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Special Issue "Renewable Energy Production from Energy Crops and Agricultural Residues"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "A4: Bio-Energy".

Deadline for manuscript submissions: closed (25 September 2020) | Viewed by 21425

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Special Issue Editor

Dr. Luigi Pari
E-Mail Website
Guest Editor
Council for Agricultural Research and Economics, Research Center for Engineering and Agro-Food Processing (CREA-IT), Via della Pascolare, 16, 00015 Monterotondo, Italy
Interests: energy crops and byproducts; harvesting efficiency; mechanization; biofuel; bioeconomy
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Special Issue Information

Dear Colleagues,

We are inviting submissions to a Special Issue of the journal Energies on the topic of “Renewable Energy Production from Energy Crops and Agricultural Residues”.

Biomass represents an important source of renewable and sustainable mean for energy production. Its increasing consumption is mainly related to the increase in global energy demand and fossil fuel prices, but also to a lower environmental impact compared to non-renewable fuels, also taking into consideration the RED II directives. In the past, forestry interventions were the main supply source of biomass, but in recent decades, two others sources have entered the international scene. These are dedicated energy crops and agricultural residues, which are nowadays important sources of biomass for biofuel and bioenergy. We will consider four main value chains below.

  • Oil crops. Oil production from non-food oilseed crops (such as camelina, Crambe, safflower, castor, cuphea, cardoon, etc.), oil extraction, and oil utilization for fuel production;
  • Lignocellulosic crops. Biomass production from perennial grasses (miscanthus, giant reed, switchgrass, reed canary grass, etc.), woody crops (willow, poplar, Robinia, eucalyptus, etc.), and agricultural residues (pruning, maize cob, maize stalks, wheat chaff, sugar cane straw, etc.), considering two main transformation systems:
    1. Electricity/heat production
    2. Second-generation ethanol production
  • Carbohydrate crops (cereals, sweet sorghum, sugar beets, sugar cane, etc.) for ethanol production;
  • Fermentable crops (maize, barley, triticale, Sudan grass, sorghum, etc.) and agricultural residues (chaff, maize stalks and cob, fruit and vegetable waste, etc.) for production of biogas and/or biomethane.

Energy production from the mentioned above sources is a multistage process where only a well-structured assessment of all the phases—from energy crop production techniques; both energy crop and agricultural residue harvesting, handling, pretreatment, and transport to transformation plants; and transformation systems tailored for these biomasses—can lead to a virtuous value chain with positive externalities concerning all three pillars of sustainability (economy, environment, and society).

This Special Issue would like to encourage original contributions regarding recent developments and ideas in energy production from energy crops and agricultural residues. Potential topics include but are not limited to comparison of different harvesting systems, logistic efficiency assessment, analysis of biomass quality, biofuel development processes, biomass chain logistic, and socioeconomic implications.

Dr. Luigi Pari
Guest Editor

Manuscript Submission Information

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Keywords

  • biofuel
  • bioenergy
  • co-products
  • byproducts
  • biomass quality
  • biomass-dedicated crops
  • marginal lands
  • pruning residues
  • harvesting efficiency
  • LCA
  • work productivity
  • cost analysis

Published Papers (20 papers)

