On February 4, 2019, the City Council voted for yet another development on the Southwest side. That development would place additional stress on already overloaded electric infrastructure in this part of town. Before voting, they received the warning copied below from a retired Water & Light executive.  Of course it was ignored.

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Good Morning,

Because the City Council has failed to address the electric load issue in the south part of Columbia, further development puts all southern Columbia residents at risk of outages, particularly during the summer peak season.  All development should be stopped until that issue is addressed.

I do not live in the area impacted by this overloading (or development) and I can not attend the Council meeting tomorrow night but I wanted to make you aware of this issue since it is not being addressed.

The proposed development would receive power from the Perche Substation.  That substation is loaded over 150% of design capacity.  The electric system requires redundancy.  Substations should never be loaded to the point that if one transformer fails, the load can’t be switched to another transformer.  At the Perche Substation, that point was reached several years ago and if something happens now a prolonged outage would occur.

The bond issue, that citizens passed by a large majority in 2015, would have addressed the issue by building a new substation in south Columbia; off-loading the current overloading; and, built a second transmission line to the Perche Substation (currently there is only one transmission line to Perche).  The original plan would have had the work completed by late spring 2017.

Currently there is no decision on what is to be done to address the overloading across south Columbia, yet development continues without addressing the consequences.   A study was completed several months ago that showed that the “Option E”, proposed by the mayor, would have cost nearly double the original Option A; however, that report has not been publicly discussed and nothing is being done to address the issue.

The only way this development could be serviced without attaching to the Perche Substation would be to build an “express” feeder from the Harmony Substation.  That would cost hundreds of thousands of dollars (maybe over a million) more than connecting to Perche.

I am retired now, but was responsible for forecasting electric system load.  Some Council members insist that the load hasn’t grown and therefore there isn’t an issue in southern Columbia.  There are two major flaws in that argument:

1. The historic system load occurred when the actual temperature reached 105 and the nighttime temperature never got below 80.  The recent highest summer temperatures have not exceeded 100.  Until similar high temperatures occur the actual system load can only be projected.

2. The forecast is for the “system” not for individual substations.  To be connected to the larger national grid, electric utilities have to forecast how much energy will flow into their system (transmission system) during peak conditions (subject to fines for failure).  Forecasting loads on individual substations (the distribution system) is not regulated and was not done.  As I stated previously Perche is well beyond design criteria that allows redundancy in the system.

This development should not even be discussed until the City Council addresses the electric system overloading in south Columbia.

A local attorney, with electric utility experience, has been attempting to educate the public on this issue.  For more information go to the following link

https://1community1columbia.wordpress.com/2018/09/05/transparency-and-transmission-option-e-costs-more/

Jim Windsor

Assistant Director of Utilities – Retired