Abstract
Sunrise Wind has proposed to construct and operate a 924 megawatts (MW) wind energy facility located on the Outer Continental Shelf (OCS) in the designated Bureau of Ocean Energy Management (BOEM) Renewable Energy Lease Area OCS-A 0487 (Lease Area). The SRWF will consist of installation of 84 wind turbine generators (WTGs) connected by a network of Inter-Array Cables and a single Offshore Converter Station (OCS-DC). The WTGs and OCS-DC will be sited in a uniform east west/north-south grid with 1.15 mi (1 nm, 1.8 km) by 1.15 mi (1 nm, 1.8 km) spacing that aligns layouts proposed for other projects in the Rhode Island/Massachusetts Wind Energy Area (MA WEA). This Plan includes mitigation measures associated with the sequential installation of WTG monopile (MP) foundations (two or three piles/day), as well as concurrent installation (proximal assumptions4) of WTG MP foundations (one vessel installing two MPs per day) and the OCS-DC foundation (one vessel installing four pin piles per day). Concurrent installation (distal assumptions5) of WTG MP foundations (one vessel installing two MPs per day) and OCS-DC jacket foundation (one vessel installing four pin piles per day) may occur during OCS-DC foundation installation campaign as well. However, the mitigation measures and associated zone sizes for concurrent installation of WTG MPs and OCS-DC jacket foundation included in this Plan are based on the proximal assumptions which result in the most conservative ranges to auditory (marine mammal and sea turtles)/physical (fish) injury and behavioral thresholds.
Each WTG will be installed on MP foundations that will be driven using an impact hammer with a maximum hammer energy of 4,000 kJ. The underwater acoustic analysis and exposure modeling assumed WTG MP foundations supported by a tapered MP foundation that is 7 m on top and 12 m diameter at the mudline (7/12 m). The final engineering design of the MP results in diameters of 10 m for all WTG MPs. Installation of a single MP foundation is expected to require a maximum of 4 hours of active impact hammering, which can occur either in a continuous 4-hour interval or intermittently over a longer period of time. It is anticipated that a maximum of three WTG MP foundations can be driven into the seabed per day using a single installation vessel, assuming 24-hour pile driving operation6. Additionally, it is possible that two separate vessels may work simultaneously which would result in installation of up to four total monopiles per day (maximum two per day on each of the two vessels), assuming 24-hour pile driving operations. WTG foundation installation is expected to be completed within a 4 – 5-month period from Q2 – Q4 2025 and Q2 – Q3 2026 (outside of December7 through April). A noise abatement system (NAS) consisting of simultaneous use of a double big bubble curtain (DBBC) and a Helmholtz resonator (AdBm) will be deployed during each WTG pile driving event to reduce sounds propagated into the marine environment. Information on components of the NAS are provided in Appendix A.