Globalt sett används fossila bränslen fortfarande till största delen, och industrisektorn är den med störst energianvändning. Därför är det viktigt att fortsätta arbetet med att hitta nya sätt att använda befintliga resurser, att utveckla energibesparande tekniker och att göra detta med hållbarhetsperspektivet i fokus. Denna studie är förlagd på kraftvärmeverket i Sandviken, som producerar fjärrvärme och elektricitet. Anläggningen ägs av Sandviken Energi AB som är ett kommunalt energibolag med ansvar för infrastrukturen i Sandvikens kommun. Syftet med studien är att undersöka möjligheten att sänka halten av kväveoxider, NOx, som släpps ut med rökgaserna, samt att rena det kondensat som bildas när rökgaserna värmeväxlas. Det finns en stor vinning i att minska NOx-utsläppen ur ett miljöperspektiv, eftersom de orsakar försurning och andra problem i naturen. Tillvägagångssättet är att dosera extra ammoniak vid förbränningen. Vid höga temperaturer reagerar ammoniak med kväveoxiderna och utsläppen av dessa minskar. 90 % av ammoniakutsläppen kan sedan återvinnas med en ammoniakstripper för att även dessa ska hållas inom gränsvärdena. Möjligheten att använda det vatten som bildas då rökgaserna kondenserar undersöks också. Många anläggningar skulle teoretiskt sett kunna bli helt självförsörjande i sin vattenanvändning eftersom stora volymer bildas. Det som krävs är att kondensatet blir tillräckligt rent för att kunna användas i de industriella processerna. På kraftvärmeverket i Sandviken bildas 30 000 m3 kondensat per år. Det renas och släpps ut via avloppet. År 2016 köptes 21 700 m3 stadsvatten in och användes i produktion och kontor, och även om inte alla processer tekniskt går att ersätta med renat kondensat kan stora besparingar ändå göras. Den enskilda processen med störst potential är processvattnet till de två fastbränslepannorna. Vattenanvändningen till dessa är i genomsnitt 6 000 m3 per år. Det finns även ytterligare potentiella användningsområden för det renade kondensatet som kan öka möjligheten att genomföra en installation. Resultatet av utredningen är att en ammoniakstripper skulle möjliggöra att NOx-utsläppen minskade med 10 700 kg per år. Detta resulterar i en kostnadsbesparing på 536 000 SEK och en återbetalningstid på ca nio år. Om rökgaskondensatrening också installeras ökar investeringen, men besparingen kan i bästa fall bli 20 000 m3 vatten per år. Inköpskostnaden för vatten skulle då minska med 800 000 SEK och återbetalningstiden skulle kunna bli ca två år. 67 % av det kondensat som i dagsläget bara släpps ut kan istället användas.

This master thesis is a comparison between green roofs (vegetation placed on roof tops) and roof mounted photovoltaic (PV) systems, which is done with the method life cycle assessment (LCA). The aim is to compare the different installations from a sustainability perspective and to present how each installation contribute to a more sustainable community. For this purpose three different green roofs are investigated (one extensive, one semi-intensive and one intensive) and also three different PV systems (5,2 kW with a 43° slope, 8 kW with a 20° slope and 13 kW with zero slope). Beyond these six scenarios a seventh installation is designed and this is a PV green roof, which is an extensive green roof placed under an 8 kW PV system. The LCAs are done through an inventory of production data for each installation and by developing performance indicators for a number of parameters in the use phase of each roof, such as electricity production, storm water delay and carbon accumulation. In the result these numbers are presented and compared to each other, which shows that the production of PV systems have a greater climate impact than the production of green roofs. On the other hand the PV systems can have a greater climate impact compared with green roofs. With the PV green roofs the benefits of both installations are combined which is shown to be a preferred alternative. One of the main conclusions of the project is that each installation would have a greater positive impact on the environment if the materials were produced with renewable energy instead of fossil fuels. Another conclusion is that if considering installing a PV system the cost of adding a green roof underneath is small but the benefits increase, which again indicates that a combined roof is a preferable alternative.

In this master thesis, a methodology is proposed for building stock classification and archetype building development based on deterministic information available in Energy Performance Certificates (EPCs) of existing buildings in the city of Uppsala.This study aims to answer if the EPC database can be used as a reliable data source for archetype development and further UBEM models.The EPC data is cleaned and organised using Matlab. The building stock is then categorised into archetypes by energy performance and building characteristics and a model of each archetype building is created in the software EnergyPlus.The South-West part of Uppsala is used as a case study and to represent the building stock of that area 20 archetypes is developed. Simulations in EnergyPlus shows that the defined archetypes is a reliable estimation of buildings in Sweden with the same characteristics and construction period.By using GIS data the results can be aggregated to city level with the resulting total energy demand for heating calculated to 1455,7 GWh, compared to the actual value of 1397,0 GWh.The lack of validation data on a smaller scale is a large issue for this study, as well as some issues with data reliability in the EPCs. Despite this, the results of this study points to that the gathered values are a decent enough estimate to make a reliable assumption of the total energy demand for heating. The EPCs thus provide a useful source of data for energy demand purposes and building characteristics.

