Storage of biomass is associated with problems like heat development, biomasslosses, and reduction of the fuel quality. Certain processes such as biological- andchemical degradation are responsible for these storage problems. This master?sthesis was carried out at Vattenfall Research and Development AB and is alignedtowards quantifying the biomass losses from short-term storage (1-2 months) ofbark and recovered wood. The biomass was stored in outdoor piles during differentseasons, campaign 1 (summer) and campaign 2 (autumn).

Stump biomass is energy rich and stump harvesting for use as fuel become more and more interesting in Sweden. Swedish Forest Agency (2009) has estimated that stump harvesting in Sweden would respond to an annual energy supply of 57 TWh/year. However, stump has not been recognized as a bioenergy resource in Sweden. Suitable methods for pre-treatment of stump are probably of great importance to make it accepted as fuel. It is therefore rewarding to carry out an investigation in this area for stump. This report represents results from a diploma project, which was aimed to develop a fixed bed reactor for experimental study of biomass torrefaction, followed by TG analysis and kinetic modelling employing Ozawa method and different kinetic models including one-step and three-pseudo-component models.

Storage of biomass is often associated with problems such as heat development, dry matter losses and reduction of fuel quality. The rise in temperature can potentially cause a risk of self-ignition in the fuel storage. Moreover, emissions from storage piles can cause health problems in the surrounding. The dry matter losses and reduction of fuel quality can have economical effects. The aim of this thesis project is to develop guidelines on how to store large amount of biomass at Vattenfalls heat and power plants in an optimal way.

Recent turmoil surrounding nuclear power as an energy source, especially since the accidentat Fukushima, has largely contributed to the debate of whether or not nuclear power should beused as an energy source. This study has examined the economic feasibility of replacingForsmark?s 3rd nuclear reactor with a bio fueled power plant, and find out how this could bedone.The power generation that has to be replaced is equal to 1170 MWe. To replace this, 6 largescaleCFB-boilers, each providing over 200 MWe, were necessary. In addition to this, eachboiler required their respective turbine sets, comprising one high-pressure-, and one lowpressureturbine with intermediate reheating capacities.Based on this, a rankine-cycle was modeled using the software EES, to be able to calculatethe total heat required in the power plant.

There are several energy systems in the Swedish society and to ensure the comfort and health of the citizens it is of importance that the different energy systems are functioning properly. District heating is one of these energy systems and many household depend only on district heating to warm up their homes. District heating is dependent on several processes where every step needs to function in order to deliver the produced heat to the end consumer. Previous studies have investigated the distribution of district heating and how to make customers choose district heating as their heating method. The supply of fuel to the district heating plant has not been studied as much, even though it is an important part of the whole system. This thesis is a part of the project NORD-STAR (Nordic Strategic Adaption Research), which has focused on climate adaption in the Nordic countries.

The annual demands for forest fuels increases in Sweden. At present, large unutilized biomass resources is found in young, dense forests from which about five million oven-dry tonnes (ODt) (23 TWh) could annually be extracted as forest fuel. But harvesting small trees give high logging costs and new cost-efficient harvesting techniques are therefore required. The aim was to study the productivity of Vimek 608 BioCombi in forest fuel thinning of Lodgepole pine and to calculate the economy of the harvesting and estimate the thinning quality. The time study was performed in Åmarken in the county of Västerbotten.

A recommendation for stand treatment of lodgepole pine (Pinus contorta) is, in a scientific point of view, lacking when it comes to harvesting for biomass energy. Within the next decades it is expected that 280 000 hectares of lodgepole pine will have reached thinning age on the domains of Svenska Cellulosa Aktiebolaget (SCA). Due to this the interest has grown rapidly for studying the possibilities of harvesting biofuel assortments already in the first thinning. In this study the distribution of the biomass within lodgepole pine trees has been studied and taken into account for estimating the proportions of harvested assortments when using different methods of thinning. The methods studied were conventional biofuel-harvesting (with delimbed branches gathered separately from the round wood) and thinning with cutting of round wood and long tops (incl.

