Guest post by John Goetz
I keep an active watch of the news for progress being made in the areas of renewable and alternative energy sources. One area that has caught my eye is algal fuel (biofuel produced by algae). One company that has been in the news lately is Sapphire Energy, which claims to be able to produce ASTM compliant 91-octane biogasoline. Sapphire Energy says their technology “requires only sunlight, CO2 and non-potable water – and can be produced at massive scale on non-arable land”.
I am not trying to pick on any one solution or Sapphire Energy in particular. I simply wondered how massive a scale of CO2 and non-arable land is needed to make a noticeable dent in our gasoline demand.
First, how much CO2 do we need? The IPCC guidelines for calculating emissions require that an oxidation factor of 0.99 be applied to gasoline’s carbon content to account for a small portion of the fuel that is not oxidized into CO2. To calculate the CO2 emissions from a gallon of fuel, the carbon emissions are multiplied by the ratio of the molecular weight of CO2 to the molecular weight of carbon, or 44/12. Thus, the IPCC says the CO2 emissions from a gallon of gasoline = 2,421 grams x 0.99 x (44/12) = 8,788 grams = 8.8 kg/gallon = 19.4 pounds/gallon.
Now let’s assume Sapphire Energy simply reverses the process and consumes the CO2 to produce gasoline. In other words, we take 19.4 pounds of CO2 out of the atmosphere for every gallon of gasoline we produce. This seems like is a nice “carbon neutral” process.
What is the cubic volume of atmosphere required to make 1 gallon of gas? Let’s assume for the moment an efficiency factor of 100%, meaning our process will consume 100% of the atmospheric CO2 it is fed. This is unrealistic, but it is unrealistic on the “optimistic” side. According to the EPA, one cubic meter of CO2 gas weighs 0.2294 lbs. At an atmospheric concentration level of 385ppm, one cubic meter of atmosphere contains 0.000088319 lbs of CO2. Thus, 19.4 / .000088319 = 219658 cubic meters (yes, I am ignoring the atmospheric density gradient as one moves from the ground upward, but hang with me). This equates to roughly 4553 gallons of gasoline per cubic kilometer of air.
According to the US Energy Information Administration, US gasoline consumption is currently averaging (4-week rolling) 9.027 million barrels of gasoline per day, or about 379 million gallons (42 gallons per barrel). Thus, to completely replace US gasoline consumption, Sapphire Energy would need to “scrub”, at 100% efficiency, just over 83000 cubic kilometers of air per day. Certainly there is plenty of air available – this volume represents less than 0.02% of the volume of air in the first 1 km of atmosphere. Nevertheless, it is an enormous amount to process each day.
Of course, Sapphire Energy’s near-term goals are much more modest. As CEO Jason Pyle told Biomass Magazine, “the company is currently deploying a three-year pilot process with the goal of opening a 153 MMgy (10,000 barrel per day) production facility by 2011 at a site yet to be determined.” Using my fuzzy math above, that equates to a minimum of 92 cubic kilometers of air a day. Still seems like a lot.
So where will all of the CO2 come from?
Presumably the answer is coal-fired power plants. But let’s see if that makes sense. According to Science Daily, the top twelve CO2-emitting power plants in the US have total emissions of 236.8 million tons annually, or 1.3 billion pounds per day. Now, if that can be converted completely to gasoline, it would amount to 67 million gallons per day, or roughly 1/6 of the daily gasoline consumption.
(Science Daily refers to the twelve as the “dirty dozen,” which I found somewhat humorous given that CO2 is colorless and odorless, and is presumably needed to sustain some forms of life. But then again, so is dirt.)
Sounds great, except that a lot of land is needed to grow all that algae. According to Wikipedia, between 5,000 and 20,000 gallons of biodiesel can be produced per acre from algae per year. Assume for the moment that biogasoline can be produced at the same rate per acre. If we attempted to produce 67 million gallons of gasoline from our “dirty-dozen” every day, we would need between 1.2M and 4.9M acres of land to do this on. The low-end of the scale puts the area needed at more than that of Rhode Island. The high-end adds in Connecticut.
