Regarding Time citing Isaac Berzin and his work with algae as something exciting and hopeful, my own view is that anything being touted up on one of Time's 'lists' (or worse yet, People's lists) is, apriori, of suspect value and not to be taken too seriously.
Consistent with that admittedly cynical view, let us remember that Isaac Berzin's company, Green Fuel Technology, is the one which was doing work blowing power plant stack gas up through vertical plexiglas tubes filled with an algae suspension. Surely, there cannot be any serious thought on the part of anybody even halfway technically competent that such a scheme for capturing CO2 from power plants is even remotely scalable. (Try to visualize square mile upon square mile of clear plastic tubes filled with specially bred algae, or dozens of clear plastic domes the size of the Astrodome.)
To me, this is one of those things that is such a non-starter as to be capable of being dismissed 'by inspection'. Yet, venerable publications such as Time really eat this stuff up, mainly because on the surface it looks exciting and makes for good ink. The level of technical illiteracy among the journalist establishment never ceases to amaze me.
The popular mainstream media is not the place to look if you really want to know what important technological developments are taking place.
I will close this little rant by saying that I'm a firm believer in developing better technology in a wise manner, simply because technology is what humans DO and the application of technology is one of main things that seperates us from the beasts (including the higher primates of which we share most of our genes).
Surely, there cannot be any serious thought on the part of anybody even halfway technically competent that such a scheme for capturing CO2 from power plants is even remotely scalable. (Try to visualize square mile upon square mile of clear plastic tubes filled with specially bred algae, or dozens of clear plastic domes the size of the Astrodome.)
Nice links and photos. I presume the 3rd photo is an artist rendering? Anyway, read National Geographic's article on the potential for algae ethanol and was impressed by how much more fuel could potentially be produced over a year's time. It was 3,000 gallons for corn ethanol, and as much as 50,000 gallons for algae ethanol, due in great part to the speed at which algae grows year round. Most people are not aware that the oil we use is the result of millions of years of compression and heat applied to dead algae. As the oceans stagnated algae filled them, then sank to the bottom, the ocean life died due to a lack of oxygen and soil filled over those layers, techtonic plates slipped and moved and eventually all that algae ended up as oil in two distinct layers in the crust, dating back from two eras 90 and 150 million years ago.
So it would seem that if oil can be mass produced as a viable form of ethanol, our best bet is to find ways to scale up algae ethanol production. We flew back from Oklahoma to California via an airline that flew too slow and too low, but what I realized from the view was just how many empty valleys there are in Arizona, Utah and Nevada that could be used to make ethanol.
I think the process of using CO2 enriched air as a way to capture it from Coal should not be requisite to make algae ethanol. It would seem that if plain old simple air is pumped fast enough the CO2 will get converted and we should have lots of fuel, but I'm not certain of that - please illuminate me. As a result, as an investor, I have been keeping my eye on Greenfuel Tech., waiting for that right company to invest in. My understanding is Verasun has a stake in Greenfuel, so if it does take off they may be a good bet. Right now I'm taking a wait and see approach. But certainly one to watch.
The window frame of opportunity to catch the world economy before it dumps in catastrope, by way of a scaled up mass produced fuel, is still open but we must move fast. Otherwise at some threshold of price for energy the world economy will stagnate, then price of energy and economic activity will balance/stalemate at some tepid level not conducive to well being of 6.5 billion people.
Corn yields perhaps 2.8 gal/bu and averages ~150 bu/acre, so you're going to see around 420 gal/acre. Anyone claiming 3000 gallons from corn is smoking something.
Credible algae claims are in the region of 5000 to 10000 gal/ac. Even 2000 would be pretty darn good for a cheap process.
I'm probably stating the obvious or asking a stupid question, but...
Corn is a solid, is it not? So you ned to add the liquid, do you not? If making ethanol is anything like brewing drinking alcohol, then you need sugar, water, yeast. So wouldn't making ethanol have an impact on the water supply?
Corn yields perhaps 2.8 gal/bu and averages ~150 bu/acre, so you're going to see around 420 gal/acre. Anyone claiming 3000 gallons from corn is smoking something.
That is for oone crop. Maybe some areas can have 3 crops a year, assuming 350 bushsls/acre and 3gal/bu, that would work. But it seems to be a stretch.
BTW, How much biomass is in the cobs and stalks, compared to corn kernels?
To me it seems that there is more potential in processing the "waste".
That is for oone crop. Maybe some areas can have 3 crops a year
What strain of maize can come to maturity in 120 days at that yield? With enormous amounts of water, phosphate and nitrate I suppose you can do anything, but algae seem cheaper.
How much biomass is in the cobs and stalks, compared to corn kernels?
Around half (maybe more if cobs are included, I haven't checked lately). A bushel of corn is 56 pounds, so 150 bu/ac is 4.2 tons. The Corn Stover Collection Project found roughly 2 tons/acre of harvestable stover, after allowing for erosion control.
The last picture with the great field of long narrow ponds in which algae are to be grown in from Solix Biofuels. On the web it is said that they are based in Boulder Colorado. But I can't find them locally here in Boulder County. They are also said to be cooperating with the New Holland Brewery in Fort Collins on a demonstration project using the CO2 from brewing beer to feed some algae. The picture is surely wishful thinking. There is no place in northern Colorado with such a wide open expanse of flat, unoccupied land, and open ponds (copied from the long gone algae project on a predecessor organization of Dept of Energy, NREL) would surely be uneconomic in our northern latitude, high elevation location.
