Renewable energy sources have dominated energy use throughout human history and biomass is one of the world's oldest energy sources. The use of biomass as a fuel has increased in recent decades and has led to great technological development as a result of the growing demands for sustainable solutions. The main source of energy in households in sub-Saharan Africa is traditional biomass, such as firewood and charcoal. Charcoal production in Zambia is estimated to require 6,089,000 tonnes per year, which with its inefficient energy production and unsustainable forestry means that the country has one of the highest deforestation rates in the world in percentage terms. Since 2012, Emerging Cooking Solutions Ldt (ECS) has been supplying modern pellet stoves and producing fuel pellets in Zambia to phase out the use of charcoal in cooking. Pellet stoves minimize emissions of volatile particles and carbon monoxide emissions and reduces health risks. ECS is actively working to improve its cooking stoves and the purpose of the studies is to increase knowledge about how pellets' properties affect combustion. The study designed and built a test facility to be able to analyze the combustion of pellets in cooking stoves at the Faculty of Health, Science and Technology at Karlstad University. The plant includes measurement of carbon monoxide, nitrogen oxides, temperature and velocity in outgoing flue gases. The fuel consumption of the stove and the temperature of the water are measured during the entire combustion process. The test unit and its design meet the majority of the requirements of ISO 19867-1 and can be used for tests on the combustion of different types of pellets in different types of cooking stoves. The study analyzed the effect of the pellets' properties on emissions of carbon monoxide and nitrogen oxides during combustion. The analysis was conducted on purchased straw pellets, pellets from Zambia and pellets from bark, heartwood, sapwood and from Laxåpellets that were pelletized at Karlstad University. The combustion tests also included analyzes of efficiency, power, usable energy and fuel consumption for the pellet stove. Incineration of produced pellets, purchased straw pellets and pellets from Zambia in the test facility reported that higher moisture content, ash content and extractives lead to higher carbon monoxide emissions and poorer combustion with lower fuel consumption and efficiency. According to the study, ECS should focus the production of pellets on biomass with a low ash content and extractives to ensure efficient combustion with low carbon monoxide and nitrogen oxide emissions. Using bark pellets in the cooking stove in of lack of other fuel should be avoided. This entails greater health risks such as pellets with increased moisture content. It should thus be avoided to store pellets openly in a humid environment, which can occur during the rainy season in Zambia.

