Vliegen naar de toekomst: duurzame brandstoffen in de luchtvaartindustrie
Moeten we stoppen met vliegen?
“Ik vlieg niet vanwege de enorme klimaatimpact van de luchtvaart” is een uitspraak van Greta Thunberg die de groeiende bezorgdheid over de impact van de luchtvaart op het milieu onderstreept. Deze bezorgdheid is terecht, want de luchtvaartsector verbruikt maar liefst 27% van ons koolstofbudget om de opwarming van de aarde onder de 1,5 °C te houden tot 2050. Dit cijfer dwingt ons om innovatieve oplossingen te zoeken. Gelukkig zijn er alternatieven, zoals duurzame vliegtuigbrandstoffen, ook bekend als Sustainable Aviation Fuel (SAF).
Vliegen op planten?
Maar wat zijn SAF's? Deze brandstoffen worden doorgaans geproduceerd uit biomassa, zoals planten. Terwijl deze planten groeien, slaan ze CO2 op, wat de uiteindelijke uitstoot van SAF tot een neutraal niveau kan terugbrengen. Dit staat in schril contrast met traditionele luchtvaartbrandstoffen, waarbij de CO2 miljoenen jaren geleden is opgeslagen, resulterend in een onevenwichtige uitstoot.
Slechts één op de duizend vliegtuigen
Het potentieel van SAF is enorm; het kan de CO2-uitstoot met maar liefst 94% verminderen in vergelijking met conventionele brandstoffen. Toch is de realiteit zorgwekkend: in 2023 maakte SAF slechts 0,1% uit van alle vliegtuigbrandstoffen. Dit benadrukt de noodzaak voor een toename in zowel het aanbod als de vraag naar SAF. Het doel van mijn scriptie is dan ook om inzicht te bieden in de barrières die de ontwikkeling van SAF nog in de weg staan en haalbare oplossingen aan te reiken.
Hoe zit het aanbod van SAF in elkaar?
Het aanbod van SAF wordt voornamelijk beïnvloed door drie factoren: de gekozen grondstoffen, de productietechnieken en de producenten. Een van de grootste uitdagingen is het verschil tussen de minimale verkoopprijs van SAF en de prijs van conventionele vliegtuigbrandstoffen. Er is dus dringend behoefte aan strategieën om deze kloof te verkleinen, zonder daarbij het milieu uit het oog te verliezen.
Appels kun je niet met peren vergelijken
De mogelijkheden van biomassa die voor SAF-productie gebruikt kunnen worden, zijn simpelweg oneindig. Echter, het vinden van grondstoffen die zowel duurzaam, schaalbaar als financieel haalbaar zijn, en bovendien niet in strijd zijn met de voedingsindustrie, is een complexe uitdaging. Om de grondstoffen voor SAF’s beter te kunnen vergelijken, verdelen we ze in vier generaties, elk met unieke voordelen en uitdagingen. De eerste generatie richt zich op eetbare planten en gewassen, zoals palmolie. Deze grondstoffen zijn vaak goedkoop, maar niet altijd duurzaam en soms zelfs in strijd met onze voedselvoorziening. De tweede generatie omvat niet-eetbare planten en gewassen, evenals afval van ons voedsel en resten van de landbouw. In deze generatie is productiviteit echter vaak een probleem. De derde generatie betreft complexere maar productievere biomassa, zoals microalgen. Deze kleine organismen groeien in water en hebben een groot en duurzaam potentieel om op te schalen, maar zijn pas op lange termijn realiseerbaar. Tot slot gaat de vierde generatie nog een stap verder door microalgen genetisch aan te passen om ze nog productiever te maken.
De grondstoffen vormen de basis van het aanbod, en daarom is het belangrijk om per generatie kansen te zoeken om ze productiever en duurzamer te maken. Uit het brede scala aan oplossingen zijn er per generatie enkele winnaars. Bij de eerste generatie kunnen innovatieve landbouwtechnieken worden toegepast. Voor de tweede generatie kan gebruik worden gemaakt van de stijgende hoeveelheid afval in niet-OECD-landen zoals Egypte en India. Bij de derde en vierde generatie is het telen van algen in woestijngebieden naar voren gekomen als een veelbelovende optie.
Puur natuur
Een volgende stap in de productie van SAF is het omzetten van de grondstof naar brandstof. Bij het verbeteren en ontwikkelen van de chemische processen is het cruciaal om te focussen op de mogelijkheid van 100% pure SAF-productie. Momenteel kan SAF namelijk nog niet in zijn pure vorm worden gebruikt en moet het gemengd worden met traditionele brandstoffen, wat de duurzaamheid vermindert.
Over de hele aardbol
Bij de SAF-producenten die de grondstoffen omzetten in SAF zijn er ook meerdere kansen. Er moet worden ingezet op de ontwikkeling van een internationale handel in SAF, iets waar momenteel bijna geen gebruik van wordt gemaakt. Zo heeft Zuid-Afrika veel ervaring op het gebied van SAF-technologieën en beschikt het over duurzame grondstoffen, maar kampt het met een tekort aan middelen om de productie op te zetten.
Wie drijft de vraag naar SAF?
Ook de vraag naar SAF is cruciaal; luchtvaartmaatschappijen, luchthavens en consumenten spelen een belangrijke rol in deze vraag.
De winnaars van morgen zetten vandaag in op SAF
Er is een wereldwijde tendens om de beste te zijn op vlak van duurzaamheid, wat een ‘competitie’ creëert tussen bedrijven wat betreft hun duurzaamheidsinspanningen. Dit kan door luchtvaartmaatschappijen uitgespeeld worden door het percentage SAF-implementatie te gebruiken als middel om te communiceren naar de buitenwereld. Ook luchthavens kunnen hun positie in de markt versterken door luchtvaartmaatschappijen te ondersteunen bij de implementatie van SAF. Investeringen in infrastructuur, R&D en SAF-productie, alsook samenwerkingen met de maatschappijen, zijn hierbij essentieel.
Informatie is de sleutel tot goede beslissingen
Tot slot staat de luchtvaartsector voor uitdagingen bij de adoptie van SAF door individuen. Veel reizigers zijn zich niet bewust van de CO2-uitstoot van hun vluchten, anderen willen meer informatie over de daadwerkelijke impact. Daarom wordt er gewerkt aan de ontwikkeling van een ecologisch label om de impact op het milieu te verduidelijken. Daarnaast hebben consumenten vaak beperkte kennis over SAF en de voordelen ervan. Sociale media en educatieve campagnes kunnen hierbij een positieve impact hebben. Ook bekende figuren kunnen hier een belangrijk aandeel inspelen: denk bv. aan Coldplay, die tijdens hun concerten meermaals trots verkondigen dat ze vliegen met SAF. Maar, eenmaal men goed geïnformeerd en overtuigd is, zijn de hogere kosten van SAF nog steeds een groot pijnpunt voor consumenten. Door bij de 'verkoop' van SAF meer focus te leggen op de voordelen in plaats van enkel de kosten, kan dit wederom een positieve invloed hebben op de vraag naar SAF.
