## Wednesday, March 14, 2007

### Biofuel from Algae - Salvation from Peak Oil?

It is nice to have an optimistic note on which to mark the start of Spring, and that could be the production of biofuels from algae. I have considered the viability of biofuels in various of these postings, and concluded that without seriously compromising food production (or eliminating it entirely) it is impossible to provide enough crop-based fuels to replace the massive quantities of oil that we currently use to run our transportation fleet of cars and planes. However, I am abruptly more upbeat about the situation potentially, having seen some truly astounding figures about the amount of biodiesel that might be obtained from farming algae, rather than from growing crops. For example, whereas the yield of biodiesel from soybean is 357 kg/hectare/year and 1,000 kg/ha/year from rapeseed, it is 79,832 kg/ha/year from algae, i.e. about 80 tonnes/ha! There are some algae that yield around 50% of their own weight of oil, and from one study it might be deduced that the yield is around 125 tonnes/ha on the basis that 200,000 hectares of land could produce 7.5 billion gallons (one quad) of biodiesel.

[Since there are 3.875 litres to the US gallon, that equals 7.5 x 10^9 x 3.875 = 2.91 x 10^10 litres. Since there are 159 litres to the barrel and 7.3 barrels to the tonne (accepted average), that amounts to: 2.91 x 10^10/(159 x 7.3) = 2.51 x 10^7 tonnes of biodiesel produced from 200,000 hectares, i.e. 2.51 x 10^7/200,000 = 125.5 tonnes/ha].

I am going to attempt some rough calculations, just to deduce some estimates of scale. In the UK we use around 57 million tonnes of oil to run all our transport - cars, planes, the whole lot. Another 16 million tonnes are used as a chemical feedstock for industry etc. However, I will look at only the fuel budget for now. Diesel engines are more efficient in their tank to wheel use of fuel than spark-ignition engines which burn gasoline (petrol), meaning that we could reduce that total by 30%, to 40 million tonnes by switching all forms of transport to run on Diesel "compression" engines. If we take the optimistic 125 tonnes/ha figure for the yield of biodiesel from algae, that implies a crop area of 40 x 10^6/125 = 320,000 hectares, or 3,200 square kilometers (km^2).
Now this is only 1.3% of the area of the UK mainland, which does look feasible, especially in comparison with values of up to five times the entire area of arable land there is, that I have deduced would be necessary to provide sufficient biofuels derived from land-based crops!
There is no need to use arable land in any case, since the algae would be grown in ponds, and these could be installed essentially anywhere, even in off-shore locations, i.e. growing the material on seawater, because salt concentration appears to assist the algal-growth.
We can make some guess as to the thickness of the algae too. One hectare = 100 m x 100 m = 10,000 m^2. Hence, 320,000 ha = 3.2 x 10^9 m^2. The volume of 40 million tonnes of biodiesel at a specific gravity of 0.84 (based on 79,832 kg = 95,000 litres; so, 80 tonnes = 95 m^3) = 4.76 x 10^7 m^3. Hence, spread over 3.2 x 10^9 m^2 gives a thickness of 4.76 x 10^7 m^3/3.2 x 10^9 m^2 = 0.015 m = 1.5 cm. So, assuming that 50% of it is "oil", that gives a thickness of around 3 cm, which seems reasonable.
How much water would be needed to fill the tanks? Let's assume they are one metre deep (with the algae floating on top of that). That's 3.2 x 10^9 m^2 x 1 m = 3.2 x 10^9 m^3. Since this amounts to 3.2 km^3 it is a significant volume of water, and if freshwater would account for about 2% of the UK's total. However, as I have indicated, seawater can be used instead, or the "ponds" could be fashioned from floating ("boon") structures off-shore. Closed ponds might be better, since that would permit a much closer control of nutrient supply, and if they were covered restrict the potential for invasion by algae with a lower oil yield.

