California Tariff Changes - Good news, bad news!

February 16, 2023

As many know, the California utilities are in the process of changing their summer tariff time-of-use (TOU) schedules because the high volume of solar installations in California have shifted utility supply requirements to the later afternoon, as solar generation is winding down.  

In areas served by Southern California Edison, this shift is now part of the rate schedule.   Summer, beginning June 1, peak demand periods moved generally from Noon-6PM to 4PM-9PM.  SDG&E implemented a similar schedule previously with PG&E likely to follow suit.

At MACH, our energy management software has always included a utility-grade tariff engine, so we thought it would be valuable to look at the potential impact so that enterprise and facility energy managers can include the utility TOU shift in their thinking.  

Good news – strong savings impact for typical office buildings - we estimate ~5-7% on average.  The typical office is winding down in the afternoon so visibility into usage and proactive energy management software should help reduce costs.    Demand will also likely have a significant drop during the Summer months.

SCE demand change chart 1.png

Bad news –  on the other hand, based on what we see as a typical solar load profile below, it appears that the changes may result in lower solar payments.  

SCE demand change chart 2.png

We have presented these estimates assuming there are no changes to your building operations.  

But there may be opportunities to further reduce on-peak demand by increasing the building cooling before 4PM and ‘coasting’ a bit.  There are typically significant savings available by changing your building’s operating schedule, though understanding your (changing) tariff is required!  

And of course tenant comfort / engagement is always an important consideration (see our previous tenant billing software blogs).

If you have questions or want to talk energy savings, please reach out at!