Year 2025,
Erken Görünüm, 1 - 1
Osman Furkan Kapıkıran
,
Halil İbrahim Variyenli
,
Mert Ökten
,
Semih Sadi Kılıç
References
- [1] United Nations. Treaty of Paris. 2024. https://www.unep.org/environmental-moments-unep50-timeline.
- [2] Ökten M. An investigation on provincial production & consumption of electric energy: A case analysis for Ankara. Kocaeli Journal of Science and Engineering (KOJoSE). 2021; 4(1): 59-68.
- [3] Brown A, Smith B. Environmental impacts of biodiesel versus diesel fuel: A comparative study. Journal of Environmental Science. 2017; 15(2): 123-135.
- [4] Aydın K, Keskin A. Dizel motorlarında motorin, bitkisel yağlar ve alkol karışımlarının performans ve emisyona etkilerinin araştırılması Yanma ve Hava Kirliliği Kontrolü V. Ulusal Sempozyumu. 2000.
- [5] Yücesu HS, Altın R, Çetinkaya S. Dizel motorlarında alternatif olarak bitkisel yağ kullanımının deneysel incelenmesi. Türk Journal Engineering Environment Science. 2001; 25: 39-49.
- [6] Taşyürek M, Acaroğlu M. Biyoyakıtlarda (Biyomotorinde) emisyon azatlımı ve küresel ısınmaya etkisi. Uluslararası Küresel İklim Değişikliği ve Çevresel Etkileri Konferansı. 2007.
- [7] Çaylı G, Küsefoğlu S. Increased yields in biodiesel production from used cooking oils by a two-step process: Comparison with one step process by using TGA. Fuel Processing Technology. 2008; 89(2): 118-122.
- [8] Özbay N, Oktar N, Tapan NA. Esterification of free fatty acids in waste cooking oils (WCO): Role of ion-exchange resins. Fuel. 2008; 87(10-11): 1789-1798.
- [9] Gürü M, Koca A, Can A, Çınar C, Şahin F. Biodiesel production from waste chicken fat based sources and evaluation with Mg based additive in a diesel engine. Renewable Energy. 2010; 35: 637–643.
- [10] Altinok F, Albayrak S, Arslan NP, Taskin M, Aygun E, Sisecioglu M, Adigüzel A. Application of Anoxybacillus gonensins UF7 lipase as a catalyst for biodiesel production from waste frying oil. Fuel. 2023; 334(1): 126672.
- [11] El-Khair MAA, El Saied M, El Naga AOA, Morshedy AS. Rapid and low-temperature biodiesel production from waste cooking oil: Kinetic and thermodynamic insights using a KOH/ZnAl2O4 nanocatalyst derived from waste aluminum foil. Energy Conversion and Management. 2024; 318: 118898.
- [12] Anil N, Rao PK, Sarkar A, Kubavat J, Vadivel S, Manwar NR, Paul B. Advancements in sustainable biodiesel production: A comprehensive review of bio-waste derived catalysts. Energy Conversion and Management. 2024; 318: 118884.
- [13] Antolin G, Tinaut FV, Briceño Y, Castaño V, Pérez C, Ramírez AI. Optimisation of biodiesel production by sunflower oil transesterification. Bioresource Technology. 2002; 83(2): 111-114.
- [14] Vicente G, Martínez M, Aracil J. Integrated biodiesel production: A comparison of different homogeneous catalysts systems. Bioresource Technology. 2004; 92(3): 297-305.
- [15] Ayhan V, Tunca S, Özsert İ, Ergen G, Cesur İ. Ayçiçek yağı metil ester karışımlarının bir dizel motorunun performans ve emisyonlarına etkisi. APJES. 2019; 7(1): 67–73.
- [16] Samuel OD, Okwu MO, Oyejide OJ, Taghinezhad E, Afzal A, Kaveh M. Optimizing biodiesel production from abundant waste oils through empirical method and grey wolf optimizer. Fuel. 2020; 281: 118701.
- [17] Foroutan R, Peighambardoust SJ, Mohammadi R, Peighambardoust SH, Ramavandi B. The potential of biochar derived from banana peel/Fe3O4/ZIF-67@K2CO3 as magnetic nanocatalyst for biodiesel production from waste cooking oils. Results in Engineering. 2024; 22: 102005.
