Exploring Microalgae as Solutions to Global Fuel Issues

[Ivan Seeking]

In order to maximize the effective area of the reactor, perhaps the ideal cycle would be to drain one-half of the volume of water from given cell once every doubling period That is, if the algae doubles in mass every two days, then every two days we harvest half of a 1% solution and replace the water. There are any number of variations that one can imagine here, and which is best might be debated. However, perpetual systems are prone to contamination concerns and mutations that reduce yields. Based on this information and a number of discussions with algae biologists supporting those views, it was decided that a hybrid batch system was the best approach. Cells will need to be drained and sterilized periodically, so cell recovery time is a critical concern. It takes a long time, perhaps 20 doubling periods, to get from even hundreds of gallons of algae water, to many million of gallons. To me it seemed imperative to ensure that a ready supply of innoculant is avaiable and and a clear strategy in place that minimizes the recovery time for any cell taken out of service. However, this could be treated as a perpetual system to the extent that the yields and resident biologist allow.

 

[Ivan Seeking]

11-12 c / kWh sounds overly optimistic, but I don't see anything wrong with your figures. Note that's the bus-bar, or wholesale price of electricity. Even large industrial customers would pay an extra 20%, double for residential daytime.

Consider that our assumptions were based loosely on the wholesale price of fuel. That in turn drove the budget plans. So I guess it isn't surprising that the two numbers would agree.

We paid the price for this in part when our bioreactor was reduced to lined, covered ditches, in a pressed clay form. What is the amortized equipment cost and operating cost for the solar farm mentioned, on a per sq-ft per year basis? Do they come anywhere close to 12 cents? I would bet that just the cost of the reflectors kills any chance of meeting that budget requirement.

At the same time algae has the advantage of providing a direct method to store the solar energy indefinitely as diesel, where as solar arrays catch a week of snow or clouds and shut down. That is, algae can 'do baseload', solar concentrators not, not more than ~24 hours. Given these pros and cons, its not clear to me whether algae biofuel works better economically as a transportation fuel or for electric generation.

I couldn't get this out of my head and had to make a quick post. This had never occurred to me before. Using the business strategy discussed, the algae farm itself becomes a transition technology that supplies carbon-neutral fuel for more efficient diesel technologies in today's hydrocarbon world, while having the ability to transition to electrical power generation as plug-in hybrids and all-electrics increase the load on the grid. In any event, any site might be planned with future additional generating capacity implicit to the design. After considering the equipment costs for processing the fuel, the cost of additional generating capacity is relatively minor.

Should algae produce fuels for less than $5 or so, and assuming that traditional fuels are similarly priced, I don't tend to think people will want to give up the power of diesel for batteries. So unless electric vehicles gain a siginficant market-price advantage, I don't tend to expect a large swing to electric-powered transporation.

 

[Ivan Seeking]

... i.e 47500 KW-Hrs per a-y and assuming a %100 duty cycle --> 5.5 KW per acre. Using a price est of $50 per KW for the generator, we can amortize a cost of about 0.6 cents per sq-ft over ten years min... at scale, perhaps 30 years. This assumes a 100% generating capacity - a 1:1 ratio of fuel produced to fuel that can be used to sell power.

 

[mheslep]

In any event, any site might be planned with future additional generating capacity implicit to the design. After considering the equipment costs for processing the fuel, the cost of additional generating capacity is relatively minor.

Yes, ok, so the tanks need (or growth is greatly enhanced by?) the CO2 from some fosile burning electric plant and is collocated. An appealing economic plan might be that the a. farm sells diesel to transportation nominally, but the generation plant is dual fuel - say coal boiler or diesel engine? If the price of transportation fuel falls for some reason, the a. farm diverts to electric generation.

Should algae produce fuels for less than $5 or so, and assuming that traditional fuels are similarly priced, I don't tend to think people will want to give up the power of diesel for batteries. So unless electric vehicles gain a siginficant market-price advantage, I don't tend to expect a large swing to electric-powered transporation.

