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.

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The concept of a cavity absorber for use with a focusing parabolic trough is developed in this paper. A mathematical model is formulated and used to compare different absorber geometries. Limitations of the model are discussed and within the range of materials and fabrication methods available, the choice of a cylindrical cavity is substantiated. Relative sizes of the gap and cylinder are chosen for a given mirror arc length, focal length, and alignment error. The model is used to optimize these parameters and predict absorber and collector efficiency. The processes of building and testing the absorber are detailed, and test results are reported. Observed performance is significantly below that predicted. Mirror alignment errors are considered the most likely reason for the discrepancy. Other possible improvements to the experiment are suggested.

The aim of the thesis is to investigate the opportunities and limitations that utilizations of Vehicle tohome (V2H) and a buildings thermal inertia has in detached houses with respect to demand flexibility.In the transition phase of energy sources there has to be a compensation to the use of fossil energy tofulfill the energy demand. Along with transition there’s a growing need for smarter way of usingelectricity as the consequences otherwise are likely capacity shortages and increase electricity prices.Results from recent research suggest that private household could contribute to even out the powerpeaks by using household appliances based on demand for electricity. Results from earlier surveyresearches has shown that demand flexibility comes with challenges of household comfort andeconomic incentive. With annual data of electricity use from an area of detached houses, provided by Karlstads EnergiAB, a model has been created in MATLAB and Simulink to simulate scenarios of utilizations of V2Hand thermal inertia of a building. The purpose of the model is to provide answer to the goals of thestudy; proportions of moved electricity when using V2H, proportions of moved electricity whenutilize the building thermal inertia and the economic consequences of them both. The results shows that it is possible to move up to 5000 kWh/year in the V2H model and up to 2800kWh/year in the heating model without a theoretical impact on the comfort. Furthermore, the cost forbought electricity can be reduced up to 11 % in simulations from data of 2017 and up to 20 % fromdata of 2021, which corresponds to 700 and 3000 Swedish crowns (SEK) respectively. As for theheating model the reduced costs of simulations of 2017 were up to 17 % and 34 % in 2021, whichcorresponds to 500 and 2000 SEK respectively. Results from this study suggest that it is possible to move electricity from occasions with high to lowdemand and simultaneously reduce the electricity costs. The results are limited to the assumptionsthat the construction of all houses are identical and has the same heating systems along with a fixedtime of the day when the car is connected to the home. The accuracy of the results could be increasedwith complementary information of these assumptions. An omitted question in this study was whetherdifferent strategies for utilizing the varying electricity price affect the result, which is proposed forfuture research.

With the ongoing increasing focus on the development of intermittent renewable sources, there is a clear need for energy storage solutions that can handle large fluctuations in power and store large amounts of energy. Hydrogen i seen as a candidate as a possible energy carrier for this purpose, and many hydrogen projects have been seen occurring over the world. In order to enable further development of hydrogen systems for the production and utilization of hydrogen fuel, modeling can be performed to investigate the performance, feasibility, and responses of these systems. There is, however, a need for further development of electrolyzer models for production, and fuel cell models for the utilization of hydrogen fuels. The goal of this thesis is to further develop models of electrolyzers and fuel cells with an electrical engineering perspective to be used in further research. This is done by reviewing relevant research related to these topics and narrowing down the findings into comprehensive, simple, and dynamic models in MATLAB/Simulink. These models are described in this thesis, along with the obtained static and dynamic results of the hydrogen production and utilization systems. The models include the option to parameterize to the steady-state data to replicate the static behavior and specify dynamics in terms of capacitive effects and reactant pressure controls for the fuel cell. The Simulink models created can be utilized to further develop various other system components.