Insect Biomass for Fuels in the Transport Sector

By Rashid Ahmad Hadi & Michael Palocz-Andresen

Transport is playing an increasingly important role in a globalised world. However, in view of climate change, the use of biomass as a fuel is becoming increasingly important. Processes for obtaining fuel from plant biomass are complicated and costly. Research projects with the larvae of the black soldier fly show how refining processes can be simplified by using insects.

Growing populations, increasing mobility, dwindling resources, and the desired energy transition require alternative energy sources for sustainable mobility. For Germany as a business location, solutions cannot only be imported from abroad, but must also be found domestically. Analyses of future energy requirements show that biowaste and biomass must also be increasingly used to generate energy in the future.

Biofuels have so far been developed from different parts of plants, with varying degrees of efficiency. Production quantities are limited by land and groundwater resources and the refining processes are very complex. An alternative could be the production of biofuels from insect biomass of black soldier fly larvae (BSFL). It requires less land and groundwater resources and is a simpler refining process (see figure 1).

In Germany, this possibility is being investigated in the InBiRa (InsektenBioRaffinerie) research project. In addition to the production of insect biofuel, the possibility of utilising other components of insect biomass for high-quality industrial products is also being investigated. However, the fattening and utilisation of BSFL within the EU is subject to EU regulations, which currently still prohibit such a process. If energy transition requires innovative methods, a rethink and changes are also required at the level of EU legislation.

Current Situation and Prognoses

An essential prerequisite for the development of a sustainable mobility concept is the analysis of the current situation and future developments. Key criteria are population development, the impact of CO₂ emissions on climate development, and the forecast energy requirements.

Population Development

Around 1800, the world population was around one billion people. The development of vaccines and artificial fertilisers led to rapid population growth. Only safe birth control and pension systems slowed down growth. Nevertheless, the human population reached eight billion in 2022. In the meantime, the number of births worldwide has stagnated and growth is solely due to the increase in life expectancy. However, life expectancy curves are now gradually levelling off again on all continents. Experts therefore expect the population to remain constant at around ten billion by the year 2100.

CO₂ Concentration, Global Temperature and Its Effects

Studies have shown that the concentration of CO₂ in the air increased by around 45 per cent between 1900 and 2020 and that average temperatures have risen by around 1°C. Most scientists and the prevailing politicians see a direct correlation between the two values. At the same time, an increase in extreme weather events such as hurricanes, extreme droughts, and extremely heavy rainfall can be observed. These weather extremes not only lead to serious crop failures, but also threaten the livelihoods of many people, as well as animal and plant species. To stop this development, a global reduction in CO₂ emissions is planned. To this end, the consumption of fossil fuels is to be reduced and replaced by climate-neutral energies.

Energy Requirements – Global and for Germany

In the period between 1940 and 2020, global energy consumption increased by almost 600 per cent and was largely generated from the fossil fuels coal, petroleum, and natural gas. Forecasts up to the year 2100 show a trend towards a further increase in energy consumption (see figure 2). This is due to a further increase in the world population and mechanisation in developing countries. The proportion of fossil fuels will gradually decrease and the proportion of alternative energy sources will increase. Waste and biomass will make up an increasing proportion of this (see figure 2).

While the forecasts for global energy demand are rising, the figures for German energy demand have been falling since 2010 (see figure 3). This is due to energy savings mainly in the household sector, but also in the transport sector. Nevertheless, the global rise in energy demand is also having an impact on Germany, as it is leading to an increase in global energy prices. In order not to be dependent on expensive energy imports, Germany must produce energy sources for transport domestically.

Plant Biomass as an Energy Source

The energy industry term “biomass” covers plant and animal substances that can be used to generate heating energy, electrical energy, and fuels. To date, however, almost exclusively plant-based materials have been used to produce biofuels.

Synthetic Fuels – XtL

Conventional fuels are produced from petroleum. In the case of synthetic fuels, the raw material source petroleum is replaced by another energy source, e.g. gas (G), coal (C), or biomass (B). This energy source is converted by chemical processes into a carbon-containing liquid fuel (XtL). The letters “tL” are the abbreviation for “to Liquid”, which means that the raw material is processed into a liquid fuel. The “X” stands for G, C, or B (GtL = Gas-to-Liquid, CtL = Coal-to-Liquid, BtL = Biomass-to-Liquid).