I think that this might be the only way to provide significant amounts of "oil" post peak-oil (other than by coal-liquefaction), and large scale production should be attempted as soon as possible - well before the world's supply of naturally occurring petroleum begins to wane significantly, which gives us just a few years. The "crop" would take-up CO2 from the atmosphere, thus reducing the burden of greenhouse gas that many are worried about, and that amount of carbon would be re-emitted once the fuel was burned, but with a continual crop production working in symbiosis with the CO2 content of the atmosphere, taking it up through photosynthesis. There would be no additional CO2 emitted, other than in the production of an alcohol, methanol or maybe ethanol, which is needed to trans-esterify the initial oil into the final biofuel. This would be in a proportion of about 10% of the oil yield, and could be provided from agricultural waste, e.g. wheat grass, some minor compromise of food crops, say to grow sugar beet to ferment into ethanol, and ultimately by hydrolysis and fermentation of cellulosic material once that technology is underway, thought to be by 2015.
I have never hankered after a return to the "Stone Age", but my notion of living in localised communities remains the only means by which to survive in a fuel-poor world. If we are to produce "alternative" fuel on a large scale, doing so from algae appears to be the best bet, and from an environmental aspect it seems ideal, in that it produces fuel by absorbing a greenhouse gas without producing any more greenhouse gases during the process.
What about costs? If we assume a cost per hectare of \$80,000, that would equate to \$80,000 x 320,000 = \$25.6 billion, or around £13 billion. Annual maintenance/operating costs have been estimated at \$12,000 per hectare, which is about £2 billion. Assuming a price of \$60 a barrel, that may be compared with an annual cost for 40 million tonnes of oil of \$60 x 40 million x 7.3 (barrels/tonne) = \$17.5 billion or about £9 billion. This would mean money that is not going out of the country to unstable regions of the world, and it would break completely our dependence on imported oil. It would also reduce the nation's CO2 emissions by probably 30%. We could even use biodiesel to substitute for coal in power stations and cut our dependence on coal imports too, while reducing CO2 emissions yet further.
Now, this approach seems to have everything to recommend it and surely it must be investigated on the large scale immediately.

#### 12 comments:

Anonymous said...

Hello, it's me again
I've found this link
http://www.algaefuels.org/index.html
http://www.algaefuels.org/algaepond.htm
I wonder if actually the figure of 120 tons (I think mt is metric ton, is it?) per hectare ("Our record is 120mt of Algae Oil per Ha per annum") can be realistic. Yet all good news it seems on this front.
cheers,
marco

Professor Chris Rhodes said...

Hi Marco!
As you say there are various estimates. For example in the "Algaculture" section in wikipedia it says that between 5,000 and 20,000 gallons of oil per acre might be obtained from algae. In my head, that looks like, between about 40 and 160 tonnes per hectare/annum. But even that lower estimate still looks pretty good compared to biofuels, doesn't it? I'll do a bit more research and some more thinking about "algae".

Cheers,

Chris.

Professor Chris Rhodes said...

Hi Martin,
yes, I too am fired-up about the possibilities of making fuel from algae, which seems about the only way to make significant quantities of "biofuels" without compromising growing food. It is the one and only time I have not felt despondent about the subject since doing my first sums on the matter about a year ago!

No, there isn't any necessity to be totally self-contained and it would make sense to grow the algae further south where there is more sunshine. It has even been suggested that desert might be used for this purpose in the US, although I think evaporation of water might prove a problem.

Quite right, because it could be produced all over the world, that would effectively end cartels and the need to go to war to grab other people's oil resources.

However the oil industry is very powerful and oil is intimately tied-in with the World Bank and the IMF and so the balance of world power. Hence on this basis, I can imagine there might be some resistance to change from the petroleum status quo. But in principle anyway this does appear to be a means to cut CO2 emissions and secure an infinite supply of oil - in one felled swoop!

I still think that energy-efficiency should be pursued, rather than imagining we can simply carry as we are, even if we can make enough biodiesel to do so. There are other resources that our status quo is steadily depleting - not the least of which is "water". Perhaps that will prove to be the ultimately limiting resource, rather than oil!

However, we may thus be rescued from a sharp return to the Stone Age"!

Chris.

Ecacofonix said...

