Current proxy indicators of innovation although insightful, tend to provide more relevance in both larger scale markets, (such as in the pharmaceuticals or electronics industry) and for codifiable innovative activity, (such as patents and bibliometrics). These measures could be capitalised on further if a more robust measure of functionality performance that included informal innovative activity could be gained to help assess the overall performance of the system under inspection. This work uses the emerging UK wave energy sector as a primary case study to explore early stage innovation systems through the novel application of network analysis as well as existing innovation systems theory. It was hoped that a clearer understanding of which metrics were related to which system functionality and how representative they were would help to create more robust and transferable measures of emergent system functionality. The question as to whether this increased confidence and insight into system operation could allow for benchmarking comparisons between spatially or socially different emerging innovative networks, such as different countries or stakeholder types was then addressed, as well as wether this could provide a higher level of efficacy to applied policy support? A further goal of this work was to assess the current wave energy sector through these methodologies and provide insightful feedback into activity, potential opportunities and threats present within the system. The main methodological findings show that the novel application of Social Network Analysis provided a strongly correlated and insightful metric of innovative activity however (as with established metrics), there were clearl limitations on applicability and that a ‘one size fits all’ application of methods is not available for any innovation assessment tools. Additionally, many existing metrics used within analysis are often un-clearly defined or presented leaving largely presumptuous levels of interpretation within the final analysis. Sectoral findings showed a range of narratives regarding the sector. Clear prominence of Scotland and higher levels of all system functionality within the country make it a strong performer within the system. Likewise, a lack of coherent and ‘first-past-the-post’ funding policy has produced a ‘gating’ of technology support that in turn has disillusioned many early device developers while pulling out a fortunate few. This ‘Mathew Effect’ within the system may (among other things) leave the sector open to system shocks from outside competition and reduce the level of market entrance due to a perception of unfair or secretive support provision.

To accommodate future power demands, wave energy converters will be deployed in arrays, but largely unanswered questions of the annual energy production and environmental impact of such installations present regulatory dilemmas. In recent years, Sandia National Laboratories (SNL) has developed a modified version of the Simulating Waves Nearshore (SWAN) wave model to simulate WEC energy extraction in a propagating wave field. This thesis presents a novel WEC meta-model that calculates the power intercepted by a WEC from the incident wave field. Two representations were developed with which a user could model a WEC’s impact on the incident waves in a spectral wave model. These alterations are based on power a WEC captures from the sea and power dissipated by hydrodynamic losses calculated in an external six degree of freedom (DOF) time domain WEC simulation. The two WEC meta-models were compared in terms of significant wave height reduction in the WEC’s lee and annual power production. The first WEC representation removes a constant percentage of power from each frequency bin while the second representation employs frequency dependent energy extraction. The representations were then applied in modelling a 54 MW WEC array off of Amphitrite Bank on the West Coast of Vancouver Island. Over the course of a year, the power captured by a farm when represented with a constant percentage extraction is reduced by 2.9% while a frequency dependent percentage extraction reduced the farm’s total captured power by 2.3% when compared to the reference case. Similarly small changes were observed in significant wave height reductions. The significant wave height in the lee of a farm was reduced by less than 2% for both representations at the shoreline, approximately six kilometres behind the farm. / Graduate / 0775, 0547, 0548 / eluczko91@gmail.com

