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Filling Up On Algae
grqb writes "News.com is reporting that GreenFuel Technologies, a Cambridge, Mass. based start-up, is using algae fed with sunlight, water and emissions from power plants to make biodiesel. The benefits are that heavy polluters can cut back on their emissions and at the same time make biodiesel. The algae consumes carbon dioxide as part of photosynthesis and they also break down nitrogen oxide, reducing the amount of polluting gas released. Once the algae are grown, the conversion to biodiesel is a relatively simple process. The company uses technology licensed from a NASA project. The only barrier now is to prove that it is economically viable."
>> This is unAmerican and you hippies should be ashamed of yourselves! ;)
I'm not American, so hopefully I can get away with linking to www.greasecar.com
If you're interested in running your vehicle on biodeisel or straight vegatable oil, it's a good place to start reading. Very interesting stuff..
http://request-header.info
Step 1: grow algae
Step 2: refine into biodiesel
Step 3: Profit!
I always thought step 2 was the hard part, because it requires methanol (biodiesel is basically a methanol-fatty acid ester), and methanol is tough to make. It gets made by cracking petroleum catalytically at very high temperatures and pressures, which takes a lot of energy. Where are these people getting their methanol?
But, in saying this, growing crops for fuel is just not sustainable, for one thing it requires a lot of land, for another it sucks up all of the soil nutrients and so you can't continue to grow crops in the same location indefinitely.
But there are a couple of things that are being done about this problem. For instance, the biotech industry doesn't want to use corn/wheat directly, they focusing on using the waste streams of agricultural products (such as corn stover) to extract sugars using advanced enzyme systems. We can also make ethanol from by products of making paper using the same techniques.
Well, some varieties of algae can be pretty high in oil. Some are as high as 50% oil by weight. By crushing the algae, separating the oil, and performing transesterification (the same process used to convert soy or rape oil), you can get biodiesel from it. There has been a lot of talk in the biodiesel circles about using algae, so lets hope this group can bring it to market. BTW, people also talk about using algae in pools that capture the run off from, I believe, cattle grazing land. Not only does it clean the water, it also has a very nice byproduct.
They're probably using the high-oil algaes investigated by the University of New Hampshire here. UNH says some algae are made of over 50% oil. algae are some of the most efficient photosynthesis machines around. once you've got the oil, it's just a matter of standard transesterification, a normal part of biodiesel production (and really, the only step necessary when you have clean oil).
fear is the mind killer
However, you are right in terms of your observations of present diesel vehicle emissions. Until relatively recently, diesel particulate emissions were pretty much unregulated. That's changing rapidly. New diesels are a hell of a lot cleaner than the old ones.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
Thermal depolymerization and this algae farming *might* be practical, but conventional crops to ethanol is a waste of time (or, at least, is not worth subsidising on environmental grounds).
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
A mature forrest (One where the oldest trees are beginning to die), all of the CO2 absorbed by the trees is replaced by the CO2 being emitted by the organisims breaking down the leaf litter. Indeed, during droughts, forests have been measured as _emmitting_ CO2.
The only CO2 sinks on this planet are the oceans, where, interestingly, algae consume CO2, and their dead bodies sink to the ocean floor, where, the standard theory goes, they are compressed and heated and form - Oil!!
There is indeed nothing new under the sun.
What I have see are numbers that make the whole proposition somewhat marginal without advances in genetics of algae.
To get an idea of what you are going to get out an optimal system (using Calchemy's Unicalc):
.8gm_oil/cm^3; .6gm_prepressed_oil/gm_algae; .7gm_oil/gm_prepressed_oil?$/(acre*month)
50$/barrel_oil; 50gm_algae/(m^2*day);
= 1016.17 $/(acre*month)
Please check for any errors, but it appears that under optimal conditions, meaning a sunny desert with warm nights year round and algae production consistently at the height achieved by ASP during their 20 year study, using a species modified to produce optimal oil and a consistently high price for oil, one can get $1000 per acre per month.
We have $1000/month to make this realistic and to pay the rest of the expenses of the operation per acre.
