The conversion of wave energy into electrical energy has the potential to become a clean and sustainable form of renewable energy conversion. However, like all forms of energy conversion it will inevitably have an impact on the marine environment, although not in the form of emissions of hazardous substances (gases, oils or chemicals associated with anticorrosion). Possible environmental issues associated with wave energy conversion include electromagnetic fields, alteration of sedimentation and hydrologic regimes and underwater radiated noise. Underwater noise has the potential to propagate over long distances and thus have the potential to disturb marine organisms far away from the noise source. There is great variation in the ability to perceive sound between marine organisms, one sound that is clearly audible to one species can be completely inaudible to another. Thus, to be able to determine potential environmental impact from WECs associated with underwater noise, the noise radiated from the WECs must be known. This thesis presents results from studies on the underwater radiated noise from four different full-scale WECs in the Lysekil Wave Power Project. Hydrophones were used to measure the underwater radiated noise from operating point absorbing linear WECs. The main purpose was to study the radiated noise from the operating WECs with emphasis on characteristics such as spectrum levels, Sound Pressure Level (SPL), noise duration and repetition rate. This to be able to determine the origin of the noise and if possible, implement design changes to minimize radiated noise. The results identified two main operational noises (transients with the bulk of the energy in frequencies &lt;1 kHz). The SPL of the radiated noise fluctuated significantly, depending on wave height. Broadband SPLrms of the measurements ranged between ~110 dB and ~140 dB re 1 µPa and SPLpeak of specific noises ranges between ~140 and ~180 dB re µPa. Audibility was estimated range from 1km to 15 km depending critically on species and on assumptions of propagation loss. The noise is not expected to have any negative effects on behaviour or mask any signals, unless in the vicinity (&lt;150m) of the WECs in significant wave heights. No physical damage, even in close vicinity are expected on either fish or marine mammals. Having the aim to have as little impact on the environment a possible, these studies are important. This way precautions can be implemented early in the technical development of this kind of renewable energy converters. The benefits from the WECs the Lysekil wave power project are believed to outweigh possible environmental impacts due to underwater radiated noise. / <p>Vid avhandlingens tryckläggning upptäcktes inte att tidpunkt för disputation var fel.</p>

A new concept, extracting energy from sea waves by parametric pendulor, has been explored in this project. It is based on the conversion of vertical oscillations to rotational motion by means of a parametrically-excited pendulor, i.e. a pendulum operating in rotational mode. The main advantage of this concept lies in a direct conversion from vertical oscillations to rotations of the pendulum pivot. This thesis, firstly, reviewed a number of well established linear and nonlinear theories of sea waves and Airy’s sea wave model has been used in the modelling of the sea waves and a parametric pendulum excited by sea waves. The third or fifth order Stokes’s models can be potentially implemented in the future studies. The equation of motion obtained for a parametric pendulum excited by sea waves has the same form as for a simple parametrically-excited pendulum. Then, to deepen the fundamental understanding, an extensive theoretical analysis has been conducted on a parametrically-excited pendulum by using both numerical and analytical methods. The numerical investigations focused on the bifurcation scenarios and resonance structures, particularly, for the rotational motions. Analytical analysis of the system has been performed by applying the perturbation techniques. The approximate solutions, resonance boundary and existing boundary of rotations have been obtained with a good correspondence to numerical results. The experimental study has been carried out by exploring oscillations, rotations and chaotic motions of the pendulum.

