Biogas is a renewable form of energy that can be produced by a various type of organic materials. In order to reduce the proportion of fossil fuel emissions bioenergy is seen as a future energy source that can be used for different purposes. This report studies biogas from gasification and the purpose has been to investigate the potential for increased biogas production from agriculture and forestry by doing a sociotechnical system study. The study is focusing on a restricted area outside of Uppsala, Sweden, and has been carried out in two parts. The first part consists of calculation of the biomass potential in the area. The second part investigates the social factors of the bioenergy system and interviews are used to study relevant actors in the area. Social barriers are crucial to the realization of technical potentials, and are therefore important to identify. The result shows that there are some areas that need further development to fulfil the bioenergy potential in the area. All farmers and foresters say that the market is the most important factor for the bioenergy future. The result shows that the reliance for politicians and energy companies need to be increased in all parts of the system. There is also a need for long-term political guidelines at a global and local level. The information and knowledge exchanges about bioenergy need to increase between all actors involved in the system. This implies for example farmers, foresters, researchers, politicians and energy companies. Among these, new networks and collaboration need to be developed. There is also a need to develop more commercially viable technologies throughout the system to promote the development of a future bioenergy system. The result however, shows a large interest in bioenergy from farmers and foresters and a willingness to invest in future bioenergy projects which creates an advantageous starting point for the bioenergy system development.

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 5 uppsatser.

Currently, only 2.8% of total energy use in the world is renewable energy. As a climate target in 2020, the European Union has set a goal of increasing the renewable energy to 20%. Renewable energy includes biofuel such as pellets.   Pellets use has already increased significantly and several large production units have been built in recent years. To achieve a competitive pellet, production must be improved in terms of quality, environmental impact, and electricity consumption. Adding additives can improve pellets strength, reduce CO2eq emissions and reduce energy consumption.   The purpose is to investigate how different percentages of additive affect pellets to achieve a more sustainable and competitive biofuel.   In the quality analysis where sustainability and hardness were investigated, oxidized corn starch showed the best result where sustainability increased from 94.8% to 97.86%. The hardness varied greatly from pellets to pellets from the same sample. Since the hardness varied so widely, it was impossible to say which sample who had the highest hardness. On the other hand, it is concluded that the oxidized cornstarch samples received higher hardness than the zero sample.   In the environmental section, CO2equivalents for pellet production were investigated in Sweden, OECD member countries and non-OECD member countries in Europe. In Sweden and in OECD member countries, pellets production did not reduce the CO2eq emissions with any added additive. In non-OECD member countries, wheat starch was the best additive and reduced CO2eq emissions by 2.4%.   The energy consumption in the pellet press was also analyzed and the results showed that all additives reduced energy consumption. The best additive in this study was wheat starch, which reduced electricity consumption by 3.9%.

