Life Cycle Analysis (LCA) of Hydrogen Boosted Biomethanization with Alternative Power Scenarios

doi:10.21203/rs.3.rs-6923416/v1

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Life Cycle Analysis (LCA) of Hydrogen Boosted Biomethanization with Alternative Power Scenarios

https://doi.org/10.21203/rs.3.rs-6923416/v1

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published 05 Nov, 2025

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This study aimed to assess the environmental impacts of biogas-to-biomethane conversion using ex-situ (hydrogenotrophic) methods, with hydrogen (H₂) sourced from alternative production lines, electricity from the national grid (base scenario), solar power via photovoltaic panels (scenario 1), and wind power (scenario 2). Life Cycle Analysis (LCA) was conducted for scenarios using different energy sources for H₂ production. The results were evaluated using the impact assessment method ReCiPe 2016 Midpoint (H) V.1.02, considering 18 impact categories. A model was developed based on production data from a real biogas plant in İzmir, where activity data were obtained directly from the plant's logs. The LCA analysis revealed that hydrogen production from grid electricity resulted in 10.3 kg CO₂ eq in the climate change category, which decreased to 1.27 kg CO₂ eq when using solar energy. The overall carbon footprint decreased from 8.66 kg CO₂ eq to -0.494 kg CO₂ eq. In the second scenario, hydrogen was produced using wind energy rather than grid electricity. The analysis showed that hydrogen production from grid electricity resulted in 10.3 kg CO₂ eq in the climate change category, while using wind energy reduced this to 0.199 kg CO₂ eq. According to the LCA results, energy sources and electricity demand play a crucial role in determining GHG emissions, and the LCA can assist companies and governments in decision-making and policy development.

Hydrogenotrophic biomethanization

impact categories

solar energy

wind energy

biogas

life cycle analysis

Carbon dioxide (CO₂) is one of the most important greenhouse gases in the atmosphere contributing to global warming (Blamey et al., 2010; Mikkelsen et al., 2010). In the last fifty years, CO₂ concentration in the atmosphere has significantly escalated from about 310 ppm to more than 419 ppm due to the overuse of fossil fuels and other gases (e.g. SF₆) used for cooling processes (Hu et al., 2016; Lackner et al. 2012rhodes; Yu et al., 2008). As a result of this negative effect, the EU European Green Deal goals followed by the Paris Climate Agreement have sparked global actions to develop and initiate new technologies for the reduction of carbon dioxide emissions to combat global warming (Wu et al. 2024; He et al., 2016; Jacobson, 2009; Obergassel et al., 2016; Wang et al., 2011). At the 21st conference on global warming, a significant agreement (the Paris Agreement) was established to limit the increase in global average temperature to 2.0°C by 2100 (Rhodes, 2016). To achieve this target, carbon dioxide emissions from energy and industry should be substantially reduced after 2030 and reach a net-zero level between 2050 and 2060 (Rogelj et al., 2016).

Carbon capture, which involves removing carbon dioxide either before it is released into the atmosphere, through post-capture physical-chemical or biological processes, or via direct capture from the atmosphere, plays a crucial role in achieving zero and/or negative carbon dioxide emission goals (Buckingham et al. 2022). In addition to chemical methods, biological carbon capture and utilization technologies are also presented as a solution (Hanson et al. 2025). Technologies for carbon capture, utilization, and storage have become essential parts of the endeavor to lower CO₂ emissions. In order to stop CO₂ from being released into the environment, these technologies are made to directly capture it from emission sources such power plants and industrial facilities (Yaashikaa et al., 2023). Captured CO₂ can be used for a variety of purposes, including better oil recovery and chemical synthesis, or it can be stored in deep geological formations. The conversion of CO₂ to biomethane due to upgrade biogas through biomethanization technology is a promising approach from a biological perspective. Microorganisms act as catalysts in biological upgrading processes, converting carbon dioxide into hydrogen and methane in this process (Kim et al. 2013; Munoz et al. 2015; Azbar et al. 2021; Pierroa et al. 2023; Daglıoglu et al. 2021; Chatzis et al.2024). Ex-situ biogas upgrading involves the introduction of CO₂ (from sources such as biogas, syngas, etc.) and H₂ from external sources into the liquid phase of a reactor containing hydrogenotrophic microbes. These microbes then convert the CO₂ and H₂ into CH₄ through a biological process (Kapoor et al., 2019). The most challenging aspect of biomethane production is the issue of hydrogen production and the hydrogen source is typically electrolysis. This is because energy is required to produce the hydrogen needed for the archaea to use. Several studies have reported that the energy source for this process must come from renewable sources, otherwise the biomethane produced will not be meaningful in terms of environmental impact (Sieborg et al. 2024).