Beleidsopties voor een duurzame toekomst
Om de touwtjes aan elkaar te knopen, is het van belang dat ook de overheid zich achter SAF schaart. Aan de aanbodzijde worden vier hoofdstrategieën voorgesteld: directe overheidsfinanciering, thematische financiering, signalering strategieën en financiële maatregelen.
Aan de vraagzijde kan de 
overheid de adoptie verder ondersteunen door middel van mandaten, subsidies, educatie en sensibiliseringscampagnes, en door zelf ook SAF te gebruiken als voorbeeld.
Bovendien is het overkoepelend voor vraag en aanbod van essentieel belang om bestaande wetgeving bij te werken zodat SAF erkend wordt als een gekwalificeerde alternatieve brandstof. Ook dient er een duidelijk certificeringssysteem te worden ontworpen om duurzame van niet-duurzame SAF te onderscheiden. Dit zal bijdragen aan de verbetering van de marktpositie van SAF en het waarborgen van geloofwaardige milieukenmerken.
Iedereen aan boord
Er is duidelijk een noodzaak voor multidisciplinaire samenwerking om de uitdagingen rondom SAF aan te pakken. De integratie van de voorgestelde strategieën biedt een waardevol kader voor onderzoekers, beleidsmakers en industriële leiders om de productie en acceptatie van SAF te versnellen. Zo kunnen we gezamenlijk werken aan een klimaatneutrale luchtvaart tegen 2050.
Bibliografie
Abdullah, B., Muhammad, S. A. F. S., Shokravi, Z., Ismail, S., Kassim, K. A., Mahmood, A. N., & Aziz, M. M. A. (2019). [Review of the journal article Renewable Sustainable Energy Rev., 107, 37– 50].
Adnan, N., Nordin, S. M., bin Bahruddin, M. A., & Ali, M. (2018). How trust can drive forward the user acceptance to the technology? In-vehicle technology for autonomous vehicle. Transportation research part A: policy and practice, 118, 819-836.
Aerospace Technology Insitute. (2022). Sustainable aviation fuel (SAF) integration. Retrieved from
https://www.ati.org.uk/wp-content/uploads/2022/06/saf-integration.pdf
Ahmad, S., & Xu, B. (2021). A cognitive mapping approach to analyse stakeholders’ perspectives on sustainable aviation fuels. Transportation Research Part D: Transport and Environment, 100, 103076.
Ahmad, S., Xu, B., Greening, P., & Ouenniche, J. (2019). Public attitude towards aviation biofuels: A pilot study findings. In Phil Greening, and Jamal Ouenniche. in Proceedings of 11th International Conference on Applied Energy Vasteras, Sweden.
Air bp. (2022). Retrieved from https://www.bp.com/en/global/air-bp
Air Transport Action Group. (2021). Waypoint 2050. Retrieved February 20, 2024, from
https://www.ceresis.eu/media/com_spproperty/docs/w2050_full.pdf
Ajzen, I. (2011). The theory of planned behaviour: Reactions and reflections. Psychology & health, 26(9), 1113-1127.
Alcock, I., White, M. P., Taylor, T., Coldwell, D. F., Gribble, M. O., Evans, K. L., ... & Fleming, L. E. (2017). ‘Green’on the ground but not in the air: Pro-environmental attitudes are related to household behaviours but not discretionary air travel. Global Environmental Change, 42, 136-147.
Alexiades, A., Kendall, A., Winans, K. S., & Kaffka, S. R. (2018). Sugar beet ethanol (Beta vulgaris L.): A promising low-carbon pathway for ethanol production in California. Journal of Cleaner Production, 172, 3907-3917.
Allen, W.; Kilvington, M.; Horn, C. Using Participatory and Learning-Based Approaches for Environmental Management to Help Achieve Constructive Behaviour Change. New Zealand Ministry for the Environment. 2002.
Alonso, D. M., Bond, J. Q., & Dumesic, J. A. (2010). Catalytic conversion of biomass to biofuels. Green Chemistry, 12(9), 1493-1513. Alternative Fuels Data Center. (n.d.). Sustainable Aviation Fuel (SAF) grants. Retrieved from
https://afdc.energy.gov/laws/13376
Amin, L., Hashim, H., Mahadi, Z., Ibrahim, M., & Ismail, K. (2017). Determinants of stakeholders’ attitudes towards biodiesel. Biotechnology for biofuels, 10, 1-17.
Ammanagi, A., Satapute, P., Adhoni, S. A., Adhikari, S. S., Gupta, S. K., & Mulla, S. I. (2021). Biomass Conversion and Green Chemistry. In Catalysis for Clean Energy and Environmental Sustainability: Biomass Conversion and Green Chemistry-Volume 1 (pp. 803-822).
Anderson, B. J., Mueller, D. W., Hoard, S. A., Sanders, C. M., & Rijkhoff, S. A. (2022). Social Science Applications in Sustainable Aviation Biofuels Research: Opportunities, Challenges, and Advancements. Frontiers in energy research, 9, 771849.
Anto, S., Mukherjee, S. S., Muthappa, R., Mathimani, T., Deviram, G., Kumar, S. S., ... & Pugazhendhi, A. (2020). [Review of the journal article Chemosphere, 242, 125079].
Atmowidjojo, A., Rianawati, E., Chin, B. L. F., Yusup, S., Quitain, A. T., Assabumrungrat, S., ... & Eiad-Ua, A. (2021, December). Supporting clean energy in the ASEAN: policy opportunities from sustainable aviation fuels initiatives in Indonesia and Malaysia. In IOP conference series: earth and environmental science (Vol. 940, No. 1, p. 012031). IOP Publishing
Ayodele, B. V., Alsaffar, M. A., & Mustapa, S. I. (2020). An overview of integration opportunities for sustainable bioethanol production from first- and second-generation sugar-based feedstocks. Journal of Cleaner Production, 245, 118857.
Banerjee, S., & Ramaswamy, S. (2017). Dynamic process model and economic analysis of microalgae cultivation in open raceway ponds. Algal Research, 26, 330-340.
Bauen, A., Bitossi, N., German, L., Harris, A., & Leow, K. (2020). Sustainable aviation fuels: Status, challenges and prospects of drop-in liquid fuels, hydrogen and electrification in aviation. Johnson Matthey Technology Review, 64(3), 263-278. doi:https://doi.org/10.1595/205651320x15816756012040
Baumeister, S., & Onkila, T. (2017). An eco-label for the airline industry? Journal of Cleaner Production, 142, 1368-1376.