Not power, range is the EV limitation, that and turn around time at depletion.
On a cost per mile basis, including battery cost and electricity cost versus petroleum cost per gallon, EVs are cheaper now: battery cost ($800/kWh or lower) + US electric energy cost = diesel at $3.5/gal.

It turns out interestingly, it's nearly always been this way: EV's were a better deal economically but didn't have the range. I just finished B. Schiffer's https://www.amazon.com/dp/1588340767/?tag=pfamazon01-20, fascinating story about EVs running all over America from 1900 to ~1920:

o Edison's involvement, developed the Nickel Iron battery just the EV.
o Edison and Henry Ford attempted together an electric version of the model T
o New York to Chicago 1000mile long distance demonstration trips
o 70mph stunt EV that lost control and killed some gawkers.
o Some three dozen US EV makers at the peak.
o EVs were more reliable, lasted longer than the gasoline cars.
o Women loved them as they didn't need a hand crank.
o City-local EV truck fleets all over, i.e., the milk truck was often an EV.
o EV taxicabs with charging stations in front of all the big north east city hotels where they charged and waited for fairs.
o Price of electricity dropping while the price of gasoline was rising (!).
o Towards the end a few hybrids were made.
o "MIT performed a study" (!) demonstrating better economics per mile in EVs.​

Seems this whole thing already happened 90 years ago.

In the end, people wanted to dash long distances and "enjoy with his family the blessings of happy hours spent in God's great open spaces." - Ford. America was just too big, and at that time, had too little electrification.

 

[mheslep]

One the better known EV manufacturers, closely tied to Edison, was Baker Electric. 1912 model:

Edison in an early Baker EV

Walker Vehicles Electric Truck 1918. Made in Chicago.
Top speed 14 mph, range <40 mi

1923 Advertisement for the Walker:
"Marshall Field & Co. operate 276 Walker Electric Trucks -- the largest store fleet of electrics in the world."
http://www.megawattmotorworks.com/classifieds/filelist_download_poster.asp?id=745

 

[Ivan Seeking]

Yes, ok, so the tanks need (or growth is greatly enhanced by?) the CO2 from some fosile burning electric plant and is collocated. An appealing economic plan might be that the a. farm sells diesel to transportation nominally, but the generation plant is dual fuel - say coal boiler or diesel engine? If the price of transportation fuel falls for some reason, the a. farm diverts to electric generation.

I see, a hybridized algae-coal plant that plays the numbers according to growth rates, fuel prices, and electrical prices. Interesting. Immediately one wonders about ratios of biomass or algae oil, to coal, as a fuel option for the plant as well. The volatility of energy prices has always been one of the most difficult problems for alternative options to power through, so to speak.

Not power, range is the EV limitation, that and turn around time at depletion.

Okay, but there are limits. For example, it is hard to carry groceries in the Tesla. We have to include weight and space considerations as a function of hp, range, and torque.

On a cost per mile basis, including battery cost and electricity cost versus petroleum cost per gallon, EVs are cheaper now: battery cost ($800/kWh or lower) + US electric energy cost = diesel at $3.5/gal.

Yes, but it is the combined cost of the fuel and the vehicle that will determine the winner. The cost is weighed against range, peformance, carrying capacity, comfort, handling, etc. Either way I think we agree that the decider will be the consumer. Beyond making EVs affordable, and I think sticker price has to be heavily weighted, they also have to be competitive on a variety of levels. The fact that EVs have always been a better per-mile price option is evidence that this alone is not enough.

 

[Ivan Seeking]

It would be interesting to compare the price and energy density of coal, and efficiency of coal compared to diesel, for example, in burners. If someone else doesn't do this first... hint hint...

 

[joelupchurch]

I'm very interested in electric cars. IBM is working on something called the Battery 500 Project. They want battery technology that can give a car a range of 500 miles. The main interest is in what is called the Lithium-Air battery.

http://www.almaden.ibm.com/institute/agenda.shtml"
http://www.youtube.com/watch?v=ZmHZhBqI500"

If we can build a reasonably priced battery with a storage capacity of 1 Kilowatt-hour per kilogram then it is a whole new ball game.