- [18] Usta N, Conkur ES, Can AC, Topcu M, Öztürk E, Can O, Nas S, Çon AH. Combustion of biodiesel fuel produced from hazelnut soapstock/waste sunflower oil mixture in a diesel engine. Energy Conversion and Management. 2005; 46(5): 741-755.
- [19] Kalam MA, Masjuki HH. Biodiesel from palmoil—an analysis of its properties and potential. Biomass and Bioenergy. 2002; 23(6): 471-479.
- [20] Torres EA, Cerqueira GS, Ferrer TM, Quintella CM, Raboni M, Torretta V, Urbini G. Recovery of different waste vegetable oils for biodiesel production: A pilot experience in Bahia State Brazil. Waste Management. 2013; 33(12): 2670-2674.
- [21] Ramadhas AS, Jayaraj S, Muraleedharan C. Biodiesel production from figh FFA rubber seed oil. Fuel. 2005; 84: 335-340.
- [22] Çanakçı M, Van Gerpen JH. Comparision of engine performance and emissions for petroleum diesel fuel, yellow-grease biodiesel and soybean-oil biodiesel. Trans ASAE. 2003; 46: 937-944.
- [23] Çaynak S, Gürü M, Biçer A, Keskin A, İçingür Y. Biodiesel production from pomace oil and improvement of its properties with synthetic manganese additive. Fuel. 2009; 88(3): 534-538.
- [24] Tashtoush MG, Al Widyan MI, Al Jarrah MM. Experimental study on eveluation and optimization of conversion of waste animal fat into biodiesel. Energy Conversion and Management. 2004; 45: 2697-2711.
- [25] Reyes JF, Sepulveda MA. PM-10 emissions and power of a Diesel engine fueled with crude and refined Biodiesel from salmon oil. Fuel. 2006; 1-6.
- [26] Altıparmak D, Keskin A, Koca A, Guru M. Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends. Bioresource Technology. 2007; 98(2): 241-246.
- [27] Moraes PS, Igansi AV, Cadaval Jr TRS, Pinto LAA. Biodiesel produced from crude, degummed, neutralized and bleached oils of Nile tilapia waste: Production efficiency, physical-chemical quality and economic viability. Renewable Energy. 2020; 161: 110-119.
- [28] Sharma P, Usman M, Salama ES, Redina M, Thakur N, Li X. Evaluation of various waste cooking oils for biodiesel production: A comprehensive analysis of feedstock. Waste Management. 2021; 136: 219-229.
- [29] Fawaz EG, Salam DA. Preliminary economic assessment of the use of waste frying oils for biodiesel production in Beirut Lebanon. Science of The Total Environment. 2018; 637-638: 1230-1240.
- [30] Fonseca JM, Teleken JG, de Cinque Almeida V, da Silva C. Biodiesel from waste frying oils: Methods of production and purification. Energy Conversion and Management. 2019; 184: 205-218.
- [31] AlYammahi J, Chelaifa H, Hasan A, Darwish AS, Lemaoui T, Hernandez HH, Galvan AR. Salicornia seed oil: A high-yielding and sustainable halophytic feedstock for biodiesel and energy in underutilized hypersaline coastal deserts. Energy Conversion and Management. 2024; 318: 11891.
- [32] Nahas L, Dahdah E, Aouad S, El Khoury B, Gennequin C, Aad EA, Estephane J. Highly efficient scallop seashell-derived catalyst for biodiesel production from sunflower and waste cooking oils: Reaction kinetics and effect of calcination temperature studies. Renewable Energy. 2023; 202: 1086-1095.
- [33] Adib AR, Rahman MM, Hassan T, Ahmed M, Al Rifat A, Novel biofuel blends for diesel engines: Optimizing engine performance and emissions with C. cohnii microalgae biodiesel and algae-derived renewable diesel blends. Energy Conversion and Management: X. 2024; 100688.
- [34] Ivkovicˇ I, Kaplanovicˇ S, Zˇezˇelj S. Višekriterijumsko rangiranje konstrukcijsko-koncepcijskih rešenja autobusa u cilju stvaranja odrzˇivog JMTP-a u Beogradu. Journal of Applied Engineering Science. 2007; 5(15): 57–66.
- [35] Petrovicˇ J, Ivkovicˇ I, Vujacˇicˇ I, Zˇezˇelj S. Possibilities of buses on alternative fuel in public urban transport in Belgrade. Technology Econimical Devolution Economy. 2009; 15(1): 78–89.
