Gust Power LLP Fact Sheet

PROJECT DESCRIPTION Gust Power LLP (Gust) proposes to construct and operate a commercial wind energy facility 11 miles off the southeastern coast of Massachusetts within Nantucket Sound. The project calls for 150, 5.0 megawatt (MW) wind turbine generators (WTGs), each with a hub height of 315 feet, as well as an electrical service platform (ESP), inner-array cables, and 2 transmission cables. Each of the 150 WTGs would generate electricity independently of each other. The total capacity of the project is 750 MW, with a derated capacity of 250 MW (i.e., expected annual output), enough to supply up to 85% of the electricity needs of 5-8 Massachusetts coastal communities. Solid dielectric submarine inner-array cables from each WTG would interconnect with the grid and terminate at their spread junctions on the ESP. The ESP would serve as the common interconnection point for all of the WTGs. Each WTG will be mounted on a tubular conical steel tower, supported by a monopile foundation system. An access platform and service vessel landing would be provided at the base of each tower. The proposed project footprint would be approximately 27 square miles; the entire area to be used for project activities is approximately 35 square miles. The project would be situated so as to maximize the production of energy from wind. In order to generate maximum wind energy production, the WTGs would be arranged in parallel rows in a grid pattern. For this area of Nantucket Sound, the wind power density analysis conducted by the applicant determined that orientation of the array in a northwest to southeast alignment will provide optimal wind energy potential for the WTGs. This alignment would position the WTGs perpendicular to prevailing winds, which are generally from the northwest in the winter and from the southwest in the summer for this area of Nantucket Sound. The WTGs would have a computer-controlled yaw system to ensure that the nacelle is always turned into the wind and perpendicular to the rotor. In addition to maximizing potential wind energy production, the WTGs must also be sufficiently spaced within the array in order to minimize power losses due to wind shear and turbulence caused by other WTGs within the array. Gust proposes to use 5.0 MW turbines, a new technology produced by REPower. The turbines will include a monopole foundation driven approximately 85 feet into the seafloor; three blades with a rotor diameter of 430 feet; and each tower will reach a hub height of 315 feet. The monopoles would utilize two different diameter foundation types depending on water depth. For shallower waters, the monopole would be 16 feet in diameter; for deeper waters, they would be 18.5 feet in diameter. Turbines generally “turn on” when the wind speed reaches 3 to 5 meters per second and shut down when wind speeds exceed 25 meters per second to avoid damaging the turbine components. The turbines will have a spacing of 0.34 nautical miles by 0.54 nautical miles, and will include Federal Aviation Administration (FAA) and U.S. Coast Guard (USCG) approved lighting for safety measures. The individual turbines will be connected to an electrical service platform by 33 kV inner-array cables. Within the nacelle of each turbine, a wind-driven generator would produce low voltage electricity, which would be “stepped up” by a transformer to produce 33 kV electric transmission capacity. The inner array submarine cable system would use a three-conductor cable with all phases under a common jacket. The electrical service platform will be located in the middle of the array. It will collect all the electricity from the turbines, and then send the electricity to shore via 115 kV cables that would make landfall in Cape Town on Cape Cod in Massachusetts. In addition to the electrical equipment, the ESP would include fire protection, battery backup units, and other ancillary systems. These systems will include ventilation, safety, communications, and temporary living accommodations. The living accommodations are for emergency periods when maintenance crews cannot be removed due to severe weather conditions. These accommodations would utilize waste storage holding tanks that would be pumped to the service vessel for proper disposal. All equipment would be contained within an enclosed weather-protected service area. Maintenance and service access to the ESP would normally be by service boat. A boat landing dock consisting of a fender structure with ladder is attached to the ESP to allow boat landing and transfer of personnel and equipment and temporary docking of the service craft. The ESP would have a helicopter deck to allow personnel access when conditions preclude vessel transport and for emergency evacuation. Equipment and material transfer would be by a crane mounted on the ESP. All cables will be buried beneath the seafloor to a depth of 6 feet. Two 115 kV transmission circuits would interconnect the ESP with the existing Massachusetts Electric transmission grid serving Cape Cod. Two AC circuits are necessary to provide the required electric transmission capacity when operating at high capacity to the Massachusetts Electric transmission system and to provide increased