Biofuels from Plant Biomass

Biofuels can be produced in a liquid state (bioethanol, biodiesel) or a gaseous state (biomethane). They are generally intended for combustion engines in vehicles. The carbon in the biomass can be almost completely converted into fuel carbon. However, a distinction is made between first- and second-generation biofuels in terms of the source material.

First-Generation Plant Biofuels

In the case of first-generation biofuels, only fruit (oil, sugar, starch) is used to produce the fuel. However, extra acreage must be provided for this. And this is precisely what poses a problem. Germany has a total area of around 36 million hectares, of which around 18 million hectares are agricultural land. Between 14 and 15.5 million hectares are needed to supply food and animal feed and only 2.5 to 4 million hectares are available for the cultivation of energy crops. However, 34 million hectares would be required to cover the demand for energy crops. Due to the limited land capacity and low land efficiency, energy crops grown in Germany could cover a maximum of 10 per cent of Germany’s energy requirements³.

Biodiesel is produced from vegetable oils by transesterifying vegetable oil with methanol (in a ratio of 9:1), to which 0.5-1 per cent of a catalyst (sodium or potassium hydroxide) is added. This mixture is stirred at temperatures of 50-80 °C for several hours. The vegetable oil molecule, which consists of glycerol and three fatty acid chains, is broken down. The trivalent alcohol glycerol is exchanged for the monohydric alcohol methanol, so that the fatty acids combine with methanol to form biodiesel⁴.

Second-Generation Plant Biofuels

Second-generation biofuels, on the other hand, utilise the parts of biomass that are left over as waste from food production. Second-generation bioethanol, for example, is produced from cellulosic materials such as wood and straw. The advantage is that no separate cultivation areas are required, as their starting material consists mainly of waste products. To this end, a process has been developed in the USA to convert maize straw directly into biofuels (see figure 4).

First, the moist biomass is dried (step 1). Then it is broken down into coke and tar-containing carbonisation gas in a low-temperature gasifier at about 450 °C (step 2). In a high-temperature gasifier, entrained-flow gasification takes place at around 1,500 °C to produce tar-free raw gas (step 3). The raw gas is cooled in the recuperator (step 4) and de-dusted in the dust remover (step 5). The carbon monoxide content is reduced in the gas shift reactor (step 6). Pollutants such as chlorine and sulphur are removed in the scrubber (step 7). Finally, the gas is converted into liquid fuel in the Fischer Tropsch reactor (step 8)⁵.

The problem with this process is that it is technically very complex and, in some cases, also very cost-intensive. The supply costs for the electricity generated in this way are somewhat lower than for conventional products (~1-9 per cent). However, depending on the end product, the costs for fuels are significantly higher (~45-300 per cent) compared to conventional products. In addition, it requires complex pre-treatment, has a high water consumption, and leads to considerable secondary pollution.

Insect Biomass as an Energy Source

Until now, non-plant biomass has only been utilised in the form of animal excrement and household or industrial waste. The targeted production of animal biomass has not played a role here as, in most cases, it requires high investment in water, feed, and land. However, for some years now, research has been conducted into the production of insect biomass as a resource-saving alternative.

Insects as Part of a Biorefinery System

However, it would be an inappropriate simplification of the process to regard insects merely as an alternative raw-material source to plant-based raw materials. At this point, the difference between first- and second-generation biofuels plays an important role. The refining of first-generation biofuels from plant parts with a high oil, sugar, and starch content is comparatively simple. Refining second-generation biofuels from cellulose-containing raw materials such as straw, wood, and food waste requires a complex and cost-intensive preparation process at the beginning. And it is precisely this process in a biorefinery plant that is carried out by insect larvae. The initial biomass consists mainly of cellulose-containing plant waste products such as straw or food waste. Fresh insect larvae are added to these. These eat the plant biomass and thereby increase their own body mass. In doing so, they convert plant cellulose into animal fats and proteins. The fats can then be refined into biofuel in a relatively simple process.