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Research

Article
Optimizing Resource Utilization in Biomass Supply Chains by Creating Integrated Biomass Logistics Centers
Energies 2020, 13(22), 6153; https://doi.org/10.3390/en13226153 - 23 Nov 2020
Cited by 7 | Viewed by 933
Abstract
Bio-based supply chains are by nature complex to optimize. The new logistic concept of integrated biomass logistical center (IBLC) provides us the opportunity to make full use of the idle capacity for a food/feed plant to produce biobased products so that the entire [...] Read more.
Bio-based supply chains are by nature complex to optimize. The new logistic concept of integrated biomass logistical center (IBLC) provides us the opportunity to make full use of the idle capacity for a food/feed plant to produce biobased products so that the entire chain efficiency can be improved. Although research has been conducted to analyze the IBLC concept, is yet to be an optimization model that can optimally arrange the activities in the supply chain where an IBLC stands in the middle. To fill the knowledge gap in the literature, this paper makes the first step to develop a MILP model that enables biobased supply chain optimization with the IBLC concept, which supports logistic and processing decisions in the chain. The model is applied in a case study for a feed and fodder plant in Spain where managerial insights have been derived for transferring the plant to a profitable IBLC. Full article
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Article
A GIS Approach Land Suitability and Availability Analysis of Jatropha Curcas L. Growth in Mexico as a Potential Source for Biodiesel Production
Energies 2020, 13(22), 5888; https://doi.org/10.3390/en13225888 - 11 Nov 2020
Cited by 4 | Viewed by 832
Abstract
Jatropha curcas L. (JCL) commercial plantations in Mexico, one of the most important JCL origin centers, have failed due to a variety of biological, political and technical factors affecting their productivity. This study explores feasible sites of JCL cultivation as a potential source [...] Read more.
Jatropha curcas L. (JCL) commercial plantations in Mexico, one of the most important JCL origin centers, have failed due to a variety of biological, political and technical factors affecting their productivity. This study explores feasible sites of JCL cultivation as a potential source for biodiesel production in Mexico, given agroclimatic and agroecological considerations. We propose a GIS-based approach for estimating suitable and available lands to grow JCL by integrating an Analytical Hierarchy Process (AHP) in the ArcGIS software. Spatial analysis combined multiple data, different evaluation criteria, three land availability classes (high, medium and low potential) and took into account ecological, ethical, and political restrictions, and considering two scenarios with different restriction levels. Suitability and availability maps were generated using agroclimatic information (climatic, land use/soil, and climate change and extreme weather events risk) together with other socioeconomic factors. Approximately 15.3% of Mexican territory is available for JCL production yielding a biodiesel production of 9.683 Mm3/year. Amelioration of the available land is necessary to improve land selection. GIS-based analysis represents a first approach to establish a successful biodiesel project that avoids, competition with food or feed production, maintains biodiversity conservation, and promotes biofuel supply chain development. This procedure would also be applicable to other energy crops such as oil palm and Ricinus communis. Full article
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Article
A Comparative Analysis of Two Cable Yarder Technologies Performing Thinning Operations on a 33 Year Old Pine Plantation: A Potential Source of Wood for Energy
Energies 2020, 13(20), 5376; https://doi.org/10.3390/en13205376 - 15 Oct 2020
Cited by 5 | Viewed by 571
Abstract
In central Italy, there are extensive European black pine (Pinus nigra Arn.) plantations which range from 30 to 60 years of age and where no thinning operations have been made. The main purpose of this study was to provide a comparative analysis [...] Read more.
In central Italy, there are extensive European black pine (Pinus nigra Arn.) plantations which range from 30 to 60 years of age and where no thinning operations have been made. The main purpose of this study was to provide a comparative analysis of two cable yarder technologies (Maxwald, mobile pulley carriage and Savall, semi-automatic carriage), in terms of fuelwood production and cost, from the first thinning of a 33 year old plantation in slope areas of these plantations. The results showed that fuelwood production was cost-effective in both systems (Savall by 15.1 and Maxwald by 14.8 € m−3), although the productivity of the Savall system was higher than the Maxwald system (6.1 vs. 5.7 m3 h−1). The respect amounts of productivity have the potential to increase by 27% for the Savall yarder and 25% for the Maxwald yarder upon condition that the delay times are reduced to minimum level by proper training of workers, by a better organization, and planning of operations. The total effective CO2 emission by the Savall yarder was lower than the Maxwald yarder (1735 vs. 1772 g m−3). A sustainable production of fuelwood that is economically advantageous and environmentally sound in these plantations can be realized through an appropriate mechanization level and constant interaction with the silvicultural planning. This must be completed with adequate and efficient worker training. Full article