I kind of doubt there is that much land around each of the dirty dozen facilities. This means the gas would have to be sent by pipeline to a giant algae field. Given our ability to pipe oil and natural gas all over the place, sending CO2 across the country via pipeline is probably doable. There may also be plenty of unused or abandoned land (think abandoned oil fields) available to produce the gasoline. Nevertheless, the production scale and transportation logistics required to make this a viable alternative do indeed look massive.
So while the technology holds promise at the micro-scale, it remains to be seen what can actually be done at a scale that matters.
Talk among yourselves.
Best line of nonsense in the MIT Algal Emission Scrubber Video:
“…once the CO2 is turning into organic carbon there is nothing bad in it…”
LOL
Frederick Davies,
At some point (2005?) Realclimate actually had a post where they claimed to be able to use isotopes of Carbon 12 and Carbon 13 to tell the difference between “new” Carbon and “old” Carbon. (Let us hope we are not required to only use the “new” Carbon.)
Personally I like the idea of small systems. In the 1970’s some headway was made at solar systems that heated hot water, up on roof-tops. Then the “oil glut” put a lot of those businesses under. However you would be amazed how much energy is used each year simply heating water in America. I read we use as much energy heating water as we do driving. Not sure it’s true, but it raised my eyebrows.
I like small systems because it gets us back to the social strength that the small family farm allowed us. Yes, there are problems involving upkeep, but it is more wholesome to potter about your own yard, with your kid tagging along asking questions, than it is to commute to some cubicle and work nine to five as your kid moulders at some daycare center.
Jefferson expressed a concern at some point about how Democracy would handle a shift away from farming to urban life. That is one factor we are facing, as we deal with these energy issues. It is actually social, as much as it is economic.
Americans seem to like big projects like Hoover Dam, more than some little paddle-wheel in a back yard brook, however the problem with a Bigger-is-better attitude is it tends to lock us in to socialism and Five-year-plans, and all the inherant problems.
That’s why I always perk my ears up at ideas that are small, that you can pop up on your roof.
The trick would be to make it sell. If you could mow your lawn, pop the clippings into some inexpencive compactor, and have pellets for a pellet stove, it might be worth the bother, if it freed you from a huge heating bill involving oil or gas heat.
Therefore what is needed is an entrepreneur to produce an Algal-omatic.
Speaking of which, I heard a coal stove heating system advertized on Boston radio. First time I ever remember, since my boyhood, hearing coal heat advertized. The ad stressed that the coal was washed, came in bags weighing “only” 40 pounds, and you “only” had to load the stove every three days. The very fact such an ad can exist shows you how freaked-out people this far north are, about paying for heat next winter.
antioxexpress : “Why is it [really?] important to be “carbon neutral” when in elementary school everyone was taught that CO2 was a necessary gaseous exchange in the human inhalation-exhalation cycle?”
I don’t think it is necessary, or it seems, even desirable to be carbon-neutral. There is a deeper agenda behind AGW devotees, IMO. Even if we were a carbon neutral society they would seek to derail human progress in other ways.
Does the $18K for a roof top system include the cost of reinforcing your roof, walls and foundation to support all of that weight? Water is heavy!!!
And when the majority of the world is using this or any other biofuel, and when all the engines, equipment and delivery technology are adjusted to make it the exclusive fuel, speculators will drive the price up just like any other commodity that is valued by the masses. A little off topic but, has anyone considered requiring all rooftops to be made of a material that reemits sunlight in a wavelength that CO2 cannot absorb? Is that even possible?
Demesure –
Kind of like government-sponsored fusion projects?
The typical gallon of gasoline can, at most, theoretically produce
18.2 lbs of CO2 per gallon. The true figure is lower and in
California it approaches 16 lbs per gallon.