Quality of the Insect Biodiesel

In a research project at Wuhan University, insect biodiesel was produced from the insect biomass of yellow mealworm and BSFL and analysed for its fuel properties. The specifications of the European biodiesel standard EN 14214 were used for this purpose. The main fuel properties are kinetic viscosity, density, cetane number, flash point, cloud point, and acid number. These parameters were determined according to ASTM standard methods. Accordingly, the properties of the biodiesel obtained from the larval fat were comparable with the European biodiesel standard EN 14214 and biofuels from used cooking oils and fodder plants⁶.

German Research Project InBiRa

In Germany, the research project InBiRa (running from October 2021 to March 2024) is being conducted under the leadership of the Fraunhofer Institute. The research is focusing exclusively on the larvae of the black soldier fly⁷.

The research project covers three areas:

1. Processing of biowaste and fattening procedure
2. Primary refinement: larval biomass into high-purity
   starting products
3. Secondary refinement: development end products

Processing of Biowaste and Fattening Procedure

In this area of the research project, the aim is to find the right starting substrate and its composition and to develop the optimum fattening process. When selecting the starting substrate, it is important to use a raw material that is available in sufficient quantities as a waste product in Germany. The choice fell on food waste. In 2020, Germany generated almost 11 million tonnes of food waste, which contains a mixture of plant and animal waste. This waste was composted or fermented into biogas. However, the waste utilised in this way has the potential to be converted into more valuable fat- and protein-based raw materials by use of an insect biorefinery⁸.

For the fattening process, 10 kg of optimised food waste are placed in a plastic tub as a food substrate and inoculated with one gram of freshly hatched BSF larvae. After around 14 days, the larvae have shed their skin several times and reached a larval mass of 8 kg. Ten per cent of the larvae are allowed to mature into reproductive flies and produce new larvae. The remaining 90 per cent are inactivated with hot water and are now available for further processing (see figure 5).

In this first area of research, the optimal feed composition is also being investigated. Different compositions result in the fattened larvae containing different amounts of water, lipids, or proteins at the “harvest stage”. Depending on the desired industrial final product, different feed mixtures lead to optimal results. The feed mixtures are therefore adapted accordingly.

Primary Refinement: Larval Biomass into High-Purity Starting Products

The second area of the research project is investigating how the primary raw materials can be converted into secondary raw materials. The fresh larval biomass consists of up to 60 per cent water. This is removed from the larvae by a dehydration process. Around 10 kg of lipids and 22 kg of protein can be obtained from 100 kg of fresh larval biomass. With an optimised feed mixture of 10 kg of feed substrate, 8 kg of larval biomass can be obtained, from which, after deducting 800 grams of larvae for reproductive purposes, 720 g of lipid and 1,584 g of protein can be obtained (see figure 6). Chitosan can be obtained from the chitin of the larval skins. The remains of the feed substrate mixed with larval faeces are the starting material for plant fertiliser.

Secondary Refinement: Development of End Products

In the area of secondary processing, it is being investigated how various end products can be manufactured from the secondary raw materials obtained. The lipids obtained by the fattening process and primary refining are suitable for processing into biofuel in a biofuel production process, as described above. As a biofuel for combustion engines, the lipids can make a direct contribution to sustainable mobility.

However, the lipids can also make an indirect contribution to sustainable mobility. The chemical composition of the insect lipids obtained from the BSF larvae is very similar to tropical oils such as palm kernel oil and coconut oil. These are currently imported to Germany in large quantities for use in the manufacture of cosmetics and cleaning products. Parts of the rainforest are cut down for the production of tropical oils and fuel is needed to transport them by ship. Both cause high costs and have a harmful effect on the climate. The insect lipids produced in Germany could replace the tropical oils and thus help to reduce further deforestation of the rainforest and save fuel for transport⁹.

The InBiRa project is also researching the potential uses of the remaining insect biomass. The protein components can be used for the production of adhesives, cosmetics, paper coatings, or packaging films, as well as for the enrichment of animal feed or food. Chitosan can be obtained from the chitin of the larval skins, which can be used for the production of artificial blood vessels, artificial skin, and haemostatic bandages, due to its bactericidal, fungicidal, and haemostatic properties¹⁰. Finally, the residues of the feed substrate and the excretions of the larvae can also be used to produce fertiliser or biogas.

