Biopolttoaineiden on-line -laadunmittauksen hyödyt energiantuotannossa

Biopolttoaineet ovat tärkeä energianlähde suomalaisessa energiantuotannossa. Biopoltto- aineille on kuitenkin ominaista laadun vaihtelevuus. Yksi tärkeimmistä laatutekijöistä on kosteus, joka vaikuttaa myös polttoaineen energiasisältöön. Laatutekijät puolestaan vai- kuttavat polttoainekäsittelyyn, polttoprosessiin ja koko laitoksen hyötysuhteeseen. Tämän työn tarkoituksena oli tutkia voisiko biopolttoaineiden online-laadunmittaus tuoda lisäarvoa energiantuotantolaitokselle. Esimerkkinä käytettiin yhtä online-laadunmittaus- sovellusta, InrayFuel-röntgenmittausjärjestelmää. Sillä voidaan seurata biopolttoaineiden kosteutta ja polttoaineen sisältämiä vierasaineita. Työssä on laadittu kustannusanalyysi, jolla pyritään selvittämään, onko nykyisen kertaluontoisen mittausmenetelmän korvaami- nen jatkuvatoimisella kannattavaa. Esimerkkilaitoksena on Etelä-Savon Energian Pur- sialan voimalaitos, jossa röntgenmittausjärjestelmään on testattu. Saatujen tulosten mukaan investoiminen esimerkkimittausjärjestelmään maksaisi itsensä takaisin alle vuodessa. Kun laitoksella pystytään seuraamaan polttoaineen laatua jatkuva- toimisesti, laadunhallinta paranee ja sitä kautta voidaan saavuttaa kustannussäästöjä. Polt- toaineesta johtuvat häiriötilanteet vähenevät, polttoaine on mahdollista optimoida edulli- semmaksi polton kannalta ja poltto-olosuhteita voidaan säätää paremmin, jolloin päästöt vähenevät ja hyötysuhde kasvaa. Työssä käytetty laskenta analysoi kuitenkin hyvin ylei- sellä tasolla, sillä käytössä ei ollut laitoksen omaa taselaskentajärjestelmää. Laskenta siis sisältää paljon oletuksia. Tämän ja rohkaisevien tulosten vuoksi tutkimusta jatkuvatoimi- sen laadunmittauksen hyödyistä kannattaa tehdä enemmän.

Puuperäiset polymeerit synteettisten sideaineiden korvaajina

Tämän kandidaatintyön aiheena oli löytää biojalostamon näkökulmasta käyttökelpoisia tuotantoreittejä puuperäisistä materiaaleista bioperäisiin kemikaaleihin, joilla olisi mahdollista korvata synteettisiä sideaineita. Tällä hetkellä suurin osa sideaineista ja päällystemateriaaleista tuotetaan uusiutumattomista luonnonvaroista, kuten maakaasusta ja öljystä. Lopputuotteiden kierrätettävyyden ja vihreyden ohella yksi metsäteollisuuden tulevaisuuden trendejä on pyrkiä irti öljy- ja maakaasuriippuvuudesta. Muutoksella voidaan säästää sekä ympäristöä, että rahaa. Biopohjaisilla drop-in kemikaaleilla ja muilla biopohjaisilla vaihtoehdoilla tämä on mahdollista Tässä työssä tutkittiin ja havainnollistettiin mahdollisin tuotantoreitein useiden tällä hetkellä käytössä olevien sideaineiden korvaamista biopohjaisilla versioilla. Työ tehtiin kirjallisuustutkielmana, eikä siihen kuulunut laboratoriokokeita. Työn ensimmäisessä osassa painopiste on biojalostamossa ja dispersiopäällystyksessä. Toisessa osassa esitellään tällä hetkellä käytettyjä sideaineita ja niiden mahdollisia biopohjaisia korvaajia tuotantoreitteineen. Työn toissijainen tarkoitus oli selvittää lyhyesti mitä muita puuperäisiä komponentteja voidaan käyttää suoraan paperin ja kartongin päällystämiseen. Viimeiseksi on esitelty vielä lyhyesti kaupallisesti käytössä olevia biomuoveja ja päällysteitä.