Here’s how you get 18.2 lbs: I made several assumptions of the
extremely conservative variety to simplify things. For instance,
rather than use current oxygentated gasoline or normal water content
gasoline or special formulations that decrease density or increase non
carbon content, I assumed the densest, most pure C8H18 possible
chemical make up. I used several online references and my old MIT
Press softcover Taylor and my
TransAmerica Manual and my Obert. For the uninitiated, Taylor was
Charles Fayette Taylor, Director of the Sloan Labs Aircraft and Auto
Engines at MIT. The TransAmerica DeLaval Manual is a basic properties
reference book for the industry. Obert is Edward F. Obert, UWis
author of “Internal Combustion Engines and Air Pollution.” These are
all books within reach of my chair. I also dug out an old Marks
Handbook for background and double checking.
Water 8.33 lbs per gallon (pounds mass as slugs would lose everyone)
C8H18 density 0.707 relative to water.
C8H18 molecular mass, (12×8)+(1×18)=114
Carbon share of octane (that’s the -8- in C8), 96.
96/114ths of 8.33×0.707 is 4.96 pounds of carbon per gallon of “gas.”
Now, the further assumptions, perfect combustion to C02, etc.
4.96 pounds of C(12) plus 2xO(16) resultant CO2 molecular mass 44.
With all these assumptions there are only enough Carbon atoms in a
gallon of perfect gasoline to assemble 18.19 pounds of carbon dioxide.
Note that to my ability the assumptions are all weighted
conservatively. There may be a few chemical level nitpicks such as
aromatics and relative carbon ratio versus density but these are all
masked by the extremely conservative assumptions above.
Sounds like a plan and since it is carbon neutral maybe God will cut us some slack to get the system operational since we are repenting of our grievous sin of carbon emission.
Why stop with god. Why not Thor, or Zeus?
Keep the good work and i wish you a nice weekend
PetroSun recently opened the first commercial scale (1100 acres) algae-to-biofuels farm in Rio Hondo, TX. Relative to other algae producers the process these guys use sounds fairly low tech. Then again, it must work or they wouldn’t have gone to commercial scale. No other company has done that yet. As far as I know, everyone else is still saying “another 2-3 years”. Don’t you wish you had a nickel for every time you heard that.
And they appear to have very ambitious plans to expand — they claim plans to establish algae farms and algal oil extraction plants in Alabama, Arizona, Louisiana, Mexico, Brazil and Australia during 2008. Good luck to PetroSun.
Let’s see, what part of the world is there where there are vast expanses of otherwise unusable land that gets a very high number of solar hours per day?
Hey, I know! The Middle East! We can buy all of our algal fuels from Middle Eastern countries!
Anthony,
At the risk of being the dweeb of the day, I have a point that is both significant and insignificant. It is insignificant because the numbers are so huge it doesn’t really detract from your message, but significant in that it changes your calculation by about 33%.
The atmospheric content of CO2 is 385 ppmv (volume basis), so it needs a molecular weight correction. Assuming ideal gas behavior (not a bad assumption), the weight of CO2 you calculated needs to be multiplied by 44/29 (MW CO2/avg MW air), or by ~1.52. So the volume of air needed is only ~2/3 of what you calculated.
As I said, the answer is still OBGN (one big-gas number). 🙂
REPLY: John Goetz wrote this post, see name at top.
See the prospect of vertical farming of algae and, “Produc[ing] about 100,000 gallons of algae oil a year per acre, compared to about 30 gallons per acre from corn; 50 gallons from soybeans.” at:
http://www.cnn.com/2008/TECH/science/04/01/algae.oil/
Several “algae acres” on a rooftop, with continuing prospect to grow food. Very intriguing.
John:
Like you, I follow all the hopeful possibilities for energy production. We need electricity (long term) and liquid fuel for transportation (for the forseeable future.
My viewpoint: We should drill oil, dig coal, convert shale, build fission, build solar and build windpower NOW. We should research algae, biomass, fusion and everything else.
There is some interesting experiments going on right now with Polywell fusion:
http://www.emc2fusion.org/
John M,
Thanks, you are correct. The numbers might still be big, but they are 1/3 smaller, so it is moving in the right direction. Of course, I assumed 100% efficiency in the system, which is overly optimistic.