- [36] Tica S, Filipovic´ S, ˇZivanovic´ P, & Milovanovic´ B. Test run of biodiesel in public transport system in Belgrade. Energy Policy. 2010; 38: 7014–7020.
- [37] Serrano LMV, Camara RMO, Carreira VJR, da Silva MCG. Performance study about biodiesel impact on buses engines using dynamometer tests and fleet consumption data. Energy Conversion Management. 2012; 60: 2–9.
- [38] Bunger J, Krahl J, Schroder O, Schmidt L, Westphal GA. Potential hazards associated with combustion of bio-derived versus petroleum-derived diesel fuel. Criteria Revolution Toxicology. 2012; 42(9): 732–750.
- [39] Akgül G, Sözer S, Culfa M. Atık yağlardan biyodizel üretiminde yenilikçi biyokömür katalizörü TÜBAV Bilim Dergisi. 2017; 10(4): 29-39.
- [40] Ahmadbeigi A, Mahmoudi M, Fereidooni L, Akbari M, Kasaeian A. Biodiesel production from waste cooking oil: A review on production methods, recycling models, materials and catalysts. Journal of Thermal Engineering. 2024; 10(5): 1362-1389.
- [41] IPCC. Climate change 2014: Mitigation of climate change intergovernmental panel on climate change. 2024. https://www.ipcc.ch/report/ar5/syr/.
- [42] Green C, Brown D, Black E. Effects of biodiesel on NOx emissions: A comparative analysis. Journal of Sustainable Energy. 2019; 25(4): 321-335.
- [43] Johnson F, Brown A. Reduction of CO and SOx emissions with biodiesel: A case study. Environmental Engineering Review. 2018; 10(3): 210-225.
- [44] Jones G. Sulfur compounds in biodiesel fuels. Biodiesel: Production, Properties, and Applications. 2019; 87-102, Springer.
- [45] Smith B. Impacts of greenhouse gas emissions on global warming. Environmental Health Perspectives. 2020; 128(5): 450-465.
- [46] Demirbas A. Progress and recent trends in biodiesel fuels. Energy Conversion Management. 2009; 50(1): 14–34.
- [47] De Paulo AA, Da Costa RS, Rahde SB, Vecchia FD, Seferin M, Dos Santos CA. Performance and emission evaluations in a power generator fuelled with Brazilian diesel and additions of waste frying oil biodiesel. Applied Thermal Engineering. 2016; 98: 288–297.
- [48] TÜİK. Adrese dayalı nüfus kayıt sistemi sonuçları. 2024. https://data.tuik.gov.tr/Bulten/Index?p=Adrese-Dayali-Nufus-Kayit-Sistemi-Sonuclari-2023-496884#:~:text=%C4%B0stanbul’un%20n%C3%BCfusu%2C%20bir%20%C3%B6nceki,249%20ki%C5%9Fi%20ile%20Antalya%20izledi.
- [49] U.S. Department of Energy. Biodiesel benefits and considerations. alternative fuels data center. 2024. https://afdc.energy.gov/fuels/biodiesel_benefits.html
- [50] National Renewable Energy Laboratory. Biodiesel handling and use guide (4th edition). 2009. https://www.nrel.gov/docs/fy09osti/43672.pdf
- [51] Environmental Protection Agency. A comprehensive analysis of biodiesel impacts on exhaust emissions. 2002. https://nepis.epa.gov/Exe/ZyPDF.cgi/P1001YTB.PDF?Dockey=P1001YTB.PDF.
- [52] Ankara EGO. 2024. https://m.ego.gov.tr/haber/6155/egonun-otobus-filosu-genisliyor-16-solo-tip-otobus-daha-alindi.