The life cycle assessment (LCA) approach has been considered a method to identify environmental impacts and make biomethane production more environmentally friendly. LCA has been used to compare the environmental impacts of upgrading the produced biogas to biomethane or its direct use (Ardolino et al., 2021). In the literature, various biogas upgrading techniques have been analyzed through LCA. These LCA studies have typically concentrated on the more widely used physical and chemical methods, such as membrane separation, water scrubbing, chemical absorption, and pressure swing adsorption (Ardolino et al., 2021, Lorenzi et al., 2018). There is a lack of comprehensive information comparing in-situ and ex-situ biogas upgrading systems based on case studies (Antukh et al. 2022). Collet et al. (2017) conducted a life cycle assessment (LCA) and techno-economic assessment of biological upgrading. Jentsch et al. (2011), however, focused exclusively on greenhouse gas (GHG) emissions in the context of biological upgrading. Additional studies on LCA as a tool for evaluating biogas upgrading through the hydrogenotrophic biogas methanation method could help in the development of cost-effective and highly efficient biogas upgrading technologies for CH₄ production (Antukh et al. 2022).

This study assesses the environmental impacts of upgrading biogas to biomethane via the hydrogenotrophic method, using a life cycle assessment (LCA) approach. Hydrogen for the process is modeled as being produced through electrolysis. In the base scenario, electrolysis relies on fossil fuels, while two alternative scenarios use wind and solar energy. The study compares these scenarios, quantifying the impacts of renewable energy on greenhouse gas (GHG) emissions and 17 other impact categories. As both a case study and a novel contribution, this work evaluates 18 impact categories for ex-situ biogas-to-biomethane conversion, providing comprehensive insights into its environmental performance.

According to the ISO standards, Life Cycle Assessment (LCA) consists of several interconnected components: (i) goal and scope definition; (ii) inventory analysis; (iii) impact assessment; and (iv) interpretation of results, which involves explaining conclusions and providing recommendations.

2.1. Aim and scope

The aim of this study is to compare the environmental impacts of different electricity sources used in the production of 1 m³ of biomethane. The scope of the study includes the upgrading of gas containing 30–40% CO₂, emitted from a biogas flare, to biomethane via the ex-situ biological biomethane upgrading method. In the hydrogen production step within this process, grid electricity is used in the base scenario. In Scenarios 1 and 2, the electricity for electrolysis comes from wind and solar energy sources, respectively. These scenarios were analyzed and compared with the base scenario (Fig. 1).

According to this model, H₂ gas was produced by electrolysis. The modeled reactor is a UASB reactor operating under mesophilic conditions and filled with rings called Moving Bed Biofilm Reactor (MBBR). Since there is no trace element supplementation, circulation, pump, etc. in the model, these inputs are not included in the data inventory. The daily output data of a real biogas plant with 70% methane content was used and modeled with an ex-situ UASB reactor with biomethane content of 95% and above. The amount of H₂ required for the process was calculated according to these values. In the other two scenarios considered in the study, solar and wind energy were compared for electrolysis energy (Fig. 1).