The Variable Inertia System Wave Energy Converter (VISWEC) is a self-reacting point absorber (SRPA) type wave energy converter (WEC) capable of changing its mechanical impedance using an internal reaction mass system. The reaction mass is coupled to a rotating assembly capable of varying its inertia and this changing inertia has the effect of creating an added inertial resistance, or effective mass, to oscillations of the reaction mass. An SRPA has two main bodies, designated Float and Spar, capable of utilizing the relative motion between the two bodies to create power through a power take-off (PTO). The implementation of the reaction mass, a 3rd body, and the variable inertial system (VIS) is designed to change the response of the Spar in order to create larger relative velocities between the two bodies and thus more power. It is also possible to lock the VIS within the Spar, and when this is done the system is reduced to a conventional 2-body SRPA configuration. To better understand the effects of the implementation of the VIS on the overall stability of the VISWEC and the power conversion performance, a numerical model simulation within ProteusDS, a time-domain modelling software, was created. Power production and parametric excitation are the metrics of comparison between the two systems. Parametric excitation is a phenomenon that correlates wave excitation frequency to roll stability and has been shown to negatively affect power production in SRPAs. Simulations of the 2 and 3-body provide a basis of comparison between the two systems and allow the assessment of parametric excitation prohibited or exacerbated by the implementation of the VIS as well as power production. The simulation executed within the commercial software ProteusDS incorporates articulated bodies defined with physical parameters connected through connections allowing kinematic constraints and relations and hydrodynamics of the hull geometries as they are exposed to regular waves. ProteusDS also has the ability to apply kinematic constrains on the entire system allowing the analysis of isolated modes of motion. The implementation of the VIS demonstrates a generally higher power production and stabilization of the system with regards to parametric excitation. While the 3-body system is more stable, the bandwidth at which rolling motion is induced increased in comparison to the 2-body system. Rolling motions in both the 2 and 3-body systems are characteristic of parametric excitation and show a direct correlation to reduced power production. Overall the 3-body VISWEC outperforms the typical 2-body SRPA representation but more research is required to refine the settings of the geometric and PTO control. / Graduate

Multiple-input multiple-output (MIMO) systems are a mature technology that has been incorporated into current wireless broadband standards to improve the channel capacity and link reliability. Nevertheless, due to the continuous increasing demand for wireless data traffic new strategies are to be adopted. Very large MIMO antenna arrays represents a paradigm shift in terms of theory and implementation, where the use of tens or hundreds of antennas provides significant improvements in throughput and radiated energy efficiency compared to single antennas setups. Since design constraints limit the number of usable antennas, virtual systems can be seen as a promising technique due to their ability to mimic and exploit the gains of multi-antenna systems by means of wireless cooperation. Considering these arguments, in this work, energy efficient coding and network design for large virtual MIMO systems are presented. Firstly, a cooperative virtual MIMO (V-MIMO) system that uses a large multi-antenna transmitter and implements compress-and-forward (CF) relay cooperation is investigated. Since constructing a reliable codebook is the most computationally complex task performed by the relay nodes in CF cooperation, reduced complexity quantisation techniques are introduced. The analysis is focused on the block error probability (BLER) and the computational complexity for the uniform scalar quantiser (U-SQ) and the Lloyd-Max algorithm (LM-SQ). Numerical results show that the LM-SQ is simpler to design and can achieve a BLER performance comparable to the optimal vector quantiser. Furthermore, due to its low complexity, U-SQ could be consider particularly suitable for very large wireless systems. Even though very large MIMO systems enhance the spectral efficiency of wireless networks, this comes at the expense of linearly increasing the power consumption due to the use of multiple radio frequency chains to support the antennas. Thus, the energy efficiency and throughput of the cooperative V-MIMO system are analysed and the impact of the imperfect channel state information (CSI) on the system's performance is studied. Finally, a power allocation algorithm is implemented to reduce the total power consumption. Simulation results show that wireless cooperation between users is more energy efficient than using a high modulation order transmission and that the larger the number of transmit antennas the lower the impact of the imperfect CSI on the system's performance. Finally, the application of cooperative systems is extended to wireless self-backhauling heterogeneous networks, where the decode-and-forward (DF) protocol is employed to provide a cost-effective and reliable backhaul. The associated trade-offs for a heterogeneous network with inhomogeneous user distributions are investigated through the use of sleeping strategies. Three different policies for switching-off base stations are considered: random, load-based and greedy algorithms. The probability of coverage for the random and load-based sleeping policies is derived. Moreover, an energy efficient base station deployment and operation approach is presented. Numerical results show that the average number of base stations required to support the traffic load at peak-time can be reduced by using the greedy algorithm for base station deployment and that highly clustered networks exhibit a smaller average serving distance and thus, a better probability of coverage.