They are also associated with Colorado State University (CSU) in Fort Collins. It has been at least a year since I saw any publicity about them locally. It appears to me that their association with the CSU is somewhat of an embarrassment to CSU.
All work on algae that I have seen, always assumes that it is necessary to feed the algae with high concentration CO2. So proposers always mention working near coal fired power plants.
An association with a brewery, in a college town, is surely a good idea for experimental work, but the growing ponds in their PR vastly out size the CO2 source of the New Holland Brewery. An algae technology that requires a fossil fuel source of high concentration CO2 seems to me not to be a post fossil fuel solution.
It depends on your definition of high. While there is some increase in yield with increased concentration, the overall levels of CO2 that are productive seem to lie below 5%, depending on which algae you are growing.
If the overall concentration of CO2 in the atmosphere ever rises to 5%, we are all dead. Dead people have no energy independence issues. Problem solved.
I was referencing the feed concentrations, and this ties into the use of CO2 extraction from the flue gas. There is no economic incentive, to do that concentration since the higher levels of CO2 in the feed would not be productive. Remember also that the off-gas from the process is oxygen.
I assumed too much. In my mind, there is only one long term source of CO2, the atmosphere. Gas wells for CO2 suffer from the same depletion problems that plague methane gas wells. Their flow slows and eventually stops. On the other hand we badly need to develop some technology that depletes CO2 from the atmosphere. CO2 atmospheric concentration is already to high.
In flue gas the push is to keep the CO2 level high because it is easier to capture at high concentration, and it needs to be captured in order to address global warming problems. In an extreme, some proposals envision burning fuel in oxygen in order to eliminate dilution by nitrogen and pollution by nitrogen oxides.
I expect that there will come a time when the only source of flue gas will be from power plants that are burning biofuels, like wood or something cellulosic like dead algae. What then? The recovery of CO2 surely cannot be 100% efficient. CO2 will gradually leak into the atmosphere. The Earth will continue to warm.
The earth will continue to warm for the next 150 years, even if we halt all fossil fuel burning tomorrow:
In fact, the world's leading scientists agree that it's already too late to halt global warming entirely. "We can't prevent some damage," says Stephen Schneider, co-director of the Center for Environmental Science and Policy at Stanford University. Even if we were to magically end CO2 emissions tomorrow, the gases that we've already unleashed will continue to raise temperatures for another 150 years. "That's unpreventable," Schneider says.Source
"The (emphasis added) solution (combined with other measures of course) is geoengineering."
I strongly disagree. Geoengineering is not the solution, but a class of proposed solutions, none of which have been validated by any means excepting hype. I think nature will heal itself. It's not clear what size population of homo will remain after the healing. Geoengineering likely will have unintended consequences that will make problems much worse, and healing much slower.
Odds are your 'vision' of what geoengineering is is far different than mine - but hey - you won't be around to see the results of your plan, so why should you care?
I expect that there will come a time when the only source of flue gas will be from power plants that are burning biofuels, like wood or something cellulosic like dead algae. What then? The recovery of CO2 surely cannot be 100% efficient. CO2 will gradually leak into the atmosphere.
But if only recently grown biomass is used as feedstock, all that CO2 came from the atmosphere. You only increase atmospheric CO2 if you "mine" carbon from long-term stores, such as fossil fuels, old-growth forests, peat bogs etc.
we badly need to develop some technology that depletes CO2 from the atmosphere.
If you look at the annual cycle of the Keeling curve, you'll see it already exists: plants deplete CO2 from the atmosphere to the tune of 5-6 ppm every growing season. All we need to do is direct some of that captured CO2 to a destination other than the atmosphere, and we will create a net reduction in CO2. Easier said than done, but perhaps not all that difficult to do either.
Apparently nitrogen might be a problem. Guess we need to plant more nitrogen-fixing plants. I believe this is a feature of most sustainable farming methods, so an increase in organic farming - perhaps excepting rice due to methane production - and the use of nitrogen-fixing cover crops should help with CO2.
Being the non-scientist I am, I may well be wrong.
Yes! It will be a big job to harvest a significant fraction of natural annual plant growth and sequester it somehow.
The great bulk of the biomass in a old growth forest is less than 200yr old. Growing forest and letting it reach climax and decay is not really a good idea, but it is a beginning. If at some time in the near future there is a great deal of near climax forest, the problem of scheduling the harvest and sequestering would not be so great as it would be otherwise.
Also note that the 5-6ppm annual fluctuation is the difference between northern and southern hemisphere growth/decay. The total rate of carbon capture must be somewhat larger than 5-6ppm/y.
A method for sequestration that I find appealing is turning the biomass to charcoal and burying it. (But not as soil amendment, which has recently been shown to have environmental problems. Wardle, et al. Science v320, p 629)
If the overall concentration of CO2 in the atmosphere ever rises to 5%, we are all dead. Dead people have no energy independence issues. Problem solved.
The whole point si wrong, because there is not enought carbon in the earth crust to bring CO2 concentrations avove 0.25%. (outside of limestone that does not enter carbon cycle)
Besides this being off topic, because parent post was not referring to atmospheric CO2, it is also wrong.
And if you decomposed all limestone:
We are breathing out 5%CO2 and 15%O2. Iw we were forced to re-inhale it, we could take 3 more breaths, although very unpleasant.
It atmospheric concentration of O2 stayed at 20%, even 5% CO2 would be more manageable and we would adapt to it.
If that's the plan, then what's the difference between that and a huge concentrated-solar thermal plant? They both take up lots of space, they both chiefly utilize steel and glass, they're both probably about equally expensive to implement, except one produces electricity, and one produces liquid fuels...and one is based on already proven technology, and the other is still up in the air....
