Is Biofuel from Black Soldier Fly Larvae (BSFL) Hype? | You Decide! : The Life and Times of BSF (Black Soldier Flies)
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Is Biofuel from Black Soldier Fly Larvae (BSFL) Hype? | You Decide!

by Terry Green on 10/17/14

The natural arc in the evaluation of a new technology progresses in fits and starts beginning not surprisingly with hype and excitement, moving on to disillusionment, and ultimately adoption or rejection of the technology as a business venture based upon its practicality and viability under real world operating conditions. For a technology to succeed it must have demonstrable value. It must pay its way in the business world. This blog discusses proposed farming of Black Soldier fly larvae (BSFL) for biofuel production in the context of its practicality as a business venture.

Several BSF entrepreneurs have proposed in grant applications, and in pitches to investors, and continue to claim in spite of a dearth of evidence in support of their claims, that BSF farming of larvae for biofuel is feasible as a business venture (see, for example,Fly Larvae to Biofuel, Double the biodiesel yield: Rearing black soldier fly larvae, Hermetia illucens, on solid residual fraction of restaurant waste after grease extraction for biodiesel production, Black Soldier Fly Digesters – Converting food wastes into feed, fuel and fertilizer, Prota Culture produces biodiesel and animal feed from organic waste, and Insect Fat, a Promising Resource for Biodiesel ).  Consider however what is involved in raising BSF on waste, the effort and cost involved in the recovery of fats from larvae harvested from the waste, and the Feed Conversion Ratio (FCR), all relative to the prospects of succeeding at business through the sale of fats extracted from the larvae for the purpose of refining it into biofuel.

Depending upon the nutritional quality of the waste BSF are grown on, there is evidence that they accumulate as much as 35% of their dry weight as fat by the time they reach the prepupae stage in their life cycle (see Black Soldier Fly larvae breakdown - Biomass; Amino Acids; Mineral Content; Fatty Acids; Anti- Microbial Properties; Soil Amendment, and Insect Fat, a Promising Resource for Biodiesel ).  The water content of freshly harvested prepupae is however about 55% of their body weight (see Commercial Production of Black Soldier Flies |Preserving Harvested Larvae ).  One metric ton of harvested larvae therefore in dry weight units is only 450 Kg. Since under the best circumstances no more than 35% of the dry weight of the harvested larvae exists in the form of fats, at the very most for every metric ton of larvae harvested one cannot hope to recover more than ~158 Kg of fat (calculated by multiplying 450 Kg x 0.35).

The theoretical limit of recoverable fats extracted from harvested larvae expressed in volume units can be calculated by dividing 158 Kg of fat by the average density of the fats (0.9 Kg per L, see Densities of Vegetable Oils and Fatty Acids) which reveals that the recovery expressed in volume units  would at best be ~ 175 L (~46 gallons) per ton of harvested prepupae. The actual recovery in practice would be less than this theoretical maximum. Not all of the fat is easily recovered in the process of crushing, grinding, and organically extracting fats from the tissues in which it was stored.

For the purposes of this analysis, ignore losses.  Even assuming maximum recovery under the most ideal conditions, since the wholesale price of biofuel sold through the commodity markets is in the range of $2 to $3 per gallon (see Biodiesel Performance, Costs, and Use, Biodiesel Supply, Demand, and RINs Pricing), gross sales in round numbers, calculated by multiplying 46 gallons x $3 per gallon, would therefore not exceed roughly $150 per metric ton of prepupae harvested. This is not impressive from a business perspective by any stretch of imagination.

But wait. It gets worse! We have ignored labor and energy costs incurred in drying the  harvested larvae. We have not factored in costs incurred in capital outlay in building the BSF processing site, the cost of equipment needed for its operation, the cost of labor incurred in hauling, grinding and loading waste needed for growing BSF up to the prepupae stage, labor incurred in propagating, feeding and growing larvae into prepupae ready for harvest, maintenance costs in keeping the site operational, etc.

Additionally, factor in the FCR in growing larvae from waste, ~ 4 in terms of  dry weight of food scrap waste needed in growing larvae into prepupae relative to the dry weight of harvested larvae (see BSF Metrics & Yields| Scale Up Production of Black Soldier Flies ).  Food scrap, itself, has a water content in the range of 70 to 90% (see Profiles in Garbage: Food Waste, Profiles in Garbage: Food Waste - Part 2, and Water in food). On a wet weight basis, the FCR (assuming an average water content of 80% for food scrap and based on a water content of larvae harvested of 55% ) is therefore ~10. This means  it takes ~10 tons of wet food scrap waste to produce one ton of prepupae. So from our calculations on gross sales, namely ~$150 per ton of prepupae harvested, taking into account the FCR, to earn the paltry sum of $150 per ton of prepupae harvested you would have to handle and process 10 tons of food scrap waste as feedstock in growing the larvae to the stage where they were ready for harvesting!

There are alternate waste streams including varying sources of animal manure on which larvae will also grow. But these latter wastes have higher FCR’s then food scrap because of their poorer nutritional content meaning that it would take even more of the latter feedstocks than food scrap to achieve the same yield of prepupae. By now you get the picture. It isn’t pretty!

While it is exciting to think of producing biofuel as a byproduct of BSF farming, the simple truth is that proposals outlining schemes for generating sales through production of biofuel by extracting lipids produced by BSF grown off of waste simply don’t jive with the real world science and business associated with BSF farming.

