Can Microalgae Solve Global Fuel and Environmental Challenges?

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Microalgae present a promising solution to global fuel and environmental challenges, capable of producing biodiesel, ethanol, and hydrogen while also remediating waste and CO2. Research initiatives like the BEAM network focus on enhancing microalgal growth and efficiency for commercial biofuel production and environmental applications. Despite potential, there are significant technical and economic hurdles to overcome before microalgae can replace petroleum, although high oil prices may accelerate progress. Algae's ability to thrive on agricultural runoff and its high yield compared to traditional crops make it an attractive alternative. Overall, the discussion emphasizes the dual benefits of algae in energy production and environmental cleanup, highlighting its potential role in a sustainable future.
  • #451
One problem that bugged me for a long time was this: What about when we have high seas? Won't that destroy the algae farm?

Answer: You sink the farm when you have approaching storms.
 
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  • #452
Ivan Seeking said:
One problem that bugged me for a long time was this: What about when we have high seas? Won't that destroy the algae farm?

Answer: You sink the farm when you have approaching storms.

You sink it? I'm not sure what you mean, but it sounds interesting.
 
  • #453
Frame Dragger said:
Asolutely! Look at the cultavation of Haematococcus pluvialis for extracting Astaxanthin; it's extremely easy to do with bioreactors and minimal water usage, especially compared to the alternatives. ...
Visibly it is not easy to do economically.
 
  • #454
By sinking the farm, I was suggesting that the bioreactors would tend to be barely buoyant anyway, so they could easily be sunk to a safe depth for storms. A simple ballast system could be used to do this.
 
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  • #455
Ivan Seeking said:
By sinking the farm, I was suggesting that the bioreactors would tend to be barely buoyant anyway, so they could easily be sank to a safe depth for storms. A simple ballast system could be used to do this.
Clever idea, but doesn't this imply the reactor has to be sealed and capable of withstanding some pressure, and if that is the case what is the economic advantage of placing the farm in the ocean (vs land or lake) and having to deal with marine operations?
 
  • #456
mheslep said:
Clever idea, but doesn't this imply the reactor has to be sealed and capable of withstanding some pressure, and if that is the case what is the economic advantage of placing the farm in the ocean (vs land or lake) and having to deal with marine operations?

Many designs for bioreactors are basicaly just big plastic bags filled with water. They already have a fair degree of mechanical strength as required by the weight of the water. It would be easy to modify these for total submersion. An air gap above the algae water would normally make the reactor slightly buoyant.

As stated earlier, there are several advantages. The biggest consideration is the cost of land [and property taxes], which is siginficant to the cost of production, thus the required yields, thus the required CO2 supply. We can live with less CO2 if we don't require the maximum possible yields. Also, no land preparation is required. While the cost of a marine bioreactor may be higher than one for land [I don't know that it would be!], land preparation can be a costly proposition for a new site. Next, semi-submersion in marine environments means that we naturally have very stable temps. This is highly siginficant as closed systems are also greenhouses by nature. It takes energy to keep them cool. Also, extreme winter conditions eliminate the chance of winter crops. In fact, this is what killed the bloom used in the Aquatic Species Program! If it is even possible, temperature regulation is critical and it can be energy costly. Coastal areas generally have moderate temps. Additionally, we have a ready supply of water with no energy-expensive deep pumping required. There are other practical advantages. For example, we have no drainage problems, land use laws, or concerns about flooding. Finally, the energy cost of mixing [water circulation], which can be significant, might be reduced by cleverly tapping the energy in the wave action of the ocean.

If one can significantly reduce the cost of start-up and operations - financially and in terms of energy - one can live with lower yields. This could make algae-fuels cost-competitive sooner than they would be otherwise.

Note also that diesel generators needed for processing the algae would supply about 40% of the CO2 needed for growth. This is added to the ambient CO2. There is no reason why any closed system should be limited to the ambient CO2 supply. The fact that processing is energy costly also means that we have a signficant CO2 supply to boost the growth rate of the algae. As discussed earlier, the diesel engines might even be easily modified to "fix" a good percentage of the required nitrogen.
 
