This thesis is divided in two sections. The first part consists of an interview study with 10 participants to investigate how the industry views the demand for energy storage and how it may develop in the future. Although some views differed, the study showed that a great responsibility lies on the existing hydropower. Batteries are believed to have the greatest potential as short-term storage. The participants agree that hydrogen could have great potential as a flexibility service. The future for Underground Pumped Hydro Energy Storage (UPHES) in Sweden have the participants divided but they seem to agree on the fact that the potential will depend on how price variations develop on the electricity market. Lastly, the industry agreed that a variety of energy storage technologies will be needed for the future energy system. The second part of the study is a deeper investigation into what energy deficit and demand for long-term energy storage (longer than 8 hours) might occur in the future and how UPHES may help shorten the longest deficits. To determine the need for energy storage, the scenario Electrification Renewable from a Svenska Kraftnät (Svk) report was chosen to represent the future energy system for year 2045. The result showed that depending on how the need for energy storage is defined, the amount of energy demand and therefore UPHES facilities, varied. If the need for energy storage was dimensioned regarding the average year it would result in 0,21 TWh of long-term energy deficits and 28 facilities would be enough to cover all of them. If the number of facilities was increased, the result showed a lower usage of all the facilities. However, if the need for energy storage was dimensioned regarding the ''worst case scenario'', the longest deficit out of 35 years, the energy demand in the long deficits was 14 TWh. If 28 facilities were used only 11 % of the energy demand in the long deficits would be covered. If the number of facilities increased, 172 facilities would cover 32 % of the energy demand in the long deficits and 1834 facilities would cover 60 %.

The energy market is evolving, with a prediction of heavily increased consumption and, consequently, increased production. In parallel, EU directives with targets prioritising fossil-free electricity production, reduction of greenhouse gas emissions and becoming climate neutral by 2050, poses a challenge for the current state of electricity production in the Nordics. In managing these predictions, the electricity production from renewable energy sources is required to be increased threefold by 2045. Consequently, the share of intermittent energy sources is deemed to heavily increase, resulting in need of more capacity of energy storage, ancillary services and balancing of the grid. Energy storage systems, such as pumped storage hydropower, can play a crucial role in this energy market transition. However, pumped storage hydropower has yet to be fully explored or proven viable for large-scale investments in the Nordics. In this thesis, the viability and profitability of pumped storage hydropower plants in the Nordics are investigated. The viability assessment was conducted through a SWOT analysis based on a summary of literature and interviews within a PESTLE framework. The interviewees consisted of experts active in different fields of work at Fortum, with knowledge relevant for the purpose of this thesis. To assess the profitability, an investment analysis tool for pumped storage hydropower plants was created in MathWork’s MATLAB, focusing on one of Fortum’s already existing pumped storage hydropower plants. The investment analysis tool was built for several cases with fixed operating schedules using a weekly timeframe.  Through the SWOT analysis, potential challenges for pumped storage hydropower were found in investment costs, topology dependence, development of nuclear power production and increased difficulty in obtaining greenfield permits. Regarding opportunities, Fortum’s pumped storage hydropower plants were found to be favourably and strategically located in SE3, beneficial in generating income from different revenue streams as well as highly beneficial in assisting the development of Sweden’s future energy market. The results obtained from the investment analysis tool indicated that market volatility plays a crucial role in determining the profitability of pumped storage hydropower projects. In a highly volatile market, there is a great possibility to yield large amounts of profit. However, to fully maximise profit, especially in a low volatility market, constant optimisation of pumped storage hydropower operations through advanced forecasting and modelling is crucial.