2.2 Inventory analysis

Turkey's biogas potential of cattle manure 107.8 PJ/year, biogas potential of chicken manure 36.5 PJ/year, while the biogas potential of agricultural waste 305.3 PJ/year that was reported (Salihoglu et al. 2018). There are 106 biogas plants in Turkey and it is estimated that 12.7 million tons of digestate is produced. Apart from this, literature studies were referenced for the data that could not be obtained from the biogas plant (Table 1).

Table 1
Some production values from the biogas plant
Biogas production	Explanation	Daily
The Total amount and content of gas coming out of the chimney	Calculated with 30% CO₂ value	8568 m³/day
The total amount and content of gas coming out of the chimney	Calculated with 1–2% H₂S value	428,4 m³/day
Biogas production		28560 m³/day

The chemical composition of the biogas produced in the plant owned by a private company is 30% CO₂, 68% CH₄ and 1–2% H₂S. The daily biogas output is 28560 m³/day. The amount produced per unit of time is approximately 1190 m³/hour. The amount of carbon dioxide gas in the biogas is 8568 CO₂ m³/day (28560 m³/day * 30%). The required amount of H₂ is 34272 H₂ m³/day (8568 CO₂ m³/day x 4; 1 mole of carbon and 4 moles of hydrogen are required as the carbon source needed for CH₄ production).

According to the calculations, 2618 m³ of gas enters the biomethane reactor per hour and the electrolyser data used in the model are given in Table 2.

Table 2
Values of the electrolyser used in the model (Johnsen et al. 2023)
Electrifier	Components	Amount	Unit
Input	Water	220	kg/hour
Output	Hydrogen	200	Nm³/ hour
Output	Oxygen	100	Nm³/ hour

The amount of hydrogen to be produced with the help of the electriser device is 1428 m³/hour. The value of the required water and oxygen output from the system was adapted to our system by taking 220 kg/hour water consumption as a reference for 200 m³/hour hydrogen gas production and the calculated value was determined as 1570,8 kg/hour water consumption. As a result of the electroreduction process, 714 m³/h oxygen gas was produced.

2.3. Impact assessment

SimaPro 9.4.0.3 software was used for impact analysis. Research findings were obtained by considering 18 impact categories for functional units (1 m³ biomethane). The impact assessment was performed with ReCiPe 2016 Midpoint (H) V.1.02 (Mohammad et al., 2012; Moreno et al., 2020). Impact categories analysed; Global warming (kg CO₂ eq), Ozone depletion (kg CFC-11), Terrestrial acidification (kg SO₂ eq), Freshwater eutrophication (kg P eq), Marine eutrophication (kg N eq), Photochemical oxidation (kg NMVOC) Particulate matter formation (kg PM10 eq), Terrestrial ecotoxicity (kg 1,4-DB), Freshwater ecotoxicity (kg 1,4-DB), Marine ecotoxicity (kg 1, 4-DB ), Ionising radiation (kBq U235 ), Agricultural land use (m²a), Urban land use (m²a) Natural land conversion (m²), Loss of water resources (m³), Metal depletion (kg Fe) and Fossil fuel depletion (kg oil eq), Human toxicity including carcinogens and non-carcinogens (1,4-DB eq)' (Niloofar et al., 2021).

2.4 Interpretion

In this step, the impact categories were discussed, and the primary factors contributing to the increase in impacts and damages were analyzed. Recommendations for improving or modifying the situation from an LCA perspective were provided in discussion part.

3.1. Life cycle analysis of base-scenerio

The base scenario of this study involves the hydrogenotrophic upgrading of biogas from a biogas plant in an ex-situ reactor, while the hydrogen required for the process is obtained through electrolysis powered by grid electricity. There are 18 impact categories analyzed in the LCA. Firstly, when the GWP analysis is examined, the GWP effect of 1 m³ of biometane produced in the base scenario is calculated as 8.66 kg CO₂ eq. The most significant emission in this life cycle analysis, 10.3 kg CO2 eq, comes from hydrogen production, i.e., from electrolysis. It can be said that the impact here is due to the grid, i.e., fossil-based electricity consumption (440 grCO₂/kWh in Turkiye). Instead of releasing the residual CO₂ into the air, carbon dioxide is used as a nutrient source in a second reactor established in the plant in the process of converting biomethane, which is a renewable energy source, with hydrogenotrophic microbiota. As a result of the analysis, the prevention of carbon dioxide release into the air during the conversion of biogas to biomethane with 95% content is 1.98 kg CO₂ eq per 1 m³ biomethane functional unit.