Suomessa ja Itävallassa toimivien liiketoimintamallien siirrettävyys puupohjaisen uusiutuvan energian tuotantoon Puolaan, Romaniaan ja Slovakiaan

Tutkimus kuvaa tiedon, osaamisen ja teknologian siirtoa Suomesta ja Itävallasta Puolaan, Romaniaan ja Slovakiaan hajautetussa puupohjaisessa sähkö- ja lämpöenergian tuotannossa. Metsävaroiltaan rikas ja bioenergia-asioissa toimintatavoiltaan edistynyt Suomi toimi Metsäntutkimuslaitoksen (nykyisin Luonnonvarakeskus) johdolla tutkimuksen empiirisen aineiston tuottaneen kehittäjäverkostohankkeen pääkoordinaattorina vuosina 2011-2014. Tutkimusmenetelmänä käytettiin hankkeen dokumentaation sisällönanalyysiä. Itävalta on tunnettu edistyksellisistä bioenergia-alan tuki- ja ohjausjärjestelmistä. Suomi ja Itävalta kuuluvat EU:n viiden edistyneimmän maan joukkoon uusiutuvien energialähteiden hyödyntämisessä. Tämän työn tavoitteena oli selvittää, miten Suomessa ja Itävallassa hyvin toimivia liiketoimintamalleja voidaan siirtää kohdemaihin puupohjaisen uusiutuvan energian tuotannossa hyödynnettäviksi. Työssä kuvataan tiedonsiirtäjämaiden eli Suomen ja Itävallan ydinosaaminen kiinteän biomassan energiantuotannossa politiikkatasolta käytännön liiketoiminnan tasolle. Lisäksi työssä analysoidaan poliittisen ohjauksen merkitystä alan kehittämisessä, missä käydään läpi maakohtaiset uusiutuvan energian toimintasuunnitelmat vuodelta 2010. Lopuksi arvioidaan tiedonsiirtäjä- ja tiedonhyödyntäjämaiden välisiä eroavaisuuksia kyseisellä liiketoiminta-alueella, ja onko olemassa sellaisia tekijöitä, mitkä estävät tiedonsiirtoa tai hyväksi todettujen liiketoimintamallien soveltamista kohdemaissa. Kussakin maassa metsänomistusolosuhteet ratkaisevat kiinteän biomassan tarjonnan toimivuuden eli tilanteen toimitusketjun alkupäässä. Tuotannon ohjauksen pyrkimys on myös hyödyntää mekaanisen puunjalostuksen sivutuotevirrat mahdollisimman tarkoin energiantuotannon tarpeisiin. Yleiset taloudelliset suhdanteet vaikuttavat ketjun toimivuuteen ja tehokkuuteen. Yksin energiantuotannon tarpeisiin puunkorjuuta ei kannata suunnitella, koska se harvemmin erikseen toteutettuna on kannattavaa liiketoimintaa. Puun käyttö energiantuotantoon tarvitsee hyvin suunniteltua tuki- ja ohjausjärjestelmää, joista kansalliset hallitukset vastaavat. Suomalainen tuotannon suunnittelun ja ohjauksen ajattelutapa sekä itävaltalainen energiapuun varastointi biomassan logistiikkakeskuksiin koettiin kohdemaiden yrittäjäkunnassa varteenotettavimpina liiketoiminnan kehittämisvaihtoehtoina paikallisissa toimintaympäristöissä. Lean-tuotantoajatteluun kuuluva hukan poistaminen toimitusketjusta liittyy mm. varastonhallinnan järjestelyihin ja sivutuotevirtojen hyödyntämiseen. Näitä piirteitä oli myös löydettävissä tiedonhyödyntäjämaiden yritysten toiminnassa hankkeen toteutuksen aikana.

Capillary electrophoresis: Applicability and method validation for biorefinery analytics

Wood-based bioprocesses present one of the fields of interest with the most potential in the circular economy. Expanding the use of wood raw material in sustainable industrial processes is acknowledged on both a global and a regional scale. This thesis concerns the application of a capillary zone electrophoresis (CZE) method with the aim of monitoring wood-based bioprocesses. The range of detectable carbohydrate compounds is expanded to furfural and polydatin in aquatic matrices. The experimental portion has been conducted on a laboratory scale with samples imitating process samples. This thesis presents a novel strategy for the uncertainty evaluation via in-house validation. The focus of the work is on the uncertainty factors of the CZE method. The CZE equipment is sensitive to ambient conditions. Therefore, a proper validation is essential for robust application. This thesis introduces a tool for process monitoring of modern bioprocesses. As a result, it is concluded that the applied CZE method provides additional results to the analysed samples and that the profiling approach is suitable for detecting changes in process samples. The CZE method shows significant potential in process monitoring because of the capability of simultaneously detecting carbohydrate-related compound clusters. The clusters can be used as summary terms, indicating process variation and drift.