Reducing Carbon Footprint in Ankara: The Use of Biodiesel Produced from Waste Oils in Public Transportation
Year 2025,
Erken Görünüm, 1 - 1
Osman Furkan Kapıkıran
,
Halil İbrahim Variyenli
,
Mert Ökten
,
Semih Sadi Kılıç
Abstract
Biomass energy is a renewable energy source obtained by converting organic wastes and plant materials into energy. Biomass, which has an increasing importance in energy consumption in recent years, contributes to sustainability and carbon emission reduction targets as an alternative to fossil fuels. Biodiesel is derived from biomass and used as a motor fuel. Due to its renewable feature and lower carbon emission, biodiesel attracts attention as an environmentally friendly fuel alternative. This study examines the utilisation of biodiesel derived from waste oils in public transport vehicles within the province of Ankara, and the impact of this utilisation on the carbon footprint. The conversion of waste oils into biodiesel represents a promising fuel alternative that simultaneously advances environmental sustainability and fosters energy diversity. The study presents a numerical analysis of the impact of biodiesel usage on fossil fuel consumption and carbon emissions in the public transport fleet, specifically in buses. Furthermore, the impact of this practice on the local economy and its long-term implications for sustainable urban transportation are also assessed. In Ankara, 870522 liters of waste oil are collected on a monthly basis, resulting in a reduction of 76% in carbon emissions due to the production of 739943 liters of biodiesel derived from these oils. As a result, energy consumption, efficiency and carbon emission analyses show that biodiesel is an economically and environmentally sustainable alternative. It is expected that the recycling of waste oils will improve waste management and reduce the negative impacts on the environment.
References
- [1] United Nations. Treaty of Paris. 2024. https://www.unep.org/environmental-moments-unep50-timeline.
- [2] Ökten M. An investigation on provincial production & consumption of electric energy: A case analysis for Ankara. Kocaeli Journal of Science and Engineering (KOJoSE). 2021; 4(1): 59-68.
- [3] Brown A, Smith B. Environmental impacts of biodiesel versus diesel fuel: A comparative study. Journal of Environmental Science. 2017; 15(2): 123-135.
- [4] Aydın K, Keskin A. Dizel motorlarında motorin, bitkisel yağlar ve alkol karışımlarının performans ve emisyona etkilerinin araştırılması Yanma ve Hava Kirliliği Kontrolü V. Ulusal Sempozyumu. 2000.
- [5] Yücesu HS, Altın R, Çetinkaya S. Dizel motorlarında alternatif olarak bitkisel yağ kullanımının deneysel incelenmesi. Türk Journal Engineering Environment Science. 2001; 25: 39-49.
- [6] Taşyürek M, Acaroğlu M. Biyoyakıtlarda (Biyomotorinde) emisyon azatlımı ve küresel ısınmaya etkisi. Uluslararası Küresel İklim Değişikliği ve Çevresel Etkileri Konferansı. 2007.
- [7] Çaylı G, Küsefoğlu S. Increased yields in biodiesel production from used cooking oils by a two-step process: Comparison with one step process by using TGA. Fuel Processing Technology. 2008; 89(2): 118-122.
- [8] Özbay N, Oktar N, Tapan NA. Esterification of free fatty acids in waste cooking oils (WCO): Role of ion-exchange resins. Fuel. 2008; 87(10-11): 1789-1798.
- [9] Gürü M, Koca A, Can A, Çınar C, Şahin F. Biodiesel production from waste chicken fat based sources and evaluation with Mg based additive in a diesel engine. Renewable Energy. 2010; 35: 637–643.
- [10] Altinok F, Albayrak S, Arslan NP, Taskin M, Aygun E, Sisecioglu M, Adigüzel A. Application of Anoxybacillus gonensins UF7 lipase as a catalyst for biodiesel production from waste frying oil. Fuel. 2023; 334(1): 126672.
- [11] El-Khair MAA, El Saied M, El Naga AOA, Morshedy AS. Rapid and low-temperature biodiesel production from waste cooking oil: Kinetic and thermodynamic insights using a KOH/ZnAl2O4 nanocatalyst derived from waste aluminum foil. Energy Conversion and Management. 2024; 318: 118898.
- [12] Anil N, Rao PK, Sarkar A, Kubavat J, Vadivel S, Manwar NR, Paul B. Advancements in sustainable biodiesel production: A comprehensive review of bio-waste derived catalysts. Energy Conversion and Management. 2024; 318: 118884.
- [13] Antolin G, Tinaut FV, Briceño Y, Castaño V, Pérez C, Ramírez AI. Optimisation of biodiesel production by sunflower oil transesterification. Bioresource Technology. 2002; 83(2): 111-114.
- [14] Vicente G, Martínez M, Aracil J. Integrated biodiesel production: A comparison of different homogeneous catalysts systems. Bioresource Technology. 2004; 92(3): 297-305.
- [15] Ayhan V, Tunca S, Özsert İ, Ergen G, Cesur İ. Ayçiçek yağı metil ester karışımlarının bir dizel motorunun performans ve emisyonlarına etkisi. APJES. 2019; 7(1): 67–73.
