Detta självständiga arbete utfördes på kraftvärmeanläggningen Affärsverken AB i Karlskrona med syfte att minska stadens vattenförbrukning, minimera utsläpp i naturen och bidra till globala miljömål. Se bilagor (7–10) för mer information.Projektet omfattade flera perspektiv, inklusive tekniker för att rena rökgaskondensat och de ekonomiska aspekterna av ett sådant projekt. Sammanfattningsvis syftar projektet till att förbättra effektiviteten och hållbarheten i kraftvärmeverket. Studiebesöket på kraftvärmeverket i Karlskrona har gett information om flödet av kommunalt vatten och rökgaskondensat mängden som används för att bestämma återvinningen av vatten och mängden rökgaskondensat som behövs. Detta kommer att användas för att utvärdera teknikerna för att rena rökgaskondensatet och de ekonomiska aspekterna av projektet.Målet med projektet var att minska stadens vattenkonsumtion på kraftvärmeverket genom att använda rökgaskondensat istället för stadsvatten. Detta minskar kostnaden för råvatten och bidrar till att uppnå globala miljömål. Konstruktion och installation kan kombineras med befintliga anläggningar, utrustning och ekonomiska faktorer som tas i beaktning vid valet av lösning. En hållbar och kostnadseffektiv lösning bör väljas för att minska stadens vattenkonsumtion utan att påverka produktiviteten. / This independent project was conducted at the combined heat and powerplant (Affärsverken AB) in Karlskrona with the aim of reducing city waterconsumption, minimizing emissions into the environment, and contributingto global environmental goals, see appendix (7-10). The project included several perspectives, including technologies for cleaning flue gas condensateand the economic aspects of such a project. In summary, the project aimed toimprove the efficiency and sustainability of the combined heat and powerplant.The study visit to the combined heat and power plant in Karlskrona has provided information on the flow of municipal water and the amount of flue gascondensate used to determine the recovery of water and the amount of fluegas condensate needed. This will be used to evaluate the technologies forcleaning the flue gas condensate and the economic aspects of the project.The conclusion of the project was to be able to reduce city water consumption at cogeneration plants by using flue gas condensate instead of city water.This reduces the cost of city water and contributes to achieving environmental global goals. Construction and installation can be combined with existingfacilities and equipment, and economic factors should be taken into accountwhen choosing a solution. Sustainable and cost-effective solution should bechosen to reduce city water consumption without affecting productivity.

Studies suggest that diverse mixtures of plants may improve forage productivity and also be suitable as bioenergy crops. The objectives of this research were: 1) to measure the effects of native, warm-season perennial (NWSP) forage mixtures and management methods on productivity, weed biomass, nutritive value, and community composition, and 2) to identify mechanisms that generate any positive diversity-productivity relationships over a three-year establishment period. In 2008, two experiments were established to evaluate the use of native, warm-season plants in forage-livestock systems using a pool of ten native species. The first, a large-scale, three-year, experiment tested three different NWSP mixtures (switchgrass monoculture, a four-grass mixture, and a ten-species mixture) and two management methods (grazed or biomass crop). Switchgrass monocultures had the lowest forage yield and highest weed biomass in both grazed areas and biomass crop exclosures. Analysis of forage nutritive value did not show many differences among mixtures, although the monoculture tended to have higher crude protein and lower fiber concentrations than the polycultures. Management method affected community composition, with NWSP richness higher and weed species richness lower in biomass crop exclosures than in grazed areas. A second experiment examined if species richness would enhance yields through a positive biodiversity effect. It employed additive partitioning to separate the selection effect (SE) from the complementarity effect (CE) by sowing random assemblages of NWSPs at five levels of richness into small plots. Species richness was associated with increased yields in the first year only, but overyielding and positive diversity effects were present in all three years. On average, over 50% of multi-species plots overyielded and 64% exhibited a positive biodiversity effect. Both SE and CE contributed to the biodiversity effect and the importance of each effect changed over time as communities became better established. All ten species were also individually analyzed for their yield potential, nutritive value, and elemental composition. Warm-season grasses tended to be higher-yielding but of lower nutritive value. All ten NWSPs contained sufficient concentrations of eleven elements to support nonlactating cows. These experiments demonstrated that diverse NWSP mixtures may be a valuable addition to both forage and bioenergy agroecosystems. / Ph. D.