BBC. (2022). Retrieved from https://blog.bccresearch.com/10-leading-companies-in-the- sustainable-aviation-fuel-industry
BCC Research. (2022). 10 leading companies in the sustainable aviation fuel industry. Retrieved from
https://blog.bccresearch.com/10-leading-companies-in-the-sustainable-av… Becken, S., Friedl, H., Stantic, B., Connolly, R. M., & Chen, J. (2021). Climate crisis and flying: Social media analysis traces the rise of “flightshame”. Journal of Sustainable Tourism, 29(9), 1450-1469.
Behnke G D, Zuber S M, Pittelkow C M, Nafziger E D and Villamil M B 2018 Long-term crop rotation and tillage effects on soil greenhouse gas emissions and crop production in Illinois USA Agric. Ecosyst. Environ. 261 62–70
Benedetti, M., Vecchi, V., Barera, S., & Dall’Osto, L. (2018). Biomass from microalgae: The potential of domestication towards sustainable biofactories. Microbial Cell Factories, 17, 1–18.
Benetti, C. (2018). Low TRL biofuel technologies. Florence: ETA-Florence Renewable Energies.
Bhada-Tata, P., & Hoornweg, D. A. (2012). What a waste?: a global review of solid waste management.
BIO4A (n.d.). Advanced Sustainable biofuels for aviation.Retrieved from https://www.bio4a.eu/
Biofuels Digest. (2023, February 1). Study shows global SAF markets would move $402 billion by 2050. Retrieved from https://www.biofuelsdigest.com/bdigest/2023/02/01/study-shows-global-saf- markets-would-move-402-billion-by-2050/
Biotechnology Innovation Organization. (n.d.). Biofuels promise: Algae. Retrieved from
https://archive.bio.org/articles/biofuels-promise-algae
Biswas, A. (2016). A Study of Consumers’ Willingness to Pay for Green Products. Journal of Advanced Management Science, 4(3), 211–215
Borchers, A., Truex-Powell, E., Wallander, S., & Nickerson, C. (2014). Multi-cropping practices: recent trends in double-cropping.
Bosnjakovic, M., & Sinaga, N. (2020). The Perspective of Large-Scale Production of Algae Biodiesel. Applied Sciences, 10, 8181.
Boylens, H. B. (2022). Balancing growth in connectivity with a comprehensive global air transport response to the climate emergency: a vision of net-zero aviation by mid-century. ITIF. Retrieved from https://www2.itif.org/2022-sustainable-aviation-fuel.pdf
Bwapwa, J. K., Anandraj, A., & Trois, C. (2017). Possibilities for conversion of microalgae oil into aviation fuel: A review. Renewable and Sustainable Energy Reviews, 80, 1345–1354.
Cavelius, P., Engelhart-Straub, S., Mehlmer, N., Lercher, J., Awad, D., & Brück, T. (2023). The potential of biofuels from first to fourth generation. PLoS Biology, 21(3), e3002063. Chen, C. Y., Yeh, K. L., Aisyah, R., Lee, D. J., & Chang, J. S. (2011). Cultivation, photobioreactor design and harvesting of microalgae for biodiesel production: A critical review. Bioresource Technology, 102(1), 71-81.
Chew, K. W., Chia, S. R., Show, P. L., Yap, Y. J., Ling, T. C., & Chang, J. S. (2018). Effects of water culture medium, cultivation systems and growth modes for microalgae cultivation: A review. Journal of the Taiwan Institute of Chemical Engineers, 91, 332-344.
Chisti, Y. (2003). [Review of the journal article Journal of Biotechnology, 167, 201–214].
Chisti, Y. (2007). Biodiesel from microalgae. Biotechnology Advances, 25, 294–306.
Clark C. (2016, March). Video shows every airline flight in the world over a 24-hour period. Retrieved March 12, 2023, from https://www.businessinsider.com/video-shows-every-airline-flight-in-the- world-over-a-24-hour-period-2016-3?international=true&r=US&IR=T
Congress, U. S. (2007). Energy independence and security act of 2007. Public law, 2, 110-140.
Cordis, C. (2023, September 14). Sustainable On-site and Innovative Technologies for Advanced Transport BioFuels from MιcroalGae. CORDIS | European Commission. Retrieved from https://cordis.europa.eu/project/id/101122151
Davis, R., Aden, A., & Pienkos, P. T. (2011). Techno-economic analysis of autotrophic microalgae for fuel production. Applied Energy, 88(10), 3524-3531.
De Crom, B., van Diepen, J., & Scholten, J. (2020). Excellent environmental performance of beet sugar production in the Netherlands. Sugar Industry-Zuckerindustrie, 145(3), 161-165.
de Souza, N. R. D., Fracarolli, J. A., Junqueira, T. L., Chagas, M. F., Cardoso, T. F., Watanabe, M. D., ... & Cortez, L. A. B. (2019). Sugarcane ethanol and beef cattle integration in Brazil. Biomass and Bioenergy, 120, 448-457.
Dębowski, M., Kisielewska, M., Zieliński, M., & Kazimierowicz, J. (2023). The Influence of the Ultrasound Disintegration of Microalgal–Bacterial Granular Sludge on Anaerobic Digestion Efficiency. Applied Sciences, 13(13), 7387.
Demsky, S. E. (2023). Analysis of Double Cropping to Expand Sustainable Aviation Fuel Production in the United States (Doctoral dissertation, Massachusetts Institute of Technology).
Department of Energy. (n.d.). Sustainable aviation fuels: Grand fuel challenge. Retrieved March 12, 2023, from https://www.energy.gov/eere/bioenergy/sustainable-aviation- fuels#:~:text=SAF%20is%20a%20biofuel%20used,compared%20to%20conventional%20jet%20f uel Detsios, N., Theodoraki, S., Maragoudaki, L., Atsonios, K., Grammelis, P., & Orfanoudakis, N. G. (2023). Recent advances on alternative aviation fuels/pathways: A critical review. Energies, 16(4), 1904.
Dichter, A., Henderson, K., Riedel, R., & Riefer, D. (2020). How airlines can chart a path to zero- carbon flying. McKinsey & Company.
Dijst, M., Farag, S., & Schwanen, T. (2008). A comparative study of attitude theory and other theoretical models for understanding travel behaviour. Environment and Planning A, 40(4), 831-847.
Dolšak, N., & Prakash, A. (2022). Three faces of climate justice. Annual Review of Political Science, 25, 283-301.
Duarte, R. B., de França Lopes, G., Pimenta, J. L. C. W., & de Matos Jorge, L. M. (2023). A bibliometric analysis on sustainable aviation fuels: Core technologies, challenges and trends. Universal Journal of Carbon Research, 131-152.