- [16] Samuel OD, Okwu MO, Oyejide OJ, Taghinezhad E, Afzal A, Kaveh M. Optimizing biodiesel production from abundant waste oils through empirical method and grey wolf optimizer. Fuel. 2020; 281: 118701.
- [17] Foroutan R, Peighambardoust SJ, Mohammadi R, Peighambardoust SH, Ramavandi B. The potential of biochar derived from banana peel/Fe3O4/ZIF-67@K2CO3 as magnetic nanocatalyst for biodiesel production from waste cooking oils. Results in Engineering. 2024; 22: 102005.
- [18] Usta N, Conkur ES, Can AC, Topcu M, Öztürk E, Can O, Nas S, Çon AH. Combustion of biodiesel fuel produced from hazelnut soapstock/waste sunflower oil mixture in a diesel engine. Energy Conversion and Management. 2005; 46(5): 741-755.
- [19] Kalam MA, Masjuki HH. Biodiesel from palmoil—an analysis of its properties and potential. Biomass and Bioenergy. 2002; 23(6): 471-479.
- [20] Torres EA, Cerqueira GS, Ferrer TM, Quintella CM, Raboni M, Torretta V, Urbini G. Recovery of different waste vegetable oils for biodiesel production: A pilot experience in Bahia State Brazil. Waste Management. 2013; 33(12): 2670-2674.
- [21] Ramadhas AS, Jayaraj S, Muraleedharan C. Biodiesel production from figh FFA rubber seed oil. Fuel. 2005; 84: 335-340.
- [22] Çanakçı M, Van Gerpen JH. Comparision of engine performance and emissions for petroleum diesel fuel, yellow-grease biodiesel and soybean-oil biodiesel. Trans ASAE. 2003; 46: 937-944.
- [23] Çaynak S, Gürü M, Biçer A, Keskin A, İçingür Y. Biodiesel production from pomace oil and improvement of its properties with synthetic manganese additive. Fuel. 2009; 88(3): 534-538.
- [24] Tashtoush MG, Al Widyan MI, Al Jarrah MM. Experimental study on eveluation and optimization of conversion of waste animal fat into biodiesel. Energy Conversion and Management. 2004; 45: 2697-2711.
- [25] Reyes JF, Sepulveda MA. PM-10 emissions and power of a Diesel engine fueled with crude and refined Biodiesel from salmon oil. Fuel. 2006; 1-6.
- [26] Altıparmak D, Keskin A, Koca A, Guru M. Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends. Bioresource Technology. 2007; 98(2): 241-246.
- [27] Moraes PS, Igansi AV, Cadaval Jr TRS, Pinto LAA. Biodiesel produced from crude, degummed, neutralized and bleached oils of Nile tilapia waste: Production efficiency, physical-chemical quality and economic viability. Renewable Energy. 2020; 161: 110-119.
- [28] Sharma P, Usman M, Salama ES, Redina M, Thakur N, Li X. Evaluation of various waste cooking oils for biodiesel production: A comprehensive analysis of feedstock. Waste Management. 2021; 136: 219-229.
- [29] Fawaz EG, Salam DA. Preliminary economic assessment of the use of waste frying oils for biodiesel production in Beirut Lebanon. Science of The Total Environment. 2018; 637-638: 1230-1240.
- [30] Fonseca JM, Teleken JG, de Cinque Almeida V, da Silva C. Biodiesel from waste frying oils: Methods of production and purification. Energy Conversion and Management. 2019; 184: 205-218.
- [31] AlYammahi J, Chelaifa H, Hasan A, Darwish AS, Lemaoui T, Hernandez HH, Galvan AR. Salicornia seed oil: A high-yielding and sustainable halophytic feedstock for biodiesel and energy in underutilized hypersaline coastal deserts. Energy Conversion and Management. 2024; 318: 11891.
- [32] Nahas L, Dahdah E, Aouad S, El Khoury B, Gennequin C, Aad EA, Estephane J. Highly efficient scallop seashell-derived catalyst for biodiesel production from sunflower and waste cooking oils: Reaction kinetics and effect of calcination temperature studies. Renewable Energy. 2023; 202: 1086-1095.
- [33] Adib AR, Rahman MM, Hassan T, Ahmed M, Al Rifat A, Novel biofuel blends for diesel engines: Optimizing engine performance and emissions with C. cohnii microalgae biodiesel and algae-derived renewable diesel blends. Energy Conversion and Management: X. 2024; 100688.