Excessive use of fossil fuels to meet everyday energy demands has led to adverse environmental impacts like global warming and high dependence on foreign oil. Development of cellulosic feedstocks provides energy security and also reduces the burden on food crops like corn and sugarcane used for ethanol production. This thesis uses cost-benefit analysis to ascertain the profitability of producing cellulosic ethanol from Switchgrass and Sweet Sorghum Bagasse. First, breakeven price of producing Switchgrass and Sweet Sorghum is calculated to obtain a raw material (feedstock) cost for ethanol production. Next, net present value (NPV) and minimum ethanol selling price (MESP) for Switchgrass and Sweet sorghum are calculated. Lastly, risk analysis is performed and its impacts on NPV are calculated for two farmer categories. The results show that ethanol production from Switchgrass and Sweet Sorghum is commercially feasible and generates a Net Present Value (NPV) of $39.54 million for Switchgrass and $96.76 million for Sweet Sorghum at an ethanol selling price of $2.17 per gallon. At NPV zero the MESP for Switchgrass and Sweet Sorghum is estimated to be $2.10 and $1.96 per gallon respectively. The risk analysis results revealed that there is a 9.5 percent probability that the NPV for a risk-averse Switchgrass farmer will be less than zero. On the other hand, the probability of the NPV being less than zero is 67.4 percent. The overall analysis indicates that ethanol production from Switchgrass and Sweet Sorghum is a promising option. Reduction in feedstock prices, optimization of the conversion process and additional revenues from by-products can make cellulosic ethanol more competitive with current gasoline prices. / Master of Science

The recent trend in bioenergy feedstock development focuses on the use of large-statured perennial grasses that pose a relatively high risk of becoming invasive species due to the similarity in desirable agronomic traits with those of many of our worst invaders. Thus, it would be prudent to evaluate the potential ecological benefits and consequences of widespread cultivation of potentially invasive species. Miscanthus sinensis and its sterile daughter species, Miscanthus × giganteus, are two prominent bioenergy feedstock candidates due to their low input requirements and significant biomass production in a broad range of growing conditions. Despite being an extremely popular ornamental grass, and naturalizing in over half of US states, little is actually known about the biology, ecology and niche requirements of M. sinensis. Thus, the objective of our research is to characterize extant M. sinensis populations, and evaluate the niche requirements, especially in terms of the commonly limiting resources of light and soil moisture. In order to better assess the risk of M. sinensis (and subsequently M. × giganteus) cultivation, we surveyed 18 naturalized populations across the east coast to characterize habitat preferences, population structure, and plant performance across a latitudinal gradient. We found the vast majority of M. sinensis populations occurred in areas of high and low resource availability (e.g. soil nutrients and light) along roadsides and forest edges, with outlier individuals found in forest understories. We conducted a greenhouse study to compare shade and soil moisture tolerance among common ornamental cultivars and naturalized populations, where we found enhanced plant growth and vigor in naturalized biotypes compared to ornamentals across varying levels of shade. We also found that both naturalized and ornamental biotypes were not significantly affected by soil moisture stress, and thus express significant drought tolerance. Finally, we investigated the temperature and moisture requirements of M. sinensis seeds and determined a base temperature of approximately 8"C, as well as variable moisture and time to germination requirements between varieties and seed sources. These basic ecological studies will help refine and support future evaluations and weed risk assessments of both Miscanthus sinensis and M. × giganteus, which is critical in prevention of major ecological invasions. / Master of Science in Life Sciences