Logging residues from regeneration fellings for biofuel production - a GIS-based availability and supply cost analysis

Finland has large forest fuel resources. However, the use of forest fuels for energy production has been low, except for small-scale use in heating. According to national action plans and programs related to wood energy promotion, the utilization of such resources will be multiplied over the next few years. The most significant part of this growth will be based on the utilization of forest fuels, produced from logging residues of regeneration fellings, in industrial and municipal power and heating plants. Availability of logging residues was analyzed by means of resource and demand approaches in order to identify the most suitable regions with focus on increasing the forest fuel usage. The analysis included availability and supply cost comparisons between power plant sites and resource allocation in a least cost manner, and between a predefined power plant structure under demand and supply constraints. Spatial analysis of worksite factors and regional geographies were carried out using the GIS-model environment via geoprocessing and cartographic modeling tools. According to the results of analyses, the cost competitiveness of forest fuel supply should be improved in order to achieve the designed objectives in the near future. Availability and supply costs of forest fuels varied spatially and were very sensitive to worksite factors and transport distances. According to the site-specific analysis the supply potential between differentlocations can be multifold. However, due to technical and economical reasons ofthe fuel supply and dense power plant infrastructure, the supply potential is limited at plant level. Therefore, the potential and supply cost calculations aredepending on site-specific matters, where regional characteristics of resourcesand infrastructure should be taken into consideration, for example by using a GIS-modeling approach constructed in this study.

Market of biomass fuels in Finland : IEA Bioenergy Task 40 and EUBIONET III - Country report of Finland 2009

This study considered the current situation of solid and liquid biomass fuels in Finland. The fact that industry consumes more than half of the total primary energy, widely applied combined heat and power production and a high share of solid biomass fuels in the total energy consumption are specific to the Finnish energy system. Wood is the most important source of bioenergy in Finland, representing 20% of the total energy consumption in 2007. Almost 80% of the woodbased energy is recovered from industrial by-products and residues. As a member of the European Union, Finland has committed itself to the Union’s climate and energy targets, such as reducing its overall emissions of green house gases to at least 20% below 1990 levels by 2020, and increasing the share of renewable energy in the gross final consumption. The renewable energy target approved for Finland is 38%. The present National Climate and Energy Strategy was introduced in November 2008. The strategy covers climate and energy policy measures up to 2020, and in brief thereafter, up to 2050. In recent years, the actual emissions have exceeded the Kyoto commitment and the trend of emissions is on the increase. In 2007, the share of renewable energy in the gross final energy consumption was approximately 25% (360 PJ). Without new energy policy measures, the final consumption of renewable energy would increase to 380 PJ, which would be approximately only 31% of the final energy consumption. In addition, green house gas emissions would exceed the 1990 levels by 20%. Meeting the targets will need the adoption of more active energy policy measures in coming years. The international trade of biomass fuels has a substantial importance for the utilisation of bioenergy in Finland. In 2007, the total international trading of solid and liquid biomass fuels was approximately 77 PJ, of which import was 62 PJ. Most of the import is indirect and takes place within the forest industry’s raw wood imports. In 2007, as much as 21% of wood energy was based on foreign-origin wood. Wood pellets and tall oil form the majority of export streams of biomass fuels. The indirect import of wood fuels peaked in 2006 to 61 PJ. The foreseeable decline in raw wood import to Finland will decrease the indirect import of wood fuels. In 2004– 2007, the direct trade of solid and liquid biomass fuels has been on a moderate growth path. In 2007, the import of palm oil and export of bio-diesel emerged, as a large, 170 000 t/yr biodiesel plant came into operation in Porvoo.

Effect of forest-based biofuels production on carbon footprint, Case: Integrated LWC paper mill

International energy and climate strategies also set Finland’s commitments to increasing the use of renewable energy sources and reducing greenhouse gas emissions. The target can be achieved by, for example, increasing the use of energy wood. Finland’s forest biomass potential is significant compared with current use. Increased use will change forest management and wood harvesting methods however. The thesis examined the potential for integrated pulp and paper mills to increase bioenergy production. The effects of two bioenergy production technologies on the carbon footprint of an integrated LWC mill were studied at mill level and from the cradle-to-customer approach. The LignoBoost process and FT diesel production were chosen as bioenergy cases. The data for the LignoBoost process were obtained from Metso and for the FT diesel process from Neste Oil. The rest of the information is based on the literature and databases of the KCL-ECO life-cycle computer program and Ecoinvent. In both case studies, the carbon footprint was reduced. From the results, it can be concluded that it is possible to achieve a fossil-fuel-free pulp mill with the LignoBoost process. By using steam from the FT diesel process, the amount of auxiliary fuel can be reduced considerably and the bark boiler can be replaced. With a choice of auxiliary fuels for use in heat production in the paper mill and the production methods for purchased electricity, it is possible to affect the carbon footprints even more in both cases.