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Operation of a pumped storage system is dictated by the time dependent price of electricity and capacity limitations of the generating plants. This thesis considers the optimization of the Smith Mountain Lake-Leesville Pumped Storage-Hydroelectric facility. The constraints include the upper and lower reservoir capacities, downstream channel capacity and flood stage, in-stream flow needs, efficiency and capacity of the generating and pumping units, storage-release relationships, and permissible fluctuation of the upper reservoir water surface elevation to provide a recreational environment for the lake shore property owners. Two formulations are presented: (1) a nonlinear mixed integer program and (2) a discretized linear mixed integer program. These formulations optimize the operating procedure to generate maximum revenue from the facility. Both formulations are general and are applicable to any pumped storage system. The nonlinear program retains the physical aspects of the system as they are but suffers from non-convexity related issues. The linear formulation uses a discretization scheme to approximate the nonlinear efficiency, pump, turbine, spillway discharge, tailrace elevation-discharge, and storage-elevation relationships. Also, there are binary unit dispatch and either/or constraints accommodating spill and gated release. Both formulations are applied to a simplified scheme of the Smith Mountain Lake and Leesville pumped storage system. The simplified scheme uses a reduced number of generating and pumping units at the upper reservoir to accommodate the software limitations. Various sensitivity analyses were performed to test the formulations. The linear formulation consistently performs better than the nonlinear. The nonlinear solution requires a good starting point for optimization. It is most useful as a verification tool for the solution from the linear program on all occasions. The formulations yield the best schedules for generating and pumping. A coarse time interval limits the use of all pumps in the presence of the spill constraint. A sufficiently large difference in the diurnal unit price encourages short-term pump back as opposed to a weekly cycle. The Leesville (downstream) reservoir affects the power production schedule with its large (approx. 9 ft) forebay rise for every foot drop at the Smith Mountain Lake. The linear formulation provides a valuable tool for studying the system under a wide range of conditions without having to worry about the computational difficulties associated with the nonlinear formulation. / Master of Science

In this modern age of information, the demands on data transmission networks for greater capacity, and mobile accessibility are increasing drastically. The increasing demand for mobile access is evidenced by the proliferation of wireless systems such as mobile phone networks and wireless local area networks (WLANs). The frequency range over which an oxygen resonance occurs in the atmosphere (~58-62 GHz) has received recent attention as a possible candidate for secure high-speed wireless data networks with a potentially high degree of frequency reuse. A significant challenge in implementing data networks at 60 GHz is the manufacture of low-cost RF transceivers capable of satisfying the system requirements. In order to produce transceivers that meet the additional demands of high-volume, mobility, and compactness, monolithic millimeter wave integrated circuits (MMICs) offer the most practical solution. In the design of radio tranceivers with a high degree of integration, the receiver front-end is typically the most critical component to overall system performance. High-performance low-noise amplifiers (LNAs) are now realizable at frequencies in excess of 100 GHz, and a wide variety of mixer topologies are available that are capable of downconversion from 60 GHz. However, local oscillators (LOs) capable of providing adequate output power at mm-wave frequencies remain bulky and expensive. There are several techniques that allow the use of a lower frequency microwave LO to achieve the same RF downconversion. One of these is to employ a subharmonic mixer. In this case, a lower frequency LO is applied and the RF mixes with a harmonic multiple of the LO signal to produce the desired intermediate frequency (IF). The work presented in this thesis will focus on the development of a GaAs MMIC 4-X subharmonic mixer in Finite Ground Coplanar (FGC) technology for operation at 60 GHz. The mixer topology is based on an antiparallel Schottky diode pair. A discussion of the mechanisms behind the operation of this circuit and the methods of practical implementation is presented. The FGC transmission lines and passive tuning structures used in mixer implementation are characterized with full-wave electromagnetic simulation software and 2-port vector network analyzer measurements. A characterization of mixer performance is obtained through simulations and measurement. The viability of this circuit as an alternative to other high-frequency downconversion schemes is discussed. The performance of the actual fabricated MMIC is presented and compared to currently available 60 GHz mixers. One particular MMIC design exhibits an 11.3 dB conversion loss at an RF of 58.5 GHz, an LO frequency of 14.0 GHz, and an IF of 2.5 GHz. This represents excellent performance for a 4X Schottky diode mixer at these frequencies. Finally, recommendations toward future research directions in this area are made. / Master of Science