Indien är en tillväxtmarknad med många möjligheter; det är en plats för nytänkande och frugala innovationer. Frugala innovationer är ett fenomen som Indien är välkänt för. I grunden uppstår frugala innovationer genom sparsamhet i processen för att ta fram effektiva lösningar. Kunskapen om frugala innovationer och dess förhållningssätt kopplat till svenska energiföretag som är inom branschen för förnybara energikällor är dock begränsad. Därför är innovationsmyndigheten Vinnova och Energimyndigheten intresserade av att se om det finns potential för ett antal svenska energiteknikföretag att lyckas etablera sig på Indiens marknad för förnybara energikällor, där effektivitet och sparsamhet är viktigt. Undersökningen har skett genom en kvalitativ forskningsmetod i form av intervjuer med de företag som har varit tillgängliga och även med en expert med kunskap om den Indiska marknaden. Teorier har främst hämtats ifrån tryckt litteratur och vetenskapliga artiklar. Under studiens gång arbetade författarna fram en modell som kan användas för att bedöma ett företags förmåga att etablera sig på en främmande marknad. I modellen ingår ett antal viktiga aspekter inom områden som ekonomi, innovation, marknad och tillväxt. Forskningen har kommit fram till slutsatser om samtliga undersökta företags potential att lyckas i Indien. I studien fann författarna att om man ska ha potential att lyckas på den Indiska marknaden, ska man bland annat ha en aktuell och effektiv produkt, stark ekonomi, konkurrenskraftighet samt marknadsmöjligheter. / India is an emerging market with many opportunities; it's a place for rethinking and frugal innovations. Frugal innovation is a phenomenon that India is well known for. Frugal innovations arise by thrift in the process of developing effective solutions. Knowledge about the frugal innovations and its approach linked to Swedish energy companies that is in the business of renewable energy is limited. Therefore, the innovation agency Vinnova and the Swedish Energy Agency (Energimyndigheten) are interested to see if there is potential for a number of Swedish energy companies to establish in the Indian market for renewable energy, where efficiency and economy are important. The survey was done by a qualitative research in the form of interviews with the companies that have been available and also an expert with knowledge of the Indian market. Theories were mainly collected from printed literature and scientific articles. During the study, the authors came up with a model that can be used to estimate a company's ability to establish itself in a foreign market. The model includes a number of important aspects, such as financial aspects, innovation, market and growth. The research has come to conclusions about all the studied companies potential to succeed in India. In the study, the authors found that if you're going to have the potential to succeed in the Indian market, you should have an up-to-date and effective product, strong economy, competitiveness and market opportunities.

One of the key points to reduce the world dependence on fossil fuels and the emissions of greenhouse gases is the use of renewable energy sources. Recent studies showed that wind energy is a significant source of renewable energy which is capable to meet the global energy demands. However, such energy cannot be harvested by today’s technology, based on wind towers, which has nearly reached its economical and technological limits. The major part of the atmospheric wind is inaccessible to the conventional wind turbines and wind at higher altitude is the major source of potential energy which has not been fully exploited yet. The thesis paper has presented a study aimed to devise a new class of wind generator based on extracting energy from high altitude wind.A brief theoretical study is presented to evaluate the potential of an innovative high altitude wind power technology which exploits a tethered airfoil to extract energy from wind at higher altitude. Among the various concepts proposed over last few decades, a kite power system with a single kite is selected for the design purpose.The designed ground station is an improvisation over existing prototypes with an energy reservoir for having a continuous power output. A flywheel is used as the energy storage system which stores the extra energy during traction phases and supplies it during recovery phases and thus giving a continuous power generation regardless of the kite’s motion and keeping the rotor speed in a permissible range defined by the design constraints. Manufacturability of the structure, availability of the components, safety and maintenance criteria have been taken into account while building the ground station CAD model.A dynamic simulation model is developed to investigate the power transmission system of the kite power unit which reflects the torque, speed and power behaviour of the modelled ground station driveline. The functionality of the designed model for the selected concept is tested with several numerical and graphical examples.