The modernized world is over-consuming low-cost energy sources that strongly contributes to environmental stress. As a consequence, the interest for environmentally friendly alternatives has increased immensely. One such alternative is utilizing the diazotrophic nature of the heterocystous filamentous cyanobacteria Nostoc sp. as feedstock for biodiesel and hydrogen production using pulp and paper wastewater – a phosphorous and nitrogen deficient medium. In this work, biodiesel and hydrogen production was studied with respect to three main aspects: biodiesel quality properties, lipid content and hydrogen production coupled with a preliminary study investigating the luminous effects on the biomass and biodiesel quality properties when exposed to low (50 μEm-2s-1), medium (150 μEm-2s-1) and high light (300 μEm-2s- 1). The preliminary study showed that an increase of light intensity was associated with parabolic results for biomass following the 10-day cultivation period, with the medium light intensity showing an average dried weight of at the most 203% greater than the two other light intensities. When analysing the FAME- composition, similar results were demonstrated for the fatty acid constituents preferred for biofuel applications, C18:1 and C18:2 fatty acids, where the low, medium and high light showed an accumulative 34.65, 43.1 and 31.6 dwt % respectively. The strain could be of interest as feedstock for biodiesel when cultivated in pulp and paper wastewater, due to the positive results pertaining to the lipid content and biodiesel quality properties. Following the 10-day cultivation period the lipid content obtained was 35.9 dwt %. The biodiesel quality properties were tested to assess the strains suitability for biodiesel and were tested to ensure its accordance to the standards on commercial biodiesel quality; European Standard for Biodiesel as heating oil (EN 14213) and European Biodiesel Standard (EN 14214). The critical parameters tested were the regulated (iodine value, cetane number, density, viscosity, pour point, cold filter plugging point, oxidative stability) and unregulated (FAME-composition) fuel properties. Results obtained showed values within the regulated values set by the different standards. However, due to a high saturated fatty acid content, the strain showed inadequate low temperature flow properties (cloud point, pour point and the cold filter plugging point). This study shows that this strain has a low potential for hydrogen production, with a hydrogen production of 0.13 nmol/mg dry wt/h following the 10-day cultivation period. This low hydrogen production could be attributed to the among other things the current growth phase of the cyanobacteria. Chemical analyses were conducted for revealing the total nitrogen, total phosphorus and chemical oxygen demand (COD) content. Following the 10-day cultivation period, the samples showed a 22% decrease in phosphorous concentration, 11% decrease in COD concentration and 51% increase of nitrogen concentration. The probable causes for this increase is the Nostoc’s diazotrophic nature and the ammonium excretion nitrogen fixation entails, as well as the nitrogen release following the final algal growth phase – the death phase. In conclusion, the results showed great potential, however, further studies are recommended investigating the changes that occurs during cultivation period to further assess the strains potential as well as assessing the continuity of the results with a greater initial cellular concentration. Nonetheless, due to the positive results obtained regarding the nutrient uptake, biodiesel and hydrogen production, this study shows potential for further optimization for the use of Nostoc grown in pulp and paper wastewater for wastewater treatment, biodiesel and/or hydrogen production.