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Article
Mechanical Harvesting of Camelina: Work Productivity, Costs and Seed Loss Evaluation
Energies 2020, 13(20), 5329; https://doi.org/10.3390/en13205329 - 13 Oct 2020
Cited by 10 | Viewed by 937
Abstract
Camelina is a low input crop than can be cultivated in rotation with cereals to provide vegetable oil suitable for bioenergy production, industrial applications and even as source of food for livestock. At large scale farming, camelina seeds are currently harvested using a [...] Read more.
Camelina is a low input crop than can be cultivated in rotation with cereals to provide vegetable oil suitable for bioenergy production, industrial applications and even as source of food for livestock. At large scale farming, camelina seeds are currently harvested using a combine harvester, equipped with a cereal header, but the literature still lacks the knowledge of the performance of the machine, the harvesting cost and the related loss of seeds. The present study aims to fulfill that gap by reporting the results obtained from an ad hoc harvest field test. Camelina seed yield was 0.95 Mg ha−1 which accounted for the 18.60% of the total above ground biomass. Theoretical field capacity, effective field capacity and field efficiency were 3.38 ha h−1, 3.17 ha h−1 and 93.7% respectively, albeit the seed loss was 80.1 kg ha−1 FM (7.82% w/w of the potential seed yield). The presence of material other than grain was rather high, 31.77% w/w, which implies a second step of cleaning to avoid undesired modification of the seed quality. Harvesting cost was estimated in 65.97 € ha−1. Our findings provide evidence on the suitability to use a conventional combine harvester equipped with a cereal header for the harvesting of camelina seeds, although some improvements are required to reduce both seed loss and impurities. Full article
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Article
Potential of Straw for Energy Purposes in Poland—Forecasts Based on Trend and Causal Models
Energies 2020, 13(19), 5054; https://doi.org/10.3390/en13195054 - 25 Sep 2020
Cited by 12 | Viewed by 1103
Abstract
The mitigation of climate change poses a major challenge to the legal framework which aims to stimulate the development of renewable energy sources. The European Union’s direction for the use of renewable energy is distributed generation and an increased use of by-products and [...] Read more.
The mitigation of climate change poses a major challenge to the legal framework which aims to stimulate the development of renewable energy sources. The European Union’s direction for the use of renewable energy is distributed generation and an increased use of by-products and organic waste, especially in the production of next-generation biofuels. The main aim of this study is to evaluate the production potential of straw in Poland and the possibility of its use for energy purposes, including a forecast for 2030, on the assumption that the management of this resource is in accordance with the provisions of the Polish Code for Good Agriculture Practice. In Poland, in the years 1999–2018, the average annual surplus of straw harvested over agricultural consumption equalled 12.5 million tons (4.2 Mtoe). Its largest surpluses were in the Dolnośląskie, Kujawsko-Pomorskie, Lubelskie, Wielkopolskie, and Zachodniopomorskie voivodeships (NUTS2). Based on the developed panel models, forecasts for straw surpluses in Poland are presented in three perspectives: realistic, pessimistic, and optimistic. The forecasts show regional differentiation until 2030. Each of the three perspectives indicate a slow increase in these surpluses, and depending on the adopted version, it will range from 10.6% to 21.9%. Full article
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Article
Willow Cultivation as Feedstock for Bioenergy-External Production Cost
Energies 2020, 13(18), 4799; https://doi.org/10.3390/en13184799 - 14 Sep 2020
Cited by 2 | Viewed by 830
Abstract
Biomass remains one of the most important materials for the production of renewable energy in the European Union. Willow can be one of the sources of biomass, and its production can also be profitable on soils with low quality. A proper selection of [...] Read more.
Biomass remains one of the most important materials for the production of renewable energy in the European Union. Willow can be one of the sources of biomass, and its production can also be profitable on soils with low quality. A proper selection of raw material for energy production should be based not only on the cost effectiveness or crop yield, but also on the environmental impact and the cost it incurs. The aim of this work was to evaluate the external environmental costs of the production of willow chips of seven willow genotypes, produced for energy generation on marginal cropping lands. The environmental external costs of chips production were estimated against the amount of emissions calculated according to the LCA method (ReCiPe Midpoint) and its monetary value. The external environmental cost of willow chips production amounted to €212 ha−1 year−1, which constituted 23% of the total production cost of willow chips. The external cost of production of 1 Mg d.m. of willow chips for the best yielding variety averaged €21.5, which corresponded to 27% of the total production cost. The research demonstrated that a proper selection of an optimal variety may lead to the reduction of the external cost. Full article
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Article