EASA. (2024, January 25). EASA to inform air passengers on the environmental impact of their flight. EASA. https://www.easa.europa.eu/en/newsroom-and-events/press-releases/easa-i…- passengers-environmental-impact-their-flight
EASA. (2024). EASA to inform air passengers on the environmental impact of their flight. Retrieved from https://reliable-news.com/avia-tech/easa-to-inform-air-passengers-on-th…- impact-of-their-flight/
EASA. (n.d.). EASA Eco. Retrieved from https://www.easa.europa.eu/eco/eaer/topics/sustainable- aviation-fuels
EBAA. (2024). EBAA welcomes Brussels Airport's financial support for SAF use throughout 2024 - EBAA - European Business Aviation Association. Retrieved from https://www.ebaa.org/industry- updates/ebaa-welcomes-brussels-airports-financial-support-for-saf-use-throughout-2024/
ECAC-CEAC. (n.d.). Training on sustainable aviation fuels for North Macedonia. Retrieved from
https://www.ecac-ceac.org/news/1040-training-on-sustainable-aviation-fu…
Elgin, B. (2024, May 31). Waste-to-fuel company that raised $1 billion verges on collapse. The Japan Times. Retrieved from https://www.japantimes.co.jp/business/2024/05/31/companies/biofuel- company-verge-collapse/
Emmanouilidou, E., Mitkidou, S., Agapiou, A., & Kokkinos, N. C. (2023). Solid waste biomass as a potential feedstock for producing sustainable aviation fuel: A systematic review. Renewable Energy, 206, 897-907.
Environment & Transport. (2024, May 23). New technologies. Transport & Environment. Retrieved from https://www.transportenvironment.org/topics/planes/new-tech
78
Environmental Labelling Scheme for Aviation | EASA ECO. (2023). Retrieved from
https://www.easa.europa.eu/eco/aviation-environmental-label/topics/the-…- environmental-label-in-aviation
Eswaran, S., Subramaniam, S., Geleynse, S., Brandt, K., Wolcott, M., & Zhang, X. (2021). Techno- economic analysis of catalytic hydrothermolysis pathway for jet fuel production. Renewable and Sustainable Energy Reviews, 151, 111516.
EU Science. (n.d.). Retrieved from https://joint-research-centre.ec.europa.eu/welcome-jec- website/reference-regulatory-framework/renewable-energy-recast-2030-red-ii_en
European Commission. (n.d.). Blue bioeconomy: towards a strong and sustainable EU algae sector. Retrieved January 10, 2024, from https://ec.europa.eu/info/law/better-regulation/have-your- say/initiatives/12780-Blue-bioeconomy-towards-a-strong-and-sustainable-EU-algae-sector_en
European Commission. (n.d.). Consequences of climate change. Retrieved March 10, 2023, from
https://climate.ec.europa.eu/climate-change/consequences-climate-change…
European Union Aviation Safety Agency, Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), (2022).
Fernández, F. A., Sevilla, J. M. F., & Grima, E. M. (2019). Costs analysis of microalgae production. In Biofuels from algae (pp. 551-566). Elsevier.
Filimonau, V., & Högström, M. (2017). The attitudes of UK tourists to the use of biofuels in civil aviation: An exploratory study. Journal of Air Transport Management, 63, 84-94.
Filimonau, V., Mika, M., & Pawlusiński, R. (2018). Public Attitudes to Biofuel Use in Aviation: Evidence from an Emerging Tourist Market. J. Clean. Prod. 172 (January), 3102–3110. doi:10.1016/j.jclepro.2017.11.101
Fiorello, A. P. (1999). Power, Performance, and Perception (P3): Integrating Usability Metrics and Technology Acceptance Determinants to Validate a New Model for Predicting System Usage. Retrieved from https://core.ac.uk/download/478586158.pdf
Fontaine, et al. (2022). State of SAF market 2022 and beyond. Retrieved from
https://flysaba.org/2022/12/15/state-of-saf-market-2022-and-beyond/
Fu, W., Nelson, D. R., Mystikou, A., Daakour, S., & Salehi-Ashtiani, K. (2019). Curr. Opin. Biotechnol., 59, 157–164.
Fulcrum Bioenergy. (n.d.). Sierra Biofuels. Retrieved from https://www.fulcrum- bioenergy.com/sierra-biofuels
79
Geleynse, S., Brandt, K., Garcia-Perez, M., Wolcott, M., & Zhang, X. (2018). The alcohol-to-jet conversion pathway for drop-in biofuels: Techno-economic evaluation. ChemSusChem, 11(21), 3728- 3741.
GFGS. (n.d.). Retrieved from https://www.ricardo.com/en/news-and-insights/campaigns/gfgs
Gifford, R., & Comeau, L. A. (2011). Message framing influences perceived climate change competence, engagement, and behavioral intentions. Global Environmental Change, 21(4), 1301- 1307.
Gössling, S., Humpe, A., & Bausch, T. (2020). Does ‘flight shame’affect social norms? Changing perspectives on the desirability of air travel in Germany. Journal of Cleaner Production, 266, 122015.
Grassi, M. C. B., & Pereira, G. A. G. (2019). Energy-cane and RenovaBio: Brazilian vectors to boost the development of Biofuels. Industrial Crops and Products, 129, 201-205.
GreenAir News. (2024). New EU-funded FUELGAE project aims to resurrect algae as a promising source for aviation biofuels. Retrieved from https://www.greenairnews.com/?p=5193
GREENEA. (2016). Analysis of the current development of household UCO collection systems in the EU. Coivert, France.
Griffiths, M. J., van Hille, R. P., & Harrison, S. T. L. (2012). Lipid productivity, settling potential and fatty acid profile of 11 microalgal species grown under nitrogen replete and limited conditions. Journal of Applied Phycology, 24(5), 989–1001.
Guarenghi MM, Walter A, Seabra JEA, Rocha JV, Vieira N, Damame D, Santos JL. Areas Available for the Potential Sustainable Expansion of Soy in Brazil: A Geospatial Assessment Using the SAFmaps Database. Remote Sensing. 2022; 14(7):1628. https://doi.org/10.3390/rs14071628
Hathwar, G. (2022). Voluntary market for Sustainable Aviation Fuel-A case study (Master's thesis).
Heaton, E. A., Dohleman, F. G., Miguez, A. F., Juvik, J. A., Lozovaya, V., Widholm, J., ... & Long, S. P. (2010). Miscanthus: a promising biomass crop. Advances in Botanical Research, 56, 75-137.
Higham, J., Ellis, E., & Maclaurin, J. (2019). Tourist aviation emissions: A problem of collective action. Journal of Travel Research, 58(4), 535-548.
Hinnen, G., Hille, S. L., & Wittmer, A. (2017). Willingness to pay for green products in air travel: Ready for take-off?. Business Strategy and the Environment, 26(2), 197-208.
Hoek, C., van den, H. C., Mann, D., Jahns, H. M., & Jahns, M. (1995). Algae: An introduction to phycology. Cambridge University Press. Hsieh, C. H., & Wu, W. T. (2009). Cultivation of microalgae for oil production with a cultivation strategy of urea limitation. Bioresource Technology, 100(17), 3921-3926.