About 25 % of the total buildings in the European Union have been categorized as ”old buildings”. Followed the recent strickt rules for carbon emissions reduction, each house has to approximetely cut 20 % of CO2 by 2020. Countries like England, have taken the issue very seriously and planning to reduce the carbon emissions by 30 % until the end of 2020 and by an extra 80 % by 2050 (Francis Moran, 2014). The aim of the report is to present how a traditional house can be retroffited into a passive house and also to identify the key points that every passive house should have. For the purpose of the project an avtual house, based in Gävle, was provided and all the simulations are based on actual data. The initial design of the house which was used for the simulation and the 3D design, was provided by the house owner. The building was built in 1953, information regarding the current insulation of the house was provided by the owner as well. For the simulations and the 3D design a software know as IDA ICE was used, license and access to the software were given by the University of Gävle. The report simulates the current house and compares the results with two possible scenarios that are reducing the energy demand of the house. Furthermore, the possible ways and tools that could be used to reduce the energy demand of the house and cost estimation for the retrofitting is available in the paper.The first simulations were occured on the actual house, the first retrofitting package introduces new simulations based on new insulation materials, like wood and cement, that are placed mainly on the roof and on the outer walls. Also, the thickness have changed, thus the new insulations are thicker.Moreover, the second and final retrofitting package, introduces an HVAC system, which is a standard system. The aim is to achieve further energy demand reductions and prove that simple and basic changes can improve the quality of living and reduce CO2 emissions.After the completition of the first analysis, a reduction equal to 60 % and after the addition of the HVAC a further 20 % reduction achieved.

Many reasons to consider extending the useful time of ageing wind farms. Like to take advantage of it being located in a good wind source, besides existing infrastructure, etc. Repowering can be an appropriate option for the ageing wind farm that suffering less yield energy and increment of cost of operation and maintenance.  The thesis discusses the repowering potential of old wind farms. The case study is implemented on a selected wind farm in Denmark. Different repowering scenarios were considered with the technical-economic assessment for each scenario to determine which scenario is viable. The sensitivity analysis was done taking into consideration selected parameters to find out the effect of each parameter on the profitability and productivity of the repowered wind farm. More details will be explored in the following chapters.

The aim of this thesis is to examine the effect that Thermal Energy Storage (TES) sizing has on a building’s ability to meet heating and cooling demands in an energy and cost efficient manner. The focus of the research is the quantification the effects of TES for system sizing and boiler cycling. Research is accomplished by modelling TES systems with various storage capacities using thermodynamic analysis. Energy costs are subject to increase during peak usage periods due to a limited supply of energy. Peak heating and cooling periods also force thermal systems to be sized for loads that are only experienced for a small fraction of the year leading to poor efficiencies and frequent cycling during off peak times of year. TES introduces the capability to mitigate this issue by shifting peak thermal loads from one period to another, theoretically reducing the minimum necessary boiler or chiller capacity for a given system and potentially improving the efficiency of 4 thermal systems. The scope of this research is to model the operation of thermal systems with varying storage capacities in order to quantify these capabilities with respect to capacity and cycling. This is accomplished with modelling in Transient Systems Simulation Program (TRNSYS). In this software, a simple heating loop and cooling loop are independently considered and subjected to hourly load data extrapolated from heating and cooling load data originating from a retirement community in Massachusetts. The model built is intended to be robust enough to be easily applied and adapted to assess similar problems with energy storage capacity sizing.