Saccharification Yield through Enzymatic Hydrolysis of the Steam-Exploded Pinewood
Energies 2020, 13(17), 4552; https://doi.org/10.3390/en13174552 - 02 Sep 2020
Cited by 6 | Viewed by 800
Abstract
Pressure, temperature, and retention time are the most studied parameters in steam explosion pretreatment. However, this work aimed to fix these parameters and to evaluate the influences of several less investigated steam explosion parameters on the saccharification yield in hydrolysis. In this study, [...] Read more.
Pressure, temperature, and retention time are the most studied parameters in steam explosion pretreatment. However, this work aimed to fix these parameters and to evaluate the influences of several less investigated steam explosion parameters on the saccharification yield in hydrolysis. In this study, firstly, pinewood samples smaller than 200 µm were treated with steam explosion at 190 °C for 10 min. The variable parameters were biomass loading, N2 pressure, and release time. Steam-exploded samples were hydrolyzed with the Trichoderma reesei enzyme for saccharification for 72 h. The sugar content of the resultant products was analyzed to estimate the yield of sugars (such as glucose, xylose, galactose, mannose, and arabinose). The best glucose yield in the pulp was achieved with 4 g of sample, N2 pressure of 0.44 MPa, and short release time (22 s). These conditions gave a glucose yield of 97.72% in the pulp, and the xylose, mannose, galactose, and arabinose yields in the liquid fraction were found to be 85.59%, 87.76%, 86.43%, and 90.3%, respectively. Full article
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Article
Willow Biomass Crops Are a Carbon Negative or Low-Carbon Feedstock Depending on Prior Land Use and Transportation Distances to End Users
Energies 2020, 13(16), 4251; https://doi.org/10.3390/en13164251 - 17 Aug 2020
Cited by 8 | Viewed by 1188
Abstract
Few life cycle assessments (LCAs) on willow biomass production have investigated the effects of key geographically specific parameters. This study uses a spatial LCA model for willow biomass production to determine spatially explicit greenhouse gas (GHG) emissions and energy return on investment (EROI), [...] Read more.
Few life cycle assessments (LCAs) on willow biomass production have investigated the effects of key geographically specific parameters. This study uses a spatial LCA model for willow biomass production to determine spatially explicit greenhouse gas (GHG) emissions and energy return on investment (EROI), including land use conversion from pasture and cropland or grassland. There were negative GHG emissions on 92% of the land identified as suitable for willow biomass production, indicating this system’s potential for climate change mitigation. For willow planted on cropland or pasture, life cycle GHG emissions ranged from −53.2 to −176.9 kg CO2eq Mg-1. When willow was grown on grassland the projected decrease in soil organic carbon resulted in a slightly positive GHG balance. Changes in soil organic carbon (SOC) associated with land use change, transportation distance, and willow yield had the greatest impacts on GHG emissions. Results from the uncertainty analysis exhibited large variations in GHG emissions between counties arising from differences in these parameters. The average EROI across the entire region was 19.2. Willow biomass can be a carbon negative or low-carbon energy source with a high EROI in regions with similar infrastructure, transportation distances, and growing conditions such as soil characteristics, land cover types, and climate. Full article
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Article
Willow Biomass as Energy Feedstock: The Effect of Habitat, Genotype and Harvest Rotation on Thermophysical Properties and Elemental Composition
Energies 2020, 13(16), 4130; https://doi.org/10.3390/en13164130 - 10 Aug 2020
Cited by 3 | Viewed by 798
Abstract
Willow biomass is used as a bioenergy source in various conversion technologies. It is noteworthy that apart from the beneficial environmental impact of a willow plantation, the biomass quality is also very important as it has an impact on the effectiveness of its [...] Read more.
Willow biomass is used as a bioenergy source in various conversion technologies. It is noteworthy that apart from the beneficial environmental impact of a willow plantation, the biomass quality is also very important as it has an impact on the effectiveness of its use and emissions produced in various bioenergy technologies. Therefore, this study analysed the thermophysical properties and elemental composition of 15 genotypes of willow biomass from two plantations situated in the north of Poland, harvested in two consecutive three-year rotations. The differences in the moisture content, ash content and the lower heating value were mainly determined by the genotype, i.e., by genetic factors. In contrast, the content of carbon, nitrogen, sulphur and hydrogen was determined by the location (environmental factors), but also by the genotype, and by a combination of these factors. The following were the mean levels of the willow biomass characteristics, regardless of the location, genotype and harvest rotation: 48.9% moisture content, 1.26% d.m. ash content, 19.4% d.m. fixed carbon, 79.4% d.m. volatile matter, 19.53 MJ kg−1 d.m. higher heating value, 8.20 MJ kg−1 lower heating value, 52.90% d.m. carbon, 6.23% d.m. hydrogen, 0.032% d.m. sulphur, 0.42% d.m. nitrogen. The present research has shown that the selection of the willow genotype is important for the quality of biomass as energy feedstock. However, plantation location, as well as successive harvest rotations, can have a significant impact on the biomass elemental composition. Full article
