Sustainable Marine Energy and SCHOTTEL Hydro have developed a taut-moored mid-water column tidal energy platform, PLAT-O, and a semi-catenary moored floating surface platform, PLAT-I, that each host between two and four turbines. The combined platform rated power is up to 280kW.
Each platform is suitable for different environmental conditions, with PLAT-I intended for low wave climates and PLAT-O for more extreme offshore conditions. This provides the basis for site selection criteria for each system. Site criteria include flow velocity, wave conditions, water depth and bathymetry, power requirements, and station keeping requirements. These have been designated into a Site Classification System for identifying sites suitable for each of SME’s platforms.
Site assessment must be conducted to find these sites. Whilst in developed and more easily accessible locations the equipment, vessels, and expertise used are readily available, in more remote areas and off-grid communities the traditional assessment techniques must be modified for the equipment available and for the cost associated with different survey methods.
SME have developed a site assessment technique for their platform systems which is divided into four stages: Desktop Study, Visual Survey, Initial Survey, and Detailed Survey. Each stage increases complexity and cost. This allows sites to be discounted at early stages if unsuitable for further development before unnecessary money is spent. This system leads to a cost saving of up to 47% when assessing two sites using SME’s method rather than two ADP surveys, and discounting one for inadequate velocity, as an example. The assessment technique, relevance to SME’s tidal energy platforms, cost implications, and suggested modifications for applicability to other systems is presented.