Hui, T. H., Itani, N., & O’Connell, J. F. (2024). Examining Air Travellers’ Willingness to Pay for Non- voluntary Environment-related Fees: The Case of SAF Surcharge and Carbon Taxes. Highlights of Sustainability, 3(1), 61-75.
Hussain, J., & Rittmann, B. E. (2023). Algae as a source of renewable energy: opportunities, challenges, and recent developments. Sustainable Energy & Fuels.
IATA, Carbon Offsetting Scheme for International Aviation (CORSIA), 2016.
IATA. (2021). Fact Sheet: EU and US policy approaches to advance SAF production. Retrieved from
https://www.iata.org/contentassets/d13875e9ed784f75bac90f000760e998/fac…- eu-saf-policies.pdf
IATA. (2023). Fact sheet - Alternative fuels. International Air Transport Association. Retrieved from
http://www.iata.org/en/iata-repository/pressroom/fact-sheets/fact-sheet…
IATA. (2023). SAF Volumes Growing but Still Missing Opportunities. Retrieved from
https://www.iata.org/en/pressroom/2023-releases/2023-12-06-02
ICAO Committee on Aviation Environmental Protection. (2021). Guidance on potential policies and coordinated approaches for the deployment of SAF.
ICAO, Initiatives and Projects. (2020). Retrieved from https://www.icao.int/environmental- protection/GFAAF/Pages/InitiativesAndProjects.aspx
ICAO, Policies, (2021). https://www.icao.int/environmental-protection/GFAAF/ Pages/Policies.aspx. ICAO. (2017). Sustainable aviation fuels guide. In transforming global aviation collection.
ICAO. (2017). Sustainable aviation fuels guide. In transforming global aviation collection.
ICAO. (2023). Guidance on sustainable aviation fuel (SAF) policies (Version 2).
https://www.icao.int/environmental- protection/Documents/SAF/Guidance%20on%20SAF%20policies%20-%20Version%202.pdf
ICAO. (2023). Retrieved from https://www.icao.int/environmental-protection/GFAAF/Pages/Offtake- Agreements.aspx
ICAO. (2023). Second Phase of the ICAO Assistance Project with the EU Funding: “Capacity Building for CO2 Mitigation from International Aviation”. In ICAO Assistance Project [Report]. Retrieved from https://www.icao.int/environmental-protection/LTAG/Pages/LTAG-data-spre…
81
ICAO. (n.d.). SAF rules of thumb. Retrieved from https://www.icao.int/environmental- protection/Pages/SAF_RULESOFTHUMB.aspx
ICAO. (n.d.). Sustainable aviation fuels stocktaking. Retrieved from
https://www.icao.int/environmental-protection/Pages/SAF_Stocktaking.aspx
IEA Bioenergy (2023). Opportunities of bioenergy and biofuels in developing economies: Summary and conclusions from the e-Workshop, held on 22-23 May 2023. Retrieved from https://www.ieabioenergy.com/wp-content/uploads/2023/08/ExCo91workshop_…
Igini, M. (2022). Sustainable aviation fuel companies. Earth.org. Retrieved March 12, 2023, from
https://earth.org/sustainable-aviation-fuel-companies/
International Air Transport Association, Fact Sheet: Alternative Fuels, 2013.
International Civil Aviation Organization. (2019). ICAO environmental report 2019 (pp. 111-115). Retrieved March 10, 2023, from https://www.icao.int/environmental- protection/Documents/EnvironmentalReports/2019/ENVReport2019_pg111-115.pdf
International Civil Aviation Organization. (2019). Sustainable Aviation Fuels Guide. Retrieved [date you accessed the document], from https://www.icao.int/environmental- protection/Documents/Sustainable%20Aviation%20Fuels%20Guide_100519.pdf
International Civil Aviation Organization. (2022). ICAO environmental report 2022.
International Civil Aviation Organization. (n.d.). Conversion processes. Retrieved April 10, 2023,
from https://www.icao.int/environmental-protection/GFAAF/Pages/Conversion-pr… International Civil Aviation Organization. (n.d.). Sustainable Aviation Fuel (SAF) rules of thumb.
Retrieved from https://www.icao.int/environmental-protection/Pages/SAF_RULESOFTHUMB.as…
International Civil Aviation Organization. (n.d.). Sustainable Aviation Fuels Guide. Retrieved from
https://www.icao.int/environmental-protection/knowledge- sharing/Docs/Sustainable%20Aviation%20Fuels%20Guide_vf.pdf
International Energy Agency. (2023). Aviation. Retrieved March 5, 2024, from
https://www.iea.org/energy-system/transport/aviation
ISCC. (2019). RED II Implications and Latest Challenges in Waste and Residues based Supply Chains.
Jayamuthunagai, J., Selvakumari, I. A., Varjani, S., Mullai, P., & Bharathiraja, B. (2021). Valorization of industrial wastes for biofuel production: Challenges and opportunities. Biomass, Biofuels, Biochemicals, 231-245.
82
Jing, L., El-Houjeiri, H. M., Monfort, J. C., et al. (2022). Understanding variability in petroleum jet fuel life cycle greenhouse gas emissions to inform aviation decarbonization. Nature Communications, 13, 7853.
Khan, A. A., Gul, J., Naqvi, S. R., Ali, I., Farooq, W., Liaqat, R., et al. (2022). Recent progress in microalgae-derived biochar for the treatment of textile industry wastewater. Chemosphere, 306, 135565.
Klauber, A., Benn, A., Hardenbol, C., Schiller, C., Toussie, I., Valk, M., & Waller, J. (2017). Innovative Funding for Sustainable Aviation Fuel at U.S. Airports: Explored at Seattle-Tacoma International. Rocky Mountain Institute, SkyNRG, July 2017.
Kollmuss, A., Zink, H., & Polycarp, C. (2008). Making sense of the voluntary carbon market: A comparison of carbon offset standards. WWF Germany, 1-23.
Korba, P., Sekelová, I., Koščáková, M., & Behúnová, A. (2023). Passengers’ Knowledge and Attitudes toward Green Initiatives in Aviation. Sustainability, 15(7), 6187.
Korkut et al. (2021). Retrieved from
https://www.frontiersin.org/articles/10.3389/fenrg.2021.750514/full
Kotsantonis, S., Pinney, C., & Serafeim, G. (2016). ESG integration in investment management: Myths and realities. Journal of Applied Corporate Finance, 28(2), 10-16.
Kowalski, Z., Kulczycka, J., Verhé, R., Desender, L., De Clercq, G., Makara, A., ... & Harazin, P. (2022). Second-generation biofuel production from the organic fraction of municipal solid waste. Frontiers in Energy Research, 10, 919415.
Kumar, R., Ghosh, A. K., & Pal, P. (2020). Synergy of biofuel production with waste remediation along with value-added co-products recovery through microalgae cultivation: A review of membrane- integrated green approach. Science of the Total Environment, 698, 134169.