Among the impact categories considered other than climate change, Ozone depletion 1.99E^− 7 kg CFC-11 eq, Terrestrial acidification 0.0521 kg SO₂ eq, Freshwater eutrophication 0.0108 kg P eq, Marine eutrophication 0.0024 kg N eq, Human toxicity 6.9 kg 1,4-DB eq Photochemical oxidation 0.0287 kg NMVOC, Particulate matter formation 0.0885 kg PM10 eq, Terrestrial ecotoxicity 0, 000274 kg 1,4-DB eq, Freshwater ecotoxicity 0,244 kg 1,4-DB eq, Marine ecotoxicity 0,222 kg 1,4-DB eq, Ionising radiation 0,0917 kBq U235 eq, Agricultural land use 0,117 m²a, Urban land use 0.0444 m²a, Natural land conversion 0.000686 m², Loss of water resources 0.0796 m³, Metal depletion 0.104 kg Fe eq and Fossil fuel depletion 2.71 kg oil eq. The impact categories in biomethane produced from hydrogen from electrolysis using fossil-derived grid energy and residual carbon dioxide from the plant are shown in Fig. 2.

When analyzing the 18 impact categories, it is evident that the electrolysis process represents the most significant source of emissions across all categories. In the terrestrial ecosystem, categories such as ozone depletion, agricultural and land use, water depletion, and metal depletion revealed the environmental impacts associated with biogas production.

3.2 Comparison of scenarios

Since the production of electrolysis with fossil fuel-based grid electricity is the most significant source of emissions, wind and solar energy have been selected as the energy sources for electrolysis in this section.

Solar energy

As a result of the analysis, hydrogen production from grid electricity resulted in 10.3 kg CO₂ eq in terms of Global Warming Potential (GWP), which decreased to 1.27 kg CO₂ eq when solar energy was utilized. The total carbon footprint was reduced from 8.66 kg CO₂ eq to -0.494 kg CO₂ eq. The analysis of the carbon footprint in the solar energy-based hydrogen production scenario indicates that the processed aluminum and silicon used in photovoltaic panels have a significant impact.

The results of the analysis of the impact categories other than climate change are; Ozone depletion 1.41E-7 kg CFC-11 eq, Terrestrial acidification 0.00664 kg SO₂ eq, Freshwater and marine eutrophication 0.000661 kg P eq and 0.000441 kg N eq respectively, Human toxicity 1.04 kg 1.4-DB eq, Photochemical oxidation 0.00524 kg NMVOC, Particulate matter formation 0.0034 kg PM10 eq. Terrestrial, freshwater and marine ecotoxicity was determined as 0.00232 kg 1,4-DB eq, 0.182 kg 1,4-DB eq and 0.168 kg 1,4-DB eq, respectively. Ionising radiation 0,11 kBq U235 eq, Agricultural land use 0,0578 m²a, Urban land use 0,63 m²a, Natural land transformation 0,000212 m², Loss of water resources 0,0427 m³, Metal depletion 0,295 kg Fe eq, Fossil fuel depletion 0,346 kg oil eq. The categories considered for biomethane production using solar energy are given in Fig. 3.

Based on the impact category analysis, it was found that the environmental impacts of hydrogen production were reduced when solar energy was used instead of grid electricity, compared to the baseline scenario. A comparison of the environmental impacts of grid and solar energy on hydrogen production reveals that grid electricity has a more negative impact across all 14 categories (Fig. 4). Notably, the use of solar energy results in an increased negative impact in certain categories, such as urban land use, which rises from 0.0444 m²a to 0.63 m²a, ionizing radiation, which increases from 0.0917 kBq U235 eq to 0.11 kBq U235 eq, metal depletion, which escalates from 0.104 kg Fe eq to 0.295 kg Fe eq, and ozone depletion, where the impact rises from 1.99E-7 kg CFC-11 eq to 1.41E-7 kg CFC-11 eq.

