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Rooftop Solar

In this 2016 file photo, Chris Stratman, left, and Sergio Guerrero, both of Flagstaff-based Rooftop Solar, work on the solar panels covering a section of roof on a Switzer Mesa home in Flagstaff. 

On paper, everyone supports staggering our use of electric appliances throughout the day to reduce the peak demand and avoid overloading the power grid.

But in reality, that’s not practical for many people. Those who work at home need more air conditioning during the heat of the day. Those with two jobs sometimes have just a narrow window in which to cook dinner, do the wash and catch some TV. Others have inflexible schedules that put them home exactly in the window with highest demand.

And what is that window? Arizona Public Service puts it at 3 p.m. to 8 p.m., which reflects the higher use of air conditioning by Valley customers during the hottest time of the day half the year. Up here in Flagstaff, where the summers are cooler, demand for electricity in the summer is much less, and in the winter many households heat with gas.

But still, the proposed rates are higher during that window regardless of where you live in the APS territory. At one point in the rate hearings, APS even wanted to base a monthly “demand” charge on the one hour of highest electricity use by a customer in that window. Utility officials contend that higher prices will motivate customers to buy timers and load controllers for their thermostats and appliances to stagger and reduce their power use. They will also invest in more efficient electric appliances and water heaters – and perhaps even rooftop solar, which helps APS meet its renewable energy goal. (Although under the proposal, new solar customers will receive lower payments for any excess power they sell back to APS.)

The APS demand charge was dropped after state utility regulators rejected it in unrelated rate cases last year. But we can see APS’ point: Reducing or even just slowing the growth of peak load use means not having to build new power plants and transmission lines as quickly.

The problem, as we noted at the beginning, is that many homes don’t come with so-called “responsive” thermostats and appliances that can stagger electricity use. And that technology is not inexpensive, even if a family’s schedule could be reconfigured to match the hours when lower, off-peak rates are charged.

As it stands, APS is proposing to automatically put new customers on time-of-use rates that charge more between 3 and 8 p.m. but less than the standard rate at other times. They can switch to a standard flat rate after 90 days, but the idea is that they will have learned in three months to stagger their electric use and take advantage of lower rates.

We suppose that 90 days is not a particularly big burden and might impose some “tough love” re-education that will change habits among those families with flexibility or enough money to trade up to “smart” appliances and technology – or both.

But APS is also raising the basic monthly charge by $8.50 for most customers, which puts them that much more in the hole before realizing any net savings from the off-peak discounts. The effect, says APS, is that most customers will see their bills go up by a net of $6 a month, which means the off-peak discounts will only save $2.50.

That seems like a negligible amount, considering all the inconvenience and expense of shifting the typical household’s electricity use out of the 3 to 8 p.m. window. We’d hope APS would exempt new lower-income customers from the mandatory time-of-use rates or offer some discounts on upgraded technology. There will come a time when every house is fully equipped to avoid peak power use, but we haven’t arrived there yet.


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