In this thesis the aerodynamic loads for maximum power output at acceptable fatigue loads on a 1.5MW onshore wind turbine are examined. The objective mainly is to investigate pitch angles where optimal value of maximum power output at an acceptable level of fatigue loading can be achieved while studying the source of fatigue loading and the constraints of increasing the coefficient of performance of wind turbine power output. A total of thirteen hub height mean wind speed profiles, at the same turbulence level, ranging from cut-in wind speed of 3m/s to cut-out wind speed of 27m/s at 2m/s incremental are simulated. The reference wind speed is set at the hub height. For reference wind set below the hub height, the logarithm wind profile is used to determine the hub height mean wind speed, and then the power law follows to determine the mean speed at other height. The speeds are determined on a meshed grid point to examine the change of wind speed and direction in time and space or turbulence which is mainly due to the shape and hostile of the terrains. Wind profile simulation is performed by TurbSim simulation code, and the resulting profile is used as input to analyze the loads at the blade root. The loads are analyzed for the wind speed above the rated wind speed, 11m/s to 27m/s, where the blades are pitched to obtain an even power output. After performing several runs to investigate the relationship of wind speed to power output and fatigue loading, the wind speed, where the load should be analyzed, is narrowed to 21m/s which is close to the cut-out wind speed. The loads at the blade root are examined using the free simulation code, FAST, for different pitch angles ranging from 7.5 degrees to 17 degrees for each hub height mean wind speeds mentioned above. For examination of the loads at the selected locations the blade root is segmented to twelve equal points located 15 degrees away to each other. The points are located in angle between 0 and 180 degrees according to Load Rose approach. The loads at the blade root are FAST output and they are used as input for post-processor MLife to analyze the fatigue load. The fatigue loads are examined in terms of damage equivalent loads of the bending moment out of plane. It is observed that pitching a blade angle has a significant effect on the power output and fatigue load, the power output increases and with undesirable fatigue load while pitching the blade angle to capture as maximum power output as possible. On the other hand, attempting to decrease the fatigue load affects the power output as well, that indicates minimizing the fatigue load cannot be achieved without affecting the power output. Output power and fatigue load relation for different pitch angle ranging from 7.5 to 17 degrees of the selected wind speed 21m/s shows that while pitching the blade the power output increases with undesirable fatigue load. In general, it can be said that expected results are achieved at pitch angle ranging from 15 to 17 degrees. However, the fatigues loads may be not are in acceptable level, hence, it will not be appropriate to conclude that these pitch angles are the optimal angles where the maximum power output and minimum fatigue load can be achieved. Furthermore, looking at only the fatigue loads the minimum fatigue load is achieved at pitch angle of 7.5 at a sacrifice of 0.6MW of the maximum output power, 1.92MW, which is significant compared to the maximum output power that can be achieved. / Denna studie handlar om en analys av aerodynamiska laster hos en 1.5 MW landbaserad vindturbin. Målet handlar om specificering av stigningsvinkeln där kraftutbytet maximeras medan utmattningslaster hållas inom rimliga nivåer. Tretton hastighetsprofiler studerats (3 m/s till 27 m/s) för att kunna se samband mellan kraftutbytet och utmattningslaster. Vindhastighetsprofilerna simulerades med TurbSim, och de resulterande profilerna används som input för att analysera lasterna vid bladroten. Simuleringsverktyget FAST utnyttjas för olika stigningsvinklar (7,5 till 17 grader). Resultaten visar avvägningen mellan kraftutbyte och utmattningslast som funktion av stigningsvinkeln. Högre stigningsvinklar resulterar i ökat kraftutbytet, och oönskade utmattningslaster inträffar vid 16-17 grader. Skillnaden i kraftutbytet mellan lägsta och högsta stigningsvinklar kan vara så hög som 30%.

This report gives a general overview of the natural gas resources in the world, along with its importance as a source of producing energy, and technical uses. It also draws attention to the political issues raised by natural gas exploitation and the steps being taken to address them. It also discusses the long-term measures required to achieve net zero emissions. With enormous supplies spread across several locations, natural gas is essential to the world's energy balance. Its better burning characteristics makes it a desirable substitute for other fossil fuels, especially for the production of power, heating, and industrial activities. Economic growth and global energy security are significantly impacted by the availability of natural gas resources. However, natural gas extraction and use, raise additional environmental issues, particularly in light of its greenhouse gas emissions have been discussed. Despite producing less carbon dioxide than either coal or oil, natural gas is a significant source of methane emissions, a powerful greenhouse gas. So a deep dive into why methane is a stronger greenhouse gas has been presented. It is observed that the fracking, flaring and methane leaks during the mining, transportation, and storage processes are the major concerns for climate change mitigation. Furthermore, natural gas is intertwined with political issues due to its geopolitical nature and the reliance of resource-rich nations on it as a significant source of income. It is observed that geopolitical tensions and potential wars are frequently caused by disagreements over ownership, cost, and transit routes. Geopolitical stability and energy security will be impacted by a region's reliance on imported natural gas. Various mitigation measures have been proposed and implemented to tackle the environmental challenges posed by natural gas are discussed. These include improving extraction techniques such as improved drilling methods and improved leak detection systems and investing in cleaner technologies, such as carbon capture utilization and storage (CCUS). Policies and rules are also being developed to encourage the use of advance energy efficiency measures and to promote the use of renewable energy sources in addition to natural gas. These measures aim to minimize the carbon footprint of natural gas and transition towards a more sustainable energy system. However, achieving long-term sustainability and net zero emissions (NZE) will require more profound transformations. To achieve NZE, EU has proposed the fit for 55 package. Some of the proposals of the fit for 55 package to achieve NZE 2030 target have been discussed. This involves developing alternative energy sources and technologies, such as renewable energy and the use of alternate fuels in various sectors. It also entails promoting energy conservation, implementing rigorous emissions regulations, fostering international cooperation, and investing in research and development for innovative solutions. Implementing all these measures ensure a sustainable and secured energy for future generations.