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  • #457
Late edits above:

We already know that we don't want algae competing with people, live stock, or food crops, for fresh water. When one considers the annual water demand were algae fuels to replace the petroleum supply, it becomes evident that we want to drive this towards the salt-water based algae strains. This is consistent with the idea of marine-based farms.

Haha, maybe we could convert the platforms from spent oil wells into bases for algae farms!
 
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  • #458
Ivan Seeking said:
Late edits above:

We already know that we don't want algae competing with people or food crops, for fresh water. When one considers the annual water demand were algae fuels to replace the petroleum supply, it becomes evident that we want to drive this towards the salt-water based algae strains. This is consistent with the idea of marine-based farms.
Yes that is surely a strong point in favor of a marine based-farm. For every mole of the 378 million gallons of liquid hydrocarbon used per day in the US, some 2-3-4-5 moles (depending on the hydrocarbon) of water would be required to replace the petrol with biofuel. However, the difficulty in keeping wild strains and toxins out of that ~billion gallons per day of seawater seems intractable.
 
  • #459
mheslep said:
Yes that is surely a strong point in favor of a marine based-farm. For every mole of the 378 million gallons of liquid hydrocarbon used per day in the US, some 2-3-4-5 moles (depending on the hydrocarbon) of water would be required to replace the petrol with biofuel. However, the difficulty in keeping wild strains and toxins out of that ~billion gallons per day of seawater seems intractable.

I don't see why contamination would be any more problematic that it would be for a land-based system. It is a problem but true in either case. Clearly all water used in the system will require proper treatment. But from there it is a closed system.

Again, incidently, ~40% of our water is purified and returned to the system by the diesel engines.
 
  • #460
Biodiesel has over 20 hydrogen atoms per molecule - a 10 times or better multiplier for water demand, per mole of fuel.
http://www.pwista.com/Organic/Preparation%20of%20Biodiesel.pdf

Late edit: In fact, it should be more like a 15x multiplier because some hydrogens are lost to the glycerine precipitate formed during the transesterification [biodiesel] reaction. The critical fatty acids are mostly in the mid thirties, in terms of the hydrogen count per molecule.
 
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  • #461
Using some typical numbers: If we assume that we purchase land for $10K per acre, [assuming that we have 10% cash to put down] we might expect to pay 1%, or $100 per month per acre, for a 30 year fixed loan. Property taxes could easily be another $100 per acre per year, say $10 per month. Reasonably, we might also assume that land preparation doubles our start-up costs, so we assume $200 per acre-month for the startup cost of the site. With taxes this suggests an expense of about $210 per month per acre, for thirty years.

Assuming the highly optimistic case of 7000 gallons of fuel per acre-year gross, and 60% processing efficiency, we expect 4200 net gallons of fuel per acre-year, or 350 gallons per acre-month. Assuming an effective wholesale market price [after testing and taxes] of $1.00 per gallon, the cost of land and taxes alone require 60% of our gross income. Assuming a more moderate 5k gallons per acre-year, land and taxes require over 80% of our gross income.

Obviously we would look for better options such as land leases, but the numbers show how significant the cost of land and taxes can be as a percentage of the gross revenues generated. Note that we still have to pay to operate the farm.
 
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  • #462
Ivan Seeking said:
I don't see why contamination would be any more problematic that it would be for a land-based system. It is a problem but true in either case. Clearly all water used in the system will require proper treatment. But from there it is a closed system. ...
I assumed a land system would have access to fairly contaminate free water supplies? Perhaps municipal water would be available, if not then rain collection, well water, or even clean rivers. I have little or no idea what ppm of wild algae is found in those water sources. If it has to be cleaned - that's a colossal job at this scale.
 
