Abstract
While wave energy has significant potential to contribute to national power needs, the unique capabilities of the resource may also be applied on smaller scales. These applications can offer nearterm market opportunities with less risk than utility-scale generation. While most concepts for wave energy revolve around anchored or tethered wave energy converters (WECs), untethered WECs may have broader potential applications. The lack of an anchor simplifies deployment and recovery operations and eliminates a component of the WEC that constitutes approximately 10% of the capital expense. Several applications that could be enabled by the ease of deployment and recovery for freedrifting WECs, include autonomous underwater vehicle (AUV) and oceanographic sensor charging (similar to that proposed by Hamilton, et al. in), offshore, mobile aquaculture operations, and desalination or emergency power for disaster relief in coastal regions. Such a device may be well suited for these unique applications due to its portability, and added costs required by such applications may be more than offset by the removed costs of mooring and cabling to shore. While the dynamics of an unmoored WEC should be simpler than for a moored device, these have not been well explored, such as the implications for station-keeping control. Similar dynamics are likely for minimalist mooring concepts that could reduce conflict between wave energy development and other users of the ocean (e.g., fishing, crabbing, shipping). We explore the dynamics of an unmoored WEC using numerical simulations of a free drifting WEC under various environmental forcing conditions. The feasibility of device station keeping is also assessed.