Improving strategic decision-making with simulation based decision support systems

Combating climate change is one of the key tasks of humanity in the 21st century. One of the leading causes is carbon dioxide emissions due to usage of fossil fuels. Renewable energy sources should be used instead of relying on oil, gas, and coal. In Finland a significant amount of energy is produced using wood. The usage of wood chips is expected to increase in the future significantly, over 60 %. The aim of this research is to improve understanding over the costs of wood chip supply chains. This is conducted by utilizing simulation as the main research method. The simulation model utilizes both agent-based modelling and discrete event simulation to imitate the wood chip supply chain. This thesis concentrates on the usage of simulation based decision support systems in strategic decision-making. The simulation model is part of a decision support system, which connects the simulation model to databases but also provides a graphical user interface for the decisionmaker. The main analysis conducted with the decision support system concentrates on comparing a traditional supply chain to a supply chain utilizing specialized containers. According to the analysis, the container supply chain is able to have smaller costs than the traditional supply chain. Also, a container supply chain can be more easily scaled up due to faster emptying operations. Initially the container operations would only supply part of the fuel needs of a power plant and it would complement the current supply chain. The model can be expanded to include intermodal supply chains as due to increased demand in the future there is not enough wood chips located close to current and future power plants.

Effects of the partial removal of wood hemicelluloses on the properties of kraft pulp

The objective of this work was to study the effects of partial removal of wood hemicelluloses on the properties of kraft pulp.The work was conducted by extracting hemicelluloses (1) by a softwood chip pretreatment process prior to kraft pulping, (2) by alkaline extraction from bleached birch kraft pulp, and (3) by enzymatic treatment, xylanase treatment in particular, of bleached birch kraft pulp. The qualitative and quantitative changes in fibers and paper properties were evaluated. In addition, the applicability of the extraction concepts and hemicellulose-extracted birch kraft pulp as a raw material in papermaking was evaluated in a pilot-scale papermaking environment. The results showed that each examined hemicellulose extraction method has its characteristic effects on fiber properties, seen as differences in both the physical and chemical nature of the fibers. A prehydrolysis process prior to the kraft pulping process offered reductions in cooking time, bleaching chemical consumption and produced fibers with low hemicellulose content that are more susceptible to mechanically induced damages and dislocations. Softwood chip pretreatment for hemicellulose recovery prior to cooking, whether acidic or alkaline, had an impact on the physical properties of the non-refined and refined pulp. In addition, all the pretreated pulps exhibited slower beating response than the unhydrolyzed reference pulp. Both alkaline extraction and enzymatic (xylanase) treatment of bleached birch kraft pulp fibers indicated very selective hemicellulose removal, particularly xylan removal. Furthermore, these two hemicellulose-extracted birch kraft pulps were utilized in a pilot-scale papermaking environment in order to evaluate the upscalability of the extraction concepts. Investigations made using pilot paper machine trials revealed that some amount of alkalineextracted birch kraft pulp, with a 24.9% reduction in the total amount of xylan, could be used in the papermaking stock as a mixture with non-extracted pulp when producing 75 g/m2 paper. For xylanase-treated fibers there were no reductions in the mechanical properties of the 180 g/m2 paper produced compared to paper made from the control pulp, although there was a 14.2% reduction in the total amount of xylan in the xylanase-treated pulp compared to the control birch kraft pulp. This work emphasized the importance of the hemicellulose extraction method in providing new solutions to create functional fibers and in providing a valuable hemicellulose co-product stream. The hemicellulose removal concept therefore plays an important role in the integrated forest biorefinery scenario, where the target is to the co-production of hemicellulose-extracted pulp and hemicellulose-based chemicals or fuels.