I suppose one difference might be that these algae farms wouldn't need direct sunlight in order to function. The algae could make use of diffracted light, and could function on cloudy days, or in areas with a regularly cloudy climate. So why don't we get on the stick, start throwing down concentrated-solar thermal power plants in the desert southwest, and then we can try out these algae farms in whatever other locations are left?
Thanks for the links re power plant/algae projects. I am already aware of some of these. The thing to realize is that these are purely demonstration projects. Even the one with the vertical banks of horizontal tubes, while looking pretty big, is but a small fraction of the size that would be required to accomodate even a modest size power plant.
The artist's conceptual drawing showing a power plant surrounded by what looks like several square miles of covered algae ponds is more like it in terms of what a full-scale system would look like. A square mile is almost 28 million sq ft. If it costs say $20 per sq ft to build these covered ponds (probably a lot more, but I'll be generous), then the cost of one square mile of algae pond is roughly $560 million. And this thing looks like its several square miles, so we'd already be over a $1billion, and that doesn't even include the cost of the processing facilities, or the agitators to keep the ponds from stagnating. These numbers are admittedly WAGs, but I throw them out just to try to put things into perspective.
And another consideration is that algae growth requires nutrients in the form of soluble nitrogen and phosphorus. This plant is shown to be out in the middle of nowhere, so where are the many hundreds of tons of N and P per day going to come from? Sewage effluent? So now we have to build a pipeline to transport huge volumes of sewage effluent to the algae farm. Even treated sewage contains a variety of undesireable chemical constituents and microorganisms that could easily disrupt the controlled growth of the special strains of algae.
I haven't even gotten to the problems of harvesting and dewatering the algae on a massive scale and then trying to extract the lipids in a cost-effective manner. What happens to the mass of dead algae after the lipid have been extracted? If they are returned to the algae ponds, then they also consitute a nice growth medium or a variety of microorganisms in addition to the desired algae.
While the large scale growth of algae for bio fuels may look scientifically attractive, I myself see it as a very expensive engineering nightmare.
One more comment: One oft-stated selling point for oil-from-algae schemes is that with algae for a given amount of land you can grow biomass at a rate that is an order of magnitude greater than what you can do using corn or other land crops. Well, that is a highly misleading basic of comparison because a covered algae pond will cost several orders of magnitude more than plain ol' land upon which you just plant some seeds, add fertilizer, and watch things grow. The more logical basis of comparison should be lbs per day of fuel production capacity per $million of capital investment.
I am not dumping on algae because I like ethanol (I don't), but rather because, hard as I try to visualize things, I just don't see it being very practical or cost-effective for truly large-scale applications. I think the real deal killer is the need to have totally enclosed algae bioreactors covered greenhouses to prevent contamination by unwanted low-lipid strains. If you can sustainably grown high-lipid algae in simple open ponds, then that would change the whole picture entirely.
This doesn't suffer form evaporation of unenclosed ponds or allow the specialist algae to be invaded by wild strains, and makes use of the fact that the algae only needs around 1/10th of sunlight to grow, so you can slowly rotate the tiers of algae.
Drying and providing potassium and so on would still seem to present substantial difficulties.
joule, while I agree that growing algae on this scale is almost certainly a silly idea (what effect does a hailstorm have on all your glass tubes) (or how long before your plastic tubes crumble in solar UV), there is some internal inconsistency in your post -- the "where does the NPK come from" and the "what to do with the byproducts" ideas cancel each other out. The presumptive goal of this enterprise is to pull carbon out of the air, and it should be possible to do this with a more or less fixed investment of 'P' and 'K'. Some of the 'N' could probably be recycled as well.
"The more logical basis of comparison should be lbs per day of fuel production capacity per $million of capital investment."
Definitely. That measure should be the basis of an apples-to-apples comparison with any photosynthetic energy source, and could easily be extended (converting biofuel BTUs <-> kWH) to comparisons with PV and CSP systems. It's also worth noting that any sort of $/tech comparison at present is quite distorted by the (still) relatively low price of fossil carbon.
Well, it is well established that for a unit dry weight of algae, x, y, and z amounts of nitrogen, phosphorus, and potassium will be required, respectively. Those nutrients can be supplied externally, as I had indicated in reference to sewage effluent, or perhaps they could be supplied internally by recycling some or all of the dead algae after lipid extraction, thus recycling these nutrients.
With regard to the latter approach, one must realize that when you recycle dead algae, you are not only reclycling N, P, and K, but also a much larger amount of highly biodegradable carbonaceous material. As such, you will be providing an excellent growth medium for all sorts of unwanted organisms that will compete with the desired algae and also compete for the necessary oxygen. If anything, natural microorganisms are highly opportunistic, and where there's food, water, and O2, they will thrive. You can bet on that.
It is one thing to grow pure cultures at a high rate in closely controlled sterile bioreactor vessels to produce high-value pharmaceuticals, but something else again to produce huge amounts of algae in non-sterile but covered ponds or tubes. I strongly suspect that one of the major challenges will be to maintain a stable population of the desired strains of high-lipid algae and to prevent them from getting mugged by the native boyz in the hood microorganisms.
What if you throw out the idea of maintaining some sort of control over the strains of algae. Just grow it in low tech ponds in a suitable climate (i.e. one where loss of water to evaporation isn't a problem). Then you scoop up the algae, dry it and use it a generic biomass. Perhaps you burn it for power, and/or you extract methane from it. It would seem to me that we mentally are hung up on the desire to replace liquid transportation fuel. Heck bu the time anything like this can be developed and scaled up, the present fleet of vehicles will have reached the end of their useful lives anyway.