 

[joelupchurch]

There is a new paper in Nature Biotechnology:

http://www.nature.com/nbt/journal/v27/n12/full/nbt.1586.html"

They use GE bacteria to produce isobutyraldehyde. The next step is to convert isobutyraldehyde to isobutanol for fuel. They claim the process is more efficient than using algae.

 

[mheslep]

I'm very interested in electric cars. IBM is working on something called the Battery 500 Project. They want battery technology that can give a car a range of 500 miles. The main interest is in what is called the Lithium-Air battery.

http://www.almaden.ibm.com/institute/agenda.shtml"
http://www.youtube.com/watch?v=ZmHZhBqI500"

If we can build a reasonably priced battery with a storage capacity of 1 Kilowatt-hour per kilogram then it is a whole new ball game.

Yes there's been some discussion of IBM's metal air efforts in the Electric Vehicles thread, post https://www.physicsforums.com/showpost.php?p=2381699&postcount=85"
Probably best to continue over there, or:
http://www.technologyreview.com/energy/22780/
http://www.yardney.com/Lithion/Docum...rAD-JD-KMA.pdf

 

[mheslep]

. They claim the process is more efficient than using algae.

For comparision, they use the algae benchmark: "a well-designed [biodiesel from algae] production system" can produce ~1 × 10^5 liter per hectacre - year, or 10691 gal per acre - year. That's a cite from Chisti, Y. Biodiesel from microalgae beats bioethanol. Trends Biotechnol. 26, 126–131 (2008).

They claim their process can exceed this by 55%, phenomenal. That's approaching the efficiency of a solar thermal plant. Seems optimistic. I thought algae was already at photosynthetic limits.

 

[OmCheeto]

There is a new paper in Nature Biotechnology:

http://www.nature.com/nbt/journal/v27/n12/full/nbt.1586.html"

They use GE bacteria to produce isobutyraldehyde. The next step is to convert isobutyraldehyde to isobutanol for fuel. They claim the process is more efficient than using algae.

Hmmm... Would I want to live next to an algae refinery, or and isobutyraldehyde processing plant?:

Algae: smells bad when dead

http://www.cdc.gov/niosh/ipcsneng/neng0902.html"[/URL] : Highly flammable. Gives off irritating or toxic fumes (or gases) in a fire. Vapour/air mixtures are explosive. Much harder to pronounce.

And it might just be me, but I'm always afraid some genetically enhanced bug is going to turn into an Andromeda Strain type of scenario if they escape into the open ocean. Imagine a bug that lives on sunlight and CO[SUB]2[/SUB], thriving world wide, spewing flammable liquids as a byproduct. :eek:

 

[mheslep]

Algae: smells bad when dead

What doesn't?

 

[Ivan Seeking]

Actually, almost none of the algae that I grew had a noticable odor. The only exception occurred when I maximized the nutrients to determine the max growth rate, at which time it smelled a bit like vitamins.

 

[Ivan Seeking]

For comparision, they use the algae benchmark: "a well-designed [biodiesel from algae] production system" can produce ~1 × 10^5 liter per hectacre - year, or 10691 gal per acre - year. That's a cite from Chisti, Y. Biodiesel from microalgae beats bioethanol. Trends Biotechnol. 26, 126–131 (2008).

They claim their process can exceed this by 55%, phenomenal. That's approaching the efficiency of a solar thermal plant. Seems optimistic. I thought algae was already at photosynthetic limits.

None of it means anything until we have a cost comparison basis. We could solve the energy problem tomorrow if we spent enough on solar cells as well. Note also that afaik, solar thermal plants are not yet cost competitive. Options are great but they have to be cost-competitive or it is just more pie in the sky.

Algae is nowhere near the photosynthetic limit. Just check the PAR for any strain and that is easy to see. I want to say that most high-yield strains are in the 20% range, but I don't recall the reference for that. It also depends on what we mean by the limit. For example, UV is not used for hydrocarbon production and can damage the cell. All PAR charts that I saw ended at UV frequencies.

