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131 comments on Why new ideas take time to have impact

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Heading Out on May 23, 2008 - 11:38am Permalink | Subthread | Parent | Comments top

The answer comes in several parts - the easy one is to say that this is a work of fiction and the numbers could be considered that way, however there is a real, and more complicated, answer.

In the Redhawk tests they were able to considerably improve on the base NREL target of 50 gm/sq m/day, which gives the 3,500 gal/acre/day which is the commonly cited yield for algae over things such as rape or soybeans.

The growth rate—an average productivity of 98 grams/m2/day (ash free, dry weight basis) and reaching a high peak value of 174 grams/m2/day—surpassed previous lab growth rates and exceeded all expectations going into the project.

This is roughly 3.5 times the baseline and translates to 12,100 gal/acre/year. However, even at Redhawk they were only just starting to tweak the process in the right direction.

The reason this differs from Dimitrev's theory can perhaps be explained by analogy (albeit imperfect). If I sit by a river and drink a cup of water whenever I want to it is a little inaccurate to assume the relative efficiency of the process is the total power of the water as the input, and the cup of water that I drink as the output. But that is the way that the equation is being presented. There are controlling parameters on the way in which algae handle light that can be adjusted, in the same way as, to work the analogy again, I could now put a cup in both hands and drink twice as fast - without changing the input.

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Preston Sturges on May 23, 2008 - 12:46pm Permalink | Subthread | Parent | Comments top

Kudos for using the word "sparge."

Years later I still dream about going into work and streaking out my C. reinhardti stocks.

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Robert Rapier on May 23, 2008 - 1:57pm Permalink | Subthread | Parent | Comments top

This is roughly 3.5 times the baseline and translates to 12,100 gal/acre/year.

But that appears to be the growth rate of the algae, and not oil production. NREL indicated that the high oil % happened when they starved the algae. That bumps the % oil up, but growth ceases.

But that is the way that the equation is being presented.

It would be more helpful for me if you can point out which parameter/equation that Dimitrev used is wrong. I have long hoped that he was wrong, but I feared that he was right. If you can convince me that he was wrong, I will be grateful. And I am not being facetious.

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Heading Out on May 23, 2008 - 2:45pm Permalink | Subthread | Parent | Comments top

If you will forgive me I believe you are generalizing from the particular. It really depends on the species that you are growing in regard to growth rate, and lipid content, and there are a number of other factors that also come into play, that Dimitrev did not factor in.

Since the experiments with which I am familiar come at the issue from a different approach I will have to revisit Dimitrev's work in more detail ( I have it, I just have to find it) to pin down exactly where he made the error.

Incidentally, if this were more than a fictional enterprise, you might recognize the name of one of the corporate vice-presidents.

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DaveMart on May 23, 2008 - 3:07pm Permalink | Subthread | Parent | Comments top

And in this hypothetical, purely fictional world, at what stage in the 20 year enterprise would 2008 be?

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Heading Out on May 23, 2008 - 3:21pm Permalink | Subthread | Parent | Comments top

About year 3.

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Petrus on May 24, 2008 - 11:18am Permalink | Subthread | Parent | Comments top

Something is really wrong with this calculations:

In the Redhawk tests they were able to considerably improve on the base NREL target of 50 gm/sq m/day, which gives the 3,500 gal/acre/day which is the commonly cited yield for algae over things such as rape or soybeans.

50 g/m^2/day ----- NREL target
* 4047 m^2/acre
/ 850 g/l ----------- Diesel density (even if all dry contents were oil)
* 3.78 gal/l
= 900 gal/acre/day
3,500 gal/acre/day is 4 times overestimated.

The growth rate—an average productivity of 98 grams/m2/day (ash free, dry weight basis) and reaching a high peak value of 174 grams/m2/day—surpassed previous lab growth rates and exceeded all expectations going into the project.
This is roughly 3.5 times the baseline and translates to 12,100 gal/acre/year. However, even at Redhawk they were only just starting to tweak the process in the right direction.

No. 3.5 times baseline translates to 3150 gal/acre/day .

However, notice that 174 grams/m^2/day is already 35% photosynthesis efficiency over theorethical 493gm/m^2/day average solar output !

[ 493gm/m^2/day = 56gal/m^2/year / (365 day/year) * 3.78 (gal/l) * 850 g/l ]

So there goes Dimitrov's limit of 2% maximum efficiency - 17x overcome.

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Heading Out on May 24, 2008 - 11:50am Permalink | Subthread | Parent | Comments top

My apologies but i got one of the units wrong. Inadvertently I typed 3,500 gl/acre/day when it should have been 3,500 gal/acre/year - which it is in most of the other discussion.

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131 comments on Why new ideas take time to have impact

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