On March 29, Commonwealth Edison (ComEd) submitted proposed modifications to its transmission formula rate to clarify that ComEd may recover its portion of the cost to construct, operate, and maintain the Superconductor Cable Development Project (“the Project”) in the central business district of Chicago, Illinois. ComEd also requested the Abandonment Incentive for the Project. The Project is a Supplemental Project under the PJM Tariff, and thus its costs will be charged solely to transmission customers in the ComEd zone.
The Project employs high temperature superconductor technology that serves a transmission function even though it operates at a voltage (12kV) that ordinarily is characteristic of distribution facilities (the filing contains expert testimony on why this Project is a transmission facility under FERC’s seven-factor test). This will be the first such permanent 12kV high temperature superconductor addition in the United States that links substations to form a new looped transmission path. The Project is being built pursuant to the Resilient Electric Grid Program of the U.S. Department of Homeland Security (“DHS”). DHS and American Superconductor Corporation (“AMSC”) (the contractor who manufactures the high temperature superconductor material) will assume approximately 53% of the costs of the Project, leaving 47% – a projected $67 million – to be paid by ComEd. The Project will be in the very heart of the Chicago Central Business District, in an area served by three substations: Dearborn, Plymouth Court, and State. Two of the substations, Dearborn and Plymouth Court, are among the remaining radial substations in the area, served by 69kV underground cables. Only the third substation, State, is part of the looped transmission system. Due to their radial configuration, the Dearborn and Plymouth Court substations are not able to fully back-up the system in the event of a catastrophe. As planned, the proposed high temperature superconductor cable system would provide third contingency capability (“N-3”) to the substations included in the Project. This means that at a given substation, three of the transformers, or three of the supply lines, or a combination of these could be out of service and the remaining equipment could still supply the distribution load while staying within the applicable maximum equipment ratings, except at peak load, which would require outage of some load for only a matter of minutes. The Project is being developed in two phases. The installation in Phase 1 would be a high temperature superconductor cable located at the Northwest TSS 114 substation, in Chicago but a few miles north of the Chicago Central Business District. The purpose of Phase 1 is simply to learn and test the new technology, but it will connect two terminals of the substation, and by doing so will increase the design contingency of that substation to N-2. Once the Phase 1 installation is constructed, and after it has been in satisfactory operation for a year, installation will commence on Phase 2, the main portion of the Project in downtown Chicago. ComEd anticipates placing Phase 1 of the Project in service in the first quarter of 2021. Phase 2 would not begin until after a full year of operation of the Phase 1 installation, in order to evaluate any changes or considerations that should be factored into Phase 2. Current projections are that Phase 2 would come on line in the fourth quarter of 2026.
Dr. Paul Dumais
CEO of Dumais Consulting with expertise in FERC regulatory matters, including transmission formula rates.