Net Electricity and Heat Generated by Reusing Mediterranean Agro-Industrial By-Products

Optimal sites for agricultural and forest residues energy conversion plant using geographic information system

The Federal Government of Nigeria (FGN) has committed to net-zero emission development pathways to respond to the Paris Agreement adopted in 2015. However, the country is in dire need of energy to support its developmental ambitions. Therefore, it is necessary to consider green energy technologies to support both socioeconomic development and to meet the FGN's emission reduction target. In view of this, the current work presents the optimal sites for bioenergy plants in a state in Nigeria using Geographic Information System (GIS). Key findings suggest that 62.03 PJ/yr and 4.12 PJ/yr of energy could be derived from crop residues and forest residues, respectively, to support the state's bioenergy development. The crop residues considered include plantain (stem), oil palm (shell and fibre), maize (stalks) and cassava (peel and stalks). Six criteria were used in selecting the optimal sites, and include biomass residue distribution, settlement, road accessibility, nearness to waterline, slope and aspect. These criteria were incorporated into the ArcGIS platform through the weighted overlay tool. Strategically, the analysis presents seven sites for biomass plants to sustainably meet part of the energy needs. The efforts of the current work which supports not less than three SDGs-SDG 7 (Clean and Affordable Energy), SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action), will assist policymakers in Nigeria to make appropriate policies within the climate change space.

Assessment of Tomato Peels Suitable for Producing Biomethane within the Context of Circular Economy: A GIS-Based Model Analysis

Biomass is seen as one of the most dominant future renewable energy sources. In detail, agro-industrial by-products represent a cheap, renewable, and abundant feedstock useful for several new products, including biochemical, biomaterials, and above all biogas, which are taking on an ever-increasing role in Italy. In this context, the tomato chain was analysed aiming at estimating the amount of processed tomato and the related waste production as a new suitable resource for producing biofuel as a new frontier within the context of a circular economy. Due the importance of the tomato industry, this research aims at filling gaps in the knowledge of the production and yield of the by-products that are useful as biomass for energy use in those territorial areas where the biomethane sector is still developing. This aim could be relevant for planning the sustainable development of the biomethane sector by reducing both soil consumption for dedicated energy crops and GHG emissions coming from the biomass logistic supply. The achieved results show the localization of territorial areas highly characterized by this kind of biomass. Therefore, it would be desirable that the future policies of development in the biomethane sector consider the availability and the distribution of these suitable biomasses within the territory.

A GIS-Based Model to Assess the Potential of Wastewater Treatment Plants for Enhancing Bioenergy Production within the Context of the Water–Energy Nexus

The necessity of developing renewable energy sources has contributed to increasing interest in developing the anaerobic digestion for producing biomethane since it both provides green energy and reduces disposal treatment. In this regard, to assure efficient water utilization by finding alternative water sources, sewage sludge collected from the wastewater treatment plant (WWTP) was recently investigated because it could represent a suitable resource for producing biomethane within the context of a circular economy. Therefore, this study aims at improving the current knowledge on the feasibility of biomethane production from sewage sludge by optimizing the logistic-supplying phase. In this regard, a GIS-based model was developed and applied to the Emilia-Romagna region to consider the existing networks of WWTPs and biogas systems to valorize sewage sludge for bioenergy production and minimizing environmental impact. The results of the GIS analyses allowed to localize the highest productive territorial areas and highlighted where sewage sludges are abundantly located and could be better exploited within agricultural biogas plants. Finally, the achieved results could help plan suitable policy interventions that are centered on biomass supply and outputs diversification, governance, and social participation, since the regulatory framework could play a crucial role in planning the reuse of these wastes for developing a more sustainable biomethane sector in line with the green economy goals.

Assessment of Fruit and Vegetable Residues Suitable for Renewable Energy Production: GIS-Based Model for Developing New Frontiers within the Context of Circular Economy

Due to the necessity of developing renewable energy sources, the anaerobic digestion for producing biomethane has developed significantly in the last years, since it allows to both reduce disposal treatment and produce green energy. In this field, fruit and vegetable wastes have been recently put forward, since they could represent a suitable resource for producing biomethane as a new frontier within the context of a circular economy. This study aims at filling the gap in the knowledge of the production, quantities and biogas potential production of these residues. On this basis, a GIS-based model was developed and applied to the Sicily region by investigating the specific regulatory framework as well as by analysing descriptive statistics. The results of the GIS analyses enabled the localisation of the highest productive territorial areas and highlighted where fruit and vegetable wastes are abundantly located. In this regard, about 7 million Nm3 of biogas could be produced by reusing only the fruit and vegetable residues coming from the three most representative Sicilian wholesale markets among those considered. Finally, the regulatory framework is of crucial importance in inhibiting or supporting the use of the selected biomass in a specific sector, with regard to the case study considered.

Performance evaluation of digestate spreading machines in vineyards and citrus orchards: preliminary trials

This research was carried out to evaluate a local biogas plant's solid fraction digestate spreading in a citrus orchard and vineyard. Three spreaders were tested: a broadcast manure spreader in the citrus orchard, and two cylindrical-shaped spreaders in the vineyard; the first one working in broadcast configuration, the second one in localised configuration. Experimental tests assessed effective work time, mean work speed, digestate flow rate and longitudinal and transverse spreading uniformity. In the citrus orchard, the digestate was mainly spread in the centre of the inter-row (around 66%), with low variability between inter-rows (coefficient of variation (CV) equal to 2.7%) and much higher variability within inter-rows (CV = 31.4%). The effective work time was about 28% of total field time and real work capacity was about 0.96 ha h⁻¹. In the vineyard, broadcast spreading released more on the right compared to the left (ratio 1.74) due to distributor disc rotation, whereas localised spreading was more uniform. Overall, variability between inter-rows had CV = 15.1% and within inter-rows CV = 33.3%. Real work capacity was about 0.16 ha h⁻¹ for broadcast spreading and 0.26 ha h⁻¹ for localised spreading. A preliminary economic evaluation, based on sub-contractor tariffs, produced the mean tariff for transaction and spreading costs of digestate in farms near the biogas plant.

Elevated biogas production from the anaerobic co-digestion of farmhouse waste: Insight into the process performance and kinetics

The biodegradable portion of solid waste generated in farmhouses can be treated for energy recovery with small portable biogas plants. This action can be done across the Netherlands and all around the planet. This study aims to appraise the performance of anaerobic digestion of different wastes (cow manure, food waste and garden waste) obtained from a regional farmhouse. Batch reactors were established under mesophilic conditions in order to investigate the impact of ternary mixtures on the anaerobic digestion process performance. Different mixing ratios were set in the batch tests. The upshots from the experiments connoted that ternary digestion with cow manure:food waste:garden waste mixing ratio of 40:50:10 yielded higher biogas amount. The kinetics' results showed quite good congruence with the experimental study. The results from the kinetic analysis appeared to be in line with the experimental one.