All energy scenarios show that the energy supply approach is shifting to renewable energy, in particular energy from biofuels. On the other hand, in the context of this type of energy, water which is a limiting factor in the discussion of agricultural products, arises. In this research, using the water footprint index, the amount of water consumed for the production of each energy unit was calculated from wheat biomass. In this regard, six provinces of the country with the highest production value were selected. The purpose of this study was to determine the most desirable province for producing bioenergy from wheat biomass from the perspective of the water footprint index. The results of this study showed that Golestan, Kermanshah, Ardebil, Khuzestan, Fars and Khorasan Razavi provinces devoted 25. 1, 33, 35. 5, 39. 4, 43. 9 and 83. 7 cubic meter of water per GJ, respectively and this values showed the priority to produce bioenergy from wheat biomass. In other words, from the perspective of the water footprint, the productivity of bioenergy production in Golestan province is more than other provinces. Therefore, this situation has created an advantage for the use of wheat biomass in the province.

AbstractThe limitation of fossil resources and the environmental impacts resulting from their combustion have increased the importance of using renewable energies, including biomass energy. One of the approaches to energy production from biomass is the simultaneous generation of electricity and heat from animal manure. Given the substantial share of animal manure in biomass resources and its improper management in the country, it is essential to evaluate the potential for bioenergy production and to determine the spatial distribution of this renewable resource in different regions of Iran. Accordingly, the present study was conducted to assess the feasibility of bioenergy production from animal manure in Lorestan Province. The data required for this research were collected from relevant organizations, library resources, and the Agricultural Statistics Yearbook for the year 1402 (2023–2024). Based on the results, the total amount of collectable animal manure in the province was estimated at 355,069.7 tons, and the amount of methane produced from it was calculated to be 54.319 million cubic meters. The electrical and thermal energy and power outputs of the combined heat and power (CHP) system from animal manure were obtained as 236,287.68 MWh of electricity with a power of 33.75 MW and 265,823.62 MWh of heat with a power of 37.96 MW, respectively. The counties of Khorramabad, Borujerd, and Aligudarz ranked first to third in the province, with electricity generation potentials of 41,781.75, 38,335.68, and 32,695.04 MWh, and thermal energy generation potentials of 47,004.47, 43,127.64, and 36,781.91 MWh, respectively. In addition, the global warming potential index associated with energy production from animal manure was calculated to be 118,274.74 tons of CO₂ equivalent. According to the results, the use of electricity generated from animal manure can supply 7.11% of the total electrical energy consumption in Lorestan Province. EXTENDED ABSTRACT IntroductionPopulation growth and technological advancement mean that human activities now consume high levels of energy. This causes significant problems, including the depletion of fossil fuel resources and environmental pollution. Energy managers and planners are therefore developing options to meet these increasing demands for energy while maintaining a low environmental impact. The application of advanced energy-saving techniques, renewable energy resources, and technologies presents a viable solution to these problems. Bioenergy is a widely available resource, making it an attractive form of renewable energy. Biomass is abundant and easily accessible, making it a low-cost resource with great flexibility in terms of potential applications. One effective way to harness biomass energy is through the simultaneous production of electricity and heat from animal waste. Cogeneration, a highly efficient technology, produces both electricity and thermal energy using a variety of technologies and fuels, offering a cost-effective solution to reduce CO2 emissions. Given the significant amount of animal waste in biomass resources and its inadequate management in the country, it is crucial to assess the potential for bioenergy production and analyze the distribution of this renewable resource across different regions of Iran. This research aims to evaluate the bioenergy production potential from animal waste in Lorestan province. Material and Methods Data for this study were gathered from relevant organizations, library sources, and agricultural statistics for the year 2023. This section of the research focuses on the geographical location of the region, livestock and poultry data, the amount of animal waste, methods for calculating the theoretical and potential for biogas and methane production from animal waste, the examination of simultaneous electricity and heat production, and the estimation of pollutant emissions from bioenergy production using animal waste. Finally, the share of reducing the production of electric energy from fossil fuels by replacing the electric energy produced from animal waste in Lorestan province was calculated. Results and Discussion Based on the results, the amount of waste that can be collected from much livestock in the province was calculated to be 280318.6 tons, and heavy (cow) and light (sheep and goat) livestock with a production amount of 152594.9 and 127723.7 tons, respectively, accounted for 54.44% and 45.56% of the waste that can be collected from much livestock, respectively. Additionally, the amount of waste that can be collected from poultry units in the province was estimated to be 74,751.1 tons. Broiler and egg-laying chicken breeding units, with production amounts of 68,626.3 and 6,124.8 tons, respectively, accounted for 91.81% and 8.19% of the waste from poultry units. The annual methane production potential from livestock and poultry waste in the province was calculated to be 34.136 and 20.183 Mm3, respectively. Additionally, the total amount of animal waste (from livestock and poultry) that can be collected in the province was estimated at 355,069.7 tons, and the annual amount of methane produced from it was estimated at 54.319 Million Cubic Meters. Khorramabad, Borujerd, and Aligudarz counties were ranked first, second, and third in the province, with annual production potentials of 9.605, 8.813, and 7.516 Mm3, respectively.Additionally, the energy, electrical, and thermal power of the CHP (combined heat and power) system derived from animal waste were calculated as 236,287.68 MWh of electricity with a power of 33.75 MW and 265,823.62 MWh of heat with a power of 37.96 MW, respectively. Khorramabad, Borujerd, and Aligudarz counties were ranked first, second, and third in the province, with the potential to produce 41781.75, 38335.68, and 32695.04 MWh of electricity, and 47004.47, 43,127.64, and 36,781.91 MWh of heat, respectively. The amount of greenhouse gas emissions from the production of electrical energy from animal waste was 118,148.45 tons/year, and the share of CO2, N2O and CH4 in the emissions was 118,143.84, 0.1181, and 4.49 tons/year, respectively. Additionally, the global warming potential (GWP) index for energy production from animal waste was calculated to be 118,274.74 tons of CO2 equivalent. Compared to gas-fired power plants, generating electricity from animal waste reduces greenhouse gas emissions by 64,309.01 tons of CO2 equivalent/year (35.2%).Conclusions The current significant dependence of the energy sector on fossil fuel resources has led to numerous problems worldwide, including energy security issues and environmental pollution. Many abandoned renewable resources could be utilized to generate energy and balance the energy consumption profile in this sector. One of the energy sectors that significantly relies on fossil fuels is the electricity generation sector. In addition, one of the most overlooked renewable sources of biomass originates from the agriculture sector, i.e., animal waste. Hence, the present study aimed to assess the potential for bioenergy production from animal waste in Lorestan province. Based on the results, the use of electrical energy produced from animal waste can supply 7.11% of the electrical energy consumed in Lorestan province. Therefore, by producing bioenergy from animal waste, we can take steps to reduce dependence on fossil resources and greenhouse gas emissions, and thus achieve sustainable development.Acknowledgements"Not applicable"Author ContributionsMovahed Sepahvand: Conceptualization, Methodology, Software, Validation, Formal analysis, Data curation, Writing-original draft preparation, Writing-review and editing, Supervision, Project administration.Hadis Nematpour Malek Abad: Conceptualization, Methodology, Formal analysis, Resources, Writing-original draft preparation.Mohammad Ali Ghahremani Aghbolagh Rostam Khan: Methodology, Formal analysis, Resources.Data Availability StatementThe original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.Ethical ConsiderationsThe authors avoided data fabrication, falsification, plagiarism, and misconduct.Conflict of InterestThe 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.Funding StatementThe author(s) received no specific funding for this research.

