On June 13th, 2013 the University of Maine’s VolturnUS 1:8 floating offshore wind turbine was energized and began delivering electricity through an undersea cable to the Central Maine Power electricity grid. Deployment continued until late November 2014. The following describes the results of extensive environmental monitoring at the Castine site. The primary observations of the site were derived from weekly visual surveys, bat echolocation detectors, underwater acoustic receivers, and web camera surveillance. The latter method consisted of observing the turbine and platform by web camera every 15-30 seconds throughout the deployment. If a bird was present in a 15-30 second snapshot, video footage was examined to determine if there was a collision.
Although a summary of the monitoring follows, one major finding was that there were no observed collisions. Also, there were no observed marine mammal haul outs (i.e., no seals hauling out on the floating wind turbine platform). Environmental monitoring corroborated the Finding of No Significant Impact issued by the Department of Energy. Bat echolocation detectors were deployed near the site on a nearby lighthouse (in 2012 and 2013) and also on the turbine itself (in July-December 2014). This may be the first deployment of anabat detectors on a floating wind turbine to date. While these detectors would not be able to detect bat collisions, they can detect major shifts in habitat use. Results indicated a bat assemblage that did not change appreciably before and after the deployment of the floating turbine as measured by the number and type of calls. Unsurprisingly, the number of calls per night at the turbine were lower than those recorded at the lighthouse (the lighthouse being adjacent to foraging and roost habitat whilst the turbine was deployed over open water). Finally, NOAA deploys an acoustic array that listens for tagged Atlantic salmon, Atlantic and shortnose sturgeon. NOAA (James Hawkes, a research fishery biologist at the NOAA Orono Field Office) reported no change in the detection frequency on receivers located close to the wind turbine site. In sum, overall findings were consistent with the analyses described in the Draft Supplemental Environmental analysis (Appendix A) and the Department of Energy’s Finding of No Significant Impact (Appendix B)