Increasing global electricity consumption and population growth have resulted in conflicts between renewable energy sources, such as bioenergy and ground-mounted photovoltaic systems, owing to the limited availability of suitable land caused by competing land uses. This challenge is further compounded by the intertwined relationship between energy and agri-food systems, where approximately 30% of global energy is consumed. In addition, considering that agricultural irrigation accounts for 70% of water use worldwide, its impact on both land and water resources becomes a critical concern. Agrivoltaics offers a potential solution to this land use conflict. However, a knowledge gap remains regarding the impact of integrating these techniques on microclimatic conditions. Addressing this gap is crucial because these conditions directly affect the growth and development of crops, as well as the efficiency of energy yields in photovoltaic panels. Experimental facilities offer valuable insights tailored to specific locations and system designs. Although they provide an in-depth understanding of a particular location, the extrapolation of this information to different locations or alternative systems may be limited. Therefore, the broader applicability of these insights to diverse settings or alternative systems remains unclear. In this thesis, a modelling procedure was developed to evaluate the photosynthetically active radiation reaching crops in typical agrivoltaic configurations across three diverse geographical locations in Europe. This is essential for understanding how solar panel shading affects the incoming photosynthetically active radiation required for crop photosynthesis. Furthermore, computational fluid dynamics were employed to model and assess the microclimate of an experimental agrivoltaic system. The developed model revealed significant variations in photosynthetically active radiation distribution across different agrivoltaic systems and locations, emphasising the need for tailored designs for optimal energy yield and crop productivity. Computational fluid dynamics analysis demonstrated its effectiveness in evaluating microclimatic parameters such as air and soil temperature, wind speed, and solar irradiance within agrivoltaic systems, providing valuable insights for system optimisation. By bridging a knowledge gap, this thesis contributes to the understanding of the modelling and simulation of agrivoltaic system microclimates, thereby facilitating the sustainable coexistence of renewable electricity conversion and agriculture.

Industry is responsible for approximately 30 % of the total emissions of greenhouse gases, both globally and in Sweden. Given the climate targets set out in the Paris agreement, the industry is facing a challenging future, requiring effective policies to aid the transition. Energy system optimisation models are commonly used for analysing the impact from different policies and for assessing the transition to a climate-neutral energy system. In the past, the primary focus of the models has been on the stationary energy sector, and less on the industry. This thesis work, therefore, aims to improve energy system optimisation models as a tool for decision support and policy analysis about the industry. An improved modelling structure of the industry sector is developed and a wide range of future technology options that can support the transition to a climate-neutral industry is identified. The improved model is then applied in different scenario analysis, assessing how the Swedish industry can meet net-zero CO2-emission under resource limitations. The methodology applied is energy system analysis with a focus on the process of modelling, an iterative process of i) model conceptualisation, ii) model computation and iii) model result interpretation. Two different models for the evaluation of the Swedish industry are developed and used; a TIMES based model (cost-minimisation) and a small linear optimisation model (resource optimisation). An outcome from developing the model structure was that the following important aspects need to be represented in the model to capture the transition to a climate-neutral industry sector; i) synergies between different types of industrial processes, ii) setup of process chains based on important tradeable materials, iii) detailed technology representation. When identifying and analysing future technologies, it was concluded that there are plenty of technology options for Swedish industry to become fossil-free. Technology options were identified that enable all studied site categories (representing approximately 92 % of the CO2 emissions from Swedish industry in 2015) to reach net-zero CO2-emissions via either electrification (direct electric heating or via power to gas) or biofuels usage. CCS options were implemented for iron and steel industry, chemical industry, cement- and limestone industry and aluminium industry, and for most of the industrial energy conversion technologies. Although technology options for deep reductions in CO2 emissions exist, many of them require further development to enable full-scale implementation, as concluded in paper III. The scenario analysis performed in paper I and paper II gives insights into key resources and technologies enabling the industry to reach net-zero CO2 emissions. About resources, biomass is seemingly the most cost-efficient option for reaching ambitious climate targets, e.g. according to the findings in paper II biomass is consistently preferred over electrified alternatives. However, the availability of biomass is limited, and increased electrification of technologies is unavoidable to achieve sustainable use of it (as seen in paper I and paper II). Finally, there is not one key enabling technology but rather key groups of enabling technologies that create cross-technology synergies, providing different benefits depending on resource availability and the overall needs of the system in different scenarios.

