• Energy Research

Abstract Agro-ecosystems have large potentials for supporting human well-being and local development, also by providing large amounts of organic matter for bioenergy generation. The use of agricultural residues was proposed as a possible solution to support energy transition, while avoiding conflicts for the use of agricultural land destined to food production. The present work uses an Ecosystem Services (ES) approach to map and estimate the potential availability of agricultural residues (potential ES supply) in the Emilia-Romagna region (Italy), where high productive croplands are present. The map was overlapped with the bioenergy plants currently present in the region (ES demand) that could be sustained by residues, considering a buffer area of 10 km radius for a sustainable supply chain and under the assumption of using only the 25% of total residues. Additionally, suitable areas for bioenergy development were mapped by means of a hotspot analysis. The results showed that the Emilia-Romagna region has a large availability of agricultural residues to be potentially used for bioenergy generation. The 82.4% of the total installed power of biogas plants and the whole installed power of those using woody biomasses may be supported by using agricultural residues. When considering buffer areas for sustainable supply chains, agricultural residues could meet the 95% and 50% of total demand from biogas and solid biomasses plants, respectively. However, competition for agricultural residues among bioenergy plants could arise because of the overlap of their buffer zones. Moreover, hotspot analysis revealed large suitable areas for the development of environmental and cost-effective biogas plants. Contrasting ES supply and demand may unveil unexplored forms of sustainable development in agro-ecosystems, thus contributing to a more rational use of agricultural production which supports renewable energies without competing for the agricultural land.

Bioenergies are considered sustainable alternatives to fossil energy sources in the European Union (EU) renewable energy targets for 2030. However, their performances in terms of greenhouse gases (GHG) savings may be affected by indirect emissions related to the required land-use-change (LUC) that should be taken into account when modelling their sustainability. The European Renewable Energy Directive (RED) introduced a number of GHG emission criteria, in comparison with fossil fuels, that bioenergy deriving from agricultural biomasses must comply with. The Emilia-Romagna region (North-Eastern Italy), the second largest Italian biogas producer, has recently issued its Regional Energy Plan (REP), which set an ambitious increase of about 40% of the current installed electric power from biogas up to 2030. The aim of this study is to assess the sustainability of Emilia-Romagna REP accounting for the required indirect land-use-change (ILUC), due to the bioenergy crop expansion, potentially needed to reach the targets. Based on regional data available on biogas production, the amount of land used for maize silage to be destined to biogas production (as a model agricultural feedstock) has been calculated for the actual state-of-the art and towards 2030 scenarios provided by the REP. Starting from average GHG emissions associated with biogas production from 100% maize silage of 35 gCO2 eq/MJ, a further contribution of 8–18.5 gCO2 eq/MJ due to LUC has been found. Our findings indicate that it is difficult to assess the global GHG savings from the bioenergy targets fixed by regional energy plans when LUC effects are considered. Careful analysis is necessary in each case to avoid creating negative impacts.

The need to reduce the environmental impacts of the food industry is increasing together with the dramatic increment of global food demand. Circulation strategies such as the exploitation of self-produced renewable energy sources can improve ecological performances of industrial processes. However, evidence is needed to demonstrate and characterize such environmental benefits. This study assessed the environmental performances of industrial processing of maize edible oil, whose energy provision is guaranteed by residues biomasses. A gate-to-gate Life Cycle Assessment (LCA) approach was applied for a large-size factory of Northern Italy to describe: (i) the environmental impacts related to industrial processing and (ii) the contribution of residue-based bioenergy to their mitigation, through the comparison with a reference system based on conventional energy. The results showed that oil refinement is the most impacting phase for almost all the considered impact categories. The use of residue-based bioenergy was found to drastically reduce the emissions for all the impact categories. Moreover, Cumulative Energy Demand analysis revealed that the use of biomass residues increased energy efficiency through a reduction of the total energy demand of the industrial process. The study demonstrates that the exploitation of residue-based bioenergy can be a sustainable solution to improve environmental performances of the food industry, while supporting circular economy.

Bioenergy production is an important Ecosystem Service (ES) provided by natural and semi-natural ecosystems, which can concur to reach EU targets of 20% of total energy production from renewable sources. Environmental concerns with respect to bioenergy are multiple. Certification Schemes, aimed at reducing the negative effects of biomass energy supply chains, are not effective in controlling possible cumulative effects at regional level caused by both macro and micro feedstock producers and users. Sustainable feedstock production is often underestimated in energy planning and in the issuing of plant permits. This study applies an ES-based approach in order to quantify and map bioenergy sustainable potential in the Province of Rovigo (Region of Veneto, Italy), an intensively farmed agro-environment, and translate bioenergy environmental impacts in terms of ES trade-offs. The results show that the share of bioenergy potential from trade-offs with other ESs is limited. The magnitude and variability of ESs trade-offs are analyzed and discussed, resulting in a spatial distribution which is place-based and context dependent. Management solutions should be considered in order to mitigate trade-offs with other ESs, increasing ecological and social acceptability.