Intensification of hemicellulose hot-water extraction from spruce wood by parameter tuning

The growing population on earth along with diminishing fossil deposits and the climate change debate calls out for a better utilization of renewable, bio-based materials. In a biorefinery perspective, the renewable biomass is converted into many different products such as fuels, chemicals, and materials, quite similar to the petroleum refinery industry. Since forests cover about one third of the land surface on earth, ligno-cellulosic biomass is the most abundant renewable resource available. The natural first step in a biorefinery is separation and isolation of the different compounds the biomass is comprised of. The major components in wood are cellulose, hemicellulose, and lignin, all of which can be made into various end-products. Today, focus normally lies on utilizing only one component, e.g., the cellulose in the Kraft pulping process. It would be highly desirable to utilize all the different compounds, both from an economical and environmental point of view. The separation process should therefore be optimized. Hemicelluloses can partly be extracted with hot-water prior to pulping. Depending in the severity of the extraction, the hemicelluloses are degraded to various degrees. In order to be able to choose from a variety of different end-products, the hemicelluloses should be as intact as possible after the extraction. The main focus of this work has been on preserving the hemicellulose molar mass throughout the extraction at a high yield by actively controlling the extraction pH at the high temperatures used. Since it has not been possible to measure pH during an extraction due to the high temperatures, the extraction pH has remained a “black box”. Therefore, a high-temperature in-line pH measuring system was developed, validated, and tested for hot-water wood extractions. One crucial step in the measurements is calibration, therefore extensive efforts was put on developing a reliable calibration procedure. Initial extractions with wood showed that the actual extraction pH was ~0.35 pH units higher than previously believed. The measuring system was also equipped with a controller connected to a pump. With this addition it was possible to control the extraction to any desired pH set point. When the pH dropped below the set point, the controller started pumping in alkali and by that the desired set point was maintained very accurately. Analyses of the extracted hemicelluloses showed that less hemicelluloses were extracted at higher pH but with a higher molar-mass. Monomer formation could, at a certain pH level, be completely inhibited. Increasing the temperature, but maintaining a specific pH set point, would speed up the extraction without degrading the molar-mass of the hemicelluloses and thereby intensifying the extraction. The diffusion of the dissolved hemicelluloses from the wood particle is a major part of the extraction process. Therefore, a particle size study ranging from 0.5 mm wood particles to industrial size wood chips was conducted to investigate the internal mass transfer of the hemicelluloses. Unsurprisingly, it showed that hemicelluloses were extracted faster from smaller wood particles than larger although it did not seem to have a substantial effect on the average molar mass of the extracted hemicelluloses. However, smaller particle sizes require more energy to manufacture and thus increases the economic cost. Since bark comprises 10 – 15 % of a tree, it is important to also consider it in a biorefinery concept. Spruce inner and outer bark was hot-water extracted separately to investigate the possibility to isolate the bark hemicelluloses. It was showed that the bark hemicelluloses comprised mostly of pectic material and differed considerably from the wood hemicelluloses. The bark hemicelluloses, or pectins, could be extracted at lower temperatures than the wood hemicelluloses. A chemical characterization, done separately on inner and outer bark, showed that inner bark contained over 10 % stilbene glucosides that could be extracted already at 100 °C with aqueous acetone.

The feasibility of torrefaction for the co-firing of wood in pulverised-fuel boilers