The most-reliable and largest untapped renewable power engine lies in the great ocean currents of the seas. The problem is energy transport, thus far requiring near-shore installations on megawatt scale (yes, megawatt).
To exploit them will require a different kind of power delivery method, I suspect with large flotillas of ships capturing sea current energy using deep turbines. To store that energy as a high-density power source would require gigawatt-scale energy storage, perhaps involving FT synthesis, etc.
http://www.treehugger.com/files/2007/06/12_megawatts_wo.php
http://www.technologyreview.com/Energy/19584/
And FWIW the quality of turbine design is still developing:
http://www.greenoptimistic.com/2008/03/31/jet-engine-like-wind-turbine-4-times-more-efficient/
FWIW the biggest power draws in a typical household are the compressors in air conditioning & refrigerator units. Perhaps ammonia-based systems will make a comeback, or high-ratio pulley-based solar-activated cooling systems.
Wood vs diesel
Wood waste runs about $3.50 to $5.00 per decatherm in most applications, about $6.00 to $7.00 for “useful” wood. The cost of diesel/natural gas is about $16.00 per decatherm. Coal has been rising but is usually 30% to 100% more than wood. Yet since it is cheaper why aren’t there more wood generators?
They require a lot of handling equipement, and the boilers are much much more expensive to make. They do not burn in control as well as diesel. coal or natural gas. The particulate matter, PM, is regulated in most parts of the world. The supply can vary such that dependability is an issue. The ash requires handling equipment and is often regulated. They are generally cheaper than even coal. Wood boilers are generally only economical near a good wood supply region.
Thus the real reason there are few wood boilers appears to be dependability of supply and control. Coal, petroleum, natural gas are better. The other reason is the capital costs with the investment.
I’ve looked into this technology – its potential is large, but the biggest issues are that algae is a tricky little bugger. Sometimes it grows well, sometimes not. The land area required (theoretically) for these systems are dramatically less than what would be required for ethanol production. Somewhere I have a paper on the cost for production. I can send it on to Anthony for linkage if he wishes…
Other items – algae actually doesn’t like direct sunlight – its best growing potential is with about 10% light, so it would grow well in most areas of the country as long as there was a temperature source to keep it going. That’s why you can use verticle growth systems… But the techniques for those are still in development.
Since one of the plans out there is to capture CO2 for injection into the earth (a plan that is untennable for all sorts of reasons) a pipeline network could be used to pull CO2 from power plants and transported to nearby open lands…
I usually like to say its all economics, and I’d need to do a lot of work to get into the economics of this. But the bioscience is still in development. NREL assessed multitudes of algae looking for the proper type. A lot were promising, but they did their work on more traditional racetrack systems (where outside strains can often have a major negative impact). That’s why they’re looking at systems like what are seen in the MIT video.
Overall, its a promising technology, where commercial interests (including Arizona Power) are putting money into research. Needless to say, any breakthroughs will come from the public sector… And it needs some breakthroughs.
By the way – two extra points- the group that says it can be turned directly into gasoline level fuel. That is a breakthrough, if true. Algea is actually better suited for biodiesel.
Point two – there’s some belief that algae may be the original source of our current oil reserves… Who knows?
Ah, folks, gasoline is not C8H18. If it was, good luck ever starting your car, especially in the winter. Also, C8H18 would fail most gasoline specifications.
Gasoline is composed of hundreds of different hydrocarbons. Butane is the lightest hydrocarbon in gasoline (I guess it is possible to have small amounts of lighter compounds). It adds volatility to the fuel to help it quickly vaporize so your car starts easy. The rest of the various hydrocarbons are heavier and the heaviest has a boiling point of about 380F – about C12s. Heavier than 380F starts cutting into kerosene and jet fuel, but when one is maximizing gasoline vs kerosene one can include compounds up to about 400F or so. There are many, many different specifications that gasoline must meet, which forces one into a wide mixture of hydrocarbons.
There was an item in a Dutch newspaper last week about algae farms. It said most calculations ignore the staggering amount of energy to keep the algae cool in their shallow pools under the burning sun. Taken that into account, or so the article said, the nett yield of energy per acre comes very close to zero.
