Diesel or Jatropha Biodiesel? A life cycle assessment approach for sustainable energy decisions

 Corresponding author: Jorge Nhambiu Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Diesel or Jatropha Biodiesel? A life cycle assessment approach for sustainable energy decisions Jorge Nhambiu 1, *, José Gui Naldo Muchanga 1 and Fernando Chichango 2 1 Mechanical Engineering Department, Faculty of Engineering, Eduardo Mondlane University, Maputo, Mozambique. 2 ECROT Department, Faculty of Environmental and Natural Resource Engineering, Zambeze University, Chimoio, Mozambique. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 Publication history: Received 08 October 2025; revised on 15 November 2025; accepted on 17 November 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.28.2.3875 Abstract This study compares the environmental and economic performance of diesel and Jatropha biodiesel using Life Cycle Assessment (LCA) and cost analysis for a functional unit of 1,000 km traveled. Results indicate that Jatropha biodiesel reduces overall environmental impact by approximately 37%, primarily due to net negative CO₂ emissions from carbon sequestration during cultivation, and offers significant improvements in global warming potential, fossil fuel depletion, and particulate matter formation. However, biodiesel requires 111.1 liters versus 100 liters of diesel for the same distance, reflecting its lower energy density (37 MJ/L vs. 43 MJ/L), and incurs a 42.7% higher cost per unit of useful energy (USD 0.157/MJ vs. USD 0.09/MJ), raising the total cost for 1,000 km from USD 136 to USD 225.53. Qualitatively, Jatropha biodiesel emerges as a cleaner alternative with strong climate benefits, but its competitiveness is constrained by higher production costs, land use, and water consumption. These findings highlight the need for technological improvements and policy support to enhance the economic viability of biodiesel while leveraging its environmental advantages. Keywords: Life Cycle Assessment; Jatropha Biodiesel; Environmental Impact; Renewable Energy; Sustainable Fuel Alternatives 1 Introduction The global energy sector is undergoing a significant transformation driven by the urgent need to reduce greenhouse gas emissions, mitigate climate change, and transition towards more sustainable energy systems. Fossil fuels, particularly diesel, remain dominant in transportation and industrial applications, but their environmental impacts and economic volatility have prompted the exploration of renewable alternatives [1, 2]. Biofuels have emerged as a promising solution, offering the potential to reduce carbon emissions and promote energy independence. Among them, biodiesel derived from Jatropha curcas has attracted considerable attention due to its nonedible nature, adaptability to marginal soils, and relatively high oil yield [3]. Unlike first-generation biofuels, jatropha biodiesel does not compete directly with food crops, making it a viable option for sustainable development in regions such as sub-Saharan Africa [4]. Mozambique, with its vast agricultural potential and growing energy demand, is well-positioned to benefit from the cultivation and use of jatropha-based biodiesel. Several initiatives have explored its feasibility, and recent policy frameworks have encouraged the integration of biofuels into the national energy mix [5]. However, the environmental and economic viability of jatropha biodiesel must be rigorously assessed to support informed decision-making. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1417 Life Cycle Assessment (LCA) is a standardized methodology that evaluates the environmental impacts of a product or process throughout its entire life cycle—from raw material extraction to end use and disposal [6]. By applying LCA to compare diesel and jatropha biodiesel, researchers can identify trade-offs, quantify emissions, and assess resource consumption across multiple impact categories [7]. This study aims to apply LCA to evaluate the environmental performance of diesel and jatropha biodiesel used in internal combustion engines. The analysis is based on a functional unit of 1,000 km traveled by a light-duty vehicle and includes a complementary economic assessment based on the cost per unit of useful energy. The findings are intended to inform sustainable energy strategies in Mozambique and contribute to the broader discourse on renewable fuel adoption. 