 

[mheslep]

Algae is nowhere near the photosynthetic limit. Just check the PAR for any strain and that is easy to see. I want to say that most high-yield strains are in the 20% range, but I don't recall the reference for that. It also depends on what we mean by the limit. For example, UV is not used for hydrocarbon production and can damage the cell. All PAR charts that I saw ended at UV frequencies.

I was referring to a general photosynthetic limit of about 11% for any from sources like this:

[...]Only light within the wavelength range of 400 to 700 nm (photosynthetically active radiation, PAR) can be utilized by plants, effectively allowing only 45 % of total solar energy to be utilized for photosynthesis. Furthermore, fixation of one CO2 molecule during photosynthesis, necessitates a quantum requirement of ten (or more), which results in a maximum utilization of only 25% of the PAR absorbed by the photosynthetic system. On the basis of these limitations, the theoretical maximum efficiency of solar energy conversion is approximately 11%.

http://www.fao.org/docrep/w7241e/w7241e05.htm#1.2.1 photosynthetic efficiency

I see references on various algae strains at http://www.bioenergywiki.net/images/d/de/Egger_Energy_Efficiency.pdf" (page 9). Thus this bio-isobutanol process, if it is indeed 50% higher yield than algae, would be at or near the photosynthetic limit.

 

[joelupchurch]

For comparision, they use the algae benchmark: "a well-designed [biodiesel from algae] production system" can produce ~1 × 10^5 liter per hectacre - year, or 10691 gal per acre - year. That's a cite from Chisti, Y. Biodiesel from microalgae beats bioethanol. Trends Biotechnol. 26, 126–131 (2008).

They claim their process can exceed this by 55%, phenomenal. That's approaching the efficiency of a solar thermal plant. Seems optimistic. I thought algae was already at photosynthetic limits.

If you look back at my post of Nov 19th, the paper I quoted said the theoretical limit for Biodiesel is 28,000 gallons per acre/year. 10,000 gallons was my guess for the practical limit.

Another thing to consider is to also adjust for BTUs per gallon. Biodiesel is around 130,000 BTUs per gallon, while isobutanol is around 95,000. That is still a lot better than ethanol, which is around 76,000.

 

[joelupchurch]

And it might just be me, but I'm always afraid some genetically enhanced bug is going to turn into an Andromeda Strain type of scenario if they escape into the open ocean. Imagine a bug that lives on sunlight and CO₂, thriving world wide, spewing flammable liquids as a byproduct.

Considering we share our planet with Methanogens, that generate a flammable gas, the additional risk seems small. Of course, we now know that the big risk is when the methane doesn't catch on fire and is released into the atmosphere. Burning the methane reduces it's GHG potential by a factor of over 20.

I'm reading Stewart Brand's new book, "Whole Earth Discipline". Once you understand that we live in a genetic soup with organisms constantly swapping genes with other species, then what scientists do in the lab is small potatoes and extremely safe by comparison.

 

[OmCheeto]

Considering we share our planet with Methanogens, that generate a flammable gas, the additional risk seems small. Of course, we now know that the big risk is when the methane doesn't catch on fire and is released into the atmosphere. Burning the methane reduces it's GHG potential by a factor of over 20.

I'm reading Stewart Brand's new book, "Whole Earth Discipline". Once you understand that we live in a genetic soup with organisms constantly swapping genes with other species, then what scientists do in the lab is small potatoes and extremely safe by comparison.

A quick google of methanogens shows them to be predominantly anaerobic, hence minimizing their flourishment in our very aerobic surface world.

Now the methanogen-cow symbiotic system on the other hand:

http://microbewiki.kenyon.edu/index.php/Methanosarcina_barkeri
M. barkeri is also seemingly efficient. It has been said that a well-fed dairy cow can produce as much as 500L of intestinal gas in one day, 35% of which is methane. M. barkeri is thought to be primarily responsible for that 35%.