On October 1st, 2013, a mandate was adopted by the California Public Utilities Commission (CPUC) requiring that 1.325 GW of energy storage capability be installed on the California electricity grid by 2024, through the actions of the state’s three investor-owned utilities. While this is a bold first step towards mandated energy storage in the United States, it may be only the beginning for an energy storage industry in this state. It has been well established that energy storage would prove to be a useful asset on the California electrical grid, but the development of storage capacity past the requirements of the mandate will depend upon whether storage can be made cost-effective. Much of the value that storage creates is a public good: many storage applications allow the grid to operate more efficiently as a whole, but not necessarily in a way that can be monetized by any particular party. As a public good, these systemic benefits of storage capacity will be supplied sub-optimally in the absence of government intervention. The energy storage industry will accordingly be one that is strongly affected by the tides of change in technology, regulation and economics in the California energy market. This report will focus primarily on the intersection of the second two of these factors, largely leaving the technological questions to more well-informed parties while seeking to establish what regulatory and economic considerations might be undertaken to ensure that the road to deployment of appropriate energy storage systems is made as clear as possible so that this technology can reach the socially efficient level on the California electricity grid. It is the aim of this report not to promote a specific technology or even an energy storage industry, but rather to shed some light on the effects that the development of such an industry could have on the California electricity market and the energy use paradigm that governs modern electricity grids worldwide. With the adoption of AB 2514, a grand experiment was set in motion that will benefit the entire world as California tests the uncharted technological, regulatory and economic territories of grid-scale energy storage capacity. It is a time of change in the electricity industry, and energy storage is a potentially transformative technology that could very well enable the shattering of an energy use paradigm that has held the world captive to fossil fuels for over a century.

Energy intervention programs have gained prominence in governmental policies and development agendas as a prevailing practice of improving rural livelihoods and protecting local environment and resources in developing rural areas since early 1970s. In spite of the increasing evidences of small-scale renewable energy systems being advantageous over traditional ones towards rural sustainability, the introduction and diffusion of the new energy systems in many developing rural areas has suffered program ineffectiveness in terms of slow construction, limited utilization, and high risks of being idled or abandoned by the adopters. While there are substantial studies documenting the challenges of rural energy planning, few scholars have devoted to the processes and efficacy of the planning practice. Literature has obvious gaps between planning theory and rural energy planning practice as no prior academic efforts were uncovered to use planning theory to examine the rural energy planning practice and to provide directions to future practice. Meanwhile, literature suggests that the integration of efficacy-oriented and context-dependent principles of planning theory into the energy planning processes can contribute to the effectiveness of rural energy intervention programs. Vital to the integration is the conduct of a study that critically assesses the rural energy planning processes against the insights drawn from planning theory and then provides policy implications for bridging the gaps between theory and practice. A review of literature on energy, planning, and community development in relation to sustainability led to an evaluative framework containing 24 criteria which were aggregated into six groups of principles, i.e., equity, flexibility, efficiency, participation, continuity and reflectivity. The principles were coupled respectively focusing on the operationalization, implementation, and monitoring processes of rural energy planning. Employing a primary case study design, the researcher conducted the field study in southern China’s Hainan province to examine whether the aggregated criteria were upheld and performed in local practices. In the field research, the author collected relative information and data through interviews, surveys, secondary sources, and direct observation. The data were analyzed in a mix of inter-related qualitative and quantitative methods. Where possible, the author used triangulation to limit individual and methodological biases. Hainan’s rural energy intervention programs of introducing and diffusion renewable energy systems such as anaerobic digesters and solar heaters in developing rural areas were significant contents of the provincial eco-village program and eco-province strategy. Although the energy programs had satisfactory effectiveness sporadically in a few villages, the majority of the programs suffered from problems like slow construction, limited utilization, and high risks of being idled or abandoned by the adopters. A number of challenges were recognized and mentioned by the administrative interviewees, including financial, technical, social, cultural, institutional and other constraints that support and conform to the discussions in literature. The study advances the understandings by identifying the gaps between planning theory and local rural energy planning practice in Hainan. Specifically, the equity principle was recognized but not totally fulfilled; the flexibility principle remained contentious and singularly executed; the efficiency principle was accepted but performed without enough scrutiny; the participation principle was emphasized but challenging; the continuity principle was aware of but not compulsorily executed; and the reflectivity principle was vague and overlooked. The author further analyzes that there will be barriers at the micro, meso, and macro levels to impede the integration of planning theory into rural energy planning practice. Extending the findings to a broader discussion on planning for development projects in developing rural areas, the author highlights a number of external and internal problems that harm the program effectiveness and calls for immediate and meaningful attention to ensuring program effectiveness. Several suggestions are provided for policy reconsideration and reorientation.