Wind energy

In the second scenario, instead of drawing the energy required for hydrogenotrophic biomethane production from the grid, it was tried to produce hydrogen using wind energy. As a result of the analysis; while hydrogen production from grid electricity was 10.3 kg eq in the climate change category (GWP), it was reduced to 0.199 kg CO₂ eq with the use of wind energy. The total carbon footprint decreased from 8.66 kg CO₂ eq to -1.57 kg CO₂ eq. Another important results is that when the effects in the tree diagram are followed, the numerical effects of steel and iron used in wind turbines are revealed (Fig. 4).

Ozone depletion 1.43E-8 kg CFC-11 eq, Terrestrial acidification 0.000975 kg SO₂ eq, Freshwater eutrophication 9,38E-5 kg P eq, Marine eutrophication 6.99E-5 kg N eq, Human toxicity 0.153 kg 1,4-DB eq. Photochemical oxidation 0.00095 kg NMVOC, Particulate matter formation 0.000682 kg PM10 eq, Terrestrial ecotoxicity 3.23E-5 kg 1,4-DB eq, Freshwater ecotoxicity 0.0624 kg 1,4-DB eq, Marine ecotoxicity 0.0547 kg 1,4-DB eq, Ionising radiation 0.0135 kBq U235 eq. Agricultural, Urban and Natural land use is 0.00562 m²a, 0.0188 m²a and 3.4E-5 m² respectively. Loss of water resources is 0.00573 m³, metal and fossil fuel depletion is 0.149 kg Fe eq and 0.0578 kg oil eq respectively. The impact categories analysed in the process of biomethane production using wind energy are given in Fig. 4.

When biomethane production using wind energy was analysed, almost all of the environmental impacts were effective on hydrogen production in eighteen impact categories (Fig. 3). In the climate change impact category, there is a positive effect of biogas production. The use of wind energy reduces the environmental impacts of hydrogen production in the categories analysed. Compared to the baseline scenario of grid electricity, a negative increase in the environmental impact from 0.104 kg Fe eq to 0.149 kg Fe eq was determined only in the category of Metal toxicity in the use of wind energy. When the environmental impacts of hydrogen production using grid and wind energy are compared, it can be said that the environmental impacts of grid energy are more negative in 17 categories. In the use of wind energy, it was determined that it had a more negative impact, especially in the Metal depletion category, increasing from 0.104 kg Fe eq to 0.149 kg Fe eq (Table 3).

Table 3
Comparison of scenarios according to impact categories
Impact Categories	Mains Energy	Solar Energy	Wind Energy
Climate change.	8.66	-0.494	-1.57
Ozone depletion	2.08E-07	1.45E-07	1.84E-08
Terrestial acidification	0.0535	0.00771	0.00204
Freshwater eutrophication	0.011	0.000882	0.000315
Marine eutrohication	0.00333	0.000507	0.000136
Human toxicity	7.07	1.19	0.294
Photochemical oxidant formator	0.0295	0.00583	0.00154
Particulate matter formation.	0.0905	0.00521	0.00249
Terestial ecotoxicity	0.0003	0.00233	3.79E-05
Freshwater ecotoxicity	0.25	0.187	0.0674
Marine ecotoxicity	0.228	0.172	0.0592
Ionising radiation	0.0945	0.112	0.0154
Agricultural land occupation	0.126	0.0602	0.00803
Urban land occupation	0.0478	0.631	0.0197
Natural land occupation	0.000713	0.000226	4.81E-05
Water depletion	0.0822	0.0442	0.00729
Metal depletion	0.112	0.298	0.151
Fossil depletion	2.78	0.401	0.113

A percentage comparison of the environmental impacts of solar and wind energy is given in Table 4.