Methane has an energy content of about 1000 BTU/cubic foot, which equals about 35 BTU/L. If M. barkeri produces only 20% of the methane passed by a dairy cow, which yields 100L of methane, enough to produce 3500BTU. This is enough energy to melt 24.5 pounds of ice or run a 1hp motor for 20 minutes. By this conservative estimate, M. barkeri holds enormous potential as an alternative energy supplier. (Wikipedia references: British Thermal Unit, Methane)

Perhaps we need to put pilot lights on all the cow butts.

Wait! Let's feed the algae to the cows and collect the gas. I'm sure no one has thought of that before.

google, google, google...

Drat!

All the good ideas are always taken...

http://www.environmentalgraffiti.com/ecology/scientists-attach-rectal-methane-collecting-backpacks-to-cows/1390"
Thu, Jul 10, 2008



And just to put this idea to rest:

Cow Flatulence Power
1.90E+09 cows on the planet
3.50E+03 btu/cow/day
2.43E+15 btu/yr

worldwide energy usage
4.49E+17 btu/yr

conclusion:
After spending money on 1.9 billion rolls of duck-tape and pink inflatable bags, cows will produce 0.54% of our energy needs.

Next idea please!

 

[joelupchurch]

That's a coincidence. I used the same picture for something I wrote on the GHG footprint of cheese. I'm thinking about a doing a follow up on Velveeta.

The picture is from some research on cattle emissions in Argentina and the tube is running into the cow's stomach, not the rectum.

http://www.physorg.com/news135003243."

 

[mheslep]

I'm reading Stewart Brand's new book, "Whole Earth Discipline". Once you understand that we live in a genetic soup with organisms constantly swapping genes with other species, then what scientists do in the lab is small potatoes and extremely safe by comparison.

I'm not sure that's a fair comparison. Yes nature does a great deal of gene swapping, but it also puts up strong impediments that rule out most of the swaps. That is, elephants can't breed with mice in nature, but scientists can make it so in the lab. More generally speaking, nature constantly seeks low energy optimizations and throws up high energy hurdles that makes some combinations unseen in three billion years of of mix and match. We can leap those energy hurdles on what may be an ill-considered moment.

 

[joelupchurch]

I'm not sure that's a fair comparison. Yes nature does a great deal of gene swapping, but it also puts up strong impediments that rule out most of the swaps. That is, elephants can't breed with mice in nature, but scientists can make it so in the lab. More generally speaking, nature constantly seeks low energy optimizations and throws up high energy hurdles that makes some combinations unseen in three billion years of of mix and match. We can leap those energy hurdles on what may be an ill-considered moment.

Actually it appears to be that at the microbial level, that almost anything can swap genetic material with almost anything else and if you are surprised, it wasn't the way I learned it in school either. There is a whole new science called Metagenomics, where they talk of microbial communities, rather than individual species. Here is a link to the National Academies about Metagenomics:

http://dels.nas.edu/metagenomics/about.shtml"

Amazingly enough, Metagenomics is actually relevant to the climate forum. Here is link to a discussion about bacteria in the carbon cycle:
http://dels.nas.edu/metagenomics/global_change.shtml"

 

[mugaliens]

Now the methanogen-cow symbiotic system on the other hand..

Best gut-busting picture I've seen in a long time, and I'm not talking about the cow!

Wait! Let's feed the algae to the cows and collect the gas. I'm sure no one has thought of that before.

Why not just feed them sawdust rendered less acidic?

conclusion:
After spending money on 1.9 billion rolls of duck-tape and pink inflatable bags, cows will produce 0.54% of our energy needs.

Next idea please!

Termites! If I'm not mistaken, they produce several times the methane of cows. Then again, is there even a tube that small?

Perhaps we could simply raise termite farms.

Ok, next idea:

Bacteria. But that's the cause of the amounts of methane steaming off our landfills. So why not just cover them, collect the methane and burn it?

Actually, it's already http://www.epa.gov/lmop/" .