  • #463
Ivan Seeking said:
Using some typical numbers: If we assume that we purchase land for $10K per acre, [assuming that we have 10% cash to put down] we might expect to pay 1%, or $100 per month per acre, for a 30 year fixed loan. Property taxes could easily be another $100 per acre per year, say $10 per month. Reasonably, we might also assume that land preparation doubles our start-up costs, so we assume $200 per acre-month for the startup cost of the site. With taxes this suggests an expense of about $210 per month per acre, for thirty years...
Interestingly there's a detailed business analysis report authored by a US national lab on the failure of a California solar farm for just these kinds of reasons - they failed to identify property taxes, etc. until too late.
 
  • #464
mheslep said:
I assumed a land system would have access to fairly contaminate free water supplies? Perhaps municipal water would be available, if not then rain collection, well water, or even clean rivers. I have little or no idea what ppm of wild algae is found in those water sources. If it has to be cleaned - that's a colossal job at this scale.

A significant energy cost is paying to run the pumps that push the water through the filters. No way to avoid that one. But it isn't practical to purify the water to laboratory standards, so it becomes a race to create a harvestable bloom before the bad things take over. This is why, in my own plans, it was critical to innoculate a new batch using as much pure growth as possible.

Presumably, chlorination would also play a role in treating raw water, but I have never worked with salt-water systems, so I don't know what the options may be.

As for municipal water sources, they have the same energy and financial costs as would a large farm. And, with possibly a few rare exceptions, there is no natural water source that could be considered "clean".
 
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  • #465
As mentioned above. This is on-topic IMO - solar shares all of the same land costs / taxes as algae (would).
Barriers to Commercialization of Large Scale Solar Electricity: Lessons Learned from the LUZ Experience
http://www.nrel.gov/csp/troughnet/pdfs/sand91_7014.pdf

See in particular the Barrier Sections
V: Energy Pricing Policy
VI: Artificial Size Limitations Under PURPA
VII: Annual expiration of the energy tax credits and AMT limitations.
VIII: Property taxes
IX: Other taxes
and so on
 
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  • #466
An interesting perspective that sort of popped off the page at some point:

Not surprisingly, while trying to write a business and technical plan for all of this, it soon became evident that the cost-siginficance of any particular component of the farm, is related, in a sense, to its dimensionality. The cost of anything having a specific location, such as a generator, tends to be relatively small as compared to the total cost of the farm. When we consider things measured linearly, such as pipe, the cost becomes significant. Anything measured in terms of area, such as land, or bioreactor surface, becomes cost-critical. The reason for this is the scale of the project. It is difficult to remember just how much area we are talking about.

I found there was an intuitive disconnect for me when we start talking about thousands of gallons per acre-year. In fact this is a very low energy density over area. In the end we are only talking about 100 watts or so of captured, recoverable power, per sq meter, and only during the day. We get nothing by night. How much does it cost to run a lightbulb? There is your energy and operating budget, including profits, per square meter. That is difficult to keep in perspective. It is easy to imagine that any additional cost for marine reactors, as opposed to land-based reactors, may be insignficant compared to the cost of land, and land preparation, which are both heavy-hitting area problems.

The energy cost of mixing keeps coming to mind as well. Mixing, or stirring, becomes problematic because we have to keep the water moving over the entire surface of the reactor bed [an area problem]. If we have one foot of water in our reactor, this means that we have to stir 326,000 gallons of water per acre, or about 80 gallons per lightbulb, over thousands, or hundreds of thousands of acres, per farm. Likewise, if we can steal wave energy over the entire surface of the reactor, while the energy density of the wave action may be small, we are talking about a very large area, so the energy savings are signficant.
 
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  • #467
In my own efforts, what ultimately drove the choice for the depth of the water in the reactor bed, was the need to avoid wild fluctuations in the temperature of the algae water. The mass of water required per square meter - thus the depth of the water - was calculated according to the anticpated solar and ambient energy input to the system during the day, the energy [heat] lost at night, heat energy lost to and gained from the land, and the maximum acceptable water-temperature swings. This in turn determines not only the energy required for mixing per unit [surface] area, but also the time that any particular algae cell spends at the surface of the water; thus the efficiency of the reactor. Presumably, there are ideal periods of time spent on the surface - the only photosynthetically active period for the cell - and then below the surface, for any given algae cell, and perhaps for each strain of algae. If temperature control is not an issue [due to contact cooling with the ocean water], then it would seem that the reactor design can be driven by the ideal circulation rates and activity periods, for any given strain of algae.