Converting energy from ocean waves is an exciting concept aimed at reducing our dependency on fossil fuels. Ocean energy devices must convert the large forces and relatively small movements from ocean waves into electrical power with a minimum carbon and energy intensity in order to be economically viable. The research herein focuses on the Oyster, a flap-type pitching wave energy converter developed by Aquamarine Power. A device that has the minimal carbon or energy intensity is not necessarily the most mechanically efficient. A commercially viable wave energy converter should have a competitive cost of energy and be as carbon negative as possible. In order to expedite the route to commercialisation, successive designs should iterate towards a minimum lifetime cost of energy. The sheer complexity of wave energy converter systems makes for a vast optimisation problem to determine the system parameters that exhibit the minimum carbon and energy intensities. This thesis presents a study of the oscillating flap-type wave energy converter to determine the trends between design parameters, total power output and carbon and energy throughput. The minimum carbon and energy intensities have been shown to be strongly dependent on minimising maintenance requirements. In order to determine the design criterion a range of flap widths and system pressures are investigated and their effect on component service lives assessed. The results are then converted to lifetime carbon and energy intensities for a direct comparison. To achieve this, fundamental research on the maintenance requirements of critical components such as the hinge bearings and hydraulic power system is required. A hydrodynamic model describes the dynamic response and links the system energy inputs to its modelled energy output. This work is intended to help guide developers of flap-type wave energy converters towards commercialisation. It enhances the understanding of the routes to failure and service life predictions, providing avenues to balance service lives to optimise maintenance and maximise uptime. This will assist in the development of more energy efficient wave energy converters over their lifetime. This information will better enable the marine energy sector to offset our fossil fuel dependence, ultimately reducing our impact on the environment and leading to a ‘greener’ future.

Increasing attention to climate change in combination with ever-growing energy consumption worldwide has boosted the demand for new green energy sources. Wave power is developing in many different branches to become part of the new era of electricity production. This thesis deals with a wave power system in its primary stages of development. The system was investigated in order to estimate its potential to produce electric power from sea waves. It is a system consisting of a moored buoy to which the energy is transferred when the wave tilts the buoy in the pitch direction. Due to the increased pitch angle, an amount of liquid contained inside the buoy is allowed to flow via ramps to an upper container, from where it flows down through a hydroelectric turbine. A computer program was used to calculate the properties of the buoy in sea waves. Another program was written in MATLAB to simulate the movements in sea waves and from a set of given parameters calculate the power output. A brief economic study was made to determine if the power output was large enough for the concept to be of financial interest to any future investors. The results show that the wave power system produced 0.9 kW in a wave climate equal to that off the coast of Hanstholm, Denmark, and 1.6 kW in a wave climate off the coast of San Diego, USA. The economic study shows that the power output needed to be improved by a factor of at least five to have a chance of being economically viable. A number of enhancements were suggested to increase the power output of the system, and further investigation could be of use to improve the concept. The created computer simulation model, as well as the results in this thesis could be valuable in any future research on the concept.

This study aims to search the optimal system structure for a specific type of oscillatory wave-energy acquisition system, which owns the highest efficiency in acquiring the energy from sea wave. The system is mainly consisted of a float, a generator and several oscillators that are connected to the float or to each other by the elastic springs. In addition, all the components are capsulated in the float. For the purpose of comparison, when aided with an active control, the acquiring efficiency of the system with a near optimal structure is analyzed. Under the assumption of random sea wave, three steps are adopted to investigate the optimal system structure. First, the mathematical model of the capsulated float that can acquire the maxima power from sea wave is derived by the spectrum analysis. They offer the messages that what the dynamic properties of an optimal structure should be in order to acquire the maxima power. Second, the dynamic properties of the general system are analyzed. It is to examine the effect of increasing system¡¦s degrees of freedom in offering the flexibility of varying system dynamics to match the desired ones. The limitation of increasing the degrees of freedom is especially examined. Then, the maxima attainable powers for the systems with different degrees of freedom are simulated by the genetic algorithm. It is to support the inference made from the analysis about the effect of increasing the system¡¦s degrees of freedom. Finally, a preliminary examination of the effect of active control in power acquisition is done. The study indicates that an oscillatory system structure with two degrees of freedom is a near optimal structure for energy acquisition. An increase of system¡¦s degree of freedom shows little effect in improving system¡¦s dynamic characteristics in the main frequency range of sea wave. The proposed active control scheme is shown to be effective in improving the system¡¦s dynamic characteristics to enhance the energy acquisition from sea wave. However, the extra-energy consumed in the control action makes the increase of net energy acquisition negligible.