Thanks for the article...it is heartening to see algae getting a lot of publicity, something I feel they deserve.

I co-ordinate Oilgae, a site that explores use of algae as a feedstock for biodiesel, and I can say with some amount of confidence based on my researches that algae appear to be one of the most qualified candidates for biodiesel production.

While the math certainly appears to favor algae, there are a number of issues to be overcome. These have to do with (1) choosing optimal algal strains, (2) issues faced in cultivation and harvesting (believe me there are some serious bottlenecks here), and (3) cost-effective methods to extract oil and transform it into biodiesel.

So yes, there is still a long way to go before it can be proven with certainty that algal biodiesel can be cost-effective on a large scale, but it is gratifying to see brilliant minds (not to forget VC money) getting into this field. And with institutes like MIT (Boston) getting into the act, I'm optimistic most of the above-mentioned issues will be overcome.

Time will tell if algae are our future source of energy, but for now, they certainly appear to have many of the qualifications required for the same.

Narsi from Oilgae - Oil from Algae

Professor Chris Rhodes said...

Hi Martin,

sorry, I missed your reply, but just to say: Good! I hope sense is seen and there is a real "push" toward biofuel technology such as this and indeed coal to liquids. I think if the biofuels can't match demand, then it will be coal that comes to our aid, but we need to really make that push now, not in 10 years say. I have a few reservations about gas to liquids, as you see from my latest posting (today, 28th of April), as it might be that in Europe and the CIS gas could begin to fall in short supply? Do you have any thought about this?

Nice to hear from you again, and glad you are still reading my efforts on here.

Chris.

Professor Chris Rhodes said...

Hi Narsi,

thanks for these interesting links and your comments. Yes, I feared that biodiesel from algae was not entirely cut-and-dried! It's potential is huge, but as yet it reamins an untested technology on the large scale - like so many others.

My main worry is that any alternative technology needs to be implemented against the back-drop timescale of cheap oil running in short supply, i.e. 10 years maybe?

So the sooner we get started the better!

Chris.

algoil said...

Fascinating reading, this oil from algae and i too think that the sooner we start the better but the question is where to start?
I have approx 60,000sqft of commercial glasshouse available to experiment with on the south coast(uk)if anyone has the knowhow or ideas on funding?
cheers,
gary

Professor Chris Rhodes said...

Hi algoil/gary,

that sounds very interesting, and it sounds like you have a potentially good "location" to explore this. As far as I know there is little investigation going on in universities relatively and most organisations that are exploring algae are in industry.

Hence I suspect that there is more known about this technology than is reported in the scientific literature.

I also get the impression that it's more difficult than appears at first sight. There are academic groups in the US, including one at Harvard? They seem to be looking at long-term projects but of course university groups are always after 3-5 year project funding or even better rolling-contacts. My feeling is that if anybody is serious about it then let's try to make a batch on a large scale...

yes that's another thing, it's all fairly small scale set-up that I have seen.

I am curious Gary... how is it you are int he fortunate circumstance of having such a large glass-covered area?

I am sure there is funding that could be got for this, given its importance but the right network of people would need to be put together.

Please e.mail me if you want a more private discussion:
cjrhodes@fresh-lands.com

Cheers,

Chris.

Unknown said...

I'm glad to see that you people are very hopeful with Algae, while oil which we cannot stop overnight is slowly poisoning our planet- why don't we just plug-in something to control fossil fuel burning and mitigate it's anthropogenic effect right away then conserve the remaining oil and still preserve our way of life...

The BlackGold SAVER
http://green.juneayasolalternatives.co.cc

Professor Chris Rhodes said...

Hi June,

the interest in algae has stepped-up considerably during the past couple of years since I wrote this article, with a lot of private companies involved.

I saw ExxonMobil advertising their interest in the algae to fuel conversion business on tv the other night, and at the Eurostar railway terminus last weekend on my way to Paris.

I think that the technology could provide fuel in the future once it is fully-developed but there is clearly a case for a "power-down" strategy, in which societies become more localised and hence less dependent on extensive transportation.

Regards,

Chris.

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