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Article
A GIS Approach to Locate a Small Size Biomass Plant Powered by Olive Pruning and to Estimate Supply Chain Costs
Energies 2020, 13(13), 3385; https://doi.org/10.3390/en13133385 - 01 Jul 2020
Cited by 13 | Viewed by 1018
Abstract
The valorization of agricultural residues plays a fundamental role in renewable energy production. Particularly, the management of olive orchards in Lazio region generates a considerable amount of biomass that is currently unexploited, but it could represent a valid source of solid biofuel for [...] Read more.
The valorization of agricultural residues plays a fundamental role in renewable energy production. Particularly, the management of olive orchards in Lazio region generates a considerable amount of biomass that is currently unexploited, but it could represent a valid source of solid biofuel for energy production in the Lazio region (Italy). Using a Geographic Information System (GIS) approach entirely based on open source software, five suitable areas (A, B, C, D and E) have been selected as eligible for hosting and feeding a 1 MWe power plant. Harvesting and transportation costs were also calculated. The harvesting operation costs were EUR 96.79 Mgfm−1 in A, while they ranged from EUR 49.83 Mgfm−1 (E) up to EUR 56.51 Mgfm−1 (D) for the other sub-areas. Sub-area A showed also higher transport costs, EUR 21.55 Mgfm−1 while the same value ranged from EUR 14.75 Mgfm−1 (E) to EUR 16.59 Mgfm−1 (B) in the other sub-areas. However harvesting costs resulted higher than those reported in the literature, mainly due to the low pruning yield per surface unit, an aspect which is directly related to the olive grove’s management in the region where annual pruning is the usual practice. Future developments of the present study should encompass the social and environmental aspects of residual biomass supply chains herein proposed. Full article
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Article
Medium Rotation Eucalyptus Plant: A Comparison of Storage Systems
Energies 2020, 13(11), 2915; https://doi.org/10.3390/en13112915 - 06 Jun 2020
Viewed by 774
Abstract
Eucalyptus spp. are among the most suitable species for biomass production, even for the firewood derived from medium-rotation coppice (MRC). The general problem of wood is that it cannot be utilized immediately because of the high moisture content, which in the combustion process [...] Read more.
Eucalyptus spp. are among the most suitable species for biomass production, even for the firewood derived from medium-rotation coppice (MRC). The general problem of wood is that it cannot be utilized immediately because of the high moisture content, which in the combustion process would reduce remarkably the yield of energy. In this context, outdoor storage of whole stems without branches (WS), outdoor storage of whole stems with branches (WSB), open shed storage of firewood logs in mesh bags (OSF), and outdoor firewood logs in mesh bags (ODF) of Eucalyptus spp woody biomass were compared in term of moisture and dry matter loss to evaluate the most convenient form of storing biomass deriving from a medium-rotation coppice. During the storage period, ODF showed higher moisture values than OSF, WSB, and WS, underlining that moisture reduction is related to local climatic conditions, pile size and permeability (compaction). However, at the end of the storage period, the four options reached a similar moisture to the commercial one of fuel wood (around 15%). WSB showed the highest loss of dry matter (18%), which can be ascribed to the drying and falling process of the leaves. In conclusion, the qualitative and quantitative characteristics of the biomass were similar after the different storage systems, producing firewood suitable for new market opportunities. Full article
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Article
Storage of Fine Woodchips from a Medium Rotation Coppice Eucalyptus Plantation in Central Italy
Energies 2020, 13(9), 2355; https://doi.org/10.3390/en13092355 - 08 May 2020
Cited by 8 | Viewed by 963
Abstract
Eucalyptus spp. has received attention from the research and industrial field as a biomass crop because of its fast growth and high productivity. The features of this species match with the increasing demand for wood for energy production. Commonly, the wood used [...] Read more.
Eucalyptus spp. has received attention from the research and industrial field as a biomass crop because of its fast growth and high productivity. The features of this species match with the increasing demand for wood for energy production. Commonly, the wood used for energy production is converted in chips, a material susceptible to microbial degradation and energy losses if not properly stored before conversion. This study aims at investigating two outdoor storage systems of Eucalyptus wood chips (covered vs. uncovered), assessing the variation in moisture content, dry matter losses and fuel characteristics. The class size of the material was P16, which was obtained using a commercial chipper appositely searched to conduct the study. The results highlighted how the different storage methods were influenced by the climatic condition: the woody biomass covered showed the best performances in terms of dry matter losses achieving 2.7% losses vs. the 8.5% of the uncovered systems. However, fuel characteristics displayed minor changes that affected the final energy balance (∆En = −0.2% in covered; ∆En = −6.17% in uncovered). Particle size varied in both methods with respect to the start conditions, but the variation was not enough to determine a class change, which remained P16 even after storage. Full article
