Structural Design of wave energy devices

The ongoing debate about climate change and the decreasing amount of available fossil fuels makes it inevitable that more renewable energy sources must be developed. Although wave energy cannot compete economically against mature renewable technologies like hydro and wind today, wave energy has a huge potential to become a major contributor of energy in Europe and world wide. The capture of renewable energy from ocean sources is at an early stage of development. Almost no commercial devices have been deployed today, although several devices are in the full-scale testing phase and close to demonstration. The objective of the project is to link the future development of wave energy as closely as possible to Denmark through creating the basis for increasing the reliability of wave energy structures and reducing their cost. This overall objective can be broken down into several sub-objectives: • Increase knowledge on wave loads on the wave energy devices. • Develop models for floating structures taking into account hydrodynamic loads, moorings and power take-off. • Provide the basis for establishing protocols for design of wave energy devices. • Create lasting relations between international top institutions working in the field and Danish institutions. • Increase the reliability and decrease the cost of Wave Energy Devices in such a way that they can feasibly contribute to the energy supply. • Repeat the ‘Danish Wind Adventure’ in a new sector. Today the reliability of the wave energy devices and their moorings is not well defined, because the characteristics and goals of design in this sector deviate from what is the basis of structures placed at sea today. For example, when designing moorings for floating offshore structures for the oil and gas industry, the aim is normally to keep the structures as steady in the waves as possible, and the required safety level is set very high, as large assets and often also human lives are at risk. For wave energy devices, often the moorings should allow for large motions of the structure, in order to serve their primary function (absorption of power), while the device should be orders of magnitude cheaper and unmanned, compared to oil and gas related structures, which means the required safety level can be lowered. An important point is also that for floating wave energy structures, the mooring arrangements are to a very large extent influencing the hydrodynamic loading on the structure, as well as the power extraction capabilities.