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Many entrepreneurial firms risk falling into a cash flow “Valley of Death”‐the stage of a young firmʼs life when seed funding is running dry but the firm has yet to secure sufficient additional funding to carry it through to product commercialization.This is particularly true in the nascent cleantech sector, where investments are often complex and capital intensive. Drawing on an in-depth interview with seasoned entrepreneur Brian Cunningham, CEO of the Wave Energy Conversion Corporation of America, this article explores the role of persistence in entrepreneurship, distinguishing between “calculated” and “blind” persistence.

The purpose of this paper is to present a double‐sided tubular linear machine layout direct‐drive applications, with particular focus on wave‐energy conversion. The paper documents both the computational and mathematical analysis of this novel machine layout.

The selection and finite‐element optimisation of the permanent‐magnet array is presented. The machine is then modelled using magnetic circuit theory. By simultaneously solving the system of equations, a demonstrative design is developed and simulated so as to validate the mathematical model and compare the performance of the new layout with a traditional layout.

A surface‐mounted magnetic array, with unshaped‐poles, is most suitable for the proposed layout. The mathematical model exhibits a suitable level of accuracy for design and analysis purposes. The calculated resultant force differs from the FEA calculation by 1.85 per cent. A higher force‐density is exhibited by the proposed layout, when compared with flat layouts, with a reduction of 36.5 per cent in the spatial footprint and magnetic material of the machine.

Although the research is focused on the application of wave‐energy conversion, the techniques are application‐independent. However, certain design decisions should be reviewed for other applications.

The practical implementation of such a machine poses many mechanical obstacles. These have been solved in theory, and are being implemented at the time of writing.

The combination of a double‐sided and a tubular layout has not previously been researched. This research fills that void and provides designers with the technical background and a mathematical model for development of such devices.

The purpose of this paper is to look at the UK's tidal and wave energy resources and the numerous technologies in this area.

The paper looks at the innovations in the UK's tidal and wave energy technology.

While the Government may have been slow in recognizing the potential of the UK's tidal and wave energy resources, this has not stopped the country's marine renewable energy sector becoming a world leader, and a “hotbed” for innovation. For instance, a major area of technology where the UK is among the world leaders is in tidal stream systems, and numerous technologies are at various stages of research, development and commercialization. The same is true for wave energy conversation, where again a number of UK companies are developing and delivering some of the world's most advanced systems.

The paper provides useful information on the innovations in marine renewable energy sector.

The limited supply of fossil fuels, constant rise in the demand of energy and the importance of reducing greenhouse emissions have brought the adoption of renewable energy sources for generation of electrical power. One of these sources that has the potential to supply the world’s energy needs is the ocean. Currently, ocean in West African region is mostly utilized for the extraction of oil and gas from the continental shelf. However, this resource is depleting, and the adaptation of ocean energy could be of major importance. The purpose of this paper is to discuss the possibilities of ocean-based renewable energy (OBRE) and analyze the economic impact of adapting an ocean energy using a thermal gradient (OTEC) approach for energy generation.

The analysis is conducted from the perspective of cost, energy security and environmental protection.

This study shows that adapting ocean energy in the West Africa region can significantly produce the energy needed to match the rising energy demands for sustainable development of Nigeria. Although the transition toward using OBRE will incur high capital cost at the initial stage, eventually, it will lead to a cost-effective generation, transmission, environmental improvement and stable energy supply to match demand when compared with the conventional mode of generation in West Africa.

This study will be helpful in determining the feasibility, performance, issues and environmental effects related to the generation and transmission of OBRE in the West Africa region.

The study will contribute toward analysis of the opportunities for adopting renewable energy sources and increasing energy sustainability for the West Africa coast regions.

The purpose of this paper is to describe the design and function of Fred. Olsen's wave energy converter (WEC) system Lifesaver with special focus on the stand-alone electrical system that is implemented for operation without grid-connection.

The paper focus on the detailed design of the DC-Link system that drives the industrial 400 VAC inverters and generators for the production system. The DC-Link is stabilized by an ultra capacitor bank and has no external source or grid-connection.

The system has been tested through extensive sea trials since April 2012 and has proved its function. Some results from real sea testing are presented.

This paper proves the viability of the specified design and may serve as a basis for the design if similar systems in the future.

This paper presents a WEC system that has proven successful operation through practical tests, and is therefore regarded as a high-value paper as there is limited experience on this subject.

The purpose of this paper is to propose a method to estimate the magnetic saturation and end effect of linear switched reluctance machines (LSRMs) with fully pitched winding configuration used in the wave energy conversion.

The magnetic saturation and strong coupling make it very difficult to derive a comprehensive mathematical model for the behavior of the LSRMs. Meanwhile, the various end effects could not be comprehensively considered in the two‐dimensional model which is widely studied. Therefore, the magnetic equivalent circuit model including the three‐dimensional (3‐D) effects is presented in this paper and 3‐D finite element analysis (FEA) is used to validate the mathematical model.

The results from 3‐D FEA are in good agreement with the numerical simulation, which validates the accuracy of the magnetic equivalent circuit modeling method.