The purpose of this project was to investigate the viability of daily production planning of the small-scale hydropower plants owned by Småkraft AB in Jädraån. In order to achieve this a number of characteristics of the river and the power plants first had to be estimated. This included the size of the reservoirs located by the power plants as well as the efficiency profiles of the power plants. The above data was combined with already available information regarding the head, peak power production, maximum discharge and flow times between the power plants. A model of the river and the included power plants was then developed using Matlab and Simulink. In the model the reservoir levels by the power plants are directed towards different levels during different hours of the day, depending on when electricity prices are the highest. Data that can be inserted into the model includes river runoff and electricity prices. The model can then be used to evaluate the best way to operate the power plants under certain conditions. For this project, the model was then used to evaluate different modes of operation for three different runoff schemes. The electricity prices that the operation was evaluated for were the average hourly prices during 2022. The model was also used to examine the potential benefits of increasing the maximum discharge at one of the power stations. The evaluation found that moving production to hours with higher electricity prices enables an increase in revenue of about 7-14% depending on the present water flows. There are however many uncertainties involved in the modelling and physical tests would be required to validate the results. No clear benefits of increasing the maximum discharge were found.

Sweden has several environmental goals and one of them is to have net zero emissions from greenhouse gases. Emissions of greenhouse gases are strongly connected to usage of energy and 40% of the energy produced goes to buildings. A method of reducing energy usage is by using an energy audit and energy analysis.An energy audit and energy analysis has been done on a building in Stockholm. The building is 22165m2and consists of offices, laboratories and a restaurant, The aim of the study is to analyze the buildings energy usage with help of the energy audit and then find solutions that reduce the buildings energy usage. The method that has been used in this study have been a case study, observations, measurements and collections of data. A literature study has also been conducted to find potential solutions for reduction in energy usage that may be applicable to Apelsinen. To analyze the building observationswere conducted and information regarding energy usage and statistics where collected. Long term measurements were also conducted on power outlets and the indoortemperature. The energy analysis shows that there is big potential to reduce costs for energy usage by using cost efficient investments and by utilizing existing equipment and operating strategies. The study could show interesting results like that there where a big difference between the invoiced energy and the actual energy used. The study also discusses alternative solutions that might have been used and how they would affect the result like installation of a battery storage.If the proposed solutions are used the energy usage of the building can be reduced by around 392 MWh/year which results in a cost saving around 501 kkr

