Sea wave energy is being increasingly regarded in many countries as a major and promising resource. The paper deals with the development of wave energy utilization since the 1970s. Several topics are addressed: the characterization of the wave energy resource; theoretical background, with especial relevance to hydrodynamics of wave energy absorption and control; how a large range of devices kept being proposed and studied, and how such devices can be organized into classes; the conception, design, model-testing, construction and deployment into real sea of prototypes; and the development of specific equipment (air and water turbines, high-pressure hydraulics, linear electrical generators) and mooring systems.

Wave energy utilization: A review of the technologies

Beyond Oil and Gas: The Methanol Economy

Ocean waves are a huge, largely untapped energy resource, and the potential for extracting energy from waves is considerable. Research in this area is driven by the need to meet renewable energy targets, but is relatively immature compared to other renewable energy technologies. This review introduces the general status of wave energy and evaluates the device types that represent current wave energy converter (WEC) technology, particularly focusing on work being undertaken within the United Kingdom. The possible power take-off systems are identified, followed by a consideration of some of the control strategies to enhance the efficiency of point absorber-type WECs. There is a lack of convergence on the best method of extracting energy from the waves and, although previous innovation has generally focused on the concept and design of the primary interface, questions arise concerning how best to optimize the powertrain. This article concludes with some suggestions of future developments.

https://journals.sagepub.com/doi/pdf/10.1243/09576509JPE782

A review of wave energy converter technology

The Global Energy Assessment (GEA) brings together over 300 international researchers to provide an independent, scientifically based, integrated and policy-relevant analysis of current and emerging energy issues and options. It has been peer-reviewed anonymously by an additional 200 international experts. The GEA assesses the major global challenges for sustainable development and their linkages to energy; the technologies and resources available for providing energy services; future energy systems that address the major challenges; and the policies and other measures that are needed to realize transformational change toward sustainable energy futures. The GEA goes beyond existing studies on energy issues by presenting a comprehensive and integrated analysis of energy chalenges, opportunities and strategies, for developing, industrialized and emerging economies. This volume is a invaluable resource for energy specialists and technologists in all sectors (academia, industry and government) as well as policymakers, development economists and practitioners in international organizations and national governments.

Global Energy Assessment: Toward a Sustainable Future

The wave energy is having more and more interest and support as a promising renewable resource to replace part of the energy supply, although it is still immature compared to other renewable technologies. This work presents a complete analysis of the wave energy technology, starting with the characterisation of this global resource in which the most suitable places to be exploited are showed, and the classification of the different types of wave energy converters in according to several features. It is also described in detail each of the stages that are part in the energy conversion, that is, from the capture of the energy from the waves to the extraction of a proper electrical signal to be injected to the grid. Likewise, existing offshore energy transmission alternatives and possible layouts are described.

Review of wave energy technologies and the necessary power-equipment

The progress in wave energy conversion in Europe during the past ten years is reviewed and current activities and initiatives in the wave energy sector at National and Union level are described. Other important activities worldwide are summarized. The technical and econ

/pdf/wave-energy-in-europe-current-status-and-perspectives-29jovj6usk.pdf

Wave energy in Europe: current status and perspectives

Blue Growth is the creation of economic activity and jobs at sea, while multiple use of space makes efficient use of the available sea area by combining industries. Clearly there are many combinations and many value propositions. However, most technologies to date are considered blue sky concepts, with little robust techno-economic analysis demonstrating profitability. The paper begins by providing a comprehensive review of Blue Growth and multi-use in Blue Growth; both in policy as well as the wide range of current technologies, including ocean energy, offshore wind energy, offshore aquaculture and desalination. The Maribe H2020 project provides the vehicle for the research element of the paper. The major contribution is a new methodology for selecting, filtering, developing and ranking business propositions for multiple-use of space (MUS) and multi-use platforms (MUP). Application of the method for the first time identified three case studies where Blue Growth combination projects can be economically viable, with attractive internal rate of return (IRRs). Results presented for the case studies report standard investment metrics and show the relative contribution of each product (energy, food, water) to the system profitability, as well as socio-economic impact. Existing companies were fully engaged in the process. Co-creation between sector experts and industry led to both improved business value propositions and robust assessment of investment readiness. In contrast to the presumption that large scale platforms are commercially attractive, the highest ranking case study companies required smaller capital expenditure (CAPEX) and operated in niche subsectors. In conclusion, the positive economic performance of the case studies should provide confidence for the EC as well as investors that MUS and MUP have viable economic futures leading towards commercialisation. The macro and micro assessment methods will be particularly useful in other Blue Economy contexts and in other multiple product contexts.

