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The aim of the paper is to present the results of investigations of fine particle generation by small biomass combustion and the possibility of reducing the emissions by electrostatic precipitation.

The grains, wood‐logs, wood‐, mixed‐ and straw‐pellets were combusted in two stoves and two boilers. The set‐ups were operated according to DIN‐4702. Particle number concentration in the gas flow was measured by Scanning Mobility Particle Sizer and particle mass concentration was measured according to the Guidelines VDI‐2066 upstream and downstream a novel space charge electrostatic precipitator (ESP). The ESP consists of an ioniser and a grounded brush inside of a tube form grounded collector electrode.

The ESP ensures stable operation at gas temperatures up to 350°C. The use of sharp‐points high voltage electrode ensures effective particle charging at high particle number concentrations. The combustion of wood‐pellets is characterized by lower particle mass concentrations. The highest particle mass concentrations were observed by the straw‐pellets combustion. The ESP ensures particle collection with mass collection efficiency 87±3% for wood‐logs and 82±2% for wood‐pellets combustion.

The novel ESP is recommended for exhaust gas cleaning from small scale biomass combustion facilities and domestic heating units. The use of the ESP would reduce the emissions of fine aerosol into the atmosphere and improve the air quality.

The paper presents the comparative analysis of particle size distribution and particle mass concentrations in the exhaust gas from small‐scale combustion units for different types of biomass. The study confirms the possibility to reduce particle emissions by electrostatic precipitation. The originality of the technology and apparatus is patently protected.

In the Baltic Sea area, wood fuels have been traded internationally on a relatively large‐scale since the 1990s, with trade flows primarily from the Baltic States to Sweden and Denmark. This has been driven by strong demand for renewable energy in Scandinavia, inexpensive wood resources in the Baltic States and relatively low costs of sea transport. The purpose of this paper is to clarify if this trade has contributed to integration between the wood fuel markets of Sweden and Estonia.

The authors use co‐integration analysis of quarterly price series data from 1998 to 2010, in order to determine whether there are interconnections between wood fuel prices in the two countries. As wood fuels generally are rather bulky, transport costs often have an important impact on price levels. For this reason the analysis is expanded to include estimated transport costs from Estonia to Sweden.

It is concluded that wood fuel prices in Sweden and Estonia are not co‐integrated, regardless of whether the transportation costs are taken into account or not. In other words, the wood fuel markets in the two countries cannot be considered integrated, which could be seen as a sign that international wood fuel markets still are far from fully developed.

There are some uncertainties about data quality and lack of information on market structure – in terms of, for example, fuel delivery contract specifications and shipping arrangements.

Lack of market integration implies a lack of market efficiency in the international wood fuel market.

Co‐integration analysis has been applied to many commodity markets, but there are only very few studies of international wood fuel markets.

Second-generation biofuel is regarded as a sustainable alternatives to fossil energy in transportation where electricity is not feasible. The main purpose of this study is to analyze how large-scale second-generation biofuel based on wood may affect the competitiveness of more mature bioenergy technologies such as bioheat through competition in the biomass market. The impacts on forest industries are also included.

An economic model for the energy and forest sectors based on partial equilibrium modeling is used to quantify the impacts of four different locations of biofuel production in Norway.

The results show that there are regional variations in biomass price effects depending on local raw material availability and costs of transport and import. Technologies allowing for a larger variety of wood biomass qualities will face lower biomass prices than technologies using only one species as raw material, causing less reduction in the production of bioheat and forest industrial products. For Norway specifically, the paper concludes that even if there is a potential for both increased bioheat generation and large-scale biofuel production, the production of second-generation biofuels based on domestic wood resources will cause a 5-20 percent reduction in bioheat generation depending on the scale of biofuel production.

This study demonstrates how impacts on biomass markets from establishment of biofuel production vary quite substantially with location, production level and choice of feedstock. One main finding is the quite large biomass cost impact that is seen in the model runs when introducing large-scale biofuel production. Increased biomass costs reduce the profitability and this must be taken into account when establishing a biofuel installation.

The originality of the paper is the analyses of biofuel impacts with a detailed model for biomass supply as the bioenergy and forest sectors.

Lignite coal-fired power plants are the main electricity generators in the province of Saskatchewan, Canada. Although burning lignite coal to generate power is economical, it produces significant greenhouse gases making it a big challenge to Canada’s international commitment on emission reduction. However, abundant agricultural crops and sawdust produced in Saskatchewan put the province in a good position to produce and use agri-pellets as an alternative fuel to generate electricity. This study aims to conduct an economic and environmental analysis of the replacement of lignite coal by agri-pellets as the fuel for Saskatchewan’s coal-fired power plants.