Världens ökande energibehov och önskan om att minimera konsekvenserna av klimatförändringen har gjort att flera miljömål tagits fram både på nationella och internationella nivåer. Mycket resurser läggs ner på att utveckla nuvarande förnyelsebara energikällor och hitta nya alternativ till de fossila bränslena. En förnyelsebar energiresurs är biogas. Biogas bildas vid nedbrytning av organiskt material och bildar koldioxid och energirik metangas.   Detta examensarbete har fokuserat på två områden, det första att undersöka metanproduktionen i en samrötningsprocess med ensilage av våtmarksgräs och substrat från Mosseruds biogasanläggning. Mosserud ligger några km väster om Karlskoga och idag behandlas i huvudsak insamlat matavfall, nötflytgödsel och vallgröda. Våtmarksgräset kommer från Brosjö området utanför Säffle. Under 2010-2014 ingick Brosjö i ett EU projekt som främjar mångfaldignatur och utsatta djurarter, vilket bland annat har gett ett ekonomisk stöd i att skörda gräset. Det skördade gräset har idag ingen användning, men skulle kunna passa i en rötprocess.    Det andra området var att jämföra resultaten med tidigare rapporter inom rötning samt användandet av våtmarksgräs. Arbetet av Neldorin (2015) där en studie om substratmixen vid Mosserud gjordes, låg som grund för hur biogasproduktionen ser ut på Mosseruds anläggning idag och jämfördes med metanproduktionen i denna studie. Den andra rapporten studerade våtmarksgräs som additiv i pellets. Där Henriksson (2016) hade fokus på energiåtgången av pelleteringen när våtmarksgräs från Brosjö användes.      Rötningsförsöken skedde på Karlstads universitet, där rötningen var en semi- kontinuerlig våt process med mesofila förhållanden. Där inmatning och uttag av gas gjordes en gång om dagen, vilket var samma uppställning som Neldorin (2015) använde. Försöket varade under 10 veckors tid och 2 olika substratblandningar användes; en med 30 % gräs 70 % matavfall och en med 15 % gräs 85 % matavfall. Resultatet gav att rötningen med substratblandningen 30 % gräs 70 % substrat från Mosserud var att föredra. Den specifika metanproduktionen var 0,300 och 0,350 Nm3/kg VS/dag, vilket var mindre än de värde som kommit fram från Mosserud 0,352 Nm3/kg VS/dag. Den totala produktionen av metangas kunde ökas mellan 1,5 - 2,6 % då mer substrat fanns tillgängligt.   Våtmarksgräset var bättre att använda till rötning än till pelletering då rötning kunde öka den totala metanproduktionen, medans pelleten som tillverkades inte uppfyllde kraven på hållfasthet, bulkdensitet och andel finfraktion. De problem som är kopplade till att använda gräs i rötning är slambildning i reaktortanken och processen stabilitet under en längre tid, då pH värdet sjönk av ansamling av VFA. / The worlds increasing need for energy and the desire to minimize the consequences of climate change have led to several environmental goals at both national and international levels. Many resources are spent on developing the current renewable energy sources and to find new alternatives. One of the renewable energy resources is biogas. Biogas is formed when organic matter is decomposed which forms carbon dioxide and energy rich methane gas.   This master's thesis has focused on two areas, the first to examine methane production in a co- digestion process with silage of wetlands grass and food waste from Mosserud biogas plant. Mosserud is located a couple of kilometers west of Karlskoga city. Today the plant mainly uses food waste, manure and ley crops. The wetland grass originates from an area outside of Säffle called Brosjö. In 2010-2014 the Brosjö area was a part of an EU project that promotes bio diversity and threaten animal species, which . Due to this project the harvesting of grass has been made easier and has no use today, but could fit in an anaerobic digestion process.   The second area was to compare the results with earlier reports on anaerobic digestion and the use of wetland grass. Neldorin (2015),vconducted a study of the substrate mix at Mosserud, whihc lays as a basis for biogas production from Mosserud today compared to the results of this study. The second report studied wetland grass as an additive in pellets. Where Henriksson (2016) had focus on energy consumptions during production of pellets when using wetland grass from Brosjö.   The laboratory study was made at Karlstad University, the study was a semi continuous wet anaerobic process with mesophilic conditions. Feeding and withdrawal of gas was made once a day, using the same lab line up as Neldorin (2015) did. The experiment lasted 10 weeks and 2 different substrate mixtures were used; one with 30% grass 70% food waste and one with 15% grass 85% food waste. The result showed that digestion with 30 % grass mix was preferred. The specific methane production was 0.300 and 0.350 Nm3 / kg VS / day, which was less than those obtained from Mosserud at 0,352 Nm3 / kg VS / day. The total production of methane gas could be increased between 1.5 - 2.6% as there was access to more substrates.   Wetland grass was better used for digestion than pelleting as it could increase the total methane production, while the pellets produced did not meet the requirements of strength, bulk density and fractional fineness. The problems associated with using grass in digestion are sludge formation in the reactor tank and process stability for a long time, when the pH value fell by the accumulation of VFA.

The aim of this thesis is to enhance heterocyst-based hydrogen production inNostoc punctiforme ATCC 29133. We envision to do so by finely regulatingthe ratio of heterocyst in order to optimize the filament energy balance. Wehereby report the development of an optogenetic synthetic switch basedon the native PcpeC promoter. The optogenetic switch featured a 24-folddynamic range when measuring reporter sfGFP fluorescence. Such a geneticgate was conceived to artificially drive the expression of hetR, the masterregulator of heterocyst development. We achieved to induce enhancedheterocyst differentiation in the presence of ammonia only by changing thechromatic properties of the light source. Thus, the natural cell developmentregulation was substituted by effectively introducing a full person-drivencontrol over the process.

Biorefineries for production of fuels, chemicals, or materials, can bean important contribution to reach a fossil-free economy. Large-scaleforest-based biorefineries are not yet cost competitive with their fossil counterparts and it is important to identify biorefinery supply chain configurations with good economic, CO2, and biomass performance if biorefineries are to be a viable alternative to the fossil refineries. Several factors influence the performance of biorefinery supply chains,e.g. type of conversion process, geographical localisation, and produc-tion capacity. These aspects needs to be analysed in conjunction to identify biorefineries with good supply chain performance. There ares everal approaches to improve the performance of biorefineries, wheree.g. integration with other industries can improve the economic perfor-mance by utilisation of excess heat and by-products. From a Swedish perspective the traditional forest industry is of interest as potential host industries, due to factors such as by-product availability, opportunity for heat integration, proximity to other biomass resources, and their experience in operating large-scale biomass supply chains. The objectives of this work were to investigate how different supply chain configurations influence the economic, biomass, and CO2 perfor-mance of thermochemical biorefineries integrated with forest industries,as well as methods for evaluating those supply chains. This work shows that there is an economic benefit for integration with the traditional forest industry for thermochemical biorefineries.This is especially true when the biorefinery concept can replace cur-rent old industrial equipment on site which can significantly improvethe economic performance of the biorefinery, highlighting the role the Swedish forest industry could play to reach a cost efficient large-scale implementation of lignocellulosic biorefineries. The cost for biomass is a large contributor to the total cost of biore-fineries and for traditional techno-economic evaluations, the biomass prices are considered as static variables. A large-scale biorefinery will likely have an impact on the biomass market, which could lead to both changes in the biomass price, as well as changed biomass demand for other industries. A framework where this is accounted for was intro-duced, combining a techno-economic perspective for evaluating the sup-ply chain performance, with a market model which identifies changes in biomass price and allocation due to the increased biomass competition. The biorefinery performance can be determined from several per-spectives and system boundaries, both from a plant-level and a national perspective. To facilitate a large-scale introduction of biorefineries and  maximise the benefit from their implementations, there is a need to identify biorefinery concepts with high performance considering severa system boundaries, which has been explored in this work.