Sverige har höga ambitioner att ställa om till 100 procent förnybar energiproduktion och att tillmötesgå mål 7 i Agenda 2030, vilket är inom räckhåll. Med goda vindlägen, långa kuster och relativt grunda vatten har Sverige alla förutsättningar att lyckas om man enas politiskt, ser över riktlinjer och skapar ekonomiska förutsättningar för utbyggnad av vindkraft.   Syftet med rapporten är dels att redovisa de vanligaste hindren för utbyggnad av vindkraft i Sverige, dels vad som har föreslagits för att främja vindkraftsutvecklingen. Rapporten ger en överblick över relevanta frågor kring vindkraftsutvecklingen och fokuserar på frågorna:  Vilka är vanligaste hindren för vindkraftsprojekt? Vad har föreslagits för att underlätta för utbyggnad av vindkraft? Med hjälp av utförda myndighetsutredningar, rapporter från branschorganisationer, myndighetspressmeddelanden, debatter, intervjuer och EU-direktiv för förnybar energi och havsbaserad vindkraft utforskar den här rapporten den havsbaserade vindkraftens förutsättningar, samt betonar de vanligaste hindren för projektering och genomförande vid en framtida utbyggnad av vindkraft. Det finns stor potential för vindkraft genom direktiv från EU. De hinder som återkommande orsakar förseningar för utbyggnad av havsbaserad vindkraft är den kommunala vetorätten, Försvarsmakten intressen, anslutningskostnader som styr utbyggnadstakten, avvägning mellan riksintressen, tolkning och verkställande av artskyddsförordningen, politisk dragkamp och växande motstånd på lokalnivå.  Trots befintliga hindren är uppsatsen slutsats att det finns stor potential för vindkraften. / Sweden has high ambitions to adapt 100 percent renewable energy production and to meet goal 7 in Agenda 2030, which is within reach. With good wind conditions, long coasts and relatively shallow waters, Sweden has all the prerequisites to succeed if it agrees politically, reviews guidelines and creates economic conditions for wind power. The purpose of the thesis is partly to report common obstacles of wind power development in Sweden, and partly to report what has suggested for wind power development. The report provides an overview of relevant issues regarding wind power development and focuses on the issues: What are the most common obstacles to wind power projects?What has been proposed to facilitate the expansion of wind power? Through exploring government investigations, industry organization reports, government press releases, debates, interviews and EU directives for renewable energy and offshore wind power conditions for offshore wind power. Furthermore, highlighting what obstacles encounters for developers in the event of a future expansion of wind power. The obstacles that repeatedly cause delays in the development of offshore wind power are municipal endorsement that is being review now, the Armed Forces' interests, connection costs that control the pace of expansion, balancing national interests, interpretation and implementation of the species protection regulations, political disagreements and growing resistance at local level. Despite existing obstacles, the thesis concludes that there is great potential for wind power.