Lane, J. (2024). Semi-Sweet on GREET Street: US decision on SAF tax credits is bold for residues; tepid for grains, oilseeds. The Daily Digest. https://www.biofuelsdigest.com/bdigest/2024/04/30/semi-sweet-on-greet-s…- decision-on-saf-tax-credits-is-bold-for-residues-tepid-for-grains-oilseeds/
Lanzini, P., Testa, F., & Iraldo, F. (2016). Factors affecting drivers' willingness to pay for biofuels: The case of Italy. Journal of Cleaner Production, 112, 2684-2692.
Larnaudie, V., Ferrari, M. D., & Lareo, C. (2022). Switchgrass as an alternative biomass for ethanol production in a biorefinery: Perspectives on technology, economics and environmental sustainability. Renewable and Sustainable Energy Reviews, 158, 112115.
83
Laroche, M., Bergeron, J., & Barbaro-Forleo, G. (2001). Targeting consumers who are willing to pay more for environmentally friendly products. Journal of Consumer Marketing, 18(6), 503–520.
LEAP-RE. (n.d.). PyroBioFuel. Retrieved from https://www.leap-re.eu/pyrobiofuel/
Leavitt, E., Meyn, S., Purcell, A., & Stanton, L. (2018). Moving toward sustainable aviation fuel at
Seattle-Tacoma international airport. Journal of Airport Management, 12(4), 391-398.
Lee, J. W., Mets, L., & Greenbaum, E. (2002). Improvement of photosynthetic CO2 fixation at high light intensity through reduction of chlorophyll antenna size. In Biotechnology for Fuels and Chemicals: The Twenty–Third Symposium (pp. 37-48). Humana Press.
Leong, W-H., Lim, J-W., Lam, M-K., Uemura, Y., & Ho, Y-C. (2018). Third generation biofuels: A nutritional perspective in enhancing microbial lipid production. Renewable and Sustainable Energy Reviews, 91, 950–961.
Li, P. Y., Wang, X., Luo, Y. Q., & Yuan, X. G. (2022). Sustainability evaluation of microalgae biodiesel production process integrated with nutrient close-loop pathway based on emergy analysis method. Bioresource Technology, 346, 126611.
Liu, X., Kwon, H., Northrup, D., & Wang, M. (2020). Shifting agricultural practices to produce sustainable, low carbon intensity feedstocks for biofuel production. Environmental Research Letters, 15(8), 084014.
Lufthansa. (n.d.). Frequently asked questions concerning Sustainable Aviation Fuel (SAF). Retrieved March 10, 2024, from https://www.lufthansa.com/ae/en/discover-lufthansa/carbon-offsetting/faq- saf
Malina, R. (2022). Economic policies for technological development. UHasselt.
Malina, R., Abate, M. A., Schlumberger, C. E., & Pineda, F. N. (2022). The role of sustainable aviation fuels in decarbonizing air transport.
Malode, S. J., Prabhu, K. K., Mascarenhas, R. J., Shetti, N. P., & Aminabhavi, T. M. (2021). Recent advances and viability in biofuel production. Energy Conversion and Management: X, 10.
Mantovani, M., Marazzi, F., Fornaroli, R., Bellucci, M., Ficara, E., & Mezzanotte, V. (2020). Outdoor pilot-scale raceway as a microalgae-bacteria sidestream treatment in a WWTP. Science of the Total Environment, 710, 135583.
Martinez-Valencia, L., Garcia-Perez, M., & Wolcott, M. P. (2021). Supply chain configuration of sustainable aviation fuel: Review, challenges, and pathways for including environmental and social benefits. Renewable and Sustainable Energy Reviews, 152, 111680. Mat Aron, N. S., Khoo, K. S., Chew, K. W., Show, P. L., Chen, W. H., & Nguyen, T. H. P. (2020). Sustainability of the four generations of biofuels–a review. International Journal of Energy Research, 44(12), 9266-9282.
Mata, T. M., Martins, A. A., & Caetano, N. S. (2010). Microalgae for biodiesel production and other applications: A review. Renewable and Sustainable Energy Reviews, 14, 217–232.
McDonald, S., Oates, C. J., Thyne, M., Timmis, A. J., & Carlile, C. (2015). Flying in the face of environmental concern: Why green consumers continue to fly. Journal of Marketing Management, 31(13-14), 1503-1528.
Mitra, D., van Leeuwen, J. H., & Lamsal, B. (2012). Heterotrophic/mixotrophic cultivation of oleaginous Chlorella vulgaris on industrial co-products. Algal Research, 1, 40–48.
Mofijur, M., Ashrafur Rahman, S. M., Nguyen, L. N., Mahlia, T. M. I., & Nghiem, L. D. (2022). Selection of microalgae strains for sustainable production of aviation biofuel. Bioresource Technology, 345, 126408.
Mordor Intelligence. (n.d.). Zero emission aircraft market. Retrieved March 2, 2024, from
https://www.mordorintelligence.com/industry-reports/zero-emission-aircr…
Moss, J. (2019, May 3). Overcoming the barriers to entry for aviation biofuels. Informa Connect. Retrieved March 10, 2023, from https://informaconnect.com/overcoming-the-barriers-to-entry-for- aviation-biofuels/
Muhammad G, Alam MA, Mofijur M, Jahirul MI, Lv Y, Xiong W, et al. (2021). Modern developmental aspects in the field of economical harvesting and biodiesel production from microalgae biomass. Renewable and Sustainable Energy Reviews, 135, 110209.
Naik et al., 2010: Production of first and second generation biofuels: A comprehensive review
Nair, S., & Paulose, H. (2014). Emergence of green business models: The case of algae biofuel for aviation. Energy Policy, 65, 175-184.
Neste X Coldplay | Neste. (n.d.). Neste. https://www.neste.com/news-and-insights/neste-coldplay- sustainability-collaboration
Neste. (n.d.). Sustainable aviation fuel. Retrieved March 12, 2023, from
https://www.neste.com/products-and-innovation/sustainable-aviation/sust…- fuel#300e9e38
Nie, J., Chen, D., Ye, J., Lu, Y., & Dai, Z. (2021). Algal Res., 59, 102449.
85
Novoveska, L., Zapata, A. K. M., Zabolotney, J. B., Atwood, M. C., & Sundstrom, E. R. (2016). Optimizing microalgae cultivation and wastewater treatment in large-scale off shore photobioreactors. Algal Research.
Nunez, C. (2019, May 13). Carbon dioxide levels are at a record high. Here’s what you need to know. Environment. Retrieved March 10, 2023, from https://www.nationalgeographic.com/environment/article/greenhouse- gases#:~:text=Effects%20of%20greenhouse%20gases&text=They%20cause%20climate%20chan ge%20by,change%20caused%20by%20greenhouse%20gases.
OECD. (n.d.). Emission trading systems. Retrieved from https://www.oecd.org/env/tools- evaluation/emissiontradingsystems.htm
Official Journal of the European Union, Directive 2008/101/ec of the european parliament and of the council, 2008.