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Article
Life Cycle Assessment of Giant Miscanthus: Production on Marginal Soil with Various Fertilisation Treatments
Energies 2020, 13(8), 1931; https://doi.org/10.3390/en13081931 - 14 Apr 2020
Cited by 11 | Viewed by 963
Abstract
In Poland, unutilised land occupies approximately two million hectares, and it could be partly dedicated to the production of perennial crops. This study aimed to determine the environmental impact of the production of giant miscanthus (Miscanthus x giganteus J.M. Greef & M. [...] Read more.
In Poland, unutilised land occupies approximately two million hectares, and it could be partly dedicated to the production of perennial crops. This study aimed to determine the environmental impact of the production of giant miscanthus (Miscanthus x giganteus J.M. Greef & M. Deuter). The experiment was set up on a low-fertility site. The crop was cultivated on sandy soil, fertilised with digestate, and mineral fertilisers (in the dose of 85 and 170 kg ha−1 N), and was compared with giant miscanthus cultivated with no fertilisation (control). The cradle-to-farm gate system boundary was applied. Fertilisers were more detrimental to the environment than the control in all analysed categories. The weakest environmental links in the production of miscanthus in the non-fertilised treatment were fuel consumption and the application of pre-emergent herbicide. In fertilised treatments, fertilisers exerted the greatest environmental impact in all the stages of crop production. The production and use of fertilisers contributed to fossil depletion, human toxicity, and freshwater and terrestrial ecotoxicity. Digestate fertilisers did not lower the impact of biomass production. The current results indicate that the analysed fertiliser rates are not justified in the production of giant miscanthus on nutrient-deficient soils. Full article
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Article
Admixing Chaff with Straw Increased the Residues Collected without Compromising Machinery Efficiencies
Energies 2020, 13(7), 1766; https://doi.org/10.3390/en13071766 - 07 Apr 2020
Cited by 8 | Viewed by 943
Abstract
The collection of residues from staple crop may contribute to meet EU regulations in renewable energy production without harming soil quality. At a global scale, chaff may have great potential to be used as a bioenergy source. However, chaff is not usually collected, [...] Read more.
The collection of residues from staple crop may contribute to meet EU regulations in renewable energy production without harming soil quality. At a global scale, chaff may have great potential to be used as a bioenergy source. However, chaff is not usually collected, and its loss can consist of up to one-fifth of the residual biomass harvestable. In the present work, a spreader able to manage the chaff (either spreading [SPR] on the soil aside to the straw swath or admixed [ADM] with the straw) at varying threshing conditions (with either 1 or 2 threshing rotors [1R and 2R, respectively] in the combine, which affects the mean length of the straw pieces). The fractions of the biomass available in field (grain, chaff, straw, and stubble) were measured, along with the performances of both grain harvesting and baling operations. Admixing chaff allowed for a slightly higher amount of straw fresh weight baled compared to SPR (+336 kg straw ha−1), but such result was not evident on a dry weight basis. At the one time, admixing chaff reduced the material capacity of the combine by 12.9%. Using 2R compared to 1R strongly reduced the length of the straw pieces, and increased the bale unit weight; however, it reduced the field efficiency of the grain harvesting operations by 11.9%. On average, the straw loss did not vary by the treatments applied and was 44% of the total residues available (computed excluding the stubble). In conclusion, admixing of chaff with straw is an option to increase the residues collected without compromising grain harvesting and straw baling efficiencies; in addition, it can reduce the energy needs for the bale logistics. According to the present data, improving the chaff collection can allow halving the loss of residues. However, further studies are needed to optimise both the chaff and the straw recoveries. Full article
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Article
Machine Performance and Hog Fuel Quality Evaluation in Olive Tree Pruning Harvesting Conducted Using a Towed Shredder on Flat and Hilly Fields
Energies 2020, 13(7), 1713; https://doi.org/10.3390/en13071713 - 03 Apr 2020
Cited by 21 | Viewed by 1257
Abstract
Pruning residues from olive groves represent an important biomass source. Until now, the management of pruning residue has generally represented a disposal problem rather than an opportunity for additional revenue. The main problem is the lack of a well-organized pruning biomass supply chain. [...] Read more.