And another consideration is that algae growth requires nutrients in the form of soluble nitrogen and phosphorus. This plant is shown to be out in the middle of nowhere, so where are the many hundreds of tons of N and P per day going to come from? Sewage effluent?
What makes you think the plant would require so much?
The ultimate products of such a plant are alcohols, hydrocarbons and perhaps esters. These are made exclusively of C, H and O; phosphate, potash and nitrate aren't part of the product stream. You might have small K and P losses in the processing, but nothing like hundreds of tons per day. And aren't some archaebacteria nitrogen-fixers? Worse comes to worst, you make some ammonia on-site and replenish N losses that way.
Sewage is an interesting topic, because removing phosphorus is essential to keep waterways from being destroyed by algal blooms. If an algae system can scrub phosphorus (and potash) from a waste stream and recover it as e.g. dry ash in a gasifier, this would be an enormous step forward for nutrient recycling.
I haven't even gotten to the problems of harvesting and dewatering the algae on a massive scale and then trying to extract the lipids in a cost-effective manner. What happens to the mass of dead algae after the lipid have been extracted? If they are returned to the algae ponds, then they also consitute a nice growth medium or a variety of microorganisms in addition to the desired algae.
Dewatering is done with a centrifuge, no? Extraction can be done with a solvent, like supercritical CO2 (cheap and readily available as a byproduct of fermentation). Dead algae minus lipids are full of protein and carbohydrates. I'm sure there's something that would eat it; maybe fish? Cattle-feed supplement?
If you can feed it to terrestrial livestock, you get manure which can be digested for gas (another fuel). The digested material goes around again as algae nutrients.
I must be behind the times (not surprisingly), since everything I read about algae a while back indicated it would produce biodiesel, not ethanol. Can someone explain this?
They'll probably produce both. Corn actually produces both; distillers are trying to extract the corn oil from corn as part of the ethanol processing. The corn oil (roughly 1.5 pounds per bushel) can be made into biodiesel.
The attraction of veggie oil is that it can be separated with far less energy than it takes to distill ethanol, but algae are living things and will make carbohydrates and proteins as well. Unless there is some other use for the carbs, fermentation isn't a bad option. That gives the process two output streams, biodiesel and ethanol.
I would be loathe to be so dismissive. When the original target productivity for the algae program at NREL was set up the goal was to achieve 50 gm/sq m/day. It is this figure that is then translated into the 3,500 gal/acre/year of biodiesel. The work at the Redhawk Power Plant was able to double that rate, as an average, and increase it to 174 gm/sq m/day at peak.
While there are a number of interesting engineering challenges that have to be overcome in making algae economically viable, it is not nearly the open-and-shut case that many dismiss so easily. The economics of each part of the process are fairly tight, but the higher yields that can be achieved over those originally postulated are starting to ease those restrictions somewhat. Dr. Berzin has some rather ingenious ideas in his path forward, and I am sure there are others.
Oh, and personally I am not that dismissive of TIME's occasional lists (grin).
Why .... were you once on one of TIME's list? If so, congratulations. You no doubt deserve it more than many of the people on it. I'm probably on somebody's list somewhere, but if so, I'm sure it's a list I would rather not be on.
As I essentially said earlier, all this focus on increasing the rate of biomass production per unit of area exposed to sunlight misses a fundamental point. Area (in all except highly urbanized regions) comes relatively cheap. Physical structure, transparent plastic tubing or sheet, and process equipment does not. If you haven't priced large-diameter plexiglas tubing or sheet lately, then you're in for sticker shock. Given the price of oil and natural gas, these are not going to get any cheaper, either. All these algae schemes would use HUGE amounts.
I will go out on a limb and state that unless someone develops a way to sustainably grow high-lipid algae in open ponds and can overcome the problems associated with unwanted organisms taking over, and can cost-effectively deal with issues having to do nutrient supply and residual management, then algae for fuel will turn out to be a technological dead end. I realize that people once said the say thing with regard to the airplane, and I may eat those words someday, that's the way I currently see it.
Thanks - since I just saw someone drink an algae culture on one of the videos cited downstream, eating words may be quite tasty in this venue. As it happens I have priced plastic tubing and sheeting, and also recognize the problems of getting light into high-density cultures, which are required if the process is to become viable. However I believe that there may be engineering solutions to some of those questions.
What joule said. Either you do it in open concrete ponds or you'll never be able to afford the investment. Not to mention that a system consisting of miles of plastic tubing (or bags, for that matter) would run about a month before requiring maintenance.
Heading out, unless I misunderstand your figures, or you have stated them incorrectly, this whole thread is absurd. To wit,
assuming the US uses 8 billion barrels of oil a year [replacing gasoline with this bio-diesel , the amount of land required would be calculated as follow [being generous to your argument]:
8,000,000,000 * 20 / 8000 gallons/ acre per year
= 20 million acres of land, approximately 300,000 square miles.
Ah! Well see there are a couple of things wrong with your argument. The first is that I did not say that 8,000 gallons/acre/year was a maximum value, just that the current program had increased production rates over an earlier target. And the other thing is that you seem to be saying that if a solution does not solve the entire supply problem then it should not be tried. Tsk!
Regarding Time citing Isaac Berzin and his work with algae as something exciting and hopeful, my own view is that anything being touted up on one of Time's 'lists' (or worse yet, People's lists) is, apriori, of suspect value and not to be taken too seriously.