2 Material and methods This research applies the Life Cycle Assessment (LCA) methodology to compare the environmental performance of diesel and jatropha biodiesel used in internal combustion engines. The analysis was conducted using the SimaPro v.9.6.0.1 software and follows the guidelines of the ISO 14040 standard [8]. 2.1 General Approach The study adopts a cradle-to-grave approach, considering all stages from raw material extraction, fuel production, transportation, and final use in the engine. The analysis is focused on environmental impacts, using a causality-based model that quantifies the relationship between inputs and outputs of each system. 2.2 Goal and Scope Definition The main goal is to evaluate and compare the environmental impacts of a light-duty vehicle operating with diesel and jatropha biodiesel. The functional unit is defined as 1,000 km traveled, ensuring a fair comparison between the two fuels. Based on average consumption rates—10 km/L for diesel and 9 km/L for jatropha biodiesel—the reference flows are 100 L of diesel and 111.1 L of biodiesel [9](Table 1). Table 1 Scope Summary Fuel Diesel Biodiesel Function To run a light vehicle Functional Unit 1,000 km Performance 10 km/L 9 km/L Reference Flow 100 L 111.1 L The table shows the reference flows for diesel and jatropha biodiesel to cover the functional unit of 1,000 km with a light-duty vehicle. Diesel requires 100 liters, while biodiesel needs 111.1 liters due to its lower fuel efficiency (9 km/L compared to 10 km/L). These values establish the basis for comparing environmental impacts in life cycle assessment. 2.3 Inventory Analysis The inventory was built using data from the Ecoinvent database and complemented with bibliographic sources. The modeling in SimaPro involved defining unit processes, entering input/output flows, and quantifying emissions and resource use. 2.3.1 CO₂ Balance A CO₂ balance was performed to account for carbon sequestration during jatropha cultivation. According to Wani et al. [10], a plantation of Jatropha curcas can sequester approximately 5,323 kg of CO₂ per hectare per year. For the required seed production, this results in a sequestration of 3,792 kg of CO₂ over four years, which was subtracted from the total emissions of the biodiesel system. The CO₂ balance was calculated by Equation 1. Equation (1): 𝐶𝑂₂𝑡𝑜𝑡𝑎𝑙 = 𝛴(𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑠 𝑜𝑓 𝐶𝑂₂) − (𝐶𝑂₂𝑠𝑒𝑞𝑢𝑒𝑠𝑡𝑟𝑒𝑑 ) Where: World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1418 CO₂total - Total CO₂ released to the environment Emissions of CO₂ - Sum of CO₂ emissions from all processes CO₂ sequestered - Amount of CO₂ captured by Jatropha cultivation This equation ensures that the net CO₂ impact accounts for both emissions and sequestration. 2.3.2 Global Warming Potential (GWP) GWP measures the relative contribution of a greenhouse gas to global warming compared to CO₂. Equation (2): 𝐺𝑊𝑃𝑖=∫𝑎𝑖𝑐𝑖(𝑡)𝑑𝑡 𝑇 0 ∫𝑎𝐶𝑂2𝑐𝐶𝑂2(𝑡)𝑑𝑡 𝑇 0 [𝐶𝑂2 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: GWPi - Global Warming Potential of substance I. ai - Radiative efficiency of gas I. ci(t) - Concentration of gas i over time. T - Time horizon. aCO₂ - Radiative efficiency of CO₂. cCO₂(t) - Concentration of CO₂ over time. This ratio compares the warming effect of a gas to that of CO₂ over a specified time horizon. 