reliability and redundancy in the event of a circuit outage. Each circuit consists of two (2) three-conductor cables, resulting in a total of four (4) cables. The proposed onshore transmission cable would be located within the existing public roadways for a length of approximately 4 miles (6.4 km) from landfall to the Massachusetts Electric transmission cable right of way (ROW) located on the west side of Cape Street. The applicant has identified a new industrial port facility in New Bedford, Massachusetts as having the attributes required for construction, assembly, and development of an offshore wind project of this magnitude. The port facility is currently under construction in order to support the burgeoning offshore wind industry and is located in New Bedford Harbor in New Bedford, Massachusetts approximately 15 nautical miles from the proposed project location. As part of construction, the project includes the dredging and removal of approximately 250,000 cubic yards of PCB-contaminated sediment caused by industrial waste generated and discharged during the 1930s and 1940s. The EPA has jurisdiction over the removal of this sediment because New Bedford Harbor is a designated Superfund site. Approximately 18,300 tons of sediment will be removed from the port before it can support the vessels required for offshore wind construction. Under federal law (The Jones Act), all vessels transporting cargo or equipment between two U.S. points must be manufactured and flagged in the U.S. However, the only operational vessels that can support the offshore wind industry are manufactured in Europe. As a result, the WTGs for this project will either need to be assembled on land and placed on a barge by a walking crane in the terminal facility or will need to use a jack-up barge manufactured in the U.S. Manufacture of a specialized jack-up barge called the “RD MacDonald” is expected to be complete by the end of 2014. A jack-up barge with a crane would be utilized for the actual installation of the monopiles. The jack-up barge would have four legs with pads a minimum of four meters on a side (approximately 172 ft2 [0.0039 acre or 16 square meter [m2]). The “RD MacDonald” has a 78-foot wide hull that is 260 feet long and 22 feet deep. A crane with a 280-foot boom will be installed on the barge. The crane would lift the monopiles from the transport barge and place them into position. The monopiles would be installed into the seabed by means of a pile driving ram or vibratory hammer to an approximate depth of 85 ft (26 m). This would be repeated at all WTG locations. Only two pieces of pile driving equipment would be present within the proposed action area at any one time, and they are not planned to be operated simultaneously. Since the monopiles are hollow, sediments would be contained within them. Length of monopile, insertion distance, and finished elevation would vary by individual location due to water depth and structural and geotechnical parameters. Scour mats will be placed on the seabed by a crane onboard the support vessel. Final positioning will be performed with the assistance of divers. After the mat is placed on the bottom, divers would use a hydraulic spigot gun fitted with an anchor drive spigot to drive the anchors into the seabed. The mats are removed with divers and a support vessel in a similar manner to installation, and are expected to result in greater amounts of suspended sediments than levels associated with the original installation of the mats. Rock armor scour protection has also been proposed for an alternative approach to scour control. Rock armor design is driven by wave action (wind-driven and ocean swell) and currents (tidal and wind-driven). The armor stones are sized so that they are large enough not to be removed by the effects of the waves and currents, while being small enough to prevent the stone fill material placed underneath it from being removed. If it were used, the rock armor and filter layer material would be placed on the seabed using a clamshell bucket or a chute. In those locations where rock armoring had been used for scour protection, it would also be removed following project decommissioning. The 33 kV cable would be transported to New Bedford, Massachusetts from the Wind Cable Factory in a special cable transport vessel. The cable would be transferred onto the cable installation barge. The linear cable machines on-board the barge would pull the cables from coils on the transport vessel onto the barge, and into prefabricated tubs. The installation barge and auxiliary barge loading take place in New Bedford, Massachusetts. After the cable has been transferred, the installation barge would be towed to the New Bedford wind farm site. This would be repeated as required to deliver and install all the required cable. The proposed method of installation of the submarine cable is by the hydroplow embedment process, commonly referred to as jet plowing. This method involves the use of a positioned cable barge and a towed hydraulically-powered jet plow device that simultaneously lays and embeds the submarine cable in one continuous trench from WTG to WTG and then to the ESP. The barge would propel itself along the route with the forward