Consistent with that admittedly cynical view, let us remember that Isaac Berzin's company, Green Fuel Technology, is the one which was doing work blowing power plant stack gas up through vertical plexiglas tubes filled with an algae suspension. Surely, there cannot be any serious thought on the part of anybody even halfway technically competent that such a scheme for capturing CO2 from power plants is even remotely scalable. (Try to visualize square mile upon square mile of clear plastic tubes filled with specially bred algae, or dozens of clear plastic domes the size of the Astrodome.)
To me, this is one of those things that is such a non-starter as to be capable of being dismissed 'by inspection'. Yet, venerable publications such as Time really eat this stuff up, mainly because on the surface it looks exciting and makes for good ink. The level of technical illiteracy among the journalist establishment never ceases to amaze me.
The popular mainstream media is not the place to look if you really want to know what important technological developments are taking place.
I will close this little rant by saying that I'm a firm believer in developing better technology in a wise manner, simply because technology is what humans DO and the application of technology is one of main things that seperates us from the beasts (including the higher primates of which we share most of our genes).
Surely, there cannot be any serious thought on the part of anybody even halfway technically competent that such a scheme for capturing CO2 from power plants is even remotely scalable. (Try to visualize square mile upon square mile of clear plastic tubes filled with specially bred algae, or dozens of clear plastic domes the size of the Astrodome.)
That is, indeed, the plan:
http://www.celsias.com/2007/09/04/not-just-for-sushi-anymore/
http://thefraserdomain.typepad.com/energy/2006/12/arizona_public_.html
I saw a show recently (History channel? Discovery?) that showed this plan currently under construction:
Nice links and photos. I presume the 3rd photo is an artist rendering? Anyway, read National Geographic's article on the potential for algae ethanol and was impressed by how much more fuel could potentially be produced over a year's time. It was 3,000 gallons for corn ethanol, and as much as 50,000 gallons for algae ethanol, due in great part to the speed at which algae grows year round. Most people are not aware that the oil we use is the result of millions of years of compression and heat applied to dead algae. As the oceans stagnated algae filled them, then sank to the bottom, the ocean life died due to a lack of oxygen and soil filled over those layers, techtonic plates slipped and moved and eventually all that algae ended up as oil in two distinct layers in the crust, dating back from two eras 90 and 150 million years ago.
So it would seem that if oil can be mass produced as a viable form of ethanol, our best bet is to find ways to scale up algae ethanol production. We flew back from Oklahoma to California via an airline that flew too slow and too low, but what I realized from the view was just how many empty valleys there are in Arizona, Utah and Nevada that could be used to make ethanol.
I think the process of using CO2 enriched air as a way to capture it from Coal should not be requisite to make algae ethanol. It would seem that if plain old simple air is pumped fast enough the CO2 will get converted and we should have lots of fuel, but I'm not certain of that - please illuminate me. As a result, as an investor, I have been keeping my eye on Greenfuel Tech., waiting for that right company to invest in. My understanding is Verasun has a stake in Greenfuel, so if it does take off they may be a good bet. Right now I'm taking a wait and see approach. But certainly one to watch.
The window frame of opportunity to catch the world economy before it dumps in catastrope, by way of a scaled up mass produced fuel, is still open but we must move fast. Otherwise at some threshold of price for energy the world economy will stagnate, then price of energy and economic activity will balance/stalemate at some tepid level not conducive to well being of 6.5 billion people.
Addition to my prior post: That is 3,000 gallons per acre for corn versus 50,000 gallons per acre for algae ethanol.
Corn yields perhaps 2.8 gal/bu and averages ~150 bu/acre, so you're going to see around 420 gal/acre. Anyone claiming 3000 gallons from corn is smoking something.
Credible algae claims are in the region of 5000 to 10000 gal/ac. Even 2000 would be pretty darn good for a cheap process.
I'm probably stating the obvious or asking a stupid question, but...
Corn is a solid, is it not? So you ned to add the liquid, do you not? If making ethanol is anything like brewing drinking alcohol, then you need sugar, water, yeast. So wouldn't making ethanol have an impact on the water supply?
I'm sure it takes far more water to grow the corn than to process it, but the issue of contamination from wastewater can't be ignored.
Corn yields perhaps 2.8 gal/bu and averages ~150 bu/acre, so you're going to see around 420 gal/acre. Anyone claiming 3000 gallons from corn is smoking something.
That is for oone crop. Maybe some areas can have 3 crops a year, assuming 350 bushsls/acre and 3gal/bu, that would work. But it seems to be a stretch.
BTW, How much biomass is in the cobs and stalks, compared to corn kernels?
To me it seems that there is more potential in processing the "waste".
What strain of maize can come to maturity in 120 days at that yield? With enormous amounts of water, phosphate and nitrate I suppose you can do anything, but algae seem cheaper.
Around half (maybe more if cobs are included, I haven't checked lately). A bushel of corn is 56 pounds, so 150 bu/ac is 4.2 tons. The Corn Stover Collection Project found roughly 2 tons/acre of harvestable stover, after allowing for erosion control.
The last picture with the great field of long narrow ponds in which algae are to be grown in from Solix Biofuels. On the web it is said that they are based in Boulder Colorado. But I can't find them locally here in Boulder County. They are also said to be cooperating with the New Holland Brewery in Fort Collins on a demonstration project using the CO2 from brewing beer to feed some algae. The picture is surely wishful thinking. There is no place in northern Colorado with such a wide open expanse of flat, unoccupied land, and open ponds (copied from the long gone algae project on a predecessor organization of Dept of Energy, NREL) would surely be uneconomic in our northern latitude, high elevation location.
