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T&M Helps Con Edison Make New York City’s Energy Grid More Resilient

June 30, 2017

Performs storm hardening concept studies, detailed design and construction support services to fortify utility’s major substations

Shortly after Hurricane Sandy ravaged the region in 2012, including causing more customer outages than any storm in the utility’s long history, Consolidated Edison Company of New York, Inc. (Con Edison) initiated a $1 billion Storm-Hardening Protection Plan to build a smarter and stronger energy delivery system. The Plan would deliver state-of-the-art solutions to make the region’s energy grid more resilient to future major storm events.

In September of 2013, Con Edison retained T&M Associates to prepare storm hardening concept studies for nine major New York City substations, several of which were operationally impacted by Sandy. Multiple options for protecting the equipment at these facilities were investigated, and summary reports were presented to Con Edison for review and selection of preferred options to implement. Each option was evaluated against various criteria including constructability, cost, environmental, health and safety (EH&S) parameters, regulatory compliance, and others.

Following performance of the concept studies, T&M was tasked by Con Edison to prepare detailed, site-specific designs for storm hardening measures at four of the substations. Depending on the substation’s configuration, a combination of strategies would be implemented, including protecting the perimeter of the facility with perimeter walls and flood gates designed to withstand the FEMA 100-year flood conditions plus an additional three feet of surcharge to accommodate potential flood elevation increases in the future.

Example Sheet Pile Flood Wall – photo courtesy of Skyline Steel

T&M’s designs adapted to existing utility infrastructure below grade, at the surface, and suspended above grade, and maintained critical clearances to meet safety, regulatory and future accessibility requirements. Flood barriers were designed to allow precipitation to drain from the sites during non-storm periods, and have provisions to seal the sites and pump out precipitation during storm events. Where possible, existing structures were reused/reinforced to protect the facilities. During the work, over a mile of new sheet pile walls were constructed to enclose the substations.

During the construction of the project, T&M personnel provided Con Edison with additional support, including responding to requests for information, on-site observation, processing of contractor submissions, and supplemental designs due to the discovery of unknown conditions. Construction of the storm hardening improvements at the four substations was completed on-schedule in December of 2016.