In the pursuit of a cleaner and sustainable environment, solar photovoltaic (PV) power has been established as the fastest growing alternative energy source in the world. This extremely fast growth is brought about, mainly, by government policies and support mechanisms world-wide. Solar PV technology that was once limited to specialized applications and considered very expensive, with low efficiency, is becoming more efficient and affordable. Solar PV promises to be a major contributor of the future global energy mix due to its minimal running costs, zero emissions and steadily declining module and inverter costs. With the expanding practice of managing decentralized power systems around the world, the role of private investors is increasing. Thus, the perspective of all stakeholders in the power system, including private investors, has to be considered in the optimal planning of the grid. An abundance of literature is available to address the central planning authority’s perspective; however, optimal planning from an investor’s perspective is not widely available. Therefore, this thesis focuses on private investors’ perspective. An optimization model and techniques to facilitate a prospective investor to arrive at an optimal investment plan in large-scale solar PV generation projects are proposed and discussed in this thesis. The optimal set of decisions includes the location, sizing and time of investment that yields the highest profit. The mathematical model considers various relevant issues associated with PV projects such as location-specific solar radiation levels, detailed investment costs representation, and an approximate representation of the transmission system. A detailed case study considering the investment in large-scale solar PV projects in Ontario, Canada, is presented and discussed, demonstrating the practical application and usefulness of the proposed methodology and tools.

The increasing price of fuel and energy, combined with environmental laws and regulations, have led many different energy producers to integrate renewable, clean energy sources with non-renewable ones, forming the idea of energy hubs. Energy hubs are systems of technologies where different energy forms are conditioned and transformed. These energy hubs offer many advantages compared to traditional single-energy sources, including increased reliability and security of meeting energy demand, maximizing use of energy and materials resulting in increasing the overall system efficiency. In this thesis, we consider an energy hub consisting of natural gas (NG) turbines for the main source of energy— electricity and heat— combined with two renewable energy sources—wind turbines and PV solar cells. The hub designed capacity is meant to simulate and replace the coal-fired Nanticoke Generating Station with NG-fired power plant. The generating station is integrated with renewable energy sources, including wind and solar. The hub will also include water electrolysers for hydrogen production. The hydrogen serves as an energy storage vector that can be used in transportation applications, or the hydrogen can be mixed into the NG feed stream to the gas turbines to improve their emission profile. Alkaline electrolysers’ technology is fully mature to be applied in large industrial applications. Hydrogen, as an energy carrier, is becoming more and more important in industrial and transportation sectors, so a significant part of the thesis will focus on hydrogen production and cost. In order to achieve the goal of replacing the Nanticoke Coal-fired Power Plant by introducing the energy hub concept, the study investigates the modeling of the combined system of the different technologies used in terms of the total energy produced, cost per kWh, and emissions. This modeling is done using GAMS® in order to make use of the optimization routines in the software. The system is modeled so that a minimum cost of energy is achieved taking into account technical and thermodynamic constrains. Excess energy produced during off-peak demand by wind turbines and PV solar cells is used to feed the electrolyser to produce H2 and O2. Through this method, a significant reduction in energy cost and greenhouse gas (GHG) emissions are achieved, in addition to an increased overall efficiency.