They are also associated with Colorado State University (CSU) in Fort Collins. It has been at least a year since I saw any publicity about them locally. It appears to me that their association with the CSU is somewhat of an embarrassment to CSU.
All work on algae that I have seen, always assumes that it is necessary to feed the algae with high concentration CO2. So proposers always mention working near coal fired power plants.
An association with a brewery, in a college town, is surely a good idea for experimental work, but the growing ponds in their PR vastly out size the CO2 source of the New Holland Brewery. An algae technology that requires a fossil fuel source of high concentration CO2 seems to me not to be a post fossil fuel solution.
It depends on your definition of high. While there is some increase in yield with increased concentration, the overall levels of CO2 that are productive seem to lie below 5%, depending on which algae you are growing.
If the overall concentration of CO2 in the atmosphere ever rises to 5%, we are all dead. Dead people have no energy independence issues. Problem solved.
I was referencing the feed concentrations, and this ties into the use of CO2 extraction from the flue gas. There is no economic incentive, to do that concentration since the higher levels of CO2 in the feed would not be productive. Remember also that the off-gas from the process is oxygen.
I assumed too much. In my mind, there is only one long term source of CO2, the atmosphere. Gas wells for CO2 suffer from the same depletion problems that plague methane gas wells. Their flow slows and eventually stops. On the other hand we badly need to develop some technology that depletes CO2 from the atmosphere. CO2 atmospheric concentration is already to high.
In flue gas the push is to keep the CO2 level high because it is easier to capture at high concentration, and it needs to be captured in order to address global warming problems. In an extreme, some proposals envision burning fuel in oxygen in order to eliminate dilution by nitrogen and pollution by nitrogen oxides.
I expect that there will come a time when the only source of flue gas will be from power plants that are burning biofuels, like wood or something cellulosic like dead algae. What then? The recovery of CO2 surely cannot be 100% efficient. CO2 will gradually leak into the atmosphere. The Earth will continue to warm.
The earth will continue to warm for the next 150 years, even if we halt all fossil fuel burning tomorrow:
The solution (combined with other measures of course) is geoengineering. Many leading climate scientists now support geoengineering, including Paul Crutzen, Tom Wigley and Ken Caldeira. For example, see ALBEDO ENHANCEMENT BY STRATOSPHERIC SULFUR INJECTIONS: A CONTRIBUTION TO RESOLVE A POLICY DILEMMA?(pdf).
Sure! Because the climate system is so resilient we can just mess with it at will!
This is a very dangerous and, imho, foolish way to go. Let's just live differently and get the same results without the unknown feedbacks.
Cheers
"The (emphasis added) solution (combined with other measures of course) is geoengineering."
I strongly disagree. Geoengineering is not the solution, but a class of proposed solutions, none of which have been validated by any means excepting hype. I think nature will heal itself. It's not clear what size population of homo will remain after the healing. Geoengineering likely will have unintended consequences that will make problems much worse, and healing much slower.
The solution is geoengineering.
Sure it is 'john denver'.
Odds are your 'vision' of what geoengineering is is far different than mine - but hey - you won't be around to see the results of your plan, so why should you care?
But if only recently grown biomass is used as feedstock, all that CO2 came from the atmosphere. You only increase atmospheric CO2 if you "mine" carbon from long-term stores, such as fossil fuels, old-growth forests, peat bogs etc.
If you look at the annual cycle of the Keeling curve, you'll see it already exists: plants deplete CO2 from the atmosphere to the tune of 5-6 ppm every growing season. All we need to do is direct some of that captured CO2 to a destination other than the atmosphere, and we will create a net reduction in CO2. Easier said than done, but perhaps not all that difficult to do either.
Apparently nitrogen might be a problem. Guess we need to plant more nitrogen-fixing plants. I believe this is a feature of most sustainable farming methods, so an increase in organic farming - perhaps excepting rice due to methane production - and the use of nitrogen-fixing cover crops should help with CO2.
Being the non-scientist I am, I may well be wrong.
Cheers
"... Easier said than done, but ..."
Yes! It will be a big job to harvest a significant fraction of natural annual plant growth and sequester it somehow.
The great bulk of the biomass in a old growth forest is less than 200yr old. Growing forest and letting it reach climax and decay is not really a good idea, but it is a beginning. If at some time in the near future there is a great deal of near climax forest, the problem of scheduling the harvest and sequestering would not be so great as it would be otherwise.
Also note that the 5-6ppm annual fluctuation is the difference between northern and southern hemisphere growth/decay. The total rate of carbon capture must be somewhat larger than 5-6ppm/y.
A method for sequestration that I find appealing is turning the biomass to charcoal and burying it. (But not as soil amendment, which has recently been shown to have environmental problems. Wardle, et al. Science v320, p 629)
If the overall concentration of CO2 in the atmosphere ever rises to 5%, we are all dead. Dead people have no energy independence issues. Problem solved.
The whole point si wrong, because there is not enought carbon in the earth crust to bring CO2 concentrations avove 0.25%. (outside of limestone that does not enter carbon cycle)
Besides this being off topic, because parent post was not referring to atmospheric CO2, it is also wrong.
And if you decomposed all limestone:
We are breathing out 5%CO2 and 15%O2. Iw we were forced to re-inhale it, we could take 3 more breaths, although very unpleasant.
It atmospheric concentration of O2 stayed at 20%, even 5% CO2 would be more manageable and we would adapt to it.