 

[mheslep]

Response to earlier queries/comments about alt-jet fuel

Media Reports:
http://blogs.wsj.com/environmentalcapital/2009/06/17/veggie-power-plant-based-jet-fuel-outperforms-oil-based-jet-fuel/"

In 2008 and 2009, the consortium tested several blends of up to 50% biofuel in Boeing jets belonging to Air New Zealand, Continental Airlines and Japan Airlines. The blends were different combinations oil from jatropha (an oily seed plant that grows in arid climates), camelina (a fatty mustard-like seed) and algae, which reproduces prodigiously fast.

Tests were on normal, unmodified engines. They blended regular jet fuel w/ bio derivatives. Algae fuel was at most 8% of the blend. Edit: I didn't know that hydrogen must be added to the bio-oils to make jet fuel. That will inevitably come from natural gas.

also
http://www.wired.com/autopia/2008/06/aviation-gets-b/"

Boeing technical report:
http://www.boeing.com/commercial/environment/pdf/PAS_biofuel_Exec_Summary.pdf
Edit: Interesting to see all of the technical players that signed the report:

• GE-Aviation
• Rolls Royce
• Honeywell Aerospace
• Pratt and Whitney
• Boeing
• DARPA/STO
• CFM

and the four airlines.Of course I'm still betting on the electric airplane ;-)
https://www.physicsforums.com/showpost.php?p=2304796&postcount=34
https://www.physicsforums.com/showpost.php?p=2304796&postcount=35

 

[mheslep]

AltAir Fuels has been selected to provide the bio jet from Camelina.
On their http://www.altairfuels.com/gjf.html" they say:

5. Camelina is grown in rotation with wheat and as such, does not displace food crops. It also provides new sources of revenue and jobs for farmers.

Does not displace food crops? BS! Same game as corn ethanol.

 

[Ivan Seeking]

If it is found that a system can be run as if perpetual for extended periods of time, say on the order of months at a time, for example, we get back to the idea of a modified V. During the early stages of growth when we have perhaps 0.1 % of the mass of algae as compared to what we expect at harvest time, using a ditch shaped like a V helps to minimize the water volume - the volume of water goes as the square of the depth - which is helpful to minimize the volume of innoculant required. Also, a V shape is easy to drain. However, for the time that a system can be maintained in a perpetual state, we want to utilize the entire surface area of the reactor cell. This suggests that we want to use something like a U, perhaps with a sharper slope at the bottom of U for good drainage. The U/V might also be skewed according to the relative angle of the sun, at the given latitude, in order to reduce the amount of light that reflects from the walls [reducing the energy input]. As was mentioned earlier, the shape also affects the efficiency of aeration and circulation. The vertical or parallel walls in the upper portion of the reactor allow the volume of water to be varied without significantly reducing the effective surface area. This is where my design stood when the effort began to unwind.

If algae is grown under the conditions described, then the shape of the reactor could be significant to yields. It would seem prudent to further explore this issue. The only options to covered ditches seem to be open or covered ponds, or some variation on large plastic bags. There may be a few other twists on this out there but it would seem to be an implicit requirement that we use something very inexpensive and simple. How else could one possibly meet the budget requirement of 12 cents per sq foot per year, or anything even close to that, for the entire complex?

Here are a few questions that may merit discussion. At some point I may pop in with an answer or two, but anyone who wants to help is certainly welcome:

1). Again, what is the energy density of coal and the processing efficiency of a coal plant? What is the net efficiency of the system, from the mining to the generator, and how much water and petro fuel do we use?

2). Do we have a solid reference for the theoretical limit of algae yields. I know we had some references mentioned, but are they well-supported?

3). Using industry standards as a guideline, I estimated that it would require a minimum of about one metric ton of nitrate per acre-year, in order to produce 6000 gallons of fuel. I do recall having some references that allow for a rigorous calculation here, for the nitrogen mass required, but a few of my best links went dead long ago. Maybe someone here can find a good reference? If we produce 6000 gallons of fuel, using 7.3 pounds per gallon, we get 43,800 pounds of algae oil/fuel. If we assume this represents 40% of the dry mass of algae, then we harvested 110,000 pounds of algae, with 60% of this, or about 66,000 pounds, as plant fiber. One metric ton of nitrate is 2200 pounds, or a little over 3% of the mass of dry algae fiber. Is this enough nitrogen to produce 66,000 pounds of plant fiber? Again recall that I am working from memory here, not notes. Hopefully I have reconstructed this properly but a rigorous check of the information would be entirely appropriate. The minimum theoretical nitrogen requirement is a very important number to know.