Pruning residues from olive groves represent an important biomass source. Until now, the management of pruning residue has generally represented a disposal problem rather than an opportunity for additional revenue. The main problem is the lack of a well-organized pruning biomass supply chain. In particular, harvesting is a key stage that influences the product quality, the type of logistics chain, and the economic sustainability of the pruning supply chain. The aim of the present paper was the evaluation of the machine performance of the Facma Comby TR200 towed shredder. The harvesting tests took place in Agios Konstantinos, Fthiotida, Central Greece. Two different experimental fields were used for the evaluation of this harvesting system; these fields were characterized by different slopes to check the convenience of using such a towed shredder on both hilly slopes and flat terrains. Analysis was conducted focusing on both the work productivity and costs. Moreover, an evaluation of the obtained hog fuel quality was performed. The Facma Comby TR200 showed good work performances on both flat (2.60 tdm·h−1) and hilly (2.74 tdm·h−1) land, even if a consistent influence of the pruning biomass yield on the work performances was reported. The biomass quality could be consistently improved by modifying the pick-up systems to avoid the collection of inert materials (soil and rocks). In fact, the analysis showed a high ash content in the comminuted material (4% dry basis). Finally, the economic aspects of this study’s results were in line with those reported in the literature. The applied harvesting system showed a cost equal to 29.88 and 16.59 €·tfm−1 on flat and hilly land, respectively. Full article
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Article
Equipping a Combine Harvester with Turbine Technology Increases the Recovery of Residual Biomass from Cereal Crops via the Collection of Chaff
Energies 2020, 13(7), 1572; https://doi.org/10.3390/en13071572 - 31 Mar 2020
Cited by 10 | Viewed by 1386
Abstract
In cereal crops, chaff is a valuable lignocellulosic by-product that accounts for more than 50 Mt y−1 in Europe and is suitable for bioenergy purposes. Chaff is usually not collected due to the lack of combine harvesters that have the capability to [...] Read more.
In cereal crops, chaff is a valuable lignocellulosic by-product that accounts for more than 50 Mt y−1 in Europe and is suitable for bioenergy purposes. Chaff is usually not collected due to the lack of combine harvesters that have the capability to handle it properly. The present two years experimental study investigated the hypothesis that the overall biomass collected in wheat crop can be increased by equipping the combine harvester with an aftermarket device. Chaff, discharged from the combine harvester-cleaning system, is collected by the turbine that delivers it either on the swath or on a lateral trailer towed by a tractor. The performance of all machines involved in the harvesting (combine harvester, tractor, baler, and trailer) were assessed. The chaff was collected in bales with the straw (A mode) and separately on a trailer (C mode). Comparisons with non-collected treatment (B mode) were performed in order to estimate the total chaff collected and the biomass losses. The results showed that 1.79 t FM ha−1 per year of chaff could be collected when baled with the straw, whereas 1.27 t FM ha−1 were collected separately on a trailer. Both field and material capacity were not negatively affected by the chaff collection. Therefore, our study confirmed the hypothesis that turbine technology is a valid solution for increasing the total residual biomass collected in cereal cropping for energy purposes. Full article
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Communication
Camelina and Crambe Oil Crops for Bioeconomy—Straw Utilisation for Energy
Energies 2020, 13(6), 1503; https://doi.org/10.3390/en13061503 - 22 Mar 2020
Cited by 12 | Viewed by 1141
Abstract
Agriculture can provide biomass for bioproducts, biofuels and as energy feedstock with a low environmental impact, derived from carbohydrate, protein and oil annual crops, as well from lignocellulosic crops. This paper presents the thermophysical and chemical features of camelina and crambe straw depending [...] Read more.
Agriculture can provide biomass for bioproducts, biofuels and as energy feedstock with a low environmental impact, derived from carbohydrate, protein and oil annual crops, as well from lignocellulosic crops. This paper presents the thermophysical and chemical features of camelina and crambe straw depending on nitrogen fertilisation rate with a view to their further use in a circular bioeconomy. A two-factorial field experiment was set up in 2016, with camelina and crambe as the first factor and the N fertilizer rate (0, 60 and 120 kg·ha−1·N) as the second factor. Ash content in crambe straw (6.97% d.m.) was significantly higher than in camelina straw (4.79% d.m.). The higher heating value was higher for the camelina (18.50 MJ·kg−1·d.m.) than for the crambe straw (17.94 MJ·kg−1·d.m.). Sulphur content was also significantly higher in camelina than in crambe straw. An increase in nitrogen content with increasing fertilisation rate was visible in the straw of both species (from 1.19 to 1.33% d.m., for no fertilisation and for a rate of 120 kg·ha−1·N, respectively). Crambe straw contained more than five times more chlorine than camelina straw. In conclusion, despite certain adverse properties, camelina and crambe straw can be an alternative to other types of biomass, both for direct combustion, gasification and in the production of second-generation biofuels. Full article
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Article
Energy Value of Yield and Biomass Quality of Poplar Grown in Two Consecutive 4-Year Harvest Rotations in the North-East of Poland
Energies 2020, 13(6), 1495; https://doi.org/10.3390/en13061495 - 22 Mar 2020
Cited by 12 | Viewed by 991
Abstract