If that's the plan, then what's the difference between that and a huge concentrated-solar thermal plant? They both take up lots of space, they both chiefly utilize steel and glass, they're both probably about equally expensive to implement, except one produces electricity, and one produces liquid fuels...and one is based on already proven technology, and the other is still up in the air....
I suppose one difference might be that these algae farms wouldn't need direct sunlight in order to function. The algae could make use of diffracted light, and could function on cloudy days, or in areas with a regularly cloudy climate. So why don't we get on the stick, start throwing down concentrated-solar thermal power plants in the desert southwest, and then we can try out these algae farms in whatever other locations are left?
Barrette808 -
Thanks for the links re power plant/algae projects. I am already aware of some of these. The thing to realize is that these are purely demonstration projects. Even the one with the vertical banks of horizontal tubes, while looking pretty big, is but a small fraction of the size that would be required to accomodate even a modest size power plant.
The artist's conceptual drawing showing a power plant surrounded by what looks like several square miles of covered algae ponds is more like it in terms of what a full-scale system would look like. A square mile is almost 28 million sq ft. If it costs say $20 per sq ft to build these covered ponds (probably a lot more, but I'll be generous), then the cost of one square mile of algae pond is roughly $560 million. And this thing looks like its several square miles, so we'd already be over a $1billion, and that doesn't even include the cost of the processing facilities, or the agitators to keep the ponds from stagnating. These numbers are admittedly WAGs, but I throw them out just to try to put things into perspective.
And another consideration is that algae growth requires nutrients in the form of soluble nitrogen and phosphorus. This plant is shown to be out in the middle of nowhere, so where are the many hundreds of tons of N and P per day going to come from? Sewage effluent? So now we have to build a pipeline to transport huge volumes of sewage effluent to the algae farm. Even treated sewage contains a variety of undesireable chemical constituents and microorganisms that could easily disrupt the controlled growth of the special strains of algae.
I haven't even gotten to the problems of harvesting and dewatering the algae on a massive scale and then trying to extract the lipids in a cost-effective manner. What happens to the mass of dead algae after the lipid have been extracted? If they are returned to the algae ponds, then they also consitute a nice growth medium or a variety of microorganisms in addition to the desired algae.
While the large scale growth of algae for bio fuels may look scientifically attractive, I myself see it as a very expensive engineering nightmare.
One more comment: One oft-stated selling point for oil-from-algae schemes is that with algae for a given amount of land you can grow biomass at a rate that is an order of magnitude greater than what you can do using corn or other land crops. Well, that is a highly misleading basic of comparison because a covered algae pond will cost several orders of magnitude more than plain ol' land upon which you just plant some seeds, add fertilizer, and watch things grow. The more logical basis of comparison should be lbs per day of fuel production capacity per $million of capital investment.
I am not dumping on algae because I like ethanol (I don't), but rather because, hard as I try to visualize things, I just don't see it being very practical or cost-effective for truly large-scale applications. I think the real deal killer is the need to have totally enclosed algae bioreactors covered greenhouses to prevent contamination by unwanted low-lipid strains. If you can sustainably grown high-lipid algae in simple open ponds, then that would change the whole picture entirely.
I've got severe reservations about algae for fuel, but the most promising approach I have seen to date is vertigro:
http://www.cnn.com/2008/TECH/science/04/01/algae.oil/index.html
Algae: 'The ultimate in renewable energy' - CNN.com
This doesn't suffer form evaporation of unenclosed ponds or allow the specialist algae to be invaded by wild strains, and makes use of the fact that the algae only needs around 1/10th of sunlight to grow, so you can slowly rotate the tiers of algae.
Drying and providing potassium and so on would still seem to present substantial difficulties.
joule, while I agree that growing algae on this scale is almost certainly a silly idea (what effect does a hailstorm have on all your glass tubes) (or how long before your plastic tubes crumble in solar UV), there is some internal inconsistency in your post -- the "where does the NPK come from" and the "what to do with the byproducts" ideas cancel each other out. The presumptive goal of this enterprise is to pull carbon out of the air, and it should be possible to do this with a more or less fixed investment of 'P' and 'K'. Some of the 'N' could probably be recycled as well.
"The more logical basis of comparison should be lbs per day of fuel production capacity per $million of capital investment."
Definitely. That measure should be the basis of an apples-to-apples comparison with any photosynthetic energy source, and could easily be extended (converting biofuel BTUs <-> kWH) to comparisons with PV and CSP systems. It's also worth noting that any sort of $/tech comparison at present is quite distorted by the (still) relatively low price of fossil carbon.
DIYer -
Well, it is well established that for a unit dry weight of algae, x, y, and z amounts of nitrogen, phosphorus, and potassium will be required, respectively. Those nutrients can be supplied externally, as I had indicated in reference to sewage effluent, or perhaps they could be supplied internally by recycling some or all of the dead algae after lipid extraction, thus recycling these nutrients.
With regard to the latter approach, one must realize that when you recycle dead algae, you are not only reclycling N, P, and K, but also a much larger amount of highly biodegradable carbonaceous material. As such, you will be providing an excellent growth medium for all sorts of unwanted organisms that will compete with the desired algae and also compete for the necessary oxygen. If anything, natural microorganisms are highly opportunistic, and where there's food, water, and O2, they will thrive. You can bet on that.
It is one thing to grow pure cultures at a high rate in closely controlled sterile bioreactor vessels to produce high-value pharmaceuticals, but something else again to produce huge amounts of algae in non-sterile but covered ponds or tubes. I strongly suspect that one of the major challenges will be to maintain a stable population of the desired strains of high-lipid algae and to prevent them from getting mugged by the native boyz in the hood microorganisms.