Note that the qualifiers "presumably", "it would seem", and the like are meant to make clear that this is my impression of the problem based on a long and dedicated review of the literature - that this is representitive of the mainstream discussions and literature.
 
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  • #468
Ivan, is there any chance that algae will grow in the dead zones around sewage treatment plant outflows...? These are usually in the ocean and just off shore. the oceans temp never varies much more than 2 degrees over the year.
 
  • #469
baywax said:
Ivan, is there any chance that algae will grow in the dead zones around sewage treatment plant outflows...? These are usually in the ocean and just off shore. the oceans temp never varies much more than 2 degrees over the year.

In all likelihood, it is best to treat the runoff or discharge before it reaches the open oceans. In fact dead zones are often created by spontaneous algae blooms, often due to the presence of nitrogen, that choke off the oxygen supply for everything else. So, interestingly, the choice can be, a controlled bloom now, or an uncontrolled bloom later. :biggrin: It reminds me a bit of Judo where you use your opponent's momentum against them.

You may remember what happened along the Chinese coast, just before the Olympics. I don't know if the cause of that bloom was identified, but it typically comes down to high temperatures, and/or the presence of relatively high levels of nitrogen due to, sewage, agricultural runoff, or industrial waste products. In any case, nitrogen is critical to algae growth.

[PLAIN]http://www.pe.com/imagesdaily/2008/07-01/china_olympics_algae_400.jpg

BBC report
http://news.bbc.co.uk/2/hi/7485405.stm

In fact, algae is certainly already a part of the cleanup process in the case of constructed wetlands.
http://www.toolbase.org/Technology-Inventory/Sitework/constructed-wetlands
http://www.unep.or.jp/ietc/publications/freshwater/watershed_manual/03_management-10.pdf
 
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  • #470
...or did you mean that we tap the end of the discharge pipe for a controlled farm? Flying by the seat of my pants here, that sounds like a tempting idea. Open systems, such as wild blooms in the ocean, can be a real problem, but if the discharge was incorporated into a marine farm having a closed system, in broad strokes here, that could work.

As a best case, I would think, treatment on the front end would likely need to be significantly modifed, but waste products tend to be great sources of nitrogen and phosphorous - which is also critical to growth. The big problem that I do see here is that of toxins, industrial chemicals, and even measurable levels of drugs, like morphine! As it stands now, raw sewage is a real witch's brew. I don't know what the potential for serious drawbacks may be if algae intended for fuel is used to treat an uncontrolled discharge. For that reason, I would expect it likely that front-end treatment would be critical, with mainly the nitrogen and phosphorous left for the algae, at the discharge pipe.
 
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  • #471
Ivan Seeking said:
...or did you mean that we tap the end of the discharge pipe for a controlled farm? Flying by the seat of my pants here, that sounds like a tempting idea. Open systems, such as wild blooms in the ocean, can be a real problem, but if the discharge was incorporated into a marine farm having a closed system, in broad strokes here, that could work.

As a best case, I would think, treatment on the front end would likely need to be significantly modifed, but waste products tend to be great sources of nitrogen and phosphorous - which is also critical to growth. The big problem that I do see here is that of toxins, industrial chemicals, and even measurable levels of drugs, like morphine! As it stands now, raw sewage is a real witch's brew. I don't know what the potential for serious drawbacks may be if algae intended for fuel is used to treat an uncontrolled discharge. For that reason, I would expect it likely that front-end treatment would be critical, with mainly the nitrogen and phosphorous left for the algae, at the discharge pipe.