Table 4
Percentage comparison of environmental impacts of solar and wind energy
Impact Categories	Solar Energy	Wind Energy
Climate change.	-105.70	-118.13
Ozone depletion	-30.29	-91.15
Terrestial acidification	-85.59	-96.19
Freshwater eutrophication	-91.98	-97.14
Marine eutrohication	-84.77	-95.92
Human toxicity	-83.17	-95.84
Photochemical oxidant formator	-80.24	-94.78
Particulate matter formation.	-94.24	-97.25
Terestial ecotoxicity	676.67	-87.37
Freshwater ecotoxicity	-25.20	-73.04
Marine ecotoxicity	-24.56	-74.04
Ionising radiation	18.52	-83.70
Agricultural land occupation	-52.22	-93.63
Urban land occupation	1220.08	-58.79
Natural land occupation	-68.30	-93.25
Water depletion	-46.23	-91.13
Metal depletion	166.07	34.82
Fossil depletion	-85.58	-95.94

The use of solar and wind instead of grid energy reduced the total carbon footprint by 105.7% and 118.13% respectively. When the other impact categories were analysed, it was determined that the use of solar energy instead of grid energy increased the environmental impact of urban land use by 1220%, terrestrial ecotoxicity by 676.67%, metal toxicity by 166.07% and ionising radiation by 18.52%. In the use of wind energy, it was determined that only metal toxicity increased by 34.82% out of eighteen impact categories.

This study presents the environmental impacts through a life cycle analysis of the biological upgrading system. There are numerous reviews of chemical/physical biogas upgrading projects and demonstration plants. However, biological upgrading technology is still at an early stage of development and there is limited information on large-scale field studies (Vartiainen, 2016; Ahmadi, 2017; Bailera et al., 2017; Thema et al., 2019).

This is one of the reasons why there is very little research on the Life Cycle Assessment (LCA) of biological biogas upgrading studies. A study conducted in existing facilities in Italy measured the environmental and economic aspects of biogas upgrading technologies such as membrane separation, water washing, chemical absorption with amine solvents, and pressure swing adsorption from a life cycle perspective. In particular, the membrane separation technique shows significant improvements in global warming potential (up to 7%, i.e., up to 344 tCO₂eq/year). This technique demonstrates the most significant improvements in base case scenarios for Respiratory Inorganics Potential (ranging from 1–34%, i.e., from 8.4 kg PM2.5 eq/year to 328 kg PM2.5 eq/year), alongside enhanced performance in GWP (ranging from 2–7%, i.e., from approximately 101 tCO₂eq/year to 344 tCO₂eq/year). In contrast, pressure swing adsorption exhibits poorer performance across all examined categories, primarily due to the consumption of activated carbon and zeolite (Ardolino et al. 2021). In another study, the biogas upgrading process was carried out using the high-temperature electrolysis method in Solid Oxide Electrolyser Cells (SOECs). The study revealed that the Global Warming Potential (GWP) of the biogas upgrading routes exceeds that of fossil gas production, even with very high shares of renewable electricity. While renewable electricity shares are below 80%, the high specific energy consumption of the SOEC-based plant results in higher impacts across all categories, despite the higher methane yield. Therefore, the availability of zero-carbon electricity is crucial for this route to be favored over separation processes (Lorenzi et al. 2019). In a similar study, Liu et al. approached the energy balance by calculating the energy consumption during H₂ electrolysis as 622 MJ, while the energy content of the produced methane was calculated as 14 MJ, and the net energy as -608 MJ (Liu et al., 2013). This issue was examined and presented in terms of global warming potential in this study. In scenarios where electrolysis was powered 100% by wind and 100% by solar energy, the study showed that negative global warming potential values were achieved, and the produced methane became meaningful.