Bioenergy is extracted from biomass. What counts as biomass is generally quite diverse, but broadly speaking, it is material that previously lived. Today, energy extracted from biofuels make up around 23% of Stockholm city's total energy consumption. Stockholm city has set a goal to be a fossil-free city by 2040, i.e. zero emissions from energy use. Two sectors have been identified where emissions occur and these are the transport sector and the electricity and heating sector. This thesis will only address the electricity and heating sector. This includes all energy consumption within Stockholm city municipality. When Stockholm is developing towards a fossil fuel free city, it’s interesting to look at how important bioenergy will be as an energy source in the future. This thesis has scrutinized the role of bioenergy in reaching a fossil fuel free city. Three major policies have been investigated. The carbon dioxide tax and the emission rights system have promoted the bioenergy and its deployment in a positive way. The system of electricity certificates has shown to indirectly affect the bio energy in a negative way. The key finding is that bioenergy will have a great impact in reaching the goal mainly through its contributions with negative emissions, but it is also an important substitute to fossil fuels. / Bioenergi utvinns ur biomassa eller biobränslen. Biomassa och biobränslen är ganska diffusa begrepp då definitionen varierar runt om i världen, men generellt sett är det material som tidigare levt. Idag utgör energi från biobränslen cirka 23% av Stockholms stads totala energiförbrukning. Stockholms stad har satt upp ett mål att vara en fossilfri stad år 2040, det vill säga inga utsläpp från stadens energiförbrukning. Det finns två huvudsakliga sektorer där koldioxidutsläpp förekommer, dessa är transportsektorn och eloch värmesektorn. Detta inkluderar all energiförbrukning inom Stockholms kommuns gränser, till exempel uppvärmning av hushåll och energin de fordon som körs i staden förbrukar. När Stockholm utveckling går mot att bli en fossilbränslefri stad är det intressant att se hur viktig bioenergi kommer att vara som energikälla i framtiden. Denna rapport granskar bioenergins roll i att nå klimatmålet till 2040. De huvudsakliga slutsaterna är att bioenergi kommer ha en stor och viktig roll i att nå målet och att dess största inverkan kommer vara de negativa utsläppen. Vissa lagar har främjat bioenergin medans vissa indirekt har påverkat dess utveckling negativt. Bioenergin har en ljus framtid i Stockholm.

The aim of the project was to investigate the possibility of producing and utilizing bioenergy from available local resources in the village Linga Linga, Mozambique. Suitable conversion techniques for producing and utilizing bioenergy were identified through a literature study. The investigated techniques were the concept of gasifier cookstoves, the method of producing charcoal from biomass and anaerobic digesters. Through observations and interviews in the village, available local resources suited for the conversion techniques were identified. In the field study, it was found that there is a surplus of solid biomass which led to the conclusion that a gasifier cookstove is suitable to implement. In order to analyze if a gasifier cookstove is suitable for the households, interviews were carried out in ten households in the village. Aprototype of a gasifier cookstove was built with local resources to determine if the technique can be applied. The prototype was tested and evaluated in order to analyze if it will contributeto a more efficient use of resources. One of the conclusions of the study was that a gasifier cookstove can be valuable for the households in several ways, but that cultural differences can make it hard to implement.

Bio-oil generated from biomass is becoming one of the most promising alternatives as potential energy sources to replace fossil fuels in the transportation sector. Fast pyrolysis of biomass is one of the most economically feasible ways to produce bio-oil according to recent research on thermochemical conversion of biomass. Upgrading of oils derived from to hydrocarbon fuels requires oxygen removal and molecular weight reduction.  Catalytic cracking and hydrotreating are two efficient processes to upgrade bio-oil. Hydrotreating requires that hydrogen is added in the process to increase the H/C ratio of the product. Normally, catalytic fast pyrolysis and hydrotreating are two separated processes. In order to increase the energy efficiency of the process, exploring the fast pyrolysis of biomass with in-situ catalyst under the hydrogen atmosphere, i.e. catalytic hydropyrolysis shall be very interesting, and this is the objective of this work. In this work, biomass pyrolysis experiments using softwood have been performed in hydrogen and nitrogen atmospheres with/without catalyst. It was found that in the case of the H2 atmosphere, a higher yield on oil phase and a reduced water production is found. More oxygen was removed as CO and CO2. The catalytic fast pyrolysis (CFP) under H2 atmosphere also produce relatively more PAH (polymer aromatic hydrocarbon) and less MAH (monomer aromatic hydrocarbon) than under N2 atmosphere.