Lots of luck.
What if you throw out the idea of maintaining some sort of control over the strains of algae. Just grow it in low tech ponds in a suitable climate (i.e. one where loss of water to evaporation isn't a problem). Then you scoop up the algae, dry it and use it a generic biomass. Perhaps you burn it for power, and/or you extract methane from it. It would seem to me that we mentally are hung up on the desire to replace liquid transportation fuel. Heck bu the time anything like this can be developed and scaled up, the present fleet of vehicles will have reached the end of their useful lives anyway.
What makes you think the plant would require so much?
The ultimate products of such a plant are alcohols, hydrocarbons and perhaps esters. These are made exclusively of C, H and O; phosphate, potash and nitrate aren't part of the product stream. You might have small K and P losses in the processing, but nothing like hundreds of tons per day. And aren't some archaebacteria nitrogen-fixers? Worse comes to worst, you make some ammonia on-site and replenish N losses that way.
Sewage is an interesting topic, because removing phosphorus is essential to keep waterways from being destroyed by algal blooms. If an algae system can scrub phosphorus (and potash) from a waste stream and recover it as e.g. dry ash in a gasifier, this would be an enormous step forward for nutrient recycling.
Dewatering is done with a centrifuge, no? Extraction can be done with a solvent, like supercritical CO2 (cheap and readily available as a byproduct of fermentation). Dead algae minus lipids are full of protein and carbohydrates. I'm sure there's something that would eat it; maybe fish? Cattle-feed supplement?
If you can feed it to terrestrial livestock, you get manure which can be digested for gas (another fuel). The digested material goes around again as algae nutrients.
I must be behind the times (not surprisingly), since everything I read about algae a while back indicated it would produce biodiesel, not ethanol. Can someone explain this?
They'll probably produce both. Corn actually produces both; distillers are trying to extract the corn oil from corn as part of the ethanol processing. The corn oil (roughly 1.5 pounds per bushel) can be made into biodiesel.
The attraction of veggie oil is that it can be separated with far less energy than it takes to distill ethanol, but algae are living things and will make carbohydrates and proteins as well. Unless there is some other use for the carbs, fermentation isn't a bad option. That gives the process two output streams, biodiesel and ethanol.
I would be loathe to be so dismissive. When the original target productivity for the algae program at NREL was set up the goal was to achieve 50 gm/sq m/day. It is this figure that is then translated into the 3,500 gal/acre/year of biodiesel. The work at the Redhawk Power Plant was able to double that rate, as an average, and increase it to 174 gm/sq m/day at peak.
While there are a number of interesting engineering challenges that have to be overcome in making algae economically viable, it is not nearly the open-and-shut case that many dismiss so easily. The economics of each part of the process are fairly tight, but the higher yields that can be achieved over those originally postulated are starting to ease those restrictions somewhat. Dr. Berzin has some rather ingenious ideas in his path forward, and I am sure there are others.
Oh, and personally I am not that dismissive of TIME's occasional lists (grin).
Heading Out -
Why .... were you once on one of TIME's list? If so, congratulations. You no doubt deserve it more than many of the people on it. I'm probably on somebody's list somewhere, but if so, I'm sure it's a list I would rather not be on.
As I essentially said earlier, all this focus on increasing the rate of biomass production per unit of area exposed to sunlight misses a fundamental point. Area (in all except highly urbanized regions) comes relatively cheap. Physical structure, transparent plastic tubing or sheet, and process equipment does not. If you haven't priced large-diameter plexiglas tubing or sheet lately, then you're in for sticker shock. Given the price of oil and natural gas, these are not going to get any cheaper, either. All these algae schemes would use HUGE amounts.
I will go out on a limb and state that unless someone develops a way to sustainably grow high-lipid algae in open ponds and can overcome the problems associated with unwanted organisms taking over, and can cost-effectively deal with issues having to do nutrient supply and residual management, then algae for fuel will turn out to be a technological dead end. I realize that people once said the say thing with regard to the airplane, and I may eat those words someday, that's the way I currently see it.
Thanks - since I just saw someone drink an algae culture on one of the videos cited downstream, eating words may be quite tasty in this venue. As it happens I have priced plastic tubing and sheeting, and also recognize the problems of getting light into high-density cultures, which are required if the process is to become viable. However I believe that there may be engineering solutions to some of those questions.
A point in favor of algae as a biofuel is that it really doesn't need to compete with food crops for agricultural land.
What joule said. Either you do it in open concrete ponds or you'll never be able to afford the investment. Not to mention that a system consisting of miles of plastic tubing (or bags, for that matter) would run about a month before requiring maintenance.
Heading out, unless I misunderstand your figures, or you have stated them incorrectly, this whole thread is absurd. To wit,
assuming the US uses 8 billion barrels of oil a year [replacing gasoline with this bio-diesel , the amount of land required would be calculated as follow [being generous to your argument]:
8,000,000,000 * 20 / 8000 gallons/ acre per year
= 20 million acres of land, approximately 300,000 square miles.
Yeah, right.
Ah! Well see there are a couple of things wrong with your argument. The first is that I did not say that 8,000 gallons/acre/year was a maximum value, just that the current program had increased production rates over an earlier target. And the other thing is that you seem to be saying that if a solution does not solve the entire supply problem then it should not be tried. Tsk!
One problem with algal biofuels production is that the high advertised yields require levels of CO2 far in