Världens förlitande på fossila bränslen måste minska för att förhindra en global uppvärmning, vilket kan orsaka negativa effekter på vår miljö. En åtgärd för att hjälpa oss på denna väg är en ökad användning av biobränslen. För att få en effektiv energiutvinning från biobränsle används pelletering för att höja densiteten på biomassan. Industriell pelletering består utav flera processer: Torkning, malning, uppfuktning, uppvärmning, och slutligen pelletering.  Vid pelletering av biomassa består totalenergin (Wtot) utav tre delprocesser: Komprimering, flöde, och friktion. Komprimeringsenergin (Wkomp) mäter den vertikala kraften mot biomassan vid pelletering. Flödesenergin (Wflöde) mäter motståndet mot deformation när biomassan flödar in i presskanalen, denna deformation består utav en vertikal och radiell komprimering. Friktionsenergin (Wfrik) mäter motståndet från kontakt mellan pelletsen och matrisväggen.  Syftet med denna studie är att öka kunskapen om energianvändning vid de olika stegen i pelleteringsprocessen samt hitta ett samband mellan labbskalig pelletering (<20 kg/h) och kontinuerlig singelpelletering. Målet är att undersöka hur fukthalt och presslängd påverkar de olika delprocesser samt hur flödeskraften påverkas. Gran torkades, maldes och fuktades upp till en önskad fukthalt innan pelleteringstester. För denna studie användes tre typer av anläggningar vilket har syftet att undersöka de olika delprocesser vid pelletering. Den totala energin mäts med kontinuerlig singelpelletering, vilket innebär att ett lager biomassa komprimeras i en presskanal, varefter ett nytt lager komprimeras på det existerande lagret. Nya lager komprimeras succesivt tills flödeskraften har stabiliserats (den högsta uppmätte kraften under en pressning). För att mäta komprimering och friktion komprimeras ett gram pellets som sedan pressas ut ur presskanalen. Den sista anläggning var labbskalig pelletering, där friktion och flödeskraft kan mätas. Resultaten visar att presslängden hade en stor påverkan på alla delprocesser för kontinuerlig singelpelltering. En ökad presslängd leder till en ökad flödeskraft samt en ökad Wtot, Wkomp, Wfrik, och Wflöde. Fukthaltens påverkan på kontinuerlig singelpelletering var svagare. Det fanns inget samband mellan fukthalt och Wfrik. Det tydligaste sambandet fanns mellan fukthalt och komprimering, där en ökad fukthalt leder till en minskad Wkomp. Flödesenergin påverkades inte vid en fukthaltshöjning från 8% till 12%, men det blev en kraftig minskning vid en fukthaltshöjning från 12% till 16%. Flödeskraften stabiliserades aldrig vid 8% fukthalt. Flödeskraften stabiliserades vid både 12% och 16% fukthalt, varav 16% resulterade i ett lägre flödeskraftsbehov. Vid labbskalig pelletering ökade flödesenergin, flödeskraften, och friktionsenergin vid ökad fukthalt. Ett samband mellan kontinuerlig singelpelletering och labbskalig pelletering kunde inte hittas. / The world’s reliance on fossil fuels needs to be reduced to prevent global warming, which can have a negative effect on our environment. One way which can reduce our impact is to increase our usage of biofuels. Pelletisation is used to get an effective energy output from biofuels, since it increases the density of the biomass. Industrial pelletisation is consists of multiple processes: Drying, grinding, moisturising, heating, and lastly pelletising.  The total energy (Wtot) from pelletisation comes from three phases: Compression, flow, and friction. The compression-energy (Wkomp) measures the vertical force against the biomass when it is pelletised. The flow-energy (Wflöde) measures the resistance against deformation when the biomass enters the die-channel. This deformation is caused by radial and vertical compression. The friction-energy (Wfric) measures the resistance from the contact between the die-surface and pellet.  The purpose of this study is to increase the knowledge regarding energy usage from the pelletisation processes, and to find a correlation between laboratory scale (20 kg/h) and continuous single pelletisation. The goal of the study is to examine the impact moisture content and die-channel length has on the different phases, and how they impact the flow force.  Spruce dried, ground, and moisturised to a specific moisture content before pelletisation. Three applications were used, which purpose was to measure the different phases of pelletisation. The total energy is measure with continuous single-pelletisation, which means that you first compress a layer of biomass, which is followed by compressing another layer on top. New layers are then compressed until the flow-force has stabilised (the maximum force measured during a layer-compression). To measure compression and friction, a gram of biomass is compressed which is then pressed out of the die-channel. The last application was a laboratory scale press, where friction and flow-force can be measured.  The results showed that the length of the die-channel had a great impact on all phases when studying continuous single-pelletisation. An increase in the channel length increases Wtot, Wkomp, Wfrik, and Wflöde.  The moisture content’s effect on the phases were mixed. There was no correlation between moisture content and friction. The clearest correlation was between moisture content and compression. An increase in moisture content causes a lower Wkomp. The flow-energy was not affected when the moisture content was raised from 8% to 12%, but an increase from 12% to 16% reduced Wflöde greatly. The flow-force never stabilised when a moisture content of 8% was used. The flow-force stabilised at a moisture content level of 12% and 16%, whereof 16% resulted in a lower force required for stabilisation.  A correlation between continuous single-pelletisation and laboratory pelletisation were never found.

The Scheffler reflector is a new solar concentrator design which maintains a fixed focus while only having a single axis tracking mechanism. This design makes the construction and operation of high temperature solar concentrators accessible to developing nations. In this project, I wrote computer simulation codes to better understand the dynamics and the effect of deformation or deviations from ideal conditions in order to define necessary manufacturing and operational tolerances. These tools and knowledge drove the prototyping of new reflector concepts by myself and other students on my team. A fiberglass prototype was able to drive the cost of a reflector to sub-$50 and a wood reflector was manufactured with accessible materials and techniques used in boat building.

This master thesis aims to investigate whether an installation of a High Temperature Low Sag-conductor (HTLS-conductor) could be beneficial for a 130 kV-transmission line owned by the Swedish company Vattenfall. The HTLS-conductors investigated in this thesis were ACCC-conductors and three different models were included: Warsaw, Dublin and Stockholm 3L ACCC-conductors. The aim of an installation was to roughly double the thermal line rating without needing to replace any supporting towers in the line section that was studied.    Simulations were conducted using MATLAB and PLS-CADD Ultralite and included calculations of the thermal line rating as well as conductor sag and tension in the supporting towers. The results showed that all three ACCC-conductors fulfilled Vattenfall’s requirements for increased thermal line rating. However, conductor sag was a problem which required an increase in tension. This increase in tension was only possible for Warsaw and Stockholm 3L ACCC-conductors. The Dublin ACCC-conductor proved too heavy and would have required a replacement of supporting towers if installed in this line section.    Finally, the thesis recommends further studies of the effects of an installation of Warsaw and Stockholm 3L ACCC-conductors and also suggests investigations concerning economic profitability, environmental sustainability and suitability of other types of HTLS-conductors.