Södra Klaragatan 4 i Karlstad är en fastighet som ägs och förvaltas av Karlstads Bostads AB. Fastigheten består av två delar, en del byggdes 1895 och den nyare delen byggdes 1938. Äldre delen av fastigheten är förklarad som en byggnad med särskilt värde hos kommunens kulturmiljöprogram. Fastighetens äldre del drar mycket energi och därför är syftet med examensarbetet att kartlägga energiförlusterna samt energieffektivisera den äldre delens klimatskal och ventilation.   Metoden för detta arbete var besiktningar av fastigheten för att dokumentera installationer samt fastighetens konstruktion då upprättade konstruktionshandlingar saknas. Även termografering av fastigheten har gjorts för att undersöka luftläckage och köldbryggor i klimatskalet. För att sedan göra beräkningar i programmet simulink. Utöver det gjordes en enkät för de boende att svara på för att undersöka den termiska komforten i fastigheten.   De åtgärder som testats i arbetet är byte av ventilationssystem från självdrag till F-system eller FTX-system. Även byte av äldre fönster på tredje våningen, byte av isolering på vindsbjälklaget och tilläggsisolering av golvbjälklaget testades.   Resultatet visar att konstruktionen på klimatskalet inte är isolerat utan det är tjocka tegelväggar som beklätts med puts. Vindsbjälklaget har isolerats med lösull och har bra värmemotstånd. Golvbjälklaget är inte isolerat vilket gör att det är mer likt ytterväggarna men har bättre värmemotstånd. Via termografering av fastigheten visade det sig att det finns luftläckage vid fönster och dörrar. Det är antagligen till följd av dålig tätningslist. Ytterväggarna resulterade i störst mängd transmissionsförluster utifrån simuleringarna.   Den åtgärd som sparade mest energi av de simulerade åtgärderna var byte av ventilationssystem till FTX-system. Det kan spara närmare 28 000 kWh/år. Det är en åtgärd som inte bara sparar energi utan säkerställer ett luftflöde enligt dagens lagkrav. Det förbättrar den termiska innemiljön men det är en åtgärd som kräver ett större ingrepp i fastigheten via rördragning vilket kan vara besvärligt utan att förvanska den fina kulturhistoriska interiören. Vid byte av ventilationssystem till FTX-system tillsammans med de andra åtgärderna på klimatskalet kan energiprestandan på fastigheten sjunka från 157 kWh/m2, år till närmare 88 kWh/m2, år.

No description available.

The future energy transition will reshape the current fossil energy system with low-carbon energy sources. The new technologies and State policies will promote the implementation of different energy carrier sources such as electricity, ammonia, biomass and hydrogen. However, volatility, uncertainty, complexity, and ambiguity are defining a new global framework for energy systems. Despite Covid-19, the Russian and Ukrainian war, among other disruptive events, the pursuit of zero emissions remains one of the ambitions of the European Union, and renewable hydrogen has been selected to achieve these goals. The European Union through its Hydrogen Strategy aims to scale the hydrogen energy system based on renewable hydrogen in the coming years. For the present analysis, Sweden and Spain have been selected and it has been verified how the energy baseline, the national hydrogen strategies, and the main companies will shape the future hydrogen energy system of both countries. The selected method was a holistic qualitative and quantitative analysis of the energy systems of Sweden and Spain, focusing on the interactions inside and outside the energy system at the national level. The national strategies, the energy background of the countries, and the investments from the OMX-Stockholm30 stock exchange for Sweden and IBEX-35 for the Spanish case were analysed. Only bibliographic sources, internet news, and public reports from brokerage houses were used as material. The main results of the work show two very different ways of implementing national hydrogen policies. On the one hand, Sweden has high ambitions to produce renewable hydrogen up to 5 GW from electrolysers by 2030. Sweden is currently focusing its hydrogen energy system on renewable hydrogen steelmaking projects such as HYBRIT or GreenSteel. On the other hand, Spain has a lower national ambition with only 4 GW of electrolysers by 2030 according to its national roadmap. However, the IBEX-35 companies have already planned more than 13 GW of electrolyser capacity with the Catalina, SHYNE, HYDEAL projects, among others. The main investments will focus on sectors that are difficult to abate, such as oil & gas and fertilizers, and with the participation of the steel industry.