The study estimates the economic and environmental costs and benefits of two alternative fuels for power plants. The economic analysis is based on the pellet production and transportation costs from farms to production sites and from the production sites to power plants. In the production process, biomass precursors are densified with and without additives to produce fuel agri-pellets with appropriate mechanical durability and high heating value per volume unit. The environmental analysis involves estimation of greenhouse gas emissions and their social costs for lignite coal and different types of agri-pellets under different scenarios for pellet production and transportation.

The results show that although the total cost of electricity is lower for coal than agri-pellets, the gap shrinks when social costs and specifically a carbon price of $50/tonne are included in the model. The cost of electricity in lignite coal-fired power plants would also be on par with agri-pellets-fired power plants if the carbon price is between U$68 and $78 per tonne depending on the power plant locations. Therefore, a transition from coal to agri-pellet fuels is feasible if a high-enough price is assigned to carbon. The method and the results can be generalized to other places with similar conditions.

There are a few caveats in this study as follows. First, the fixed costs associated with the transformation of the existing coal-fired power plants to pellet-fired plants are not considered. Second, the technological progress in the transportation sector, which would favor the net benefits of using pellets versus coal, is not included in the analysis. Finally, the study does not address the possible political challenges facing the transition in the context of the Canadian federal system.

The study results indicate that the current carbon price of $50 per tonne is not sufficient to make the agri-pellets a feasible source of alternative energy in Saskatchewan. However, if carbon pricing continues to rise by $15 annually starting in 2022, as announced, a transition from coal to agri-pellets will be economically feasible.

Canada is committed to reduce its emission according to the Paris agreement, and therefore, needs to have a concrete policy to find alternative energy sources for its coal-fired power plants. This study examines the challenges and benefits of such transition using the existing agri-pellet resources in Saskatchewan, a province with abundant agricultural residues and coal-fired power plants. The findings indicate that a significant emission reduction can be achieved by using agri-pellets instead of coal to produce electricity. The study also implies that the transition to renewable energy is economical when social costs of carbon (carbon tax) is included in the analysis.

As far as the authors know, this is the first study providing a socio-economic analysis for a possible transition from the coal-fired power plants to a more clean and sustainable renewable energy source in one of the highest carbon dioxide (CO₂) producer provinces in Canada: Saskatchewan. The study builds upon the technical production of three agri-pellets (oat hull, canola hull and sawdust) and estimates the economic and environmental costs of alternative fuels under different scenarios.

One way of overcoming logistics barriers (poor transportation, handling and storage properties) towards increased utilisation of biomass is to introduce a pre‐treatment process such as torrefaction early in the biomass‐to‐energy supply chain. Torrefaction offers a range of potentially beneficial logistics properties but the actual benefits depend upon how the supply chain is configured to address various elements of customer demand. Hence, the aim of this paper is to develop a framework for torrefaction configuration in a supply chain perspective for different types of customers.

Sophisticated pre‐treatment processes are yet to reach the commercialisation phase. Identification of possible supply chain configurations is in this paper done through a conceptual approach by bringing together knowledge from related research fields such as unrefined forest fuel, pellets and coal logistics with prescriptions for configuration derived from the subject area of supply chain management (SCM).

A framework that explicates different elements of supply and demand of torrefaction is proposed, and exemplified by three distinct supply chains. Depending on demand, torrefaction serves different purposes, bridging gaps in place, time, quality and ownership. Furthermore, different supply chain configurations will pose different requirements on torrefaction in terms of producing different product quality, durability, energy density and hydrophobicity of the pellets.

The proposed framework entails a set of propositions, but requires further development through empirical studies using complementary research methods such as interviews or surveys and quantification through techno‐economical or optimisation from a supply chain perspective.

This paper provides a framework that can inform decisions makers in biomass‐to‐energy supply chains, in particular at torrefaction plants, on upstream and downstream implications of their decisions.

The findings have implications for biomass‐to‐energy supply chains in general, and in particular, the paper provides a supply chain perspective of pre‐treatment processes, where previous research has focused primarily on technical aspects of torrefaction.

The purpose of this study is to establish a vibration prediction of pellet mills power transmission by artificial neural network. Vibration monitoring is an important task for any system to ensure safe operations. Improvement of control strategies is crucial for the vibration monitoring.

