Enhancing marine energy competitiveness: Co-located offshore wind and wave energy farms

If marine energy is to become a viable alternative to fossil fuels, its competitiveness must be enhanced. In this sense, combining various renewables in the same marine space is emerging as a solution. Among the different options, this paper focuses on combined wind and wave energy farms. First, the different synergies between both renewable are analysed, such as the more sustainable use of the marine resource or the opportunity to reduce costs of both technologies by sharing some of the most important costs of an offshore project. Second, this paper focuses on two technology synergies: The reduction of the inherent intermittency of renewables; and the so-called shadow effect which implies the reduction of the wave height in the inner part of the wind farm. Both effects may suppose an important reduction in the operation and maintenance cost by reducing the balancing cost when connecting the installation to the grid and increasing weather windows to access the wind turbines. However, the benefits of this combination will depend on the site characteristics and the array layout. On this basis, the power smoothing and shadow effect in co-located farms are analysed through different case studies considering real sea conditions, wind farms currently in operation and a high resolution numerical model (SWAN). Finally, conclusions about the economic benefits of co-located farms are drawn by recalculating the levelised cost of energy when both renewable are combined.