Late edits: a bit of cleanup

 

[Ivan Seeking]

4). Can the water and the plant fiber from processed algae biomass, be treated with chlorine, presumably, or perhaps treated with a biological agent of some sort, and fed back into the reactor system? Can the algae biomass be effectively recycled in order to preserve the nitrogen? Or, perhaps the biomass is best preserved through combustion, for power production, with the exhaust gases fed back to the algae? This might also allow a fuel farm to shift the operating energy burden from saleable fuel, to less valueable biomass.

 

[mheslep]

...

1). Again, what is the energy density of coal and the processing efficiency of a coal plant? What is the net efficiency of the system, from the mining to the generator, and how much water and petro fuel do we use?

Price per short ton, energy per pound

• Central Appalachia 12,500 Btu/lb (29MJ/kg), 1.2 SO2: $55
• Northern Appalachia 13,000 Btu/lb (30MJ/kg), <3.0 SO2: $52
• Illinois Basin 11,800 Btu/lb (27MJ/kg), 5.0 SO2: $40
• Powder River Basin 8,800 Btu/lb (20 MJ/kg), 0.8 SO2: $9
• Uinta Basin 11,700 Btu/lb (27MJ/kg), 0.8 SO2: 39

http://www.eia.doe.gov/cneaf/coal/page/coalnews/coalmar.html

So it appears a zero sulfur fuel might fetch $60 per 13,000 Btu tops. Mining costs likely not relevant to the electric plant operator, just the end fuel cost.

As I posted earlier, I think algae BD must mainly target transportation, despite the advantages of a closed system electric - algae farm plant, unless there is a substantial penalty levied on coal.

 

[Ivan Seeking]

Price per short ton, energy per pound

• Central Appalachia 12,500 Btu/lb (29MJ/kg), 1.2 SO2: $55
• Northern Appalachia 13,000 Btu/lb (30MJ/kg), <3.0 SO2: $52
• Illinois Basin 11,800 Btu/lb (27MJ/kg), 5.0 SO2: $40
• Powder River Basin 8,800 Btu/lb (20 MJ/kg), 0.8 SO2: $9
• Uinta Basin 11,700 Btu/lb (27MJ/kg), 0.8 SO2: 39

http://www.eia.doe.gov/cneaf/coal/page/coalnews/coalmar.html

So it appears a zero sulfur fuel might fetch $60 per 13,000 Btu tops. Mining costs likely not relevant to the electric plant operator, just the end fuel cost.

As I posted earlier, I think algae BD must mainly target transportation, despite the advantages of a closed system electric - algae farm plant, unless there is a substantial penalty levied on coal.

Thanks. I will be getting back to this later, but my first interest was to explore the efficiency of algae biomass, as compared to coal, for engineering, not economic purposes. In particular, does it make sense to burn biomass, rather than algae oil, to power the farm? How much energy is available in the plant fiber? What then is the total yield of the farm in terms of power output?

As for price, I was hoping to get some perspective on the coal-to-power process, and how that compares to algae, step by step.

I don't see it so much as targeting fuel or electric, rather the most practical hybrid of the two. But in the end it all comes down to the price per unit of energy. As you alluded to earlier, by using the wholesale price of petro fuel as the basis for the business model, we are effectively shooting for a grid-competive price for power as well. It seems that a near zero-emissions algae farm and generating station might be constructed quickly, and would have far more flexibility than coal or nuclear, in terms of location wrt to population centers. Also, I do believe coal processing requires a great deal of water, while a closed algae system, in principle, would not. My hope is that algae power might be so benign in terms of environmental impact, political volatility, perceived and genuine risk, and public health, as compared to other sources, that it has a significant market advantage.

