• Energy Research

CONTEXT: Biogas, a clean and environmentally sustainable energy source, reduces agricultural waste pollution and contributes to solving the problem of rural energy shortages. Therefore, biogas development and use have increased in numerous nations, including China. OBJECTIVE: This study estimates the biogas potential of agricultural waste in Hubei Province, China. It also identifies the gap between the available biogas potential and actual total biogas production to find the cause of the low utilization rate. METHODS: The agricultural waste, including its biogas potential in Hubei Province, was estimated and analyzed using crop yields and livestock production through geographical approach. Based on that, the environmental and economic benefits of carbon emission reduction were also discussed. Then, a comparison was made between the estimated biogas potential and the actual biogas production via biogas production difference rate that could visualize the gap between them. RESULTS AND CONCLUSIONS: The results revealed that the estimated biogas potential of agricultural waste could reach 4.67 × 109 m3. This high biogas potential could lead to a carbon emission reduction effect of 2.33 × 106 tCO2. According to Clean Development Mechanism (CDM), these carbon emission savings could have an economic benefit of 2.33 × 107 USD. In addition, results also showed a significant difference between the estimated potential and actual biogas production, and the average production difference rate was 96.83%. The discrepancy between Hubei regions was also evident; areas with the lowest biogas production density per unit area accounted for only 0.5% of the highest areas. SIGNIFICANCE: To sum up, this study provides a visual tool to compare theoretical biogas potential to real biogas output and offers referable optimization strategies.

The exploitation of bioenergy plays a key role in the process of decarbonising the economic system. Huge efforts have been made to develop bioenergy and other renewable energy systems, but it is necessary to investigate the costs and problems associated with these technologies. Soil consumption and, in particular, soil sealing are some of these aspects that should be carefully evaluated. Agricultural biogas plants (ABPs) often remove areas dedicated to agricultural activities and require broad paved areas for the associated facilities. This study aimed to (i) assess the surfaces destined to become facilities and buildings in ABPs, (ii) correlate these surfaces with each other and to the installed powers of the plants, and (iii) estimate the consumption of soil in bioenergy applications in Italy. Two hundred ABPs were sampled from an overall population of 1939, and the extents of the facilities were measured by aerial and satellite observations. An ABP with an installed power of 1000 kW covers an average surface area of up to 23,576 m2. Most of this surface, 97.9%, is obtained from previously cultivated areas. The ABP analysis proved that 24.7 m2 of surface area produces 1 kW of power by bioenergy. The obtained model estimated a total consumption of soil by ABPs in Italy of 31,761,235 m2. This research can support stakeholders in cost-benefit analyses to design energy systems based on renewable energy sources.

Biomethane plays a key role in achieving decarbonization and sustainable development goals. According to the objectives that arise, choosing the most suitable production system allows optimization of production, thereby reducing CO2 emissions. In this study, three biomethane production scenario life cycle assessments were compared to determine which would maintain the lowest CO2 emissions. Conventional anaerobic digestion and an innovative process called two-stage high pressure anaerobic digestion were considered. These methods were combined with two upgrading processes: water scrubbing and biological upgrading. Cattle manure and sugar beets were used as substrates for the process. Emissions were 805.6 gCO2eq/m3CH4 for the traditional biogas production process combined with water scrubbing and 450.3 gCO2eq/m3CH4 for the two-stage anaerobic digestion process combined with biological upgrading. Furthermore, the analysis demonstrated that these values would be reduced by 29.5 % and 48.0 % if electrical energy were produced using only renewable energy sources.