A covering will eat into that $1000 in two ways:
1) Amortization (which has to be fast)
2) Solar flux reduction
Let's take out the solar flux from the covering first and say we lose 30% leaving us with $700 for the rest of the operation. Let's further say that we need half of that for expenses other than structure amortization, leaving us with $350. If we assume commercial lending rates of around 12% and zero amortization -- just debt service, we can afford $35,000 to cover an acre so with amortization it drops to sometning more like $10,000 to cover an acre.
Covering these ponds sounds problematic under optimal conditions, let alone constructing bioreactors -- and we haven't even gone to climates with less total solar flux.
Recalculating for volumetric production of oil:
50gm_dry_algae/(m^2*day); .8gm_oil/cm^3; .6gm_prepressed_oil/gm_dry_algae; .7gm_oil/gm_prepressed_oil?gal/(yard^2*month)
= 0.17636 gal/(yard^2*month)
What this says is that the best you can expect, under optimal species and growth conditions, of any algae-oil system that relies on the sun for its energy, is for each square yard of solar-exposed pond to produce just over a fifth of a gallon of pressed lipid oil each month -- which you must then process into biodiesel through the normal methods. If you find other energy sources you can feed to algae, you might beat this but algae are optimized to consume solar energy so you have to be very skeptical of any claims that exceed this productivity level and really find out where the energy is coming from and how the algae are metabolizing it.
Let me try to break down the parameters of the calculation:
50gm_dry_algae/(m^2*day)
This is the target productivity figure given by the National Renewable Energy Laboratory's review of the last 25 years of algae biodiesel work. It basically says for a given area, how much dry algae you should be able to get out of an _optimal_ system per day -- optimal climate, species, solar flux at pond surface, etc. If you can economically create these conditions in your "back yard" then you can get that level of productivity. Find the NREL's review at:
http://www.nrel.gov/docs/legosti/fy98/24190.pdf
.8gm_oil/cm^3;
This is the density, or specific gravity of diesel. Diesel isn't quite as dense as water. This probably should have been the density of lipid oil but I didn't have that figure handy.
.6gm_prepressed_oil/gm_dry_algae;
The _highest_ oil content, of oil-producing algae reported by the National Renewable Energy Laboratory's review, was 60%. This presumes algae grown under their high rate goal of 50gm_dry_algae/(m^2*day) but this growth rate has yet to be achieved with this high, 60% oil content (to the best of my current reading of the NREL report).
.7gm_oil/gm_prepressed_oil
This is a fairly optimistic 70% fig
Seastead this.
1 gallon of diesel = 128,000 BTU = 37.5 kilowatt hours.
Sunlight's energy content is about 1 kilowatt per square meter.
Assuming 12 hours of sunlight per day, and assuming the tube has an average cross section to the sunlight of 3 m^2, that gives us a theoretical maximum of:
12 hrs * 3 m^2 * 1 kw/m^2 = 36 kw hr per tube per day.
Or just under one gallon per tube. And that's assuming 100% efficiency. Biological processes usually have very high energy efficiencies (>80% IIRC), but some of that energy will be needed to maintain the algae's internal life functions (growth, repair, etc), so I'll use 50% as a rough estimate.
At 50%, you'll need two tubes per gallon. Standard tanker trucks carry 5000 gallons, so you'll need 10000 tubes to fill a truck per day. Assume a 2.25 m^2 footprint (to make the math easy), that's a 22500 m^2 tube farm, or an area 150 m on a side. A little more than five and a half acres, or exactly 2.25 hectares.
A legparnasom tele van angolnaval.
Put it into perspective. In 2002, the world generated about 405 quadrillion BTUs. In Joules: 4.273*10^20 J. With a radius of 6378 km, the profile of the Earth absorbing sunlight with an intensity of 250 W/m^2 (adjusted from 1600 due to atmospheric reflection) will absorb 1.0075*10^24 J in a year. This means that humans currently generate only 0.04% of the energy that the Earth absorbs from the Sun. The Earth will also radiate the same energy keeping in relative equilibrium. Some of the 0.04% will also be radiated.
