Winnetka moves to add electric capacity
Updated: August 17, 2012 2:43PM
WINNETKA — Winnetka officials knew the day would come when another source of electrical power would be needed to meet the electrical demands of local consumers and provide sufficient backup in the event of a system failure.
With usage trending upward, village administrators believe now is the time to initiate the process of adding a second transformer at its substation site on Happ Road in Northfield, which was constructed in 1996. Connected to ComEd’s transmission system, the 30 megawatt transformer reduces the voltage from 138,000 volts to 12,470 volts for distribution in Winnetka, which operates its own electric utility.
The transformer is one of three sources of power available to the village. The second source consists of three, 12,470-volt tie lines that originate at ComEd’s Northbrook substation and run down Tower Road. If need be, the village also can generate power using a third source: The diesel genererators and steam turbines at the village’s electric plant.
The Winnetka Village COuncil has authorized design work on switchgear as a first step toward constructing a second transformer at the Northfield site. Costs of the project have been estimated at $2.2 million, to be paid over four years from the capital electric fund.
During prior discussions, questions were raised about the downsides of putting a second transformer at the same location because events such as a tornado, transmission line failure or substation fire could knock out a large portion of the system. “The biggest drawback is we are putting a significant amount of capacity at a single site,” acknowledged Brian Keys, director of water and electric for the Village of Winnetka. But efforts to find another location along ComEd’s transmission lines have not proven successful. One site was identified, but not acquired because of the high costs of environmental remediation, which would have pushed costs in excess of $5 million.
Keys said changes can be made at the Northfield site that will reduce the risks of a single event knocking out both transformers.
Keys said that bids for the switchgear portion of the project would likely be ready for council approval in October.
The substation is located on property owned by the Cook County Forest Preserve. The village’s current lease runs until 2056.