White Paper Provides Answers
SF PUC white paper discussing the concept of photovoltaic systems for energy collection/transmission, as well as battery backup adaptation of PV system, applied at both a grid level and an individual facility level.
What we have learned from this white paper, when applied specifically to the TI/YBI Distribution System, is that a PV/battery system at a grid level would unfortunately not allow for additional reliability or redundancy Island-wide as the causes of unplanned all-Island power outages are on the Distribution System (equipment failures, bird strikes of HV lines, weather damage to HV lines/poles, etc). As these causes are not tied to transmission into the TI/YBI Distribution System, a grid-level PV/battery system intended to provide a backup source of electric transmission into the Distribution System would still be rendered moot on a shorted Distribution System. The Island does have two primary on-Island generators that provide alternate transmission into the Distribution System when there is a transmission-level interruption from the primary transmission source at the Port of Oakland, most recently these generators served that purpose this past August during daylong maintenance work at Port of Oakland. These generators also do not function to provide alternate resiliency to the Island Distribution if the outage cause is on the Distribution System itself. (This above statement should be considered mostly false as this is what just happened on November 5th batteries and solar would stop the following form happening!)
“ Treasure and Yerba Buena islands lost power from Davis Substation, a Port of Oakland asset, about 2:30PM yesterday. The islands went on generator power while electricians continue to troubleshoot the needed repairs. The generators run off of diesel fuel. To conserve fuel, generators were shut down last night between 12-5AM. Generators were restarted at 5AM as planned. The Generator at YBI has sufficient fuel; however, the generator at Treasure Island has insufficient fuel for continuous power. TI will experience another outage this morning and power will remain out until refueling is concluded. We are unable to refuel the generators until sometime after 10:30AM. Notifications are going out to keep people informed. Lineworkers are narrowing in on the remaining problem with the electrical grid. We will continue to keep you updated.”
The white paper also speaks to building-level applicability of combination PV/battery or standalone battery back-up systems, such as the Tesla “Powerwall”. This is a viable option for individual buildings, and was the general model employed in Puerto Rico to re-energize hospitals and other critical facilities on an emergency basis after Hurricane Maria. In speaking with SFPUC Power, individual installations of Powerwalls or similar products from other manufacturers can happen in a manner that would not cause adverse impacts on the existing Island grid.
If Island residents or households are interested in pursuing installation of Powerwall or similar systems to allow additional resiliency for their residence during Island-wide outages, they may contact their residential property manager to begin the process as a requested Modification to Residential Unit. As with any other proposed Unit Modification, costs would need to be borne by the requesting resident/household and all applicable City project reviews/approvals, including those by Department of Building Inspection related to the building electrical system modifications, must be met, along with any additional requirements or direction issued by the residential property manager.
Please feel free to let us know if there are any questions at this time, particularly on the White Paper contents, as TIDA and PUC are happy to discuss further.
Thank you.
Peter Summerville Treasure Island Development Authority Peter.Summerville@sfgov.org