Aquatic vegetation loss caused substantial decrease of ecosystem processes and services during the last decades, particularly for the capacity of these ecosystems to sequester and store carbon from the atmosphere. This study investigated the extent of aquatic emergent vegetation loss for the period 1985–2018 and the consequent effects on carbon sequestration and storage capacity of Valle Santa wetland, a protected freshwater wetland dominated by Phragmites australis located in the Po river delta Park (Northern Italy), as a function of primary productivity and biomass decomposition, assessed by means of satellite images and experimental measures. The results showed an extended loss of aquatic vegetated habitats during the considered period, with 1989 being the year with higher productivity. The mean breakdown rates of P. australis were 0.00532 d−1 and 0.00228 d−1 for leaf and stem carbon content, respectively, leading to a predicted annual decomposition of 64.6% of the total biomass carbon. For 2018 the carbon sequestration capacity was estimated equal to 0.249 kg C m−2 yr−1, while the carbon storage of the whole wetland was 1.75 × 103 t C (0.70 kg C m−2). Nonetheless, despite the protection efforts over time, the vegetation loss occurred during the last decades significantly decreased carbon sequestration and storage by 51.6%, when comparing 2018 and 1989. No statistically significant effects were found for water descriptors. This study demonstrated that P. australis-dominated wetlands support important ecosystem processes and should be regarded as an important carbon sink under an ecosystem services perspective, with the aim to maximize their capacity to mitigate climate change.

Agro-ecosystems are intensively exploited environments which are both providers and consumers of ecosystem services. The improvement of both provisioning and regulating services in cultivated landscapes is crucial for the sustainable development of rural areas. Among the provisioning services offered, producing biogas from the anaerobic digestion of residual biomass is nowadays a promising option for decreasing greenhouse gas (GHG) emissions, while avoiding the land use conflicts related to the use of dedicated crops. Based on the available quantitative data at a regional level, provisioning and regulating services provided by the use of agri-food waste, livestock waste and agricultural residues were assessed for the case of Emilia Romagna region, the second biggest biogas producer in Italy. One provisioning service, i.e., bioenergy generation, and three regulating services were considered: (i) air quality improvement by the reduction of odors derived from direct use of waste, (ii) regulation of soil nutrients by reducing organic load and digestate spreading, and (iii) global climate regulation by saving GHG emissions. A potential further generation of 52.7 MW electric power was estimated at the regional level. Digestate spreading on fields may reduce odor impact by more than 90%, while containing a higher percentage of inorganic nitrogen, which is readily available to plants. The estimated GHG emission savings were equal to 2,862,533 Mg CO2eq/yr, mainly due to avoided landfilling for agri-waste and avoided replacing of mineral fertilizers for livestock waste and agricultural residues. The results suggest that bioenergy generation from lignocellulosic, livestock and agro-industrial residues may improve some regulating services in agro-ecosystems, while helping to reach renewable energy targets, thus contributing to overcoming the provisioning vs. regulating services paradigm in human-managed ecosystems.

Abstract There have been strong calls globally to improve the sustainability of biodiesel production from oilseeds. Nevertheless, there is a lack of robust methodologies that are able to depict the local impacts of intensive feedstock production on soil properties and functions. The aim of this study is to quantify and map the potential biodiesel production from oilseed (e.g. soybean, sunflower and rapeseed), and understand possible trade-offs with other soil-related Ecosystem Services (ESs) such as i) habitat for soil organisms (supporting service), ii) soil carbon storage (regulating service), iii) groundwater quality protection (regulating service) and iv) food crops (provisioning service). This method is tested on current intensive agricultural areas of the Veneto region plain of Northern Italy. The results suggest that the study area has a sustainable biodiesel production potential of 20.7 dam 3 per year, which is only 52% of the regional target for the year 2020. The areas that are currently under other annual crops (primarily cereals and maize) can also have a significant further contribution that if exploited would greatly exceed the regional target. This finding indicates that achieving the regional target will be impossible without having significant trade-offs with other soil-related ES or causing land use change. The proposed methodology could provide a tool that could be integrated within (and potentially improve the effectiveness of) biofuel certification schemes, strategic environmental assessments of renewable energy pathways, and regional energy plans.