You may in your own analysis have a different set of numbers to work with, so I leave it to you to decide for yourself what is hype and what works. The important job to get done in this field is to move the arc forward and let the chips fall where they may. The comments offered up in this blog are written in the spirit of critically analyzing what works and what doesn’t based upon our experience in working with BSF at DipTerra LLC with the best data available at this time concerning farming of BSF.

Check back for more to follow on management and strategy issues in scaling up BSF production.

Comments on this blog, or any of our other blogs, are always welcome. Follow us through our RSS feed. For additional information or follow-up questions, visit our Forums page, or Contact Us (http://www.dipterra.com/).

Comments (9)

1. Andrey said on 10/18/14 - 08:31AM
You nailed it man, so much work done, great job!!!!
2. Tyler said on 2/19/15 - 01:55PM
I would like to point out that as a business venture, waste removal fees could be charges, as industrial composting services do. Additionally, oil is not the only product from BSFL. Their waste is a natural fertilizer. Consumers love to buy natural fertalizers. And if oil doesn't work out, BSFL are excellent as fish, reptile, and amphibian feed. Many fish farmers would love feed grown on the waste stream.
3. Terry Green said on 2/19/15 - 05:25PM
Yes, Tyler, it is true that there are other sources of potential income in raising BSFL. The main point of the present blog is that it does not make good business sense to farm BSFL as a source of biofuel. Other more practical potential sources of revenues that might be realized in farming BSFL along the lines mentioned in your comments have been addressed in earlier blogs posted on our website (see http://www.dipterra.com/blog-index.html).
4. T said on 5/16/16 - 06:38AM
Terry Green, use the larvae to produce biodiesel doesn't means that you will use them just for producing biodiesel the same way that extracting paraffin from petrol doesn't means that you can't also extract diesel, gasoline, kerosene, asphalt, etc. In case of the black soldier fly you will be doing multiple profitable actions simultaneously. While individually they aren't very profitable you add them up. So at the same time you are doing waste management, preventing pollution, producing biodiesel and protein for animal feed. Sounds better than organic farming to me and organic farming have been pretty successful lately even if I don't think you can feed the world with it.
5. Terry Green said on 5/16/16 - 07:34PM
T, you are right that it is important to consider using every option in maximizing an income stream in farming BSF. However, the economics of extracting fats from farmed BSF as an additional source of revenue does not pencil out. Even done efficiently, it is hard to justify this option as a source of any meaningful income stream – it would more likely negatively impact the overall revenue stream. If you factor in shipping costs, keep in mind that selling fats extracted and destined for use as biofuels would be sold at wholesale rather than retail prices, consider the capital outlay in equipment and materials required in extracting fats, add in also maintenance, labor and other overhead costs assigned to this type of operation, it is very difficult to see how extracting fats from BSF makes much sense. On a wholesale basis, one would be exceptionally fortunate to realize $75 in the sale of fats per 10 tons of food waste processed in today’s market.
6. bob chua said on 8/15/17 - 03:06AM
Hi Terry, read your blog and readers' comments with great interest. We're looking at the possibility of BSF farming here in Singapore, and, if it's as iffy as you say, I'm quite intrigued as to why so much money is being poured into this. Fully operational farms that started 10 years ago are now rapidly scaling up production..eg Agriprotein in South Africa, Protix in Holland and I'm sure you're aware that in the USA, Enviroflight has been acquired by Intrexon and embarking on a joint venture with Darling Ingredients to scale up production. These are both substantial NYSE listed companies that are leaders in synthetic biology and production of bio nutrients..so they must surely have done the calculations. I'm confused.Would appreciate any additional thoughts that you may have. Thanks. Bob
7. Terry Green said on 8/16/17 - 09:33AM
Bob, there is a huge difference in the operating challenges in managing a large scaled up BSF production facility and a small “fully operational” BSF site. Be careful not to conflate the two. For more on this, please see “Commercial Black Soldier Fly (BSF) Production in 2016 | Where Are We Today?” - http://www.dipterra.com/blog.html?entry=commercial-black-soldier-fly-bsf, and “Black Soldier Fly industry: more enthusiasm than scientific know-how?” - http://www.entomofago.eu/en/2016/07/04/industria-delle-mosche-nere-soldato-piu-entusiasmo-che-know-how-scientifico/. Does what has been claimed by the companies you cite match with what is known and validated in the industry? That is a question anyone looking into BSF technology will need to assess. I cannot speak for the companies you mention, nor for the expertise of the companies listed with the NYSE you cite as to whether or not (your words) they “surely have done the calculations”.
8. Sayed said on 9/29/18 - 01:40AM
Now,what is the most appropriate use for farming of Black Soldier fly larvae?
9. Terry Green said on 10/1/18 - 10:06AM
Sayed, harvesting larvae to be sold and formulated into animal feedstock as the sole source of revenue in offsetting the cost of farming BSF clearly will not on its own merits sustain a farming operation. There are however several alternate byproducts and strategies worth considering in making this novel recycling technology economically more viable. See, for example, “On the Economics of Farming BSF | Thinking Outside the Box” posted on DipTerra’s website, August, 2017, (http://www.dipterra.com/blog.html?entry=on-the-economics-of-farming), and a review on the same subject published by Jeroen De Smet et. al., February, 2018, titled "Microbial community dynamics during rearing of black soldier fly larvae (Hermetia illucens) and its impact on exploitation potential" (https://aem.asm.org/content/aem/early/2018/02/19/AEM.02722-17.full.pdf). Consider all revenue options which make sense economically in building a revenue stream that is adequate in supporting the farming operation.


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