Bioenergy accounts for 61.7% of all renewable energy sources, with solid fuels accounting for 43% of this amount. Poplar plantations can deliver woody biomass for energy purposes. A field experiment with poplar was located in the north-east of Poland on good quality soil [...] Read more.
Bioenergy accounts for 61.7% of all renewable energy sources, with solid fuels accounting for 43% of this amount. Poplar plantations can deliver woody biomass for energy purposes. A field experiment with poplar was located in the north-east of Poland on good quality soil formed from medium loam. The study aimed to determine the yield, the energy value of the yield and the thermophysical properties and elemental composition of the biomass of four poplar clones harvested in two consecutive 4-year harvest rotations. The highest biomass energy value was determined in the UWM 2 clone in the second harvest rotation (231 GJ ha−1·year−1). This value was 27–47% lower for the other clones. The biomass quality showed that poplar wood contained high levels of moisture and low levels of ash, sulphur, nitrogen and chlorine. This indicates that poplar can be grown in the north-east of Poland and that it gives a yield with a high energy value and beneficial biomass properties from the energy generation perspective. Full article
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Article
Analysis of the Work Productivity and Costs of a Stationary Chipper Applied to the Harvesting of Olive Tree Pruning for Bio-Energy Production
Energies 2020, 13(6), 1359; https://doi.org/10.3390/en13061359 - 14 Mar 2020
Cited by 17 | Viewed by 1498
Abstract
Pruning residues could represent an important biomass resources for energy production. Only in Italy it has been estimated that an annual quantity of biomass of over 2600 kt of dry matter could be obtained from olive residues. Several machines developed for pruning harvesting [...] Read more.
Pruning residues could represent an important biomass resources for energy production. Only in Italy it has been estimated that an annual quantity of biomass of over 2600 kt of dry matter could be obtained from olive residues. Several machines developed for pruning harvesting are available in the market, most of which are tractor-driven, while limited knowledge is available on performance, quality of work and costs of harvesting logistics based on stationary chippers. The aim of the present paper is to analyze machine performance of a forestry stationary chipper applied to pruning harvesting for what concerns work productivity, quality of the comminuted product and harvesting operating costs. This system is actually applied by Fiusis Company, an Italian enterprise which manages a biomass power plant exclusively powered by olive trees’ pruning residues, and it has never been analyzed in literature. The results obtained showed consistent work productivity, which resulted the highest ever found in olive pruning harvesting systems and equal to 5.23 ± 0.81 tdm·h−1. This high work productivity allowed also to obtain a little economic gain from a matter, which is actually considered a problem for olive groves’ owners and not a potential source of income. In particular, the use of a stationary chipper seemed very efficient in olive groves with a consistent amount of wooden residues to be processed and with big branches not harvestable by the most common towed pruning harvester. In addition, the stationary chipper has the advantage of avoiding the preliminary raking operation, which results in reduced costs for the farmer. Full article
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Article
An Innovative System for Maize Cob and Wheat Chaff Harvesting: Simultaneous Grain and Residues Collection
Energies 2020, 13(5), 1265; https://doi.org/10.3390/en13051265 - 09 Mar 2020
Cited by 10 | Viewed by 1324
Abstract
Maize and wheat are two of the most widespread crops worldwide because of their high yield and importance for food, chemical purposes and livestock feed. Some of the residues of these crops (i.e., maize cob and wheat chaff) remain in the field after [...] Read more.
Maize and wheat are two of the most widespread crops worldwide because of their high yield and importance for food, chemical purposes and livestock feed. Some of the residues of these crops (i.e., maize cob and wheat chaff) remain in the field after grain harvesting. In Europe, just maize cob and grain chaff could provide an annual potential biomass of 9.6 Mt and 54.8 Mt, respectively. Collecting such a biomass could be of interest for bioenergy production and could increase farmers’ income. Progress in harvest technology plays a key role in turning untapped by-products into valuable feedstocks. This article presents a study of the performance and the quality of the work of Harcob, an innovative system developed for maize cob collection. Furthermore, the feasibility of using the Harcob system to also harvest wheat chaff during wheat harvesting was also verified. The results showed that it was possible to harvest 1.72 t ha−1 and 0.67 t ha−1 of cob and chaff, respectively, without affecting the harvesting performance of the combine. The profit achievable from harvesting the corn cob was around 4%, while no significant economic benefits were observed during the harvesting of wheat chaff with the Harcob system. The use of cereal by-products for energy purposes may allow the reduction of CO2 from fossil fuel between 0.7 to 2.2 t CO2 ha−1. The Harcob system resulted suitable to harvest such different and high potential crop by-products and may represent a solution for farmers investing in the bioenergy production chain. Full article
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