Chemical Oxygen Iodine Laser(COIL) is an electronic transition high energy chemical laser having a wavelength of 1.315 /mi. This is the first chemical laser to operate on an electronic rather than a rotational or vibrational transition. In principle the COIL can be operated either in pulsed or cw mode. Its interest lies in high chemical efficiency, high power and wavelength which is shortest among all the chemical lasers. COIL finds a wide range of applications as its output wavelength at 1.315/zm couples well with the surface of most metals. The applications include surface hardening and modification of metals, welding, drilling and cutting of metals, cutting of ceramics, micro machining, laser deposition of non metallic coatings on metallic surfaces, monitoring of atmospheric pollutants and solar hazardous waste detoxification. Moreover, its wavelength is suitable for fiber optic transmission. In COIL the laser output at 1.315 /an is achieved by stimulated emission on the f (2-PL/2) -* -f (2-p3/2) magnetic dipole transition in atomic iodine. The population inversion on this transition is obtained by resonant collisions! energy transfer from metastable excited Oj^A) molecules produced by a chemical reaction of KOH, H2O? and Cl2. The chemical reaction of H2O2 and Cl2 that produces oxygen molecules is highly exothermic, and because of spin conservation considerations, channels its energy directly into the metastable electronically excited singlet delta state of oxygen molecule. Since the O2(1A) has a 45 mins lifetime and hence an extremely low small signal gain coefficient, it cannot be lased directly. Lasing can be achieved, however, if this energy is transferred to an atom or molecule which has a reasonable transition moment between its excited and ground states. The iodine 52P^2 -> 52P3/2 magnetic dipole transition has an acceptable transition moment and is nearly resonant with the 02{lA) state in oxygen. Excited iodine atoms are obtained by mixing O2(l A) and l2 molecules resulting in their dissociation and subsequent excitation. Power levels in excess of 25 kW have been reported in COIL. Due to wide range of applications and mainly for its use as a laser weapon, efforts are being made to enhance the power to higher levels. The dissociation of I2 controls the gain of the coil and hence power. In the pure COIL scheme some of the I2 remains undissociated due to the recombination reactions. Hence if we add a mechanism to dissociate the residual I2 molecules, we can enhance the performance of the COIL. So we propose to add a solar pumping to conventional COIL, which by photo exciting the undissociated I2lead to increase in efficiency. The thesis contains six chapters in which chapter 1 contains a general introduction and the definition of the research problem. The basic theory and the chemical reactions are discussed in chapter 2, The proposed model is discussed and the rate equations are solved in chapter 3. The numerical scheme and the computer code along-with the validation of the code are presented in chapter 4. The numerical results for the species concentrations, population inversion density and the output power for the proposed solar pumped COIL are presented in chapter 5, Final conclusions and future scope of the proposed research are presented in the final chapter 6. (Pl refer the original document for formulas)

Passive two-phase cooling devices such as capillary pump loops, loop heat pipes, and vapor chambers can utilize capillary-fed boiling in the porous evaporator wick to achieve high heat flux dissipation, while maintaining low thermal resistances. These systems typically rely only on passive capillary pumping through the porous wick to transport fluid. This inevitably leads to limits on the maximum heat flux and power dissipation based on the maximum capillary pressure available. To overcome these capillary pumping limitations in these passive devices, a mechanical pump can be added to the system to create a pump-assisted capillary loop (PACL). The pump can actively transport the fluid to overcome the pressure drop in liquid lines, reserving all of the available capillary action to draw liquid from a compensation chamber into the porous evaporator at the location of the heat input.<br>Previous studies on pump-assisted capillary loops have used a porous pathway to draw liquid to the heated evaporator surface from a liquid supply in the compensation chamber. This pathway typically comprises porous posts distributed over the heated surface area to ensure uniform liquid feeding during boiling and to avoid dryout regions. This thesis presents an evaporator design for a pump-assisted capillary loop system featuring a non-porous manifold connection between the compensation chamber and the evaporator wick base where boiling occurs. By using this approach, microscale liquid-feeding features can be implemented without the manufacturing restrictions associated with the use of porous wick pathways (such as sintered powder copper particles).<br>An analytical model for two-phase pressure drop prediction in the base wick is developed and used to define the evaporator geometry and feeding structure dimensions. A parametric analysis of the evaporator geometry is performed with the target of achieving a maximum heat dissipation of 1 kW/cm2 without a capillary limit. A 24 x 24 microtube array configuration with an outside tube diameter of 0.25 mm was identified as a result of this analysis. This manifold delivers liquid the base wick manufactured from sintered copper particles with a mean particle diameter of 90 microns. <br>The resulting evaporator geometry was translated into a manufacturable copper manifold design. A modular test section design consisting of a cover for attachment of fittings, a support structure for holding the manifold, a sintered copper wick base, and a carrier plate was created and manufactured, to accommodate for future testing scheduled to be performed by an external industry partner. The resulting design provides a testing vehicle to investigate the effect of different tubing arrangements and dimensions, as well as multiple base wick configurations. This knowledge can be used to engineer future evaporator architectures for enhanced performance. The improved understanding providing on the effect of liquid feeding distribution into the base wick, the effects of boiling on the base wick pressure drop, and the manufacturing limitations can each improve the performance prediction of evaporators with top feeding. <br>