2.3.3 Ozone Depletion Potential (ODP) ODP expresses the relative impact of a substance on ozone layer depletion compared to CFC-11. Equation (3): 𝑂𝐷𝑃𝑖=𝛿[𝑂3]𝑖 𝛿[𝑂3]𝐶𝐹𝐶−11 [𝐶𝐹𝐶−11 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: ODPi - Ozone Depletion Potential of substance I. δ[O₃]I - Change in ozone column due to substance I. δ[O₃]CFC-11 - Change in ozone column due to CFC-11 Equation (4): Ozone Depletion=∑𝑂𝐷𝑃𝑖×𝑚𝑖𝑖 [𝑘𝑔 𝑑𝑒 𝐶𝐹𝐶− 11 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] This equation quantifies the potential of a substance depleting ozone layer relative to CFC-11. 2.3.4 Acidification Potential (AP) AP measures the potential of substances to cause acid deposition compared to SO₂. Equation (5): 𝐴𝑃𝑖=𝑣𝑖𝑀𝑖 ⁄ 𝑣𝑆𝑂2 𝑀𝑆𝑂2 ⁄ [𝑆𝑂2 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: APi - Acidification Potential of substance I. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1419 vi - H⁺ equivalent of substance I. Mi - Mass of substance I. vSO₂ - H⁺ equivalent of SO₂. MSO₂ - Mass of SO₂. 𝐴𝑐𝑖𝑑𝑖𝑐𝑎çã𝑜=∑𝐴𝑃𝑖×𝑚𝑖 𝑖 [𝑘𝑔 𝑑𝑒 𝑆𝑂2 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] This equation expresses acidification potential relative to SO₂ as a reference substance. 2.3.5 Eutrophication Potential (NP) NP indicates the potential of substances to enrich water or soil with nutrients, causing ecological imbalance. Equation (6): 𝑁𝑃𝑖=𝑣𝑖𝑀𝑖 ⁄ 𝑣𝑃𝑂4 3− 𝑀𝑃𝑂4 3− ⁄ [𝑁 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: NPi - Eutrophication Potential of substance I. vi - Biomass potential in N equivalents. Mi - Mass of substance I. v_PO₄³⁻ Biomass potential of phosphate. MPO₄³⁻ - Mass of phosphate. Equation (7): Eutrophication=∑𝑁𝑃𝑖×𝑚𝑖𝑖 [𝑘𝑔 𝑑𝑒 𝑁 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: 𝑚𝑖 is the mass of the substance (i) This equation compares nutrient enrichment potential to phosphate as a reference. 2.3.6 Ionizing Radiation Potential (IRP) IRP measures the potential impact of radioactive emissions relative to Cobalt-60. Equation (8): 𝐼𝑅𝑃 =𝐶𝐷𝑥,𝑖 𝐶𝐷𝑐𝑜−60,𝑎𝑖𝑟 [𝐶𝑜−60 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: IRPi - Ionizing Radiation Potential of substance I. CD(x,i) - Collective dose from substance I. CD(Co-60,air) - Collective dose from Co-60 in air. Thus, ionizing radiation is defined by the following expression: Equation (9): Ionizing Radiation=∑𝐼𝑅𝑃𝑖×𝑚𝑖𝑖 [𝑘𝑔 𝑑𝑒 𝐶𝑜−60 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: m-i. is the amount of the substance emitted in kg. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1420 This equation expresses radiation potential in terms of Co-60 equivalents. 2.3.7 Particulate Matter Formation Potential (PMFP) PMFP indicates the potential of substances to form fine particulate matter (PM2.5). Equation (10): 𝑃𝑀𝐹𝑃𝑥,𝑖 =𝑖𝐹𝑥,𝑖 𝑖𝐹𝑃𝑀2,5,𝑤𝑜𝑟𝑙𝑑 [𝑃𝑀2,5 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: PMFP(x,i) - Particulate Matter Formation Potential of substance I. iF(x,i) - Inhalation factor for substance I. iF(PM2.5,world) - Global average inhalation factor for PM2.5. This equation compares particulate formation potential to global PM2.5 standards. 2.3.8 Land Use Impact This category evaluates species loss due to land occupation compared to annual crop production. Equation (11): 𝐹𝐶𝑚𝑜𝑐𝑐,𝑥 =𝑆𝑟𝑒𝑙,𝑥 𝑆𝑟𝑒𝑙,𝑎𝑛𝑛𝑢𝑎𝑙𝑐𝑟𝑜𝑝 [𝑐𝑟𝑜𝑝 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: FCm(occ,x) - Characterization factor for land occupation. S(rel,x) - Relative species loss for land use type x. S(rel,annualcrop) - Relative species loss for annual crop production. This equation expresses land use impact in crop-equivalent terms. According to ReCipe [11] the factor Srel,x. is calculated by comparing field data on the richness of local species in specific types of natural and artificial land covers, using the linear relationship described by Köllner et al [12]: Equation (12): 𝑆𝑟𝑒𝑙,𝑥 =1−𝑆𝐿𝑈,𝑥,𝑖 𝑆𝑟𝑒𝑓,𝑖 Where: SLU,x,i – It is the number of species observed under the type of land use (x). Sref,i. – It is the number of species observed from the reference land cover in the region (i). 2.3.9 Fossil Resource Depletion This category measures depletion based on cumulative energy demand compared to crude oil. Equation (13): 𝐶𝐹𝑚𝑖𝑑𝑝𝑜𝑖𝑛𝑡,𝑖 =𝐶𝐸𝐷𝑖 𝐶𝐸𝐷𝑟𝑒𝑓 Where: CFmidpoint,I - Characterization factor for fossil resource I. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1421 CEDi - Cumulative energy demand of resource I. CEDref - Cumulative energy demand of reference crude oil. 2.3.10 Mineral Resource Depletion This category evaluates scarcity based on Surplus Ore Potential - SOP compared to copper. Equation (14): 𝑆𝑂𝑃𝑥,𝑅 =𝐴𝑆𝑂𝑃𝑥,𝑅 𝐴𝑆𝑂𝑃𝐶𝑢,𝑅 [𝑘𝑔 𝑑𝑒 𝐶𝑢 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: SOPx,R - Surplus Ore Potential for mineral x. ASOPx,R - Absolute Surplus Ore Potential for mineral x. ASOP Cu,R - Absolute Surplus Ore Potential for copper. The impact of the scarcity of mineral resources is obtained through the following expression: Equation (15): 𝑀𝑖𝑛𝑒𝑟𝑎𝑙 𝑟𝑒𝑠𝑜𝑢𝑟𝑐𝑒 𝑑𝑒𝑝𝑙𝑒𝑡𝑖𝑜𝑛=∑𝑆𝑂𝑃𝑥,𝑅𝑥 [𝑘𝑔 𝑑𝑒 𝐶𝑢 𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡] Where: SOPx,R. is the Surplus Ore Potential of an (x) in a reserve (R). 2.3.11 Water Consumption This category measures the total amount of water consumed. Equation (16): 𝐹𝐶 ={ 1 𝑖𝑓 𝑡ℎ𝑒 𝑖𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦 𝑖𝑠 𝑖𝑛 𝑚3 𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑟𝑎𝑡𝑒 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟, 𝑖𝑓 𝑖𝑛𝑣𝑒𝑛𝑡𝑜𝑟𝑦 𝑖𝑠 𝑖𝑛 𝑚3 𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 Where: FC - Characterization factor for water consumption. This equation indicates that water consumption is directly proportional to the volume consumed. 2.4 Impact Assessment Method The ReCiPe 2016 method was selected for impact assessment due to its robustness and integration of midpoint and endpoint approaches [13]. The midpoint approach identifies potential impacts (e.g., global warming, acidification), while the endpoint approach quantifies final damage to areas of protection such as human health, ecosystems, and resource availability. ReCiPe includes 18 impact categories, which were grouped into 12 general categories for this study. Mathematical models and characterization factors were applied to calculate the environmental burdens of each system [14]. 3 Results and discussion This section shows the results from a Life Cycle Assessment (LCA) comparing diesel and jatropha biodiesel in internal combustion engines and discusses their environmental impacts. The study used the ReCiPe 2016 method, applying both midpoint and endpoint approaches. The analysis is based on a functional unit of a light-duty vehicle traveling 1,000 kilometers. 3.1 Environmental Impact Comparison The ReCiPe midpoint results revealed significant differences between the two fuel systems across multiple impact categories. The diesel system showed higher values in global warming potential, acidification, particulate matter World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1422 formation, and fossil resource depletion, while the jatropha biodiesel system had greater impacts in land use, water consumption, and eutrophication due to agricultural activities. In terms of global warming, jatropha biodiesel demonstrated a net negative CO₂ emission due to carbon sequestration during cultivation, resulting in a 100% reduction compared to diesel [15]. This highlights its potential to mitigate climate change when managed sustainably. 3.2 Damage to Human Health Using the endpoint approach, the damage to human health was quantified in DALY (Disability-Adjusted Life Years). Diesel use contributed more significantly to respiratory diseases due to higher emissions of PM2.5 and NOx. Jatropha biodiesel, although cleaner in combustion, showed increased water-related health risks due to irrigation demands [16] as shown in Figure 1. Figure 1 Results of damage to human health Figure 1 shows that jatropha biodiesel emits fewer greenhouse gases and fine particles than diesel, reducing global warming and health risks. Both fuels have similar carcinogenic toxin impacts, though diesel is slightly worse due to higher emissions of certain compounds. Biodiesel production, however, demands significant water, affecting local potable water access, while diesel does not have notable impacts in this area. Neither fuel substantially affects ozone depletion, ionizing radiation, or ozone formation. Key impact categories for comparison are global warming, particulate matter, carcinogenic toxins, and water consumption. 