Resource-Conserving Insect Fattening

While conventional energy crops require a lot of agricultural land and groundwater, fattening BSF larvae saves space and conserves groundwater. This means that larvae can be fattened in buildings with several floors on different levels. The buildings can be erected on land that is not suitable for agricultural use. The need for water is also very low compared to energy crops that require regular irrigation. In this respect, the production of insect biomass is also a resource-saving way of generating energy.

EU Legislation and Use of BSF Larvae

The legal framework for the research, production, and utilisation of raw materials from insect biomass in Germany is defined by EU law. Various EU regulations must be observed for the production processes and areas of application described above, of which only two of the most important areas are presented here as examples.

New EU Legislation for Internal Combustion Engines

In the area of biofuels for vehicle engines, a law restricting the use of vehicles with internal combustion engines for passenger cars and small commercial vehicles newly registered after 2035 was passed in the EU Parliament (at first reading) in February 2023¹¹. However, larger vehicles, such as agricultural vehicles or lorries, are not affected by the ban.

It also states in a recommendation that “the Commission will make a proposal for registering after 2035 vehicles running exclusively on CO₂ neutral fuels in conformity with Union law, outside the scope of the fleet standards”¹². This includes all fuels whose production saves as much CO₂ as is emitted during combustion. This means that combustion engines that can run on insect biofuel can be authorised by the EU.

EU Feedstuffs Regulation – Feed for Farm Animals

At present, the EU Feed Regulation is a major obstacle to the implementation of the InBiRa project. As a result of the BSE crisis in the 1990s, the EU Parliament banned the feeding of animal protein sources and waste to farm animals in 2001¹³. This was intended to prevent pathogens from entering the human food chain via animal feed. At that time, the view was that farm animals only served as a direct or indirect source of food for humans (e.g., meat, eggs, milk).

The fattening of insects / larvae with food waste consisting of plant and animal waste is not yet a problem under EU law. Only when the insects / larvae are given the status of farm animals is it prohibited. The BSF larvae that are fattened for the industrial production process are considered farm animals under EU law, even if they do not enter the human food chain. Therefore, the use of mixed food waste for fattening BSF larvae (in their capacity as farm animals) is currently not permitted.

The Fraunhofer Institute has submitted an application to the EU for a derogation for the feed composition of BSF larvae. The EU Commission has already signalled that it will consider exemptions. At least in cases where the fattened insects do not end up in the human food chain, feeding with mixed organic waste could be permitted.

Summary

A further increase in the world population and global energy demand is expected in the coming decades. In addition, CO₂-neutral sustainable transport and greater economic independence are to be achieved in Germany. To achieve this, a higher proportion of renewable energies must be generated domestically. Germany has large quantities of mixed food waste that can be converted into high-quality insect biomass by insect larvae. While conventional energy crops require large amounts of agricultural land and groundwater, insect biomass can be produced in a resource-efficient manner.

The biofuels obtained from insect biomass comply with the European biodiesel standard EN 14214 and can be used in appropriately adapted combustion engines. Other raw materials that can be obtained from insect biomass, such as proteins and chitin, can also be used to produce various high-quality industrial products. Insect lipids can also replace the importation of high-quality tropical oils from abroad. With regard to the feeding of mixed food waste to BSF larvae, which is currently still prohibited under EU law (as at January 2024), an exemption is expected. However, this mixed food waste is the essential basis for the resource-saving production of insect biomass.

Outlook

Whether insect biofuel will contribute to climate-friendly mobility in Germany depends, among other things, on whether the bio-combustion engine still has a future alongside the electric motor. Large commercial vehicles such as tractors and lorries cannot be powered by electric motors according to the current state of the art, so the combustion engine will continue to be used here. However, the combustion engine for biofuels also has a future in smaller vehicles. In addition, the subsidy premium for the purchase of electric cars will no longer apply in Germany from December 2023.

In view of the unstable energy supply, the German government has announced that it will prioritise switching off charging stations for cars if the power grid becomes overloaded. Both of these measures have already led to a fall of more than 20 per cent in orders for electric cars at the start of 2024. This means that the production of insect biofuel also has a future as a sustainable energy source in the car sector.

The authors would like to thank Ms Junyan Ma, Shanghai for the artistic design and drawing of all images and diagrams in the publications of the last three years in this magazine.