Ooms, M. D., Dinh, C. T., Sargent, E. H., & Sinton, D. (2016). Nat. Commun., 7, 1–13.
Park, H., Jung, D., Lee, J., Kim, P., Cho, Y., Jung, I., Kim, Z-H., Lim, S-M., & Lee, C-G. (2018). Improvement of biomass and fatty acid productivity in ocean cultivation of Tetraselmis sp. using hypersaline medium. Journal of Applied Phycology.
Pasa, V. M. D., Scaldadaferri, C. A., & dos Santos Oliveira, H. (2022). Main feedstock for sustainable alternative fuels for aviation. In Sustainable Alternatives for Aviation Fuels (pp. 69-102). Elsevier.
Per Gegg, Lucy Budd, Stephen Ison. (2014). The market development of aviation biofuel: Drivers and constraints. Journal of Air Transport Management, 39, 34-40.
Pidcock, R. & Yeo, S. (2016). Analysis: Aviation could consume a quarter of 1.5 C carbon budget by 2050. Carbon Brief. Retrieved February 25, 2023, from https://www.carbonbrief.org/aviation- consume-quarter-carbon-budget/
Prasad, S., Sheetal, K. R., Renjith, P. S., Kumar, A., & Kumar, S. (2019). Sweet sorghum: An excellent crop for renewable fuels production. In Prospects of Renewable Bioprocessing in Future Energy Systems (pp. 291-314).
PwC. (2022). Sustainable aviation fuels cost less than you think. PwC.
https://www.pwc.com/gx/en/issues/esg/the-energy-transition/sustainable-…- than-you-think.html
Qasem, N. A., Mourad, A., Abderrahmane, A., Said, Z., Younis, O., Guedri, K., & Kolsi, L. (2024). A recent review of aviation fuels and sustainable aviation fuels. Journal of Thermal Analysis and Calorimetry, 1-26.
86
Rajvanshi, S., & Sharma, M. P. (2012). Micro Algae: A Potential Source of Biodiesel. Journal of Sustainable Bioenergy Systems, 2, 49–59.
Ras, M., Steyer, J. P., & Bernard, O. (2013). Temperature effect on microalgae: A crucial factor for outdoor production. Reviews in Environmental Science and Bio/Technology, 12(2), 153-164.
Reed, M. S., Evely, A. C., Cundill, G., Fazey, I., Glass, J., Laing, A., ... & Stringer, L. C. (2010). What is social learning?. Ecology and society, 15(4).
Reuters, U.S. lawmakers to propose tax credit for sustainable aviation fuel, (2021). U.S. lawmakers to propose tax credit for sustainable aviation fuel.
Ritchie, H. (2020, October 22). Climate change and flying: what share of global CO2 emissions come from aviation? Our World in Data. Retrieved February 25, 2023, from https://ourworldindata.org/co2-emissions-from- aviation#:~:text=Flying%20is%20a%20highly%20controversial,impacts%20on%20climate%20int o%20account.
Roland Berger. (2020). Retrieved from https://www.rolandberger.com
Rony, Z. I., Mofijur, M., Hasan, M. M., Ahmed, S. F., Almomani, F., Rasul, M. G., ... & Mahlia, T. M. I. (2023). Unanswered issues on decarbonizing the aviation industry through the development of sustainable aviation fuel from microalgae. Fuel, 334, 126553.
Roxburgh, N., Guan, D., Shin, K. J., Rand, W., Managi, S., Lovelace, R., & Meng, J. (2019). Characterising climate change discourse on social media during extreme weather events. Global environmental change, 54, 50-60.
RSB. (2023). Sustainable aviation fuel (SAF) guidance for airports. Retrieved from
https://rsb.org/wp-content/uploads/2023/01/SAP-2022-SAF-Guidance-for-Ai…
SAF incentive | Brussels Airport. (n.d.). Brussels Airport Website. Retrieved from
https://www.brusselsairport.be/nl/aviation-development/charges-fees-and…
SAF Investor. (2023, March 14). Will customers pay more for SAF? Retrieved from
https://www.safinvestor.com/opinion/142634/will-customers-pay-more-for-…
Saffron C. (2020). Sustainable use of miscanthus for biofuel. Aberystwyth University. Retrieved from
https://research.aber.ac.uk/en/publications/sustainable-use-of-miscanth…
Sajjadi, B., Chen, W. Y., Raman, A. A. A., & Ibrahim, S. (2018). Microalgae lipid and biomass for biofuel production: A comprehensive review on lipid enhancement strategies and their effects on fatty acid composition. Renewable and Sustainable Energy Reviews, 97, 200-232. Sánchez, C. (2009). Lignocellulosic residues: Biodegradation and bioconversion by fungi. Biotechnology Advances, 27(2), 185-194.
Santos, K., & Delina, L. (2021). Soaring sustainably: Promoting the uptake of sustainable aviation fuels during and post-pandemic. Energy Research & Social Science, 77, 102074.
Sayre, R. (2010). Microalgae: The potential for carbon capture. Bioscience, 60, 722–727.
Schrems, I., & Upham, P. (2020). Cognitive dissonance in sustainability scientists regarding air travel for academic purposes: A qualitative study. Sustainability, 12(5), 1837.
Shahriar, M. F., & Khanal, A. (2022). The current techno-economic, environmental, policy status and perspectives of sustainable aviation fuel (SAF). Fuel, 325, 124905.
Shanmugam, S., Mathimani, T., Anto, S., Sudhakar, M. P., Kumar, S. S., & Pugazhendhi, A. (2020). Cell density, lipidomic profile, and fatty acid characterization as selection criteria in bioprospecting of microalgae and cyanobacterium for biodiesel production. Bioresource Technology, 304, 123061.
Shehab, M., Moshammer, K., Franke, M., & Zondervan, E. (2023). Analysis of the potential of meeting the EU’s sustainable aviation fuel targets in 2030 and 2050. Sustainability, 15(12), 9266.
Shokravi, Z., Shokravi, H., Atabani, A. E., Lau, W. J., Chyuan, O. H., & Ismail, A. F. (2022). Impacts of the harvesting process on microalgae fatty acid profiles and lipid yields: Implications for biodiesel production. Renewable and Sustainable Energy Reviews, 161, 112410.
Silva, L. N., Cardoso, C. C., & Pasa, V. M. (2016). Synthesis and characterization of esters from different alcohols using Macauba almond oil to substitute diesel oil and jet fuel. Fuel, 166, 453-460.
Souza, G. M., & others. (2015). Bioenergy & sustainability: Bridging the gaps. Paris: Scientific Committee on Problems of the Environment (SCOPE).
Steinmueller, W. E. (2010). Economics of technology policy. In Handbook of the Economics of Innovation (Vol. 2, pp. 1181-1218). North-Holland.
