Browsing by Subject "metsähake"
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(2014)Tarvetta tienvarsihaketuksen tutkimukseen luo kasvanut energiapuukysyntä. Varsinkin pienläpimittaisen energiapuun kustannustehokkuutta tulee kasvattaa, jotta saavutetaan energiapuun käytölle asetetut tavoitteet. Pieniläpimittaista energiapuuta on saatavissa runsaasti ensiharvennuskohteilta, varsinkin sellaisilla, joilla taimikonhoito on jäänyt tekemättä. Lisäksi ensiharvennuksilta talteen otettava energiapuu ei ole lisäksi riippuvainen teollisuuden ainespuukysynnästä niin kuin hakkuutähde. Tienvarsihaketuksessa paalit haketetaan suoraan kaukokuljetusauton hakekonttiin, josta se on valmis suoraan voimalaitokselle käytettäväksi. Fixteri Oy on keski-suomalainen yritys, joka on kehittänyt kokopuupaalaimen erityisesti nuorten hoitamattomien metsien puunkorjuun tehokkuuden parantamiseen. Paalain toimii automaattisesti yhdessä harvesterin kanssa ja siihen voidaan kerätä puita yksin puin tai joukkomenetelmällä. Paalaus helpottaa ja tehostaa erityisesti metsäkuljetusta. Paalien massa on keskimäärin puoli tonnia ja pituus 2,5?2,7 m. Kaksi Fixterillä tuotettua paalia vastaa energiasisällöltään yhtä öljytynnyriä. Pro gradu työssäni tutkin tienvarsihaketuksen tuottavuutta ja ajanmenekin jakaantumista eri työvaiheisiin. Tutkimuksen aikatutkimuksen videoaineisto kerättiin Padasjoelta viidestä haketustestistä sekä yhdestä murskaustestistä. Kerätty aineisto analysoitiin ajanmenekin suhteen sovelletulla aikatutkimuksella. Tutkimuksessa joudun tyytymään kuorman keskimääräiseen paalikokoon, koska paaleja on noin tuhat varastolla, eikä jokaiseen haketukseen otettuja paaleja pystytty erikseen punnitsemaan. Jokaisen kuorman massa ja tilavuus sekä siihen kerätty paalimäärä on tiedossa, jolloin saadaan haketuksen työn tuotos ja taakanmassa. Panos oli tarkastellessani tehoaika, joka on myös yleisesti metsätyön tutkimuksessa käytetty tehdyn työn määre. Aikatutkimuksen tarkastelun kohteena oli sekä hakkurin kouran työskentelyn jakautuminen eri työvaiheisiin että hakkurin tyhjänä pyöriminen. Lisäksi vertailtiin saatuja hakkeen palakokojakaumia ja niiden suhteutumista tavoiteltuun hakkeen palakokoon. Taakan koolla tai hakkeen kosteudella ja palokoolla ei ole merkittävää vaikutusta haketuksen tuottavuuteen. Taakan kokonaisvientiajalla ja sen vaihtelulla on tilastollisesti merkittävä vaikutus tuottavuuteen.
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(2018)During the last years renewable energy sources have risen to very important role. As countries in European and global scale are trying to fulfil the targets of international agreements, such as Kyoto protocol and Paris agreement. Targets in reducing the amount of greenhouse gases and increasing the use of renewable energy sources are achieved in many ways. In Finland the forest energy and wood based energy sources have become the most important way in reaching these goals. Also, reduction of fossil fuel has a significant role in ongoing change in energy production. As use of fossil fuels is aiming to be substituted by renewable alternatives. This thesis is based on published literature, articles, research reports and research results. Aim of this thesis is to pay attention to the use of forest energy in Finland and the topics closely related to this area. Use of forest energy is closely related to many important global issues. Such as climate change and prevention of climate change. Therefore, the topic is very important at the current situation, and this thesis aims to give a comprehensive overview of the forest energy as a whole, at the moment in Finland. The increment of forest energy and use of wood based energy sources still have many unclear questions and uncertainties. For example, nutrient loss in soil when biomass is harvested from the forest has still need to be paid more attention to. At the moment the use of forest energy, specially the use of wood chips, is heavily subsidized, which is causing disturbances at the markets. One of the most important features related to forest energy as a topic is the total overall climate effects of using the forest based energy. So far there have been wide range of opinions on the climate effects and carbon neutrality on the use of using forest biomass in energy sector. However, forest energy should not be seen as carbon neutral, because current climate effects diverge a lot from zero. Neutrality can be achieved in very long run but current effects are negative
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(2009)Political incentives often have a central role in bioenergy production. Influence of these incentives is expected to increase, because conventional fossil fuels are draining and the climate change forces policy makers to react. Hence, the demand for biofuels is also expected to grow. Woodbased fuels are the most important biofuel and renewable energy source in Finland. Woodbased fuels are almost equally divided into liquid byproducts of the pulp industry and solid woodbased fuels. This study focuses on solid woodbased fuels, because these solid fuels have markets unlike e.g. black liquor and because these shares increase. In this study, the solid woodbased fuels include forest chips, bark, sawdust, industrial chips, recycled wood and pellets. One aim of the study is to formulate a general view of the Finnish woodbased fuel markets. The demand is analysed by using the statistics of The Finnish Forest Research Institute (Metla) and the supply by using existing literature. Metla compiles statistics about the utilization of woodbased fuels from over 700 energy facilities, comparing several categories of woodbased fuels. This study overwiews the period from 2003 to 2007. Energy facilities are divided into four different so that the specifics of the demand can be identified. Another aim of the thesis is to study the impact of emissions trading on woodbased fuel utilization. Emissions trading is the most important instrument for improving the competitive advantage of renewable energy production for energy facilities that belong to the scheme, producing heat or electricity with over 20 MW nominal effect. The growth in the credit price of 2 co emissions increases the demand for biofuels and reduces the demand for fossil fuel in energy facilities of over 20 MW. Empirical analysis are carried out for different energy facility categories. Large community facilities are more sensitive to the changes of credit price than the forest industry`s plants. Energy facilities with 520 MW nominal capacities reduce the woodbased fuel utilization, when the credit price rises. This flux diminishes the effect of the emissions trading. On the other hand, it seems that changes in credit price do not affect the woodbased fuel consumption in energy facilities of less than 5 MW. The utilization of woodbased fuels will change due to the stuctural changes in the forest industry. The production of byproducts, such as bark, decreases with diminishing quantaties of traditional forest industry products. If the increasing demand was met, forest chip utilization should be added. However, especially the restriction of production in the sawmill industry decreases the supply of harvesting residues chip and forest chip production shifts more towards energy wood thinning. Also, the use of woodbased fuels among different energy facilities is changing. The utilization of woodbased fuels has traditionally been centralized in the forest industry units using industrial byproducts. Nowadays, it is also an important energy source for the energy production facilities of the communities due to different policy instruments. This has affected that the trade of woodbased fuels has increased.
Now showing items 1-3 of 3