/m^2

    When I do this calc I get 6953688000 Watt-sec/m^2?
    Why did you drop the last 3 zeros? I.e. you seem to have converted to kiloWatt Seconds?

    i.e. .63*.7 == .44, or roughly half. and 7M is not close to half of 15B.

  24. DeWitt Payne said

    This link has some numbers on theoretical and practical yield estimates for oil production from algae. The practical numbers range from 4900-6500 gallons/acre/year. Theoretical max is 38,000.

  25. Jeff Id said

    Thanks Harrry, fortunately it looks like I carried the right units forward.

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