Bioenergy production from agricultural biomass is considered a key opportunity for achieving the sustainable development goals set by various international institutions. This sector must combine efficiency and profitability with environmental protection and territorial integration. For this reason, plants location should consider the natural and anthropic characteristics of the areas where they are supposed to operate. In this paper, a multicriteria analysis is introduced for optimal location of biomass plants in a region of Northern Italy. The study was based on a detailed set of 8 constraints and 15 criteria, and eventually identified 93 potential sites for plant location. The distribution of biomass from the territory to the plants was carried out with the specific Location-Allocation algorithm that allowed considering both the attractiveness of the plants and the maximum acceptable power. This result was compared with the current bioenergy production system: three alternative scenarios were developed, considering existing plants and the natural gas distribution network. Finally, a sensitivity analysis was conducted, to study the consequences of various decision-makers decisions. The results showed the possibility of installing between 90 and 199 plants in the different scenarios, resulting in a biomethane production between 246.8·106 Nm3 and 503.6·106 Nm3.

Artificial intelligence, an emerging concept, has successfully been applied to bioenergy systems. However, highly scattered reviews were narrowly associated with either part of bioenergy systems or an isolated technique, and fewer focused on systematic induction in the agricultural context. This study reviewed 96 papers published from 2012 to 2022, focusing on generalising and comparing AI methods in agricultural bioenergy areas. Specifically, this review broke down the object of study of all previous studies into three parts: bioenergy systems, biomass materials, and AI techniques. Additionally, combined with examples of AI applications, it categorised the bioenergy systems into three phases, including (i) biomass feedstock detection, (ii) bioenergy production/process, and (iii) energy usage, for solving problems such as biomass mapping, composition analysis, cultivation monitoring, process optimisation, bioenergy planning, etc. Based on the review, 44 types of AI algorithms and 11 types of datasets were concluded, in which Artificial Neural Network, Random Forest, Support Vector Machine, Intelligence Decision Support System were mainly used for prediction, classification/regression, and optimal decision-making in issues about biomass systems with 58, 15, 13, and 13 algorithms, respectively.

Bioenergy is being increasingly used worldwide to generate energy from biogas, biomethane, and other biofuels, bringing significant environmental and economic benefits. In Italy, biogas can significantly contribute to the achievement of the renewable energy targets set at the national and European levels. The exploitation of this energy source in a particular area is determined by its environmental and anthropic properties, as well as by the incentive system and the political will of decision makers. This paper analyzes the socioeconomic drivers and natural conditions triggering bioelectricity production in Italian regions. The analysis proposed here was performed in two steps—first, by identifying groups of similar regions for some natural, social, and economic variables, and then by modeling the historical trajectory of bioelectricity production for each identified group with innovation diffusion models. As a general finding, regions pertaining to the same group in terms of natural and socioeconomic conditions revealed a similar production pattern for bioelectricity, as confirmed by the results of diffusion modeling. On the basis of the diffusion modeling procedure, some scenario simulations were performed, which suggested the set-up of suitable policy actions for each group of regions.

This paper aims to provide a bibliometric analysis of publication trends on the themes of biomass and bioenergy worldwide. A wide range of studies have been performed in the field of the usage of biomass for energy production, in order to contribute to the green transition from fossil fuels to renewable energies. Over the past 20 years (from 2000 to 2019), approximately 10,000 articles have been published in the “Agricultural and Biological Sciences” field on this theme, covering all stages of production—from the harvesting of crops to the particular type of energy produced. Articles were obtained from the SCOPUS database and examined with a text mining tool in order to analyze publication trends over the last two decades. Publications per year in the bioenergy theme have grown from 91 in 2000 to 773 in 2019. In particular the analyses showed how environmental aspects have increased their importance (from 7.3% to 11.8%), along with studies related to crop conditions (from 10.4% to 18.6%). Regarding the use of energy produced, growing trends were recognized for the impact of biofuels (mentions moved from 0.14 times per article in 2000 to 0.38 in 2019) and biogases (from 0.14 to 0.42 mentions). Environmental objectives have guided the interest of researchers, encouraging studies on biomass sources and the optimal use of the energy produced. This analysis aims to describe the research evolution, providing an analysis that can be helpful to predict future scenarios and participation among stakeholders in the sector.