Andrew Upton,
I suspect the reason that no one has commented on your link to the Fox News story is that reporting a prediction by ONE climate scientist that something MIGHT happen is not really news, as much as the media would like to think that it is. Pay close attention and you’ll begin to notice that much of what is report ON the news is really nothing more than speculation, prediction, guestimation, what if?, etc. Even if this particular scientist’s prediction comes true — so what. The people who are taking Artic tours won’t get stuck in the ice anymore. Now, if it results in the folks in Manhatten having to use a row boat to get to their 3rd floor apartment, then, yeah, that could be somewhat problematic.
Caleb, admittedly, living in the tropics helps, but for the past 17 years we have had on the roof of our house a solar heater which consists of a 55 gallon drum fastened above an 8ft x 4ft solar panel all on a frame. This has provided hot water for the hoes for all but about four days. Those were prolonged periods of cloudy weather, during which time, I powered up the enclosed immersion heater.
There is, however a downside.
On one occasion, during a hot spell, I shifted from the toilet to the bidet. (For the ignorant, look it up!) When the tap was opened, nothing happened. A few seconds went by before I realised that the mixer valve was turned to fill rather than jet. Unfortunately, when I corrected this, I discovered that the cold water in the pipes had already cleared and the hot(!) had arrived. A solar heater such as ours can almost reach boiling point in hot weather. I leave the rest to your fertile imaginations.
How about exploiting the temperature gradient between warm surface water and cooler water below? Oh, never mind, this would cause “thermal pollution” the next great environment scare.
From one fear to another
and then on to dread
they’ll never be happy
even when we’re dead.
There is a deeper agenda behind AGW devotees, IMO. Even if we were a carbon neutral society they would seek to derail human progress in other ways.
Agreed: the general working rule behind Progressivism seems to be to oppose all progress and anything good.
In turn, my current working rule in approaching what “Progressives” want and suggest has become essentially that Progressives almost always get it wrong – if not immediately, then eventually, by ruining everything they get their hands on if given enough time. And no matter what “it” is: Classical Liberalism, Environmentalism, Education, National Defense, the Safety Net, The Scientific Method, Healthcare Systems, The Family, whole Nations and Societies, etc…and even now “The Woman’s Right to Choose”!, by pursuing it to absurd extremes – and often even by getting whatever “it” is exactly 180 degrees wrong.
So far, this rule-schema works very well for me both as a heads-up and a predictor, but I check it nearly every time, even as boring and depressing as it is becoming.
Ideologically, and in terms of world-view and mental processes, and in practice, any such people* are therefore actually “Regressives”, at best, but often also fit [my] criteria for being judged as essentially having naked “control-as-self” or as even being effective “deathworshippers”: for example, as in the case of their self-glorifying brand of pacifisism – which also explains the tolerance of many Progressives for Islamofascists, who are really only their soul-bros., and who also judge the ultimate worth of their acts and “values” only according to the death of someone, or many, or at least by their enslavement.
Conversely, actual progress is taboo – maybe now even a “crime against nature”?
And I believe many current “Progressives” are striving mightily to regress even beyond the “achievements” of Communism. That would be ultra “progressive”, after all, right?
-*Disclaimer: no one needs to take this personally if the ‘shoe doesn’t fit’. Check your friendly mirror.
John,
Your initial CO2 density is wrong. The density of CO2 at 1 atmosphere and 15 C is roughly 1.8 kg/m3 or 4 pounds/m3. So, a pound of CO2 occupies 0.2294 m3. You wrote that a m3 of CO2 weighs 0.2294 pounds — the inverse. Therefore you are off by a factor of about 20. I didn’t check anything further than that.
In the end, your conclusion is probably correct for another reason. The algae are essentially solar power generators. Photosynthesis is not very efficient (~5%). Current photovoltaics can get up to 20% efficiency. Once you have power and the raw materials you can make liquid fuels. It’s probably better to use photovoltaics to produce the power and then do the chemistry ourselves.