The purpose of this thesis is to develop a novel design of the oscillatory type of wave-energy acquisition system. It is aimed to increase the efficiency of wave-power acquisition from random sea. The main feature of the new system structure is its flexibility to adjust the system dynamics to satisfy two optimal criteria. The effects of various system parameters on the system dynamics and acquired power were analyzed. To find the set of system parameters to acquire the highest power, an optimization searching method was adopted. Finally, a regression model was established to help the user to calculate the optimal system parameters under various application conditions. The study first indicated that to acquire high power from sea wave the dynamic characteristics of the system should satisfy two criteria. However, the study also revealed that the dynamic properties of a traditional acquisition system are difficult to fulfill the two criteria in a wide frequency band. Accordingly, a new system structure was proposed. It is composed of a traditional acquisition system and a vibrating platform. The platform is linked to the acquisition system through a spring. Because of the coupling effect, the dynamic characteristics of the acquisition system are altered. The effects of varying different system parameters on the locations of pole or zero of the transfer function of acquisition system were examined. It was shown that with a proper choice of system parameters, the frequency bandwidth satisfying or close to the two criteria may be increased. The study indicated that acquired power of the proposed system is higher than the traditional one by 34%.

This study aims to develop an oscillatory wave-energy acquisition system with adjustable system characteristics. The system is designed to efficiently acquire energy from the sea waves with a wide frequency band. Based on the past studies, the oscillatory wave-energy acquisition system, designed previously, can only acquire energy from the sea waves with a narrow frequency band. Such a limit causes the system to have a low efficiency in acquiring power if the wave has a large frequency band. The main goal of this novel design to allow the system adjusting its system characteristics, based on the dynamic characteristics of sea wave, to attain the optimal power acquisition. In the study, different types of oscillatory systems are first examined whether they are effective to transform their dynamic characteristics when the system parameters are varied. The effectiveness of such transformation is evaluated through an optimization procedure. This procedure is to evaluate whether the frequency response of system can acquire the highest power from a given property of sea wave. Through a detailed analysis, the system structure of a three degree-of-freedom oscillatory wave-energy system is chosen for current purpose. A careful study about the effectiveness of dynamic transformation, via the adjustment of different system parameters, is then studied. The study shows that the selected system with adjustable capability can effectively acquire energy from a sea wave with large frequency band. The acquired efficiency can increase up to 70% compared to the earlier system.

This thesis describes research into electrical power takeoff mechanisms for Oscillating Water Column (OWC) wave energy devices. The OWC application is studied and possible alternatives to the existing Induction Generator (IG) are identified. The Permanent Magnet Generator (PMG) is found to be the most promising. Results showed that the IG could almost match the output of the PMG if it could be operated significantly above its rated capacity. This improvement would require only limited changes to the overall OWC system. The ability to operate overloaded is determined by the losses and cooling of the IG. The losses in a suitable IG were measured in tests at Nottingham University. Steady state measurements were made of the cooling ability of the OWC airflow at the LIMPET wave power plant operated by Wavegen (the sponsor company) on Islay. Thermal modelling combining the loss and cooling measurements allowed the maximum capacity of the induction generator in an OWC to be found. A simplified model that accurately represents this system is proposed for use in system design and generator control.