The City Council did not have an alternate plan in place to ensure electric service reliability when in January 2016 it “paused” construction of the Mill Creek substation and related transmission lines. That project, which was intended to address load growth in the South and Southwest, was known as “Option A”. Starting in mid 2016, the Council decided to study the possibility of instead building a transmission line in north Columbia. This proposal was dubbed “Option E”. Suggestions were made that Option E was likely to be less costly than Option A. “Option E” did not, however, address the Mill Creek substation or the substation overloading that the new substation was intended to address.
In the fall of 2017, almost a year and a half after the “pause”, the Council approved, at a combined cost of almost $200,000, two consulting contracts related to electric service. The first, a contract to look at the engineering and estimated cost of “Option E” was awarded to Burns & McDonnell. The second, a contract to review electric service loads and electric distribution needs, was awarded to Quanta Technology. Both consultants sent their final reports to the City in July, 2018. We recently received these reports through an open records request.
The report also calls into question other arguments made by Council members who voted to pause Option A. For example, the Burns & McDonnell report confirms that the staff’s choice of metal poles for a 164 kV line was sound. (As the report states on “wood vertical monopole construction is impractical, as structure loading would exceed the capacity of an H6 wood pole” (p. 4-5); and also observes on p. 4-6: “[s]teel generally has a longer service life than wood and is not subject to rot, woodpecker damage, or other premature structure deterioration”). The report also documents the fact that Option E, like Option A, would impact residential neighborhoods (p. 7-2). Although the report concludes that the “proposed route is feasible,” it qualified that conclusion, stating “there are a number of route obstructions which will need to be addressed and will ultimately have additional costs that would not be recognized from an unobstructed route” (p. 9-1).
Even though the Quanta report focused on overall system loads and did not look at substation level forecasts, it identifies the Perche Creek substation as needing careful monitoring during July as well as the creation of “an offloading schedule that should be triggered in case category P1 operation conditions occur (e.g. transformer failure)”. Transformers are generally manufactured for a 20 to 30 year life. The oldest transformer at Perche Creek was manufactured in 1968, and the most recent in 1997. The other two were manufactured in 1983 and 1986.
Another concern raised by the Quanta report is its suggestion that the City might look at changing the methodology traditionally used to ensure reliability when calculating the load serving capacity of its substations. The purpose of substituting a new methodology would be to “provide the opportunity to defer substation investment” (p. 29). Quanta goes on to note that selection of an alternate methodology would be dependent on “the level of risk tolerance which they [Water & Light] have regarding substation operation.”
What is our risk tolerance when it comes to electric service outages? Our homes, our businesses, and our medical facilities are entirely dependent on reliable on electricity. The costs of an extended outage would be significant. How close do we want to come? The question should not be how to defer needed investments for as long as possible, but to ensure reliable service, both currently and for the long term. As we have stated before, we need a decision-making approach that that is more proactive, transparent, and focused on ensuring our infrastructure needs are timely met in a cost-effective way. Suggestions for how we might improve on the current process are welcome.