Sze Ki Lin, C., et al. (2013). Food waste as a valuable resource for the production of chemicals, materials and fuels: Current situation and global perspective. Energy & Environmental Science, 6(2), 426-464.
Tao, L., Milbrandt, A., Zhang, Y., & Wang, W. C. (2017). Techno-economic and resource analysis of hydroprocessed renewable jet fuel. Biotechnology for biofuels, 10, 1-16.
Transport & Environment. (2023). Sustainable aviation fuels sustainability guide for corporate buyers. Retrieved from https://www.transportenvironment.org/articles/sustainable-aviation-fuels- sustainability-guide-for-corporate-buyers
88
Transport & Environment. (n.d.). New technologies. Retrieved February 25, 2023, from
https://www.transportenvironment.org/topics/planes/new- tech#:~:text=Emissions%20from%20aviation%20are%20a,altitude%20at%20which%20aircraft% 20operate
Tye, Y. Y., Lee, K. T., Abdullah, W. N. W., & Leh, C. P. (2016). The world availability of non-wood lignocellulosic biomass for the production of cellulosic ethanol and potential pretreatments for the enhancement of enzymatic saccharification. Renewable and Sustainable Energy Reviews, 60, 155- 172.
U.S. Department of Energy. (n.d.). Bioenergy Technologies Office. Office of Energy Efficiency & Renewable Energy. Retrieved March 5, 2024, from https://www.energy.gov/eere/bioenergy/bioenergy-technologies-office
Umakanth, A. V., Bhargavi, H. A., Keerthi, L., & Tonapi, V. A. (2020). Sweet Sorghum as First- Generation Biofuel Feedstock and Its Commercialization. In Sorghum in the 21st Century: Food– Fodder–Feed–Fuel for a Rapidly Changing World (pp. 705-721).
United Nations Conference on Trade and Development (UNCTAD). (2016). Second Generation Biofuel Markets: State of Play, Trade and Developing Country Perspectives. Geneva, Switzerland: United Nations Conference on Trade and Development.
United States Department of Transportation. (2021). Airline Fuel Cost and Consumption. Retrieved from https://www.transtats.bts.gov/fuel.asp?pn=1.
University of Nebraska-Lincoln. (n.d.). Corn as a bioenergy crop. CropWatch. Retrieved March 12, 2023, from https://cropwatch.unl.edu/bioenergy/corn
Usman, M., Cheng, S., Boonyubol, S., & Cross, J. S. (2023). The future of aviation soars with HTL- based SAFs: Exploring potential and overcoming challenges using organic wet feedstocks. Sustainable Energy & Fuels, 7(17), 4066-4087.
Van Den Hende, S., Vervaeren, H., Desmet, S., & Boon, N. (2011). Bioflocculation of microalgae and bacteria combined with flue gas to improve sewage treatment. N. Biotechnol., 29, 23–31.
van Deursen, A. J. A. M., van Dijk, J. A. G. M., & Peters, O. (2011). Rethinking Internet skills: The contribution of gender, age, education, Internet experience, and hours online to medium-and content-related Internet skills. Poetics, 39(2), 125–144.
Van Grinsven, A., van den Toorn, E., van der Veen, R., Kampman, B., & Oil, C. (2020). Used Cooking Oil (UCO) as biofuel feedstock in the EU. CE Delft: Delft, The Netherlands, 200247.
89
Varela Villarreal, J., Burgues, C., & Rosch, C. (2020). Acceptability of genetically engineered algae biofuels in Europe: Opinions of experts and stakeholders. Biotechnology and Biofuels, 13, 92. Epub 20200522.
Velarde, C. (2020). Aviation Carbon dioxide Reduction Stocktaking Seminar. Retrieved from https://www.icao.int/Meetings/Stocktaking2020/Documents/ICAO Stocktaking 2020 - 3.4.1 - Cesar Velarde.pdf.
Volkman, J. K., Jeffrey, S. W., Nichols, P. D., Rogers, G. I., & Garland, C. D. (1989). Fatty acid and lipid composition of 10 species of microalgae used in mariculture. Journal of Experimental Marine Biology and Ecology, 128(3), 219–240.
Wals, A. Social Learning towards a Sustainable World; Wageningen Acatemic Publishers: Wageningen, The Netherlands, 2009; p. 542
Wang, Y., & Wu, J. J. (2023). Thermochemical conversion of biomass: Potential future prospects. Renewable and Sustainable Energy Reviews, 187, 113754.
Wang, Y., Ho, S. H., Cheng, C. L., et al. (2016). Perspectives on the feasibility of using microalgae for industrial wastewater treatment. Bioresource Technology, 222, 485–497.
Wei H, Liu W, Chen X, Yang Q, Li J, Chen H. Renewable bio-jet fuel production for aviation: A review. Fuel 2019;254:115599. https://doi.org/10.1016/j. fuel.2019.06.007.
Wolf, B. M., Niedzwiedzki, D. M., Magdaong, N. C. M., Roth, R., Goodenough, U., & Blankenship, R. E. (2018). Characterization of a newly isolated freshwater Eustigmatophyte alga capable of utilizing far-red light as its sole light source. Photosynthesis Research, 135, 177-189.
World Bank. (n.d.). Trends in Solid Waste Management. Retrieved February 1, 2024, from
https://datatopics.worldbank.org/what-a- waste/trends_in_solid_waste_management.html?ref=artshelp.com
World Economic Forum (WEF). (2023). Sustainable Aviation Fuels: Offtake Manual (White Paper).
https://www3.weforum.org/docs/WEF_Sustainable_Aviation_Fuels_Offtake_Ma…
World Energy. (n.d.). World Energy and Microsoft join forces to drive aviation decarbonization. Retrieved from https://www.worldenergy.net/doe-loan
WSU. (2020). Retrieved from https://www.portseattle.org/sites/default/files/2020- 07/PofSeattleWSU2019_final.pdf
Xu, B., Ahmad, S., Charles, V., & Xuan, J. (2022). Sustainable commercial aviation: What determines air travellers’ willingness to pay more for sustainable aviation fuel?. Journal of cleaner production, 374, 133990.
90
Yadav, K., Vasistha, S., & Rai, M. P. (2022). Algal physiology and cultivation. In Handbook of Algal Biofuels (pp. 79-96). Elsevier.
Yuriev, A., Dahmen, M., Paillé, P., Boiral, O., & Guillaumie, L. (2020). Pro-environmental behaviors through the lens of the theory of planned behavior: A scoping review. Resources, Conservation and Recycling, 155, 104660.
Zabed, H., Sahu, J. N., Boyce, A. N., & Faruq, G. (2016). Fuel ethanol production from lignocellulosic biomass: An overview on feedstocks and technological approaches. Renewable and Sustainable Energy Reviews, 66, 751-774.
Zhou, Y., Liu, L., Li, M., & Hu, C. (2022). Bioresour. Technol., 244, 126371.
