• Energy Research

Purpose: The main aim of the study is to assess the environmental and economic impacts of the lodging sector located in the Himalayan region of Nepal, from a life cycle perspective. The assessment should support decision making in technology and material selection for minimal environmental and economic burden in future construction projects. Methods: The study consists of the life cycle assessment and life cycle costing of lodging in three building types: traditional, semi-modern and modern. The life cycle stages under analysis include raw material acquisition, manufacturing, construction, use, maintenance and material replacement. The study includes a sensitivity analysis focusing on the lifespan of buildings, occupancy rate and discount and inflation rates. The functional unit was formulated as the ‘Lodging of one additional guest per night’, and the time horizon is 50 years of building lifespan. Both primary and secondary data were used in the life cycle inventory. Results and discussion: The modern building has the highest global warming potential (kg CO2-eq) as well as higher costs over 50 years of building lifespan. The results show that the use stage is responsible for the largest share of environmental impacts and costs, which are related to energy use for different household activities. The use of commercial materials in the modern building, which have to be transported mostly from the capital in the buildings, makes the higher GWP in the construction and replacement stages. Furthermore, a breakdown of the building components shows that the roof and wall of the building are the largest contributors to the production-related environmental impact. Conclusions: The findings suggest that the main improvement opportunities in the lodging sector lie in the reduction of impacts on the use stage and in the choice of materials for wall and roof.

Abstract Color of wood pellets is mainly affected by the feedstock material used for their production and which composition and characteristic affect the final product quality. Pellets made from pure wood are light in color and have low ash content, while pellets made from different mixtures of wood and bark or foliage are generally darker and richer in minerals. This study aims to verify the correlation between color and quality parameters of wood pellets available on the Italian market. All the samples were analyzed following the procedures laid down by the European Norms (EN) on solid biofuels for moisture, ash, calorific value, durability, bulk and solid density. The acquisition of the images was done with two techniques: the CIE L ∗ a ∗ b ∗ color space and RGB-HSV color spaces. Canonical correlation analysis (CCA) was performed with CIE- L ∗ a ∗ b , RGB and HSV separately showing for all the color components good degree of correlation with ash content of pellets. The PCA analysis on two principal components (total explained variance: 64.2%) showed a clear color gradient moving form good to medium or low quality parameters. This pattern is confirmed by the clustering of certified pellets in the region of lightest samples. The calculation of Δ E and ΔRGB showed a good discrimination level between whole pellets samples and their sawdust, and between ones with high and low ash content. The visual predictability of pellets quality on the basis of their color is however not so sharp when considering samples with similar colors. The industrial applicability of such methods for the evaluation of pellets quality is desirable for RGB methodologies that are less expensive and more reliable in working condition, given that specific color calibration is performed.

The global charcoal trade is steadily growing, with high-income countries importing significant quantities of this material from regions where its production is often associated with severe environmental issues, including forest overexploitation, illegal logging, and environmental pollution. Promoting local charcoal production in high-income countries is crucial to addressing these challenges. In this study, we have chosen to focus on the European context, specifically emphasizing Italy as a case study. Our study aimed to comprehensively compare five distinct charcoal production systems, including both traditional and modern solutions, with a specific focus on evaluating the quality of the resulting charcoal. Additionally, improvements were evaluated to enhance production efficiency. Traditional systems cannot satisfy production requests, resulting in inefficiencies in manpower, costs, times, and yield. Conversely, recent innovations consider mobile and stationary kiln prototypes. Mobile kilns offer flexibility and cost savings but require operator expertise, limit automation, and have long cycles. In contrast, stationary systems operate continuously, increasing productivity and efficiency, despite higher investment costs. Notably, charcoal quality showed minimal differences. These findings highlighted the potential of new technologies to enhance efficiency, reduce cost and environmental impact, and promote sustainable charcoal production.

Abstract This study uses Geographical Information Systems (GIS) to estimate woody biomass supply and demand in Northeast Italy. Demand is estimated using census data on boilers and supply calculations are derived from data on timber harvests and mill operations. The analysis is done with GIS using Large Scale Analysis at a broader resolution (for the entire region) and Small Scale Analysis at a finer resolution (for the Primiero valley only), with added information on tree species, road networks and logging systems. From large scale analysis demand results to be about 163 000 MWh, corresponding to about 71 000 tonnes per year of fuel, with a moisture content of 50 percent. As shown by results from a small scale analysis, the Primiero valley has a deficit of 21 400 MWh. A more thorough analysis shows that 93 percent of logging operations can be performed with cable cranes and that high quality chips derived from forest biomass amount to only 335 MWh of energy (20 percent of the total). The deficit calculated at a small scale confirms the value obtained in the large scale calculation. Analysis of the demand-supply balance will be helpful for decision makers and politicians and should be taken into account when allocating subsidies for new boilers or district heating.

