- What does the Long Island Replacement Cable (LIRC) project involve?
We replaced the existing seven fluid-filled cables that rest on top of 11 miles of sea bed in Long Island Sound between Norwalk, Connecticut, and Northport, New York, with three state-of-the-art solid core cables that carry the same amount of power. The new cables were buried about six feet beneath the ocean floor using water jet technology to dig the trenches.
- Why was a new cable installed?
To improve the availability and reliability of electric power in Connecticut and New York and to improve environmental conditions. The old cable system had been in service for more than 35 years and was vulnerable to damage from external sources including boat and buoy anchors or shellfish dredging equipment. By replacing the fluid-filled cables with a state-of-the-art solid core cable and burying it the entire length between Norwalk and Northport, the risk of leaks and associated environmental impacts were eliminated.
- Was the transmission line replaced primarily to sell power to Long Island?
No. The new transmission cables are a more reliable, environmentally friendly design of the same transmission capacity.
- How long is the replacement cable?
Each of the 3 new cables is approximately 11 miles long, the same length as each of the old cables.
- How were the cables buried?
The cables were installed using water jetting techniques that fluidize a trench approximately six feet deep in the ocean floor. As sediment was fluidized, the cables settled in under their own weight. This means of burying the cables helps limit sediment suspension and dispersal outside the cable trench.
- What marine and natural resources were impacted by the project?
Sea life affected by the operation may have included finfish, shellfish and other organisms living in or near the ocean floor. Since the new cables were laid where the old cables were located, the impact to marine and natural resources appears to have been minimal. Post construction monitoring and impact assessments are currently underway and results will be posted in the coming months.
- What happened to the old cables?
The old cables were de-energized, dielectric fluid was flushed from the system, and the old cables were removed from the seabed and re-cycled. A small length of each cable (<1 mile each) remains in place near the Long Island Shoreline when it was determined that removal would create additional, unnecessary, impacts to the seabed.
- Do the new cables affect boat navigation instruments?
No. The new cables do not affect navigation equipment and/or instruments.
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