As predictive control is one of the options for the vibration monitoring in this paper, the predictive model for vibration monitoring was created.

Although the achieved prediction results were acceptable, there is need for more work to apply and test these results in real environment.

Artificial neural network (ANN) was implemented as the predictive model while extreme learning machine (ELM) and back propagation (BP) learning schemes were used as training algorithms for the ANN. BP learning algorithm minimizes the error function by using the gradient descent method. ELM training algorithm is based on selecting of the input weights randomly of the ANN network and the output weight of the network are determined analytically.

The purpose of this paper is to investigate the criteria influencing the adoption of innovation in the empirical context of renewable residential energy solutions, particularly the wood pellet heating system.

The study carried out an extensive literature review on Rogers’ characteristics of innovation theory and then complemented it with a content analysis on empirically perceived characteristics of wood pellet heating systems.

The literature review shows that most of the previous studies employ the characteristics of innovation but do not confirm the usability of the Rogers framework as a whole. In addition, our empirical results demonstrate that relative advantage is the predominant characteristic in the adoption of residential energy systems.

The limitations of the literature review and the biases of empirical findings are discussed. For instance, there are limitations that the study is based on single country data and its theoretical approach relies on only one theory, Rogers’ characteristics of innovation.

In order to achieve sustainable strategic advantage, firms providing renewable energy solutions should attempt to communicate clearly the relative advantages instead of attempting to, for instance, offer an opportunity for trialling such green energy systems.

The paper highlights the use of characteristics of innovation and further empirically examines the perceived characteristics of an innovation considering green investments in residential heating systems. Owing to the exploratory nature of the study, the results provide a gateway to a number of possible avenues for future research.

Decreasing energy demand due to improved building standards requires the development of new biomass combustion technologies to be able to provide individual biomass heating solutions. The purpose of this paper is, therefore, the development of a pellet water heating stove with minimal emission at high thermal efficiency.

The single components of a 10 kW water heating pellet stove are analysed and partly redesigned considering the latest scientific findings and experimental know‐how in combustion engineering. The outcome of this development is a 12 kW prototype which is subsequently down‐scaled to a 6 kW prototype. Finally, the results of the development are evaluated by testing of an accredited institute.

Based on an existing pellet water heating stove, the total excess air ratio was reduced, a strict air staging was implemented and the fuel supply was homogenized. All three measures improved the operating performance regarding emissions and thermal efficiency. The evaluation of the development process showed that the CO emissions are reduced by over 90 per cent during full load and by 30‐60 per cent during minimum load conditions. Emissions of particulate matter are reduced by 70 per cent and the thermal efficiency increased to 95 per cent.

The result represents a new state of technology in this sector for minimal emissions and maximal thermal efficiency, which surpasses the directives of the Eco label “UZ37” in Austria and “Blauer Engel” in Germany, which are amongst the most stringent performance requirements in the European Union. Hence this design possesses a high potential as heating solution for low and passive energy houses.

Thermochemical conversion processes are one of the possible solutions for the flexible production of electric and thermal power from biomass. The pyrolysis degradation process presents, among the others, the interesting features of biofuels and high energy density bio-oil production potential high conversion rate. In this paper, numerical results of a slow batch and continuous fast pyrolyzers, are presented, aiming at validating both a tridimensional computational fluid dynamics-discrete element method (CFD–DEM) and a monodimensional distributed activation energy model (DAEM) represents with data collected in dedicated experiments. The purpose of this paper is then to provide reliable models for industrial scale-up and direct design purposes.

The slow pyrolysis experimental system, a batch of small-scale constant-pressure bomb for allothermic conversion processes, is presented. A DEM numerical model has been implemented by means of a modified OpenFOAM solver. The fast pyrolysis experimental system and a lab scale screw reactor designed for biomass fast pyrolysis conversion are also presented along with a 1D numerical model to represent its operation. The model which is developed for continuous stationary feeding conditions and based on a four-parallel reaction chemical framework is presented in detail.

The slow pyrolysis numerical results are compared with experimental data in terms of both gaseous species production and reduction of the bed height showing good predictive capabilities. Fast pyrolysis numerical results have been compared to the experimental data obtained from the fast pyrolysis process of spruce wood pellet. The comparison shows that the chemical reaction modeling based on a Gaussian DAEM is capable of giving results in very good agreement with the bio-oil yield evaluated experimentally.

As general results of the proposed activities, a mixed experimental and numerical approach has demonstrated a very good potential in developing design tools for pyrolysis development.