Elyasi et al. (2021) compared biological upgrading technologies with water scrubbing. In their scenario, ex-situ biological biogas upgrading is implemented in a trickle bed filter reactor (TBFR) operating at 55°C, with the outlet gas containing 98.5% CH₄. The hydrogen production in the electrolyzer unit is powered by surplus wind energy. The results showed that biological biogas upgrading can have better environmental impacts than water scrubbing in three endpoint damage categories: Human Health, Climate Change, and Resources. However, in the Ecosystem Quality damage category, water scrubbing outperformed biological upgrading. The induced impact caused by the water scrubbing unit was estimated at 351 t CO₂ eq/FU, while the biological upgrading unit's impact amounted to 43.7 t CO₂ eq/FU. The difference observed between the two upgrading facilities arises from the higher methane leakage and electricity consumption in the water scrubbing unit compared to the biological biogas upgrading reactor with a functional unit (FU) of 1 t upgraded biomethane (Elyasi et al., 2021). In another study; three upgrading scenarios were assessed: amine scrubbing, amine scrubbing + ex-situ biological methanation, and ex-situ biological methanation. The entire chain includes various processes such as silage production, transportation, biogas production, upgrading by amine scrubbing, electrolysis, and biological methanation. Among these processes, electrolysis is the dominant contributor for all categories except eutrophication impact. The electrolysis process alone accounts for 80% of GHG emissions, 86% of acidification, 70% of ozone depletion, and 85% of particulate matter (Vo et al., 2018a). Another study by Vo compared the economic values of these scenarios. The results show that at a net present value of zero, the minimum selling price (MSP) per m³ of renewable methane for scenarios 1, 2, and 3 is €0.76, €1.50, and €1.43, respectively (with an electricity price of €0.10/kWh for H2 production and a grass silage production cost of €27/t). The electricity price significantly affects the cost of renewable methane in both scenarios 2 and 3. The study concluded that direct biogas injection into the methanation reactor is financially more attractive than capturing CO₂ from biogas and feeding it into the methanation step. (Vo et al., 2018b).

Although all of these studies cannot be numerically compared due to having different functional units, aims and scopes, the results of all studies clearly highlight that the most significant emission in biological upgrading studies originates from hydrogen production. While this study focuses more on the Global Warming Potential (GWP) due to climate change being the most pressing environmental issue, it is also important to consider the other impact categories identified in the LCA results. In LCA studies, it is important not to focus solely on finding the best option as a whole, but to make comparisons based on the specific impact categories being analyzed.

This study presents the Life Cycle Assessment (LCA) analysis of the ex-situ biological biometan upgrading process and offers suggestions for making it more environmentally friendly through different scenarios. Greenhouse gas emissions are significantly influenced by the demand for energy sources and electricity. The study demonstrates that wind energy is the most environmentally friendly electricity source for hydrogen production through electrolysis in the frame of climate change. LCA studies on biogas upgrading have more research on physical and chemical upgrading methods, while biological upgrading studies remain limited. Biological upgrading is an emerging technology that integrates different forms of renewable energy, creating innovative possibilities such as advancements in energy storage and reducing the dependence of biofuel production on biomass availability. Therefore, this study highlights the need to increase pilot-scale studies and focus on LCA analyses.

CRediT authorship contribution statement

Rana Taskin: Writing – review & editing, Writing – original draft, Methodology, Formal analysis, Data curation, Conceptualization.

Sıdıka Tuğçe Kalkan: Writing – review & editing, Resources, Formal analysis, Data curation, Conceptualization.

Nuri Azbar: Writing – review & editing, Visualization, Supervision.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

AI was used only for language editing in this study.

Acknowledgements

The authors wish to thank TUBITAK under grant no 121Y488 for the financial support of this study.

Data availability

Data will be made available on request.

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Life Cycle Analysis (LCA) of Hydrogen Boosted Biomethanization with Alternative Power Scenarios

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Abstract

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1. Introduction

2. Material and Method

2.1. Aim and scope

2.2 Inventory analysis

2.3. Impact assessment

2.4 Interpretion

3. Results and discussion

3.1. Life cycle analysis of base-scenerio

3.2 Comparison of scenarios

4. Conclusion

Declarations

References

Status:

Journal Publication

Version 1