 

[Ivan Seeking]

3). Using industry standards as a guideline, I estimated that it would require a minimum of about one metric ton of nitrate per acre-year, in order to produce 6000 gallons of fuel. I do recall having some references that allow for a rigorous calculation here, for the nitrogen mass required, but a few of my best links went dead long ago. Maybe someone here can find a good reference? If we produce 6000 gallons of fuel, using 7.3 pounds per gallon, we get 43,800 pounds of algae oil/fuel. If we assume this represents 40% of the dry mass of algae, then we harvested 110,000 pounds of algae, with 60% of this, or about 66,000 pounds, as plant fiber. One metric ton of nitrate is 2200 pounds, or a little over 3% of the mass of dry algae fiber. Is this enough nitrogen to produce 66,000 pounds of plant fiber? Again recall that I am working from memory here, not notes. Hopefully I have reconstructed this properly but a rigorous check of the information would be entirely appropriate. The minimum theoretical nitrogen requirement is a very important number to know.

After thinking about this, I realized that I should modify that statement as it is a bit misleading. If we assume that we have 40% oil by weight, then we might expect to find that 20% of the total mass is sugar. The yields and the ratio of oil to sugar can vary greatly between strains and even between harvest cycles. In practical terms, we may only have 40%, or 43,800 pounds of plant fiber. I was implicitly assuming that we have an algae strain that only produces oil, which is ideal but not realistic. However, my exposure to the subject suggests that 40% oil yields are realistic. Additionally, biologists are working to control the chemical switch that selects for oil or sugar production. This may help to increase the oil [or sugar, if desired] content significantly beyond 40% yields.

I should have dug into my notes for this but they were stored away in a recent reorganization of my office.

 

[joelupchurch]

After thinking about this, I realized that I should modify that statement as it is a bit misleading. If we assume that we have 40% oil by weight, then we might expect to find that 20% of the total mass is sugar. The yields and the ratio of oil to sugar can vary greatly between strains and even between harvest cycles.

This is probably a stupid question; can't the sugar be converted to ethanol for additional fuel?
Does a Biodiesel/Ethanol blend make any sense? Would it lower the freezing point for the Biodiesel?

 

[Ivan Seeking]

This is probably a stupid question; can't the sugar be converted to ethanol for additional fuel?
Does a Biodiesel/Ethanol blend make any sense? Would it lower the freezing point for the Biodiesel?

I don't think a biodiesel/ethanol blend would work in diesels, but ethanol from algae is definitely an area of interest, as is hydrogen from algae, which is what the folks at MIT have been developing.

 

[mheslep]

I don't think a biodiesel/ethanol blend would work in diesels, but ethanol from algae is definitely an area of interest, as is hydrogen from algae, which is what the folks at MIT have been developing.

Right it wouldn't work in a diesel, but one could still burn the mix in an open flame steam boiler.

 

[Ivan Seeking]

Does anyone have any information on the algae-to-ethanol process? I never saw a good description of the process.

It was interesting to note than in my own investigations, when the algae was burned, there was a white residue that would literally drip [as a liquid] from the burning algae. The residue quickly cooled to a hard white blob. I think it was the sugar but I never had it tested.

I wondered, if it was the sugar, might it be possible to separate the sugar from the algae this way.

 

[mheslep]

Does anyone have any information on the algae-to-ethanol process? I never saw a good description of the process.

It was interesting to note than in my own investigations, when the algae was burned, there was a white residue that would literally drip [as a liquid] from the burning algae. The residue quickly cooled to a hard white blob. I think it was the sugar but I never had it tested.

I wondered, if it was the sugar, might it be possible to separate the sugar from the algae this way.

I would not have thought there would be anything particular to the 'algae ethanol' process, after the sugar molecules have formed. Once one has sugar, the usual drying and fermentation procedures should apply. Before that point, you've made reference to the sensitivities of various strains producing either oil or sugar, depending also on conditions, and on that point I have no information.