In this dissertation we address three different sustainability concepts: [1] modeling of biodiesel production via heterogeneous catalysis, [2] life cycle analysis for pyrolysis of switchgrass for using in power plant, and [3] modeling of pyrolysis of biomass. Thus we deal with Specific Aim 1, 2 and 3. In Specific Aim 1, the models for esterification in biodiesel production via heterogeneous catalysis were developed. The models of the reaction over the catalysts were developed in two parts. First, a kinetic study was performed using a deterministic model to develop a suitable kinetic expression; the related parameters were subsequently estimated by numerical techniques. Second, a stochastic model was developed to further confirm the nature of the reaction at the molecular level. The deterministic and stochastic models were in good agreement. In Specific Aim 2, life cycle analysis and life cycle cost for pyrolysis of switchgrass for using in power plant model were developed. The greenhouse gas (GHG) emission for power generation was investigated through life cycle assessment. The process consists of cultivation, harvesting, transportation, storage, pyrolysis, transportation and power generation. Here pyrolysis oil is converted to electric power through co- combustion in conventional fossil fuel power plants. The conventional power plants which are considered in this work are diesel engine power plant, natural gas turbine power plant, coal-fired steam-cycle power plant and oil-fired steam-cycle power plant. Several scenarios are conducted to determine the effect of selected design variables on the production of pyrolysis oil and type of conventional power plants. In Specific Aim 3, pyrolysis of biomass models were developed. Since modeling of pyrolysis of biomass is complex and challenging because of short reaction times, temperatures as high as a thousand degrees Celsius, and biomass of varying or unknown chemical compositions. As such a deterministic model is not capable of representing the pyrolysis reaction system. We propose a new kinetic reaction model, which would account for significant uncertainty. Specifically we have employed fuzzy modeling using the adaptive neuro-fuzzy inference system (ANFIS) in order to describe the pyrolysis of biomass. The resulting model is in better agreement with experimental data than known deterministic models. / Ph. D.

The purpose of this feasibility study has been to guide decision makers in the implementation of abiogas project for the region of Sønderborg, Denmark. The project has been part of Feasibility studies envisioned in the Master Plan for Sønderborg to go carbon neutral by 2029. The study tried to evolve abest alternative for the city and gives a ready document to refer all aspects of biogas. The intensive industrial farming in Sønderborg needs to evolve to compare favorably with the situationin other regions of Denmark. The interests of various stakeholders in the waste cycle should be alignedwith that of farming. Interesting developments in the Bioenergy space hold promise for farmers to usetheir capacities for additional or alternative livelihood in energy. The focus to promote biogas as part ofDanish energy strategy and multiply capacity over the next 3 years has attracted numerous biogas proposals all over Denmark. This study had started off with identifying and estimating very obvious substrate sources. At verymoderate assumptions the value of methane in these sources has been estimated at 9 million m3. Thispotential could easily be increased if economically feasible substrates like energy crops and algae areadded. The SWOT analysis of pig farming in the region brings out the perspectives of farming direction in the near future. The 5 scenarios developed help the decision maker understand the various aspects thatneed to be carefully considered when planning the plant. The best case scenario for the city would bethe energy mosaic scenario which would integrate the high tech focus of local industry, a renewable energy source and a showcase project to make the region stand out among the other regions focused inthe climate change debate. The technological system analysis should help decision makers understand the stakeholders and the various dimensions in biogas that although complicated are manageable. The business case approach to identify utilization of energy and its costs gives a clear picture on the need for using the energy in CHP.The present focus by potential investors on government subsidies to calculate profitability needs to be understood in the context of other similar plants accepting present subsidy levels and the societal benefits, which unfortunately cannot be valued in money terms. At the center of all this is the need for proper stakeholder management within a bound timeframe asidentified by the “Create acceptance process”. The various tools and data are all present in this study,that only need to be arranged and presented by the company eventually handling the strict Projectmanagement goals of this project. / <p>www.ima.kth.se</p>