3.3 Ecosystem Quality As presented in figure 2, the diesel system caused greater harm to ecosystems through acid rain and ozone formation. However, jatropha cultivation led to land transformation and nutrient runoff, affecting biodiversity in freshwater systems. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1423 Figure 2 Comparison of impact on ecosystem quality Figure 2 shows also that Jatropha biodiesel can reduce global warming and particulate pollution compared to diesel, but it uses more water and causes higher eutrophication due to fertilizer use. The key trade-off is between environmental benefits and increased resource consumption. 3.4 Resource Depletion Diesel showed a significantly higher impact in fossil fuel depletion, as expected, while jatropha biodiesel had moderate contributions due to fossil fuel use in transportation and processing stages (Figure 3). Figure 3 Comparison of impact of resource depletion Figure 3 shows that fossil fuel depletion is significantly higher for the diesel engine (≈202 USD2013) compared to the biodiesel engine (≈44.2 USD2013), highlighting diesel’s strong dependence on non-renewable resources. On the other hand, for mineral resource depletion, both systems present low values, but diesel is still higher (≈3.37 USD2013 versus 0.694 USD2013 for biodiesel). These results indicate that replacing diesel with jatropha biodiesel substantially reduces pressure on fossil fuels, although the impact on minerals remains relatively minor for both cases. In other hand, the mineral resource depletion was slightly higher for diesel due to refinery inputs, the finding was reached by Gmünder [17]. World Journal of Advanced Research and Reviews, 2025, 28(02), 1416–1426 1424 3.5 Overall Environmental Score The overall results after normalization are presented in figure 4. Figure 4 Overall Environmental Score Picture 4 shows the comparison of the normalized and weighted environmental impacts of diesel engines and jatropha biodiesel engines across multiple categories. The most striking difference is in global warming, where jatropha biodiesel shows a negative value due to carbon sequestration during cultivation, while diesel exhibits a significant positive impact. This reinforces biodiesel’s potential to mitigate climate change. In contrast, water consumption and land use are considerably higher for biodiesel, reflecting the agricultural requirements of jatropha cultivation. Diesel, on the other hand, shows negligible impact in these categories. For human health damage from particulate formation, diesel is more than twice as harmful compared to biodiesel, indicating greater respiratory risk from fossil fuel combustion. Both fuels have similar values for carcinogenic toxins, though biodiesel is slightly higher for non-carcinogenic toxins. When considering the Overall Environmental Score, diesel totals 92.47 points, while jatropha biodiesel scores 59.49 points, representing a 37% reduction in overall environmental impact when switching to biodiesel. This suggests that, despite trade-offs in water and land use, jatropha biodiesel offers significant environmental benefits, particularly in climate change mitigation and air quality improvement [19]. 3.6 Economic Considerations Considering the production efficiency of both fuels at 35%, the results of economic analysis are presented in Figure 5. Figure 5 shows that Jatropha Biodiesel is more expensive and less energy-efficient than Diesel. Its higher cost (USD 2.03/L vs. USD 1.36/L), lower energy density (37 MJ/L vs. 43 MJ/L), and greater consumption for the same distance result in a higher overall cost. These disadvantages limit its competitiveness without policy support or technological improvements. It is observed that, despite its environmental benefits, jatropha biodiesel incurs a 42.7% higher cost per unit of useful energy relative to conventional diesel in concordance with approach of Raizen [20,21].