About the Authors

Rashid Ahmad Hadi grew up in Afghanistan and Germany. Since 2021, he has been studying Business Informatics and Social Media & Information Systems. In his studies, he focuses on the development of sustainable economic concepts and the influence of EU law on national policy. He has completed an internship in a law firm specialising in business law and works as a student assistant in the field of software development at Leuphana University of Lüneburg, Germany.

Michael Palocz-Andresen is a full professor at the BUAP in Puebla. He has been working as a full professor for Sustainable Mobility since 2018, supported by the DAAD at the TEC Instituto Tecnológico y de Estudios Superiores in Mexico. He was a full professor at the University West Hungary until 2017. Currently, he is a guest professor at the TU Budapest, the Leuphana University Lüneburg, and at the Shanghai Jiao Tong University. He is a Humboldt scientist and instructor of the SAE International in the USA.

References

1. Petroblogger.com (2023). Retrieved from http://www.ingenieriadepetroleo.com/world-energy-consumption-forecast-for-the-21st-century/
2. Infografik Die Welt. In Birger, N. (2014): Deutsche Haushalte werden Energiespar-Fanatiker. Retrieved from https://www.welt.de/wirtschaft/article131464934/Deutsche-Haushalte-werden-Energiespar-Fanatiker.html
3. Jering, A., Klatt, A., Seven, J., Ehlers, K., Günther, J., Ostermeier, A., Mönch, L. (2013): Global Land and Biomass Resources.
4. Fachagentur Nachwachsende Rohstoffe e. V. (without date): Biodiesel. Retrieved from https://biokraftstoffe.fnr.de/kraftstoffe/biodiesel
5. FT-Liquids & Biomass to Liquids; ETIP Bioenergy (2023). Retrieved from https://www.etipbioenergy.eu/value-chains/products-end-use/products/ft-liquids
6. Wang Hui, Rehman Kashif ur, Liu Xiu, Yang Qinqin, Zheng Longyu, Li Wu, Cai Minmin, Li Quing, Zhang Jibin, Yu Ziniu (2017): “Insect Biorefinery: A Green Approach for Conversion of Crop Residues into Biodiesel and Protein”. In: Biotechnology for Biofuels and Bioproducts, (Vol. 10) 304, p. 10 Table 6. Retrieved from https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-017-0986-7#ref-CR2
7. Fraunhofer Institut (2022): Mit Insekten zur Kreislaufwirtschaft. Retrieved from https://www.igb.fraunhofer.de/de/presse-medien/presseinformationen/2022/inbira-mit-insekten-zu-kreislaufwirtschaft.html
8. Fritschka Nadine (2022): in Bioökonomie in BW: InBiRa: Insektenbioraffinerie verwandelt Lebensmittelreste in neue Produkte. Retrieved from https://www.biooekonomie-bw.de/fachbeitrag/aktuell/inbira-insektenbioraffinerie-verwandelt-lebensmittelreste-neue-produkte
9. Wurche, Bettina (2022): “How insect larvae should make biorefineries more sustainable”. Retrieved from https://www.heise.de/hintergrund/How-insect-larvae-should-make-biorefineries-more-sustainable-7255187.html
10. Krohm, Sven (2003): Herstellung, Charakterisierung und Anwendung von kurzkettigen Chitosanen; Dissertation Kiel 2003.
11. EUROPEAN PARLIAMENT LEGISLATIVE RESOLUTION of 14 February 2023 on the proposal for a regulation of the European Parliament and of the Council amending Regulation (EU) 2019/631 as regards strengthening the CO₂ emission performance standards for new passenger cars and new light commercial vehicles in line with the Union’s increased climate ambition; Document TA-9-2023-0039.
12. POSITION OF THE EUROPEAN PARLIAMENT adopted at first reading on 14 February 2023 with a view to the adoption of Regulation (EU) 2023/… of the European Parliament and of the Council amending Regulation (EU) 2019/631 as regards strengthening the CO2 emission performance standards for new passenger cars and new light commercial vehicles in line with the Union’s increased climate ambition; Document TA-9-2023-0039.
13. COMMISSION REGULATION (EU) 2017/893 of 24 May 2017 amending Annexes I and IV to Regulation (EC) No 999/2001 of the European Parliament and of the Council and Annexes X, XIV and XV to Commission Regulation (EU) No 142/2011 as regards the provisions on processed animal protein.