Since 2014 the Hawaiʻi Natural Energy Institute (HNEI) and ARL at UH have conducted Verification and Validation (V&V) tasking for Corps Base Hawaiʻi at the Wave Energy Test Site (WETS), which consists of three test berths installed at 30-meter, 60-meter, and 80-meter water depths. Each berth can host point absorber and independent wave energy converters (WECs).
HNEI and ARL at UH assess WEC performance (power and durability) relative to environmental conditions, and provide logistics support and critical infrastructure maintenance. A fundamental objective of WETS tasking is to document the effects of long-term exposure to the elements on WEC devices and supporting infrastructure.
Known for its mild climate, Hawaiʻi nevertheless exacted a toll on the WETS mooring systems over the past five years. In 2019 HNEI and ARL at UH, under the guidance of Naval Facilities Engineering Command, completed a major redesign of the WETS deep-berth mooring systems and installed and tested these upgrades at the 60-meter berth in May and June 2019. Similar upgrades at the 80-meter berth are planned for late 2020 or 2021.
The redesign involved a substantial increase in the size of mooring chain, improvement in the type of joining links, modification of surface floats, and the inclusion of a “no-WEC hawser” system to provide pretension in the moorings when no WEC is installed.
HNEI personnel also redesigned the cable offshore terminations and anchors, reducing their weight to facilitate recovery by smaller vessels and adding flexibility for accommodating umbilical cables of future WECs. All elements of the redesign were aimed at improving mooring fatigue life with the intent of supporting many WEC deployments in the coming years.
