This is a posting by Krassen Dimitrov, Ph.D. who has also published a very detailed case study on the economics of algae biodiesel production. This however carries the gist of his arguments and perhaps a bit more entertaining. I found the case study very welcome.
Much as one would like to see algae converting smoke stack CO2 into biodiesel, this work by Dimitrov makes short work of the economics and pretty well sets impossible goal posts for a real commercial algae industry. He also supplies the missing analysis in the work of the algae proponents that I was looking for. As usual, financial enthusiasm is forcing the pace rather than meaningful field results.
So what can be physically salvaged from this technology? The reason for asking this is that cleaning up the stack gas and then directly consuming the CO2 is by itself a laudable objective in its own right. As I posted earlier, scrubbing out the particulates, capturing the waste heat and also reducing the SOx and NOx into acids are all possible, leaving us only with CO2 to deal with. It is just not been done that way and likely will not be done until we can also deal with the CO2.
My hope listening to the algae proponents was that it might even be easy. This makes it looks like mission impossible.
That really leaves us with one remaining strategy. It is to compress the cleaned up CO2, also releasing most of the heat for which we hopefully have some use and then piping it rather than dumping it. Once in a pipe, geological sequestration is at least possible at a location independent of the power plant. This also permits transport to bioreactors and greenhouses that can use some CO2.
We are adding a cost to all thermal plants that is actually acceptable and also sound management. If we implement such a protocol nationally, then no advantage is given and the producers can simply get down to the business of doing it all as cheaply as possible.
It would still have been neat to use this primary source of CO2 as a feedstock for the production of biodiesel and that may yet somehow come to pass. It is just that the obvious ideas and their obvious improvements are not nearly good enough.
Krassen Dimitrov posted:
Our friends at GreenFuel have updated their website with a new FAQ, so it is time for an update.How much FUEL from GreenFuel?
In the news: Even old pal Saudi Arabia is giving the finger to America’s first MBA president and won’t pump more oil out. Let’s hurry with this algae greenfuel; when will GreenFuel turn the spigot on?
There is no spigot! In a refreshing change from before, GreenFuel is starting to present a more realistic picture of its potential to address the fuel crisis.
For starters, we have now a public and very clear estimate of the oil yields that they think can be achieved: ~5,500 gal/acre/yr, which comes to ~1.36 gal /sq.m/yr. As you remember we estimated 1.26 gal/ sq.m./yr The company was started on assumptions of 11 gal/sq.m., which as we know is thermodynamically impossible. So it’s good to have this one settled.
OK, so 1.26-1.36 gal/sq.m/yr. How much in total? GreenFuel says that they plan on having a commercial scale “farm” - which is defined as 100 hectares or more - in the next few years. 100 ha is a very nice number, it comes to 1 sq.km and could produce:1,000,000 sq.m. x 1.36 gal/sq.m. / (42 gal/bbl x 365days) = 88 bbl/day (bpd)
Incidentally, the world consumes 88 MILLION bbl/day! So not much fuel relief from GreenFUEL and to their credit the new FAQ does not make any bombastic claims to the contrary.How much GREEN from GreenFuel?
While we have converged on the oil estimates, we are still apart on the CO2 mitigation potential. Oddly, in their FAQ GreenFuel switched to a ‘per hectare’ estimate of 500 tCO2 (as opposed to the oil, which was ‘per acre’). This comes to 50kgCO2/sq.m./yr. We had estimated ~30kgCO2/sq.m/yr. The difference has come down substantially, however it is still significant.
For a place like Arizona, assuming 1.36 gal/sq.m./yr oil and the rest of the biomass in carbohydrates, fixing 50kgCO2/sq.m. would require energy efficiency on PAR-basis of 16.5%, or 61% of the theoretical. Pie-in-the-sky, in my view … BUT at least we are talking about things that are thermodynamically possible, even if difficult. Big difference from before!
Moving on, the company gives an example of a theoretical “average” coal plant with 655MW of nameplate capacity. Here’s what we learn:
“For this 'average' plant, when both the power plant and algae farm are in fulloperation, approximately 3400 hectares of algae growing area isrequired to consume 40% of CO2 emissions.”
Hmm, let’s see. Depending on the source, coal-fired plants emit anywhere from 900 to 1,200 kgCO2/MWh. So, for a example of 920kgCO2/MWh, based on a report from EIA
(see figure) we get:
655MW x 365 days x 24 hrs x 100% (full operation) x 920 kg CO2/MWh = 5,278,776 tCO2/yron the other hand, for the algae farm:
3400 ha x 500tCO2/ha/yr x 100% (full operation) = 1,700,000 tCO2/yr
Now if we perform a division: an operation that my third-grade son is currently learning:1,700,000 / 5,278,776 = 0.32 = 32%
Well, that’s not 40%!
So we continue to see chicanery and spin-ola here… I guess they need to do it. The CO2-mitigation potential of the technology is a needed “green lipstick” for their friends in the coal sector (see the last sentence in the link)…
Now how about the other GREEN ($$$)?
From the FAQ:
GreenFuel’s extensive economic analyses and cost estimates show that algae canbe grown economically as a commercial product. Many estimates claiming thatalgae are not commercially viable use outdated economics for product values thatare no longer valid, or assume use of initial generations of experimentaltechnology that have since been upgraded.
We scroll down, however, and see that they continue with this absurdity:
GreenFuel algae farms are enclosed systems resembling greenhouses. They areoften called algae-solar bioreactors.
Huh? It is true that both fuel prices and animal feed prices have gone through the roof, however, so have the prices of steel, plastics and many other materials needed to build greenhouses. We have shown that one needs to get about $30/sq.m. profit to justify a greenhouse, and this was in 2000! How do you get $30 profit from 1.36 gallons of vegetable oil plus some kilos of animal feed? This continues to make zero sense.Speaking of which, the comparisons with other crops become really meaningless if they keep on using the closed systems (greenhouses). Of course everything grows better in a greenhouse! We won’t know how well maize, soy, or sugarcane will grow in a greenhouse, because no-one is dumb enough to grow energy crops and animal feed in hothouses. That’s just weird!
Is there something that I like?
Yes, I like this part:
GreenFuel is actively pursuing several opportunities where nutrient-rich waterfeed streams will be used to provide some or all of the nutrients needs of the algae farm. Streams which have a potential to be used in this way include runofffrom animal facilities and treated wastewater.
Algae’s potential has always been in water treatment, so that’s probably a very good direction for the company. I hope that they put their new money in this direction…Finally, they have announced an ‘unannounced’ large-scale project in Europe, which we will learn about in the near future. I believe that it is likely in Pottsdam, where IGV is building out a hectare. Most of the numbers above, as well, as GFT’s FAQ are for Arizona; the numbers for Germany will be worse. Something to keep in mind.www
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