winches, and the other moorings holding the alignment during the installation. The six point mooring system would allow a support tug to move anchors while the installation and burial proceeds uninterrupted on a 24-hour basis. When the barge nears the ESP, the barge spuds would be lowered to secure the barge in place for the final end float and pull-in operation. The cable would be pulled into the J-tube and terminated at the switchgear. The following is a list of the primary installation equipment: • Hydroplow cable burial machine designed for 6 ft burial depth; • Installation barge 100 ft wide x 400 long x 24 height; • Anchor handling tugs – two 3000 hp twin screw (would be with the barge for the duration of the installation); • Six-point mooring system with two 60-inch (1.52 m) spuds. The mooring system would consist of 3 double winches, plus another double drum winch for controlling the two spuds. Each winch drum would contain approximately 2,000 ft (610 m) of 1 1/8 inch (28.6 mm) mooring cable and have an anchor attached. Mid-line buoys would be attached to minimize anchor cable scour. Pendant wire with 58-inch (1.48 m) steel ball buoys would be attached to the anchors for deployment and quick recovery; • Cable burial support system including pumps, and Hydroplow accessories; • Cable laying support system including cable machines, chute, tubs and complete diving operations center to support divers; • Auxiliary trencher pulling barge – a barge of 40 x 100 ft (12.2 x 30.5 m) dimensions outfitted with spuds; and • Auxiliary vessels – there would be a crew boat, two inflatable boats, and several skiffs. Jet plow equipment uses pressurized sea water from water pump systems on board the cable vessel to fluidize sediments. The jet plow device is typically fitted with hydraulic pressure nozzles that create a direct downward and backward “swept flow” force inside the trench. This provides a down and back flow of re-suspended sediments within the trench, thereby “fluidizing” the in situ sediment column as it progresses along the predetermined submarine cable route such that the submarine cable settles into the trench under its own weight to the planned depth of burial. The jet plow’s hydrodynamic forces do not work to produce an upward movement of sediment into the water column since the objective of this method is to maximize gravitational replacement of re-suspended sediments within the trench to bury or “embed” the cable system as it progresses along its route. The pre-determined deployment depth of the jetting blade controls the cable burial depth. The installation of the submarine transmission cable via jet plow embedment is anticipated to take approximately two to four weeks to complete. As the jet plow progresses along the route, the water pressure at the jet plow nozzles would be adjusted as sediment types and/or densities change to achieve the required minimum burial depth of 6 ft (1.8 m). In the event that the minimum burial depth of 6 ft (1.8 m) below present bottom is not met during the jet plow embedment, additional passes with the jet plow device or the use of diver-assisted water jet probes would be utilized to achieve the required depth. The transition of the interconnecting 115 kV submarine transmission cables from water to land would be accomplished through the use of a methodology that will minimize disturbance within the intertidal zone and near shore area. The technology (HDD) would be staged at the onshore landfall area and involve the drilling of the boreholes from land toward the offshore exit point. Conduits would then be installed the length of the boreholes and the transmission cable would be pulled through the conduits from the seaward end toward the land. A transition manhole/transmission cable splicing vault would be installed using conventional excavation equipment (backhoe) at the onshore transition point where the submarine and land transmission cables would be connected. There would be four 18-inch (457 mm) diameter HDPE conduit pipes (one for each three-conductor 115 kV cable and fiber optic cable set) installed to reach from the onshore transition vaults to beyond the mean low water level. The offshore end would terminate in a pre-excavated pit where the jet plow cable burial machine would start. The four conduits would have an approximately 10 ft (3 m) separation within the pre-excavation area. The four boreholes would be approximately 200 ft (61 m) long (borehole diameters would be slightly larger than the conduit diameter to allow the conduit to be inserted in the borehole). A drill rig would be set up onshore behind a bentonite pit where a 40 ft (12.1.m) length drill pipe with a pilot-hole drill bit would be set in place to begin the horizontal drilling. A bentonite and freshwater slurry would then be pumped into the hole. The HDD construction process would involve the use of bentonite and freshwater slurry in order to transport drill cuttings to the surface for recycling, aid in stabilization of the in situ sediment drilling formations, and to provide lubrication for the HDD drill string and down-hole assemblies. This drilling fluid is composed of a carrier fluid and solids. The selected carrier fluid for this drilled crossing