IntroductionEnergy and environmental issues are two common concerns of modern societies. Fossil fuels consumption is believed to be the primary factor contributing to severe environmental problems, such as global warming, climate change and acid rain, which are a serious threat to the world’s ecosystems. In order to stabilize the earth’s climate and prevent further global warming, the earth requires a 70% cut in present carbon dioxide emissions by 2050. In the executive summary of IEA (2006), it claims “Beyond 2020, the role of renewable energy in global energy supply is likely to become much more important”. Among these, biomass can be defined as all the biological materials produced and existing within an ecological system and as sources of renewable energy can be converted directly into energy or energy carrier materials.Regarding to biomass assessment, researchers estimated the sustainable energy potential of biomass resources in Thailand including: (i) agricultural residues, (ii) animal manure, (iii) fuel-wood saving potential through improvement of efficiency, (iv) possibility of fuel-wood saving through substitution by other fuels, (v) municipal solid wastes, and (vi) wastewater. The potential of each source was estimated for the reference year 1997 and for the years 2005 and 2010. The total energy potential of these sources in 1997, 2005 and 2010 were 525, 702 and 821 PJ, respectively. In Iran, Khorasan Razavi province is known as an important region of biomass production in the country including: crops, livestock and poultry. Hence, in this study the potential of biomass and its distribution were evaluated.