https://cronfa.swan.ac.uk/Record/cronfa49196/Download/0049196-18032019101825.pdf

Feasibility of investment in Blue Growth multiple-use of space and multi-use platform projects; results of a novel assessment approach and case studies

This project covers two fields of study: a) Wave energy predictability and electricity markets. b) Variability of the power output of WECs in diversified systems: diversified renewable systems with wave and offshore wind production. The issue of the first part of this research project is: 1) Quantify how accurately waves can be predicted and compare that value to winds predictability. 2) Estimate WECs and wind turbines power productions predictability. 3) Estimate the errors incurred in the bids to the day-ahead market, both for wave and for wind energy, if the productions had been traded in day-ahead electricity markets. 4) Evaluate economically the errors of day-ahead bids and assess the economic benefits, in terms of reduction in balancing costs, of including wave energy in a system based on wind energy solely. On the whole, the research focus has been the economic value of waves' predictability. To the authors knowledge, it is the most comprehensive study on wave power forecasting in the North Sea waters, both for waves and for WECs power productions. Results suggest that for day-ahead forecasts, waves are 23% more predictable than winds, the power output of WECs is 35% more predictable than for wind turbines, and the inclusion of wave energy in a wind-only system reduces balancing costs up to 35%. This would imply annual savings to the Danish system of 13 MEUR (i.e. 95 MDKK/y) and a balancing premium tariff for wave energy of 1.8 EUR/MWh (compared to the current premium tariff of wind turbines of 3 EUR/MWh). In a nutshell, results have shown the benefits of waves' predictability. The second research study has focused on the opportunities of combining the power production of different technologies in the same site to provide a continuous power output. Particularly, it has investigated the combined power production of WECs and of wind turbines. The study has focused on the benefits of a combined wave and wind power output compared to the individual productions. This is investigated through theoretical and real case studies that analyse the individual power productions of WECs and of wind turbines and compares them to the combined power production. To the authors best knowledge the study comprises the first research investigating and comparing real power productions of WECs and of wind turbines. The most indicative finding is that the combined power output is smoother and provides higher availability than the individual productions: both the peaks and the fast changes found in the individual productions reduce when these are combined, and the percentage of time with null production reduces to a minimum. Variability reduces up to 31% and the percentage of time with zero production decreases to 6%. Overall, the project has carried out an optimisation analysis which has sought to find the mix of WECs and of wind turbines and WECs, that resulted in an optimal electricity supply from the WEC system. The most predictable and most constant energy output has been chosen as the optimisation parameter. (LN)

Predictability and Variability of Wave and Wind: wave and wind forecasting and diversified energy systems in the Danish North Sea

The North Sea has not yet been regarded as prime area for wave energy development in Europe except in Denmark, Benelux and Germany. The reason is the relatively low intensity of waves (1217kW/m) compared to the Atlantic with a wave climate of 24-48kW/m. Further on the design wave load is almost as in the Atlantic and the distance to shore relatively long compared to sites with good wave climate like Ireland, Portugal, Spain and the west coast of UK. The increasing activities within offshore wind in the North Sea and the attempt to build a super grid connecting the wind sites with the major consumers around the North Sea are expected to change the priority in favour of utilising wave energy from the North Sea. The paper describes the opportunities for power production in the North Sea considering the competition for space and the synergy with offshore wind. Two approaches are used: a traditional national approach using very modest assumptions about how to establish a first generation of wave energy producing devices connected at a national level; and a trans-national cooperation approach taking into account the existence of a grid connecting several wind farms in the North Sea area. The former approach is resulting in a prediction of a yearly production of 23TWh; the latter is estimating a yearly production of 77TWh. This equals to 6% of the electricity demand around the North Sea, where the annual electricity consumption is about 1,300TWh.

Hans Christian Sørensen

Papers

Wave energy in Europe: current status and perspectives

Feasibility of investment in Blue Growth multiple-use of space and multi-use platform projects; results of a novel assessment approach and case studies

Predictability and Variability of Wave and Wind: wave and wind forecasting and diversified energy systems in the Danish North Sea

The Potential for Wave Energy in the North Sea

Predictability and Variability of Wave and Wind