More deaths are caused every year by indoor air pollution than malaria, HIV/AIDS and tuberculosis combined. Cooking with traditional fuels such as charcoal and fuelwood with poor ventilation causes the single most important environmental health risk factor worldwide. It also contributes to environmental issues such as deforestation as traditional biomass fuels and cooking stoves are inefficient and requires large quantities of wood. This is especially critical in Africa where the largest regional population growth in the world is expected to occur. A solution to these issues was realized through fuel pellets and modern cooking stoves by Emerging Cooking Solutions, a company started by two Swedes and based in Zambia. The production of fuel pellets in Zambia is dependent on pine sawdust from small sawmills and is a declining source of raw material. However, other sources of biomass are available in Zambia such as pigeon pea stalk, an agricultural waste product, and sicklebush, an invasive tree species. If these species are viable for pelletization, the production of pellets can increase while reducing issues with sicklebush and promoting cultivation of pigeon pea. The aim of this work is to evaluate if pigeon pea stalk and sicklebush are viable to pelletize in Zambia and how the press is affected by the different raw materials. A pilot study is done at Karlstad University with a single unit press, hardness tester and soxhlet extractor to evaluate how the material constituents correlate to friction in the press channel and hardness of the pellets. The results of the pilot study provide support for full scale tests done in a pellet plant in Zambia. The normal production of pellets from pine sawdust is used as quality and production reference for the tests with pigeon pea stalk, sicklebush, and different mixes of the raw materials. The properties used to evaluate the quality of the pellets are hardness, durability, moisture content, bulk density, and fines. The press configuration is evaluated by logging the electricity consumption by the press motor, calculating the power and specific energy consumption from the logs, and observations during the tests. The results show that sicklebush, and mixes of sicklebush with pigeon pea stalk can produce pellets with better quality than the reference pine pellets. An interesting composition is a mix of 80% pigeon pea and 20% sicklebush that produces pellets with the best quality of all the tests. However, pellets produced from sicklebush and pigeon pea show a larger variation in hardness as compared to the reference pellets from pine sawdust. Mixing pigeon pea with pine reduces these variations but reduces the hardness of the pellets below the reference. The press struggles to process sicklebush and pigeon pea stalk with fluctuating power consumption that causes the motor to trip. The inhomogeneity of the materials in sicklebush and pigeon pea are identified to cause the issues in the press. Production improvements are discussed to facilitate the production of pigeon pea stalk and sicklebush pellets.

När GROT (grenar och toppar) skördas ökar bortförseln av basverkande ämnen och näringsämnen. Syftet med rekommendationen att återföra aska, tillbaka till skogsmarken, är att undvika en försurande och näringsutarmande verkan. I dagsläget tillämpas en metod som kallas Sockenmodellen när det gäller återföring av aska tillbaka till skogen.

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The main purpose of this project was an attempt to modulate and simulate two existing biogas plant, situated in Lidköping and Katrineholm, Sweden and evaluate how the process reacts to certain conditions regarding feeding, layout and substrate mixture. The main goal was to optimize the existing processes to better performance. Both the modeling and simulation were executed in SIMBA#Biogas with accordance to the real conditions at the plant in question. The simulation of each model was validated against data containing measurements of, CH4 yield, CH4 production, TS, VS, NH4-N concentration and N-total concentration. The data was obtained from each plant in accordance with scheduled follow ups. Both models were statistically validated for several predictions. Predictions of N-total and NH4-N concentration failed for some cases. Both plants were tested with new process lay outs, where promising results were obtained. The Lidköping model was provided with a post-hygienization step to handle ABPs. The Katrineholm model was provided with a dewatering unit, where 35% of the centrate was recirculated back to the system. Both setups was configured to yield the highest CH4 production. This study suggests that SIMBA#Biogas can be a tool for predictions and optimizations of the biogas process.