Waterhammer is an undesirable event, caused by sudden flow changes in a confined pipe system. When it occurs, its consequences can be very costly and even sometimes deadly. In general, it may be encountered in the penstocks of hydropower plants, water transmission lines, water networks, etc. Therefore, the operation guidelines of the hydropower plants should be defined correctly. In this thesis, waterhammer problems in pumped storage hydropower plants are investigated. Time dependent flow conditions in the penstocks are studied by the help of computer software, HAMMER. The software solves nonlinear differential equations by using method of characteristics. Firstly, hydraulic transients for various operational cases are investigated using some scenarios. Then a surge tank, protective device for waterhammer, is added to the system and for the same operational cases, hydraulic transients are studied again. Finally, the results obtained from the operation of the system with and without surge tank are compared. Wind-hydro hybrid systems are also included in the study.

Environmental awareness and uncertainty about continued supply of fossil fuel has given rise to the renewable energy movement. Wind based power generation has been at the forefront of the motion to integrate distributed energy sources in the traditional power system. Due to various technical restrictions, wide scale penetration of wind generated power has been held back by most utilities. One such restriction is the variability of generation due to the technology’s dependence on Mother Nature. Energy storage devices can complement the wind generators by reducing this variability. These devices can store excess generation for supply during low generation periods. There are several promising technologies for both energy storage and power storage applications. Power storage devices provide short term fluctuation dampening capability while energy storage devices allow longer term storage. Pumped hydro, Vanadium Redox battery and Sodium-Sulphur battery are some of the viable energy storage technologies. This project provides a set of algorithms and guidelines to obtain the optimal configuration parameters of an energy storage device. To verify the efficiency of the algorithms, a model system has been obtained from a local utility. This system represents a typical radial distribution system in rural Ontario. The load demand, wind speed and energy prices for a period of one year have been obtained from utilities and Environment Canada. The main goal in determining the location of the storage device within a distribution system is to minimize the total cost of energy and the total energy loss during the period of analysis. Locating the storage device near the wind turbines or near the largest loads lead to the optimum results. Buses that are located near those elements can be considered as suitable locations for the storage device. The energy storage capacity and charge-discharge rate of the storage device are selected based on four criteria: maximize wind turbines’ load following capability, maximize capacity factors of the wind turbines, minimize system energy losses and minimize system energy costs. A weight based multi-objective optimization algorithm has been proposed to assign various priorities to these criteria and obtain a single solution. The larger the energy storage capacity of the storage device, the better the improvement in system performance. Lower charge-discharge ramp rates provide superior results. The parameters for storage device operating schedule, i.e. charge-discharge trigger levels, have been selected using similar criteria and weighted objective approach as for the capacity selection process. Higher charge trigger levels and moderate discharge trigger levels provide the optimum system performance. Once a set of parameters for the storage device has been selected, bus voltages over the period of study are analyzed. Voltage variations outside certain limits have been identified. Finally, a Monte Carlo based simulation approach is presented to obtain output parameter (system performance) variation ranges for pseudo random changes in input parameters.