The article hedges against someone pointing this out by admitting that Walnut Creek is an unusually optimistic location and that PG&E is also recognizing large expenses related to ongoing infrastructure buildouts, but no solutions are offered for these caveats.
The hidden problem with projects like this is that once you roll these utilities into the city’s budget it’s too tempting to start dipping into taxpayer funds for needed improvements rather than raising electricity rates. When problems arise, politicians try to kick it down the road so it becomes their successor’s problem, or they try to offload the expense onto a growing debt load because that delays the problem to the next generation. It becomes easier to keep the highly visible rate down, but taxes might go up to cover the infrastructure costs instead.
So I’m skeptical. If there was an analysis that showed a drop in rates that was not 3X higher than the profit margins of the private utility I’d be more open to the idea, but as presented this feels like back of the envelope math that generates savings by ignoring all the details that didn’t make their way onto the envelope.