Purpose The objective of research was emphasized on the optimal conditions (initial pH and C/N ratio) for enhancing bioenergyfrom food waste by a two-stage fermentation process. Methods Bioenergy production from food waste was operated by mixed culture under thermophilic temperature in batchreactor. Thermophilic biohydrogen production was optimized in terms of initial pH (5. 0– 9. 0) and then was optimized interms of C/N ratio (10– 50) in the first stage. After that, thermophilic biomethane production was optimized in terms of initialpH (6. 0– 10. 0) in the second stage. Results The results revealed that the thermophilic biohydrogen production from food waste at an initial pH 7. 0 presented themaximum hydrogen yield of 176. 10 mL H2/g COD. At this optimal initial pH, the maximum hydrogen yield of 214. 88 mLH2/g COD was achieved at C/N ratio 30. Subsequently, the effluent from the first stage of thermophilic biohydrogen productionfrom food waste under the optimal initial pH of 7. 0 and the optimal C/N ratio of 30 was used as a substrate in thesecond stage of thermophilic biomethane production. Thermophilic biomethane production from hydrogen fermentationeffluent provided the maximum methane yield of 310. 77 mL CH4/g COD at initial pH 7. 0. At these optimal conditions, CODremoval was achieved at 70– 90%. Conclusion Therefore, a two-stage thermophilic fermentation process could effectively enhance biohydrogen and biomethaneproduction, including reduction of organic waste at the same time.

The development of energy supply from biomass to reduce greenhouse gas emissions has led to focus on producing important crops from energy perspective which culminated in water consumption increase. Therefore, in this study for analyzing the water and bioenergy nexus, an index called water footprint was used. In this regard, information about maize in the plains of Khuzestan province, was collected. Based on the calculations, it was found that the water footprint of maize crop in the province has an average of 3355. 6 m3/ton and the biomass water footprint is equal to 214. 9 m3/ton. Moreover, in the study of water footprint of maize biomass, it was found that the highest and the lowest water footprints devoted to Behbahan plain (27. 1 m3/GJ) and Abbas Abad plain (10 m3/GJ), respectively. Accordingly, Khuzestan province with an average of 13 m3/GJ, has better condition in terms of water consumption in compare to countries such as Zimbabwe, Brazil and the United States with a water footprint of 200, 39 and 18 m3/GJ, respectively. Mapping the biomass energy production potential with the water footprint approach also showed that water footprint in southeastern plains of the province (especially Behbahan, Omidieh, and Hendijan) are in the interval between 12 up to 27. 1 m3/GJ and have low priority for biomass production. In contrast, the northern and eastern plains (especially Abbas Abad, Andimeshk, Sidon and Qaleh Tal) with bioenergy water footprints of 10 to 10. 9 m3/GJ have high priority to the use of maize biomass for energy production.

Due to the problems and limitations of using fossil energy sources, the use of biofuels in order to achieve the goals of sustainable development, reducing greenhouse gas emissions, regional development, and security of energy supply, has received more attention. Therefore, considering the importance of the issue, in the present study, while determining the effective factors on the tendency of farmers to accept the supply of crop residues of wheat and barley products for bioenergy production, the economic value of residues of selected products in biogas and bioethanol energy production is estimated. Accordingly, using a survey approach and by completing a questionnaire by farmers in Boroujerd in 1399, data collection and research hypotheses were tested using the logit regression model. The results of the study indicate that the variables of collection cost (with a final effect of -0.097 and elasticity of -7.39%), non-agricultural income (with a final effect of -0.028 and elasticity of -6.37%), and use from residues (with a final effect of -0.014 and a tensile strength of -11.6%) have a negative effect on the supply of agricultural residues for bioenergy production. Meanwhile, education (with a final effect of 0.09 and elasticity of 4.4%) and farmer experience (with a final effect of 0.022 and elasticity of 17.32%) have a positive effect on the supply of agricultural residues for bioenergy production. According to the results of traction, farmers' experience and farmers' use of agricultural residues have the greatest effect on the supply of agricultural residues in bioenergy production. The results also show that the annual production potential of bioethanol from wheat and barley residues is equal to 63.96 million liters. So that if the same residues are used in biogas production, the annual biogas production potential is equal to 88.98 million cubic meters. Accordingly, the economic value of bioethanol and biogas energy production from wheat and barley residues in the study area has been calculated equal to 15349 and 430 billion rials, respectively. Therefore, based on the results, by planning for the principled management of agricultural residues and investing in the use of biomass as clean sources for bioenergy production, effective measures can be taken to reduce the dependence of the country's economy on fossil energy and provide the energy needs of people in remote areas.