Deepwater Wind - Energy Highway

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VI. Interconnection
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Deepwater has developed a comprehensive interconnection plan that is based on a front
end engineering design (FEED) study that it commissioned from SGC Engineering. The
interconnection plan will be finalized through detailed engineering and design work in
consultation with LIPA, NYISO, and ISO-NE.
Shoreham 138 kV
Power from the Wind Plant, as well as exports from ISO-NE, will be delivered to LIPA at
the existing 138 kV substation at the Shoreham former nuclear power plant site.
Deepwater commissioned Siemens PTI to prepare a preliminary interconnection
feasibility assessment. This study found that there were few upgrades necessary on
LIPA’s bulk transmission system needed to support the injection of power from
Deepwater’s Project. Deepwater has also evaluated the Port Jefferson, Riverhead, and
Buell substations as alternative points of interconnection in Zone K. Interconnecting at
Shoreham increases the efficiency of the LIPA transmission system by supplying the
under-served eastern load pocket and by more fully utilizing the transmission
infrastructure that is currently in place.
Brayton Point 345 kV
In New England, the Project will interconnect at the Brayton Point 345 kV substation.
During periods of low wind energy production, power may be exported from the Brayton
Point interconnection to balance the output of the Wind Plant. During periods of high
wind energy production, when the Wind Plant’s output exceeds 600 MW the excess
power that cannot be delivered to LIPA will be diverted to ISO-NE and injected at
Brayton Point. Accordingly, the Brayton Point interconnection has been designed for
both injections and withdrawals. Siemens PTI has confirmed that the high-voltage 345
kV system at Brayton Point is able to accept both injections and withdrawals. As an
alternative to Brayton Point, Deepwater is also evaluating National Grid’s Kent County
345 kV substation.
Offshore HVDC
The Wind Plant will be connected to an HVDC transmission system at the offshore
converter station, delivering power to the AC bus before conversion to DC power.
Deliverability and Interconnection Service
Deepwater has commissioned a series of studies which suggest that the proposed 600
MW can be delivered to the Shoreham 138 kV substation. Specifically, a FEED study
performed by SGC Engineering established the optimal project configuration from the
perspective of cost and functionality. In addition, Deepwater had Siemens PTI prepare a
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