That's sort of what I was getting at. Though I hadn't thought of using the algae as part of the treatment... then using the algae as a source of fuel. Win win! I imagine controlling a bloom in the ocean would be difficult because of the changing conditions... but diverting the wastewater to a controlled environment makes sense. Thanks Ivan...!
 
  • #472
Ivan Seeking said:
In my own efforts, what ultimately drove the choice for the depth of the water in the reactor bed, was the need to avoid wild fluctuations in the temperature of the algae water.[...]
If you use water circulation that greatly reduces the temperature gradients, no?
 
  • #473
mheslep said:
If you use water circulation that greatly reduces the temperature gradients, no?

Yes, however we still have the problem of the total energy input [about 700-800 watts solar per sq meter that goes to heat, on a good day], and the resulting temperature rise.
 
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  • #474
Given my location, it was also necessary to assume a worst case of, nighttime lows of 20 degrees F, and many days - November through January - with as little as ~ 400 watts of heating per sq meter during the daylight hours. From the start it was clear that this was pushing the limits of what was manageable. Clearly it would be necessary to vary the strain as a function of the season. Strains that might work well here in the summer certainly couldn't be managed in the winter. There are low-temperature strains that it seemed might survive the winter months given the proper reactor design. One advantage that we have here is that our coldest days are usually bright and sunny. In theory, that gave me a bit of wiggle room. Also, by maximizing the contact area with the Earth [by shaping and sizing the ditches], relative to the reactor's exposed surface area, it was intended that enough heat from the Earth could be captured in order to survive the coldest nights.
 
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  • #475
The best case that I could see using processing and biotechnologies now, or, hopefully, soon to be available, and assuming that the price of fuel stays a little above $3.00 per gallon retail, was that a land-based farm might be profitable beginning at about 50k-100K acres. One of the big drivers for this was the efficiency of the power plant - for the power required to run the farm and processing equipment. At large scale, we can use systems having the highest efficiency - likely, turbine engines with heat recovery systems. Though, diesels modified for very high compression, for the nitrogen fix, are a promising avenue of thought. The very high compression makes them more efficient. Plus, we get the free nitrogen. I don't know if this same approach could be used on a turbine engine; that is, that we could get the same benefit of high NOX emissions.

100,000 acres is about 156 sq miles, or 12.5 miles on a side.
 
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  • #476
Another landmark achievement related to algae research: Bacterial Cell with a Chemically Synthesized Genome
:https://www.physicsforums.com/showthread.php?t=404603

The ability to design algae or bacteria for fuel production, has long been touted as a pinnacle achievement of future research, so this is highly significant to the viability of algae for fuel. Since microalgae and bacteria are simple life forms, one might hope for specific progress in this area - fuel production - as soon as any other. Not to mention that there is approximately a one-trillion dollar per year market incentive to replace fossil fuels, with sustainable, domestically produced, clean fuels, just in the US.

This could eventually open the door to a viable supply of organically-produced hydrogen. If we have a viable source of hydrogen, the hydrogen economy will have its currency. Note that microalgae may be a potentially good source of hydrogen, as well as ethanol, biodiesel, and perhaps even fuels similar to gasoline.
 
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  • #478
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  • #479
I will quote from the other thread and redirect any additional discussion here

Ivan Seeking said:
Oil from algae is just vegetable oil. It is non-toxic. You can drink it. And it degrades readily. Also, without a significant source of nitrogen and the proper temps, the algae won't survive in open water - that is, it wouldn't exist as a giant plume that kills everything else. If you have these conditions, you would already have an algae bloom, in most cases.

You would certainly have a lot of fish food!

Also, you wouldn't have millions and millions of gallons of oil leaking endlessly. You could only spill the oil that has been processed. The rest is still trapped in the algae.
https://www.physicsforums.com/newreply.php?do=newreply&p=2730137
 
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  • #480
Note that there are some strains of algae that release neurotoxins. Obviously these strains are not considered viable candidates for fuel production. They do present a real threat, however, to anyone working with algae. It is important to know what you're dealing with. Toxic, invasive strains, could be an issue if not checked. Again, a batch process helps to minimize this concern.