Trans Bay Cable 1 MW Emergency Generation

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Trans Bay Cable (TBC) needed to increase the reliability of their underwater DC transmission line between San Francisco and Pittsburg, CA. The interconnect is an important power supply link to the City of San Francisco and the South Bay Peninsula and plays an especially important role if power is disrupted by seismic activity.

In order to support the reliability need, TBC planned to upgrade their facilities by installing emergency power generation (1 MW total) at each of their converter stations. These new installations will provide power for station security, lighting, and system cooling in the event of an interruption to utility-supplied power.

POWER provided owner’s engineering services, helped define the overall project scope, reviewed different technologies and prepared a technical specification for the procurement of the equipment. After reviewing current available stand-by power technologies, bi-fuel generators (which can use either diesel fuel oil or natural gas) were recommended. The use of bi-fuel generators will allow TBC to meet very low emission limits for standby testing. It will also reduce the required on-site diesel fuel storage while still maintaining limited operation during a disruption of the natural gas pipeline system in the event of an earthquake or natural disaster.

POWER helped the client achieve their overall goal of low air emissions while still maintaining reliability via fuel diversity.