No abstract

In this paper, a linear mathematical and numerical model for analysing the dynamic response of a flexible electroactive wave energy converter is de- Finally, estimates are made for the energy performance of a possible prototype.

No abstract

No abstract

No abstract

No abstract

The first generations of wave energy converters have had a number of forms, but all are essentially large steel structures concentrating the power take off onto small mechanical devices. A number of prototype devices have been installed offshore, but due to their high fabrication and installation costs, coupled with significant maintenance requirements, the production of electricity at an acceptable cost has remained elusive.To avoid the limitations of these devices, a second generation wave energy converter is being developed using electro active polymers (EAP), which are capable of generating electricity directly from wave action without the need for any mechanical power take off. The resulting system is flexible and possesses an infinite number of degrees of freedom, allowing wave energy to be captured more efficiently than with conventional devices. Deployed offshore, such a device would have no complex mechanical parts, would function silently, and would require minimal maintenance. The economics of such a system lead to predictions of a cost of electricity significantly below the levels of the first generation devices.The paper explains the principals involved in using EAP for the generation of electricity, the application of EAP to wave energy conversion, and reports key results from the ongoing development program. The paper also describes the main features of the prototype wave energy converter system presently under development for deployment offshore. An overview of the Renewable Energy marketRenewable energies have become inevitable in the energy mix. Over the last 15 years renewables have evolved from a marginal, politically correct, alternative vision to a credible energy source and a booming economic sector.In 2013, for the first time in centuries, newly installed power generation capacity from renewables was higher than that of conventional energy, including coal, gas and oil combined. In 2015 the difference became even larger and the trend is not expected to change, as shown in Figure 1.The falling costs of energy from renewables and aggressive expansion in emerging countries are the main drivers for the fast growth of renewable energy. Wind and Solar energy in particular have already reached grid parity in many countries, meaning that they are produced, without subsidies, at a cost lower than the local electricity retail price.

The development of floating offshore wind farms requires the parallel development of suitable floaters to support the wind turbines. These floaters must be economic and must also exhibit good motion characteristics to limit the accelerations and inclinations imposed on the turbines during operation. This paper reviews the required characteristics of these floaters, addressing the requirements of fabrication, turbine integration, tow to site, and offshore installation, as well as the required behavior of the floater once installed. The benefits of an integrated design approach considering all of the above is demonstrated, and consideration is given to the industrialization of the production process for large numbers of floaters for full-scale wind farms.Based upon this review of requirements, an innovative light weight structural solution incorporating tensioned mooring legs has been developed as an economic solution for the floater. The modularity of the design facilitates construction, and offshore installation can be accomplished using standard anchor handling vessel (AHV) means. The floater design exhibits low turbine inclinations and low accelerations due to a combination of its mooring arrangement and its high degree of transparency to waves, which reduces fatigue loads and maintenance issues on the turbine.The floater behavior during towing to site and in the installed condition is described, and key performance characteristics are reported based on analytical simulations and model tests results conducted at 1:40 scale.The paper seeks to clarify the key factors to be considered in developing a floater to support a wind turbine, and to propose a solution that achieves good motion characteristics whilst satisfying the economic constraints of wind farm development.