The EU is one of the largest producers and consumers of wood pellets in the world, covering around 36% of the global wood pellet production and around 50% of the global consumption in 2018. The EU wood pellet consumption is expected to further increase in response to the ambitious energy and climate goals for 2030. Currently, wood pellets are mainly produced from sawdust and other sawmill residues; however, other types of forest feedstock are being investigated in order to meet the increasing wood pellet demand and move toward greater energy independence. The aim of this study is to evaluate and compare the environmental impact of different wood pellet supply chains. A comparative cradle-to-grave life cycle assessment is performed considering the following wood feedstock systems: (i) sawdust from sawmill (S1), (ii) roundwood logs (S2), (iii) whole trees from forest thinning operation (S3), and (iv) logging residues produced during forest tree harvesting (S4). The study focuses on Global Warming Potential (GWP), Ozone Depletion Potential (ODP), Photochemical Ozone Creation Potential (POCP), and Human Toxicity Potential (HTP). Results show that S3 displays the lowest figures on all the environmental impact categories considered in this study. Compared to the reference case S1, S3 shows a GWP reduction of 46%, an ODP reduction of 6.6%, a POCP reduction of 14.8%, and HTP reduction of 13.2%. S3 and S4 have lower GWP than S1 and S2, even when the biogenic CO2 emissions are considered. Overall, the life cycle phases that have the highest GWP, POCP, and HTP are the burning phase and the preparation of the material to be pelletized, particularly the drying process. Nevertheless, the main phases that contribute to the ODP are the forest operations and the pellet preparation.

Abstract The pellet market has experienced a continuous development and increase in recent years due to a number of positive properties of this enhanced biomass. However the supply chain has not been entirely able to follow the same trend, causing some issues, often related to the quality of traded products. These problems can be partially solved by ensuring a continuous and reliable flow of information regarding the quality parameters of wood pellets from the producers to the final users. The aim of this work is to define a metric index for quality parameters that can detect the certifiability of analyzed samples compared with those on the market. The model is built on measured quality parameters of certified and non-certified wood pellet samples taken from products on the market applying a multivariate class modelling methodology (soft independent modelling of class analogy, SIMCA). Results showed that the model can predict the general quality of some test samples and that its precision, already fairly high, can be constantly improved by adding new model samples. The output of the model is also the relative influence (modelling power) of each variable in the prediction of certifiability. The SIMCA model could be easily integrated and implemented on the most common digital platforms where users (private, laboratories, agencies, etc.) could test their samples and verify if the index of their pellet falls within the area defined by the model for certified samples.

The increasing demand of vegetal biomass for biogas production is causing competition with food production. To reduce this problem and to provide new opportunities it is necessary to take into consideration different kinds of vegetable biomass that are more sustainable. Grass from the maintenance of non-cultivated areas such as riverbanks has not yet been fully studied as a potential biomass for biogas production. Although grass has lower methane potential, it could be interesting because it does not compete with food production. However, there is a lack of appropriate technologies and working system adapted to these areas. In this paper, different systems that could be available for the mowing and harvesting of grass along riverbanks have been preliminarily assessed through the evaluation of the field capacity, labour requirement, economic and energy aspects. The splitting of the cutting and harvesting phases into operations with different machinery seems to be the best system for handling this biomass. However, these solutions have to take into consideration the presence of obstacles or accessibility problems in the harvesting areas that could limit the operational feasibility and subsequent correct sizing.

The quality requirements of wood biofuels are regulated by a series of harmonized international standards. These standards define the technical parameter limits that influence the quality of solid biomass as a fuel. In 2014 the European reference standard for solid biofuel was replaced by the International ISO standard. In the case of wood chips, the main difference between the European and International standards is the definition of particle size distribution classes. In this context, this study analyses the quality of wood chips and its variation over the years according to the “former” (EN 14691-4) and “in force” (ISO 17225-4) standards. A Soft Independent Modelling of Class Analogy (SIMCA) model was built to predict the best quality of wood chips and to clarify the relationship between quality and standard parameters, time and changes in the standard regulations. The results show that, compared to the EN standards, classification with the ISO standards increases the samples belonging to the best quality classes and decreases the not classified samples. Furthermore, all the SIMCA models have a high sensitivity (>90%), reflect the differences introduced to the quality standards and are therefore suitable for monitoring the quality of wood chips and their changes.