would consist of water (approximately 95 percent) and inorganic bentonite clay (approximately 5 percent). The bentonite clay is a naturally occurring hydrated aluminosilicate composed of sodium, calcium, magnesium, and iron. After each 40 ft (12.1 m) of drilling, an additional length of drill pipe is added, until the final drill length is achieved. To minimize the release of the bentonite drilling fluid, freshwater would be used as a drilling fluid to the extent practicable for the final section of drilling just prior to the drill bit emerging in the pre-excavated pit. This would be accomplished by pumping the bentonite slurry out of the hole, and replacing it with freshwater as the drill bit nears the pre-excavated pit. When the drill bit emerges in the pre-excavated pit, the bit is replaced with a series of hole opening tools called reamers, to widen the borehole. Once the desired hole diameter is achieved a pulling head is attached to the end of drill pipe and then the drill pipe is used to pull back the 18-inch (457 mm) diameter HDPE conduit pipe into the bored hole from the offshore end. As with the pilot hole drilling process, freshwater would be utilized to the maximum extent practicable as the reaming tool nears the pre-excavated pit. The drilling fluid system would recycle drilling fluids and contain and process drilling returns for offsite disposal, and while the intention is to minimize the discharge or release of drilling fluids to marine or tidal waters, the HDD operation would be designed to include a drilling fluid fracture or overburden breakout monitoring program to minimize the potential of drilling fluid breakout into the waters. It is likely that some residual volume of bentonite slurry would be released into the pre-excavated pit. The depth of the pit and the temporary cofferdam perimeter are expected to contain any bentonite slurry that may be released. Prior to drill exit and while the potential for bentonite release exists, diver teams would install a water-filled temporary dam around the exit point to act as an underwater “silt fence.” This dam would contain the bentonite fluid as it escapes and sinks to the bottom of the pre-excavated pit to allow easy clean-up using high-capacity vacuum systems. It is expected that the HDD conduit systems would be drilled through sediment overburden at the landfall location. However, it is anticipated that drilling depths in the overburden would be sufficiently deep to avoid pressure-induced breakout of drilling fluid through the seafloor bottom based primarily on estimates of overburden thickness and porosity. Nevertheless, a visual and operational monitoring program would be implemented during the HDD operation to detect a fluid loss. This monitoring includes: • Visual monitoring of surface waters by drilling operation monitoring personnel on a daily basis to observe potential drilling fluid breakout points; • Drilling fluid volume monitoring by technicians on a daily basis throughout the drilling and reaming operations for each HDD conduit system; • Development and implementation of a fluid loss response plan and protocol by the drill operator in the event that a fluid loss occurs. The response plan could include drill stem adjustments, injection of loss circulation additives such as Benseal that can be mixed in with drilling fluids at the mud tanks, and other mitigation measures as appropriate; and • Use of appropriate bentonite drilling fluids that would gel or coagulate upon contact with sea water. Depending on manufacturers, gearbox oil within each turbine is usually changed after one year of operation and thereafter every two years. For this operation a larger vessel is required than regular crew boats. Drums of oil must be transported, lifted to the transition platform and hoisted up the tower to the nacelle machine room. Equally, the old oil must be transported in reverse. This operation is usually conducted by a separate team taking approximately one day per turbine. The project would have a detailed Spill Prevention Control and Counter Measure Plan (SPCC) to ensure proper oil handling procedures are used and to provide procedures to address possible contingencies in the use of oil or other potential pollutants. Several mitigation measures will be proposed by Gust to ensure protection of the marine and human environment. In addition, Gust will purchase emission reduction credits (ERCs) to offset the emissions from vessels and equipment used during construction of the project. The project would be monitored 24/7 by a staffed control center on Cape Cod. The control center will have a direct line of communications with the USCG. In case of emergency, the turbines could be remotely shut down from the command center. The project would operate on the periphery of the Atlantic Flyway, a key migratory route for birds on the east coast, including Roseate Terns. North Atlantic right whales and grey seals have been observed in areas as close as two nautical miles from the proposed project location. All along the Cape Cod coast, piping plovers breed and nest. Nantucket Sound is a significant area for commercial and recreational fisheries. The commercial fisheries in the area typically use trawl nets.