This technique helps one to know the influence exerted by the magnet saturation and end effect of LSRMs and provides a powerful computer‐aided analysis tool. Meanwhile, this modeling method supplies accurate values for the following study of reliable control algorithm.

The paper presents a magnetic equivalent method to estimate the magnetic saturation and end effect of LSRMs with fully pitched winding configuration used in the wave energy conversion.

The purpose of this paper is to quantify the impact of the constraints of the power take-off system (PTO) on the power extraction of a point absorber wave energy converter (WEC). Such constraints include power, torque and maximum stroke limitations. Two different concepts, unidirectional and bidirectional point absorbers, are analysed, which both are relevant for practical applications in the wave energy industry.

The two different cases of unidirectional and bidirectional point absorbers are analysed and directly compared. Moreover, a simplified control strategy is considered for the point absorber, which is based on a constant torque reference. The WEC performance is first evaluated in selected sea states and then the analysis is extended to assess the impact of the different solutions on the expected yearly wave energy production of the point absorber, when deployed at a specific location. The European Marine Energy Center (EMEC) is selected as the target site for the analysis.

The analysis was performed in selected sea states and then it was extended to all the sea conditions occurring at the EMEC test site. The comparison between unidirectional and bidirectional operated devices suggested a clear superiority of the latter, ensuring similar power extraction at the expense of a halved required torque by the PTO. Moreover, a selective control strategy was implemented, and the results showed an increase in yearly energy production for the bidirectional device.

The study proved the importance of including the actual PTO constraints in the preliminary power assessment in order to avoid unrealistic overestimation of the expected power performance.

The paper quantifies the power performance obtained with the application of such control strategy considering both unidirectional and bidirectional point absorbers. This analysis and comparison is extremely relevant since both unidirectional and bidirectional devices are reaching the market.

The combination of desalination technology with renewable energy sources (RES) provides a sustainable approach for increasing potable water availability without imposing negative environmental effects. This paper aims to present the development of a platform, which is an internet-based tool integrating the design optimization of desalination systems with spatial modeling based on a geographic information system (GIS).

The proposed platform assists decision-makers to select the optimal location and configuration of both the energy- and water-related subsystems of desalination plants that are power-supplied by RES, such that the lifetime cost of the overall desalination plant is minimized. It enables to optimize the desalination plant site selection and sizing with various hybrid power supply (solar, wind, wave and electrical grid power systems) and desalination technologies combinations, while simultaneously exploiting spatial technologies in an internet-based GIS platform.

A pilot study for the optimal design of stand-alone and grid-connected desalination plants powered by RES is presented, which demonstrates the functionality and features of the proposed platform. It is also shown that a grid-connected desalination plant designed by the proposed software design tool exhibits significantly lower lifetime installation and maintenance costs compared to its stand-alone counterpart.

The proposed platform combines technological, scientific and industrial knowledge with information about societal/political conditions and geo-spatial technologies in a user-friendly graphical interface. Therefore, it provides a design tool enabling its users to secure water supply in a sustainable and economically viable manner.

To improve the power density and generation efficiency of the tubular permanent magnetic linear generators (TPMLGs) under realistic sea-stator condition, a TPMLG with 120° phase belt toroidal windings (120°-TPMLG) for wave energy conversion is proposed in this paper.

First, the structure of the 120°-TPMLG is introduced and its operation principle is analyzed. Second, the design process of the 120°-TPMLG is described. Meanwhile, the finite-element models of the 120°-TPMLG and the TPMLG with traditional fractional pitch windings (T-TPMLG) are established based on the similar overall dimensions. Then, the electromagnetic characteristics of the 120°-TPMLG are analyzed, such as air gap flux density, back electromotive force and load voltage. Finally, a comparative analysis of the magnetic flux density, flux linkage, load and no-load performance of the two generators are conducted.

The result shows that the 120°-TPMLG has higher power density and generation efficiency than the T-TPMLG.

This paper proposes a TPMLG with 120° phase belt toroidal windings (120°-TPMLG) to improve the power density and generation efficiency.

The purpose of this paper is to disseminate the lessons learned from the successful deployment of a wave energy converter (WEC) and accelerate growth in the field of ocean energy.

A thorough, well structured, documented, industrial approach was taken to the deployment because of the depth and scale of the task required. This approach is shown throughout the paper, which reflects the importance of a comprehensive project plan in success as well as failure.

The findings demonstrate the viability of the use of off shore WEC to generate electricity and that such a project can be completed on time and on budget.

The research implications of the paper include the importance of an enhanced, integrated supervisory system control in terms of efficiency, operation and maintenance, and long-term viability of WECs. This paper can be used to help guide the direction of further research in similar areas.

The practical implications include proof that WEC deployments can be carried out both on time and under budget. It highlights much of the practical data collected throughout the course of the project and presents it so that it might be used as a guide for future projects.

At the time of this paper, successful deployment of off shore WECs has been a rare accomplishment. Because the project was publicly funded, the data collected during this project, both technical and practical, is freely available.