Torrefaction is the partial pyrolysis of wood characterised by thermal degradation of predominantly hemicellulose under inert atmosphere. Torrefaction can be likened to coffee roasting but with wood in place of beans. This relatively new process concept makes wood more like coal. Torrefaction has attracted interest because it potentially enables higher rates of co-firing in existing pulverised-coal power plants and hence greater net CO2 emission reductions. Academic and entrepreneurial interest in torrefaction has sky rocketed in the last decade. Research output has focused on the many aspects of torrefaction – from detailed chemical changes in feedstock to globally-optimised production and supply scenarios with which to sustain EU emission-cutting directives. However, despite its seemingly simple concept, torrefaction has retained a somewhat mysterious standing. Why hasn’t torrefied pellet production become fully commercialised? The question is one of feasibility. This thesis addresses this question. Herein, the feasibility of torrefaction in co-firing applications is approached from three directions. Firstly, the natural limitations imposed by the structure of wood are assessed. Secondly, the environmental impact of production and use of torrefied fuel is evaluated and thirdly, economic feasibility is assessed based on the state of the art of pellet making. The conclusions reached in these domains are as follows. Modification of wood’s chemical structure is limited by its naturally existing constituents. Consequently, key properties of wood with regards to its potential as a co-firing fuel have a finite range. The most ideal benefits gained from wood torrefaction cannot all be realised simultaneously in a single process or product. Although torrefaction at elevated pressure may enhance some properties of torrefied wood, high-energy torrefaction yields are achieved at the expense of other key properties such as heating value, grindability, equilibrium moisture content and the ability to pelletise torrefied wood. Moreover, pelletisation of even moderately torrefied fuels is challenging and achieving a standard level of pellet durability, as required by international standards, is not trivial. Despite a reduced moisture content, brief exposure of torrefied pellets to water from rainfall or emersion results in a high level of moisture retention. Based on the above findings, torrefied pellets are an optimised product. Assessment of energy and CO2-equivalent emission balance indicates that there is no environmental barrier to production and use of torrefied pellets in co-firing. A long product transport distance, however, is necessary in order for emission benefits to exceed those of conventional pellets. Substantial CO2 emission reductions appear possible with this fuel if laboratory milling results carry over to industrial scales for direct co-firing. From demonstrated state-of-the-art pellet properties, however, the economic feasibility of torrefied pellet production falls short of conventional pellets primarily due to the larger capital investment required for production. If the capital investment for torrefied pellet production can be reduced significantly or if the pellet-making issues can be resolved, the two production processes could be economically comparable. In this scenario, however, transatlantic shipping distances and a dry fuel are likely necessary for production to be viable. Based on demonstrated pellet properties to date, environmental aspects and production economics, it is concluded that torrefied pellets do not warrant investment at this time. However, from the presented results, the course of future research in this field is clear.

Esiselvitys puupolttoaineen jalostamisesta torrefiointitekniikalla

Fossiilisten polttoaineiden käytöstä aiheutuvia kasvihuonekaasupäästöjä pyritään vähentämään EU:ssa mm. päästökaupan avulla. Uusiutumattomien polttoaineiden tilalle kehitetään biopolttoaineita, joita voidaan hyödyntää olemassa olevien voimalaitosten polttolaitteistoilla. Biopolttoaineiden etuna on, ettäniiden ei katsota lisäävän hiilidioksidipäästöjä, koska biomassa sitoo itseensä kasvaessaan poltossa vapautuvan määrän hiiltä. Eräs kiinnostavimmista jalostetuista biopolttoaineista on torrefioitu puu, joka vastaa useimmilta ominaisuuksiltaan kivihiiltä ja jota voidaan käyttää hiilivoimalaitoksissa ilman laitteistomuutoksia. Torrefiointi on puun eräänlaista paistamista hapettomissa olosuhteissa 250-270ºC:ssa, jolloin siitä saadaanpoistettua vesi ja osa haihtuvista aineista. Puun väri muuttuu suklaanruskeaksi, se kevenee, ei savuta poltettaessa, hylkii vettä, jauhautuu hyvin sekä sillä on pienet hiukkaspäästöt. Käsitellyn puun ominaisuudet muuttuvat säilyvyydeltään ja käyttöominaisuuksiltaan merkittävästi raaka-aineeseen verrattuna. Torrefioinnilla saavutetaan puulle polttoainekäytön kannalta myös paremmat ja kestävämmät ominaisuudet kuin hiiltämällä. Torrefiointiprosessia on tutkittu jonkin verran ja torrefioidun biomassan polttoa voimalaitosmittakaavassa on kokeiltu pienessä mittakaavassa. Torrefioitu materiaali on alhaisen tiheytensä vuoksi hankalaa ja kallista kuljettaa,joten sen tiheyttä tulee nostaa kuljetuksia varten tiivistämällä esim.pelletöimällä. Torrefionti yhdistettynä pelletöintiin on parhaimmillaan kilpailukykyinen vaihtoehto, kun kivihiiltä korvaavaa biomassaa jalostetaan kaukana käyttöpaikasta ja kuljetetaan irtotavarana aluskuljetuksina. Torrefioitua puuta on tiettävästi poltettu vain hollantilaisessa voimalaitoksessa. Tässä esiselvityksessä kootun tiedon perusteella torrefioidun puupolttoaineen tuottamiseen Suomen olosuhteissa arvioidaan olevan teknis-taloudellisia mahdollisuuksia. Kuitenkin torrefiointiprosessin soveltaminen suomen olosuhteisiin ja kotimaisiin raakaaineisiin vaatii panostusta jatkotutkimukseen ennen varsinaiseen toteutusvaiheeseen siirtymistä.