This final thesis is initiated by the wood fuel department at the Swedish forest company Sveaskog as part of a project which also involves two other final thesises. The overall goal of the project is to investigate Sveaskog´s possibilities to produce and sell different wood fuel assortments in Västerbotten and the southern parts of Norrland. The aim of this thesis is to investigate how much wood fuel Sveaskog can produce in the area during the next five years and what that would cost. Furthermore the thesis will investigate the total possible supply of wood fuel from all other possible producers in the area. Treated assortments are forest residues from final fellings, whole trees from direct wood fuel thinnings, non industrial wood and industrial by-products from sawmills. The main effort to investigate Sveaskog´s production possibilities has been made to calculate the possible annual amount of forest residues and fuel from wood fuel thinnings that can be produced.

In this study, the effects of using fine milled cassava stems as an additive in biofuel pellet production was compared to the effects of refined starch addition. The bulk Biomass fuel raw material, to which the additive was added, was a blend of spruce and pine sawdust. An experimental design in the factors cassava/starch content, moisture content and material temperature was used. Measured responses were pellet bulk density, pellet durability, amount of fines, pelletizer motor current, pellet temperature, die temperature and CV for pelletizer motor current (a measure of process stability). Each response was modeled by multiple linear regression (MLR).

Summary Today energy prices are rising. As a result Biomass fuel is getting more and more interesting. Wood chips is very popular, but also straw from grain production is on the table. Lunds Energi AB project a combined power and heating plant in Örtofta out of Lund. Wood chips is meant to be the main energy source, complemented by straw. In this thesis the transportation of straw for fuel is studied.

During consultation procedures between forest owners and the Sámi, data on, e.g., reindeer lichen biomass on the current site is needed. Hitherto, the existing methods of measuring lichen cover and biomass has been either objective methods such as the Point Intercept method, which is time consuming, or some sort of subjective visual estimation, which is faster but less accurate. However, both these methods are sensitive to different observers and/or to different inventories. This paper addresses the further development and evaluation of a photographical inventory method that uses colour distribution in images to estimate lichen biomass. During the autumn of 2011 six different locations, with different grazing pressure and lichen cover, in Norrbotten county were inventoried using both the Point Intercept method and the photographical method, complemented with collection of biomass samples.

Fast pyrolysis is a method for converting biomass into three energy rich products: char, gas and bio-oil, where the latter is most interesting.  Pyrolysis is an endothermic process where biomass is heated in an anaerobic environment and, with the right operating conditions, up to 80 %wt bio-oil can be extracted. Key parameters for fast pyrolysis are: stable reactor temperature (~500°C), short residue time for gas in the reactor (<2 s) and a very high heating rate for the biomass. Today there are several different process solutions for fast pyrolysis, where fluidized beds and rotating cones are most developed. Bio-oil has compared to fossil oil: lower heating value, low pH and also polymerizes with time. Because of this upgrading is desirable for increasing competitiveness.

The purpose of this paper is to identify the current status of fuel cell technology and to establish whether said technology is mature enough to be implemented into the Swedish Armed Forces. The question to be answered in this paper is as follows: Can hydrogen gas and fuel cells be used as an alternative source of energy within the Swedish Armed Forces?This paper is based on theoretical studies and reports from prior research done on fuel cells. By studying these facts a predictive answer has been obtained. The answer I have come to, is that the maturity of fuel cell technology is currently inadequate for the Swedish Armed Forces to implement, especially considering its harsh working conditions..

This report was written by Sofia Ericson and describes the degree thesis with the title: ?Connections between the growing site of bio fuel, the chemical composition of bio fuel ash and the deposit growth in a bio fuel fired boiler.? The purpose of this degree thesis was to avoid melted deposit growth in the bio fuel fired boiler at ENA Kraft in Enköping. Potassium and sodium are known to lower the melting point of bio fuel ashes and are therefore not wanted in the trees in higher amounts than necessary for the growth. Silicon is also known to be important for the deposit growth but it is not possible to say in general if higher or lower contents of silicon is better. The relation between silicon and other chemical substances is more important than the total amount of silicon.

The aim of this study is to describe a number of type stands of lodge pole pine in Norrbotten with respect on stem volume and total biomass. Further questions to answer is if there is stand characteristics that make the stands more suitable for pulpwood in early thinning, or if it is better to apply whole tree harvest. The study shall also give an indication if bio energy can be an economical interesting alternative for Sveaskog. Sampled trees represented the variation in the different stands. Five trees were selected from each stand to represent that stand. Stem volume and biomass (kg dry weight (DW) per hectare) for each fraction was calculated.