- [34] Ivkovicˇ I, Kaplanovicˇ S, Zˇezˇelj S. Višekriterijumsko rangiranje konstrukcijsko-koncepcijskih rešenja autobusa u cilju stvaranja odrzˇivog JMTP-a u Beogradu. Journal of Applied Engineering Science. 2007; 5(15): 57–66.
- [35] Petrovicˇ J, Ivkovicˇ I, Vujacˇicˇ I, Zˇezˇelj S. Possibilities of buses on alternative fuel in public urban transport in Belgrade. Technology Econimical Devolution Economy. 2009; 15(1): 78–89.
- [36] Tica S, Filipovic´ S, ˇZivanovic´ P, & Milovanovic´ B. Test run of biodiesel in public transport system in Belgrade. Energy Policy. 2010; 38: 7014–7020.
- [37] Serrano LMV, Camara RMO, Carreira VJR, da Silva MCG. Performance study about biodiesel impact on buses engines using dynamometer tests and fleet consumption data. Energy Conversion Management. 2012; 60: 2–9.
- [38] Bunger J, Krahl J, Schroder O, Schmidt L, Westphal GA. Potential hazards associated with combustion of bio-derived versus petroleum-derived diesel fuel. Criteria Revolution Toxicology. 2012; 42(9): 732–750.
- [39] Akgül G, Sözer S, Culfa M. Atık yağlardan biyodizel üretiminde yenilikçi biyokömür katalizörü TÜBAV Bilim Dergisi. 2017; 10(4): 29-39.
- [40] Ahmadbeigi A, Mahmoudi M, Fereidooni L, Akbari M, Kasaeian A. Biodiesel production from waste cooking oil: A review on production methods, recycling models, materials and catalysts. Journal of Thermal Engineering. 2024; 10(5): 1362-1389.
- [41] IPCC. Climate change 2014: Mitigation of climate change intergovernmental panel on climate change. 2024. https://www.ipcc.ch/report/ar5/syr/.
- [42] Green C, Brown D, Black E. Effects of biodiesel on NOx emissions: A comparative analysis. Journal of Sustainable Energy. 2019; 25(4): 321-335.
- [43] Johnson F, Brown A. Reduction of CO and SOx emissions with biodiesel: A case study. Environmental Engineering Review. 2018; 10(3): 210-225.
- [44] Jones G. Sulfur compounds in biodiesel fuels. Biodiesel: Production, Properties, and Applications. 2019; 87-102, Springer.
- [45] Smith B. Impacts of greenhouse gas emissions on global warming. Environmental Health Perspectives. 2020; 128(5): 450-465.
- [46] Demirbas A. Progress and recent trends in biodiesel fuels. Energy Conversion Management. 2009; 50(1): 14–34.
- [47] De Paulo AA, Da Costa RS, Rahde SB, Vecchia FD, Seferin M, Dos Santos CA. Performance and emission evaluations in a power generator fuelled with Brazilian diesel and additions of waste frying oil biodiesel. Applied Thermal Engineering. 2016; 98: 288–297.
- [48] TÜİK. Adrese dayalı nüfus kayıt sistemi sonuçları. 2024. https://data.tuik.gov.tr/Bulten/Index?p=Adrese-Dayali-Nufus-Kayit-Sistemi-Sonuclari-2023-496884#:~:text=%C4%B0stanbul’un%20n%C3%BCfusu%2C%20bir%20%C3%B6nceki,249%20ki%C5%9Fi%20ile%20Antalya%20izledi.
- [49] U.S. Department of Energy. Biodiesel benefits and considerations. alternative fuels data center. 2024. https://afdc.energy.gov/fuels/biodiesel_benefits.html
- [50] National Renewable Energy Laboratory. Biodiesel handling and use guide (4th edition). 2009. https://www.nrel.gov/docs/fy09osti/43672.pdf
- [51] Environmental Protection Agency. A comprehensive analysis of biodiesel impacts on exhaust emissions. 2002. https://nepis.epa.gov/Exe/ZyPDF.cgi/P1001YTB.PDF?Dockey=P1001YTB.PDF.
- [52] Ankara EGO. 2024. https://m.ego.gov.tr/haber/6155/egonun-otobus-filosu-genisliyor-16-solo-tip-otobus-daha-alindi.