Interest in Distributed Generation (DG) in power system networks has been growing rapidly. This increase can be explained by factors such as environmental concerns, the restructuring of electricity businesses, and the development of technologies for small-scale power generation. DG units are typically connected so as to work in parallel with the utility grid; however, with the increased penetration level of these units and the advancements in unit’s control techniques, there is a great possibility for these units to be operated in an autonomous mode known as a microgrid. Integrating DG units into distribution systems can have an impact on different practices such as voltage profile, power flow, power quality, stability, reliability, and protection. The impact of the DG units on stability problem can be further classified into three issues: voltage stability, angle stability, and frequency stability. As both angle and frequency stability are not often seen in distribution systems, voltage stability is considered to be the most significant in such systems. In fact, the distribution system in its typical design doesn’t suffer from any stability problems, given that all its active and reactive supplies are guaranteed through the substation. However, the following facts alter this situation: • With the development of economy, load demands in distribution networks are sharply increasing. Hence, the distribution networks are operating more close to the voltage instability boundaries. • The integration of distributed generation in distribution system introduces possibility of encountering some active/reactive power mismatches resulting in some stability concerns at the distribution level. Motivated by these facts, the target of this thesis is to investigate, analyze and enhance the voltage stability of distribution systems with high penetration of distributed generation. This study is important for the utilities because it can be applied with Connection Impact Assessment (CIA ). The study can be added as a complement assessment to study the impacts of the installation of DG units on voltage stability. In order to accomplish this target, this study is divided into three perspectives: 1) utilize the DG units to improve the voltage stability margin and propose a method to allocate DG units for this purpose, 2) investigate the impact of the DG units on proximity to voltage stability 3) conduct harmonic resonance analysis to visualize the impacts of both parallel and series resonance on the system’s stability. These perspectives will be tackled in Chapter 3, Chapter 4, and Chapter 5, respectively. Chapter 3 tackles placing and sizing of the DG units to improve the voltage stability margin and consider the probabilistic nature of both the renewable energy resources and the load. In fact, placement and sizing of DG units with an objective of improving the voltage stability margin while considering renewable DG generation and load probability might be a complicated problem, due to the complexity of running continuous load flow and at the same time considering the probabilistic nature of the load and the DG unit’s resources. Therefore, this thesis proposes a modified voltage index method to place and size the DG units to improve the voltage stability margin, with conditions of both not exceeding the buses’ voltage, and staying within the feeder current limits. The probability of the load and DG units are modeled and included in the formulation of the sizing and placing of the DG units. Chapter 4 presents a model and analysis to study the impact of the DG units on proximity to voltage instability. Most of the modern DG units are equipped with power electronic converters at their terminals. The power electronic converter plays a vital role to match the characteristics of the DG units with the requirements of the grid connections, such as frequency, voltage, control of active and reactive power, and harmonic minimization. Due to the power electronics interfacing, these DG units have negligible inertia. Thus, they make the system potentially prone to oscillations resulting from the network disturbances. The main goal of this chapter is to model and analyze the impact of distributed generation DG units on the proximity of voltage instability, with high penetration level of DG units. Chapter 5 studies the harmonic resonance due to the integration of DG units in distribution systems. Normally, the harmonic resonance phenomenon is classified as a power quality problem, however, this phenomenon can affect the stability of the system due to the parallel and series resonance. Thus, the main goal of this chapter is to study and analyze the impact of the integration of distributed generation on harmonic resonance by modeling different types of DG units and applying impedance frequency scan method.

Designing horizontal-axis wind turbine (HAWT) blades to achieve satisfactory levels of performance starts with knowledge of the aerodynamic forces acting on the blades. In this thesis, HAWT blade design is studied from the aspect of aerodynamic view and the basic principles of the aerodynamic behaviors of HAWTs are investigated. Blade-element momentum theory (BEM) known as also strip theory, which is the current mainstay of aerodynamic design and analysis of HAWT blades, is used for HAWT blade design in this thesis. Firstly, blade design procedure for an optimum rotor according to BEM theory is performed. Then designed blade shape is modified such that modified blade will be lightly loaded regarding the highly loaded of the designed blade and power prediction of modified blade is analyzed. When the designed blade shape is modified, it is seen that the power extracted from the wind is reduced about 10% and the length of modified blade is increased about 5% for the same required power. BLADESIGN which is a user-interface computer program for HAWT blade design is written. It gives blade geometry parameters (chord-length and twist distributions) and design conditions (design tip-speed ratio, design power coefficient and rotor diameter) for the following inputs / power required from a turbine, number of blades, design wind velocity and blade profile type (airfoil type). The program can be used by anyone who may not be intimately concerned with the concepts of blade design procedure and the results taken from the program can be used for further studies.