Overall, the amount of energy we generate is not really significant. The amount of energy the Earth absorbs from the Sun (which we can help out by generating CO2) is very significant.
The Boston Museum of Science has a small exhibit on the technology right as you walk between all the exhibit halls (by the map of Boston with the buttons that light up various areas of the map).
What I know about plants is that the best overall efficiency is about 10%. Algea, I'm not sure about. I suspect, however, that the 50% estimate is too generous. The best I could find doing a google search was about 15%. The acutally photosynthetic process as I understand it is approximately 90% efficient. The problem as you already noted is all the house cleaning stuff these organisms must carry out.
I drive a Jetta TDi Turbo Diesel. It will run almost anything claimed as "*-diesel" with little or no modification.
Amazing how all the hype is pointing at gas-hybrids, yet (bio)diesel is where the technology is pointing. Why run a clean diesel engine with more (and cleaner processed) torque and power per liter, when you could dump money into oil company products.
Yep..this is true. When the Diesel engine was first developed in the 1890's, the inventor choose peanut oil as the fuel to run it on. http://www.google.com/search?q=Diesel+Engine%2C+pe anut+oil
Additionally, it is possible to run a modern diesel engine on straight vegetable oil, however, there are a number of factors that could effect performance. http://journeytoforever.org/biodiesel_svo.html
My Sysadmin Blog
Sorry, I should have been more specific: why producing biodiesel from algae, when you can just use natural oil production from a single type of algae?
Producing biodiesel is inefficient; instead of relying on the diatoms' natural energy storage mechanisms (petroleum), you take sugar from other sources, ferment it into alcohol, and react the alcohol (and NaOH) with the lipids from the algae to produce readily combustible fatty acid esters. It's not very efficient no matter what method you use - you're losing most of the energy produced by the algae. It's sort of like what happens when you compare how much solar energy goes into growing corn plants vs. how much energy is in the ethanol.
Diatom shell construction is mostly limited not by energy, but by available nutrients; you get blooms when there's pollution runoff (although they're not as dangerous as, say, dinoflagellate blooms). Even with natural nutrient limitations, diatoms have been among the most prolific organisms on Earth - there are deposits of diatomaceous earth being mined that are almost a mile deep. It's used in many products, mostly due to its reflective, abrasive, and insulative properties, so it's hardly a waste product.
I don't get the point of having the process on a CO2 stream, apart from the fact that having a higher partial pressure of CO2 might help increase the speed of photosynthesis. If you release the CO2, and take CO2 from elsewhere, the net affect is the same. The only argument I could really see is to remove other pollutants - but is that really an effective solution?
Aeris Died For Your Sins.
Okay, I am an environmentalist. I have a degree in conservation biology. And I also know that studies have pretty much proven that the earth's climate fluctuations are directly linked to... total insolation from the sun. The sun's total energy output fluctuates over time, and when there is more energy coming in, the earth warms up.
But what about the perfect lock-step match between temperatures and atmospheric CO2 you ask? Easy. People talk about the tundra permafrost melting and releasing CO2 and sure, that's gonna cause some raise in temperature. But the big one? Gasses are more soluble in cold water than warm. With global warming, the oceans can't hold as much CO2, and so outgass it to the atmosphere. CO2 levels rise BECAUSE of global warming, not necesarilly the other way around.
Yes... global warming is going on. But whether it is mankind that is causing it is actually a lot more up for debate than you seem to think.
I'll never make that mistake again, reading the experts' opinions. - Feynman
Seeing that I pay (at the pump) about $2.80/gal in Olympia, WA for biodiesel .. and run it in a vehicle that gets 50 mpg (VW Jetta Wagon TDI), I'd say it's pretty darned economically viable. *grin*
I've calculated, though, that if I homebrewed it, I'd be paying $1.30 a gallon (bulk veggie oil is ~$1/gal, the amount of methanol required would be about $.30/gal...) plus I'll have more glycerine than I'll know what to do with. *grin*