[dredmorbius]

As with other impacts of shutdown and quarantine, shifts in demand and consumption patterns can mean that infrastructure isn't able to supply electricity to where it's specifically needed. It's been pointed out that electricity is not storable --- it's less an energy store as with fuel and far more energy distribution as with a transmission or driveshaft, but with far more connections. Not only must the Grid make power available when it is needed, but it must do so where.

Peak daytime demands in urban cores, offices, and factories is different from peak demands in residential exurbs, purely on distribution, even if quantity is comparable.

[eigenvector]

Your comment is completely correct in general, but I'll add that based on the information released by CAISO for this incident, it appears to have been caused by insufficient generation capacity to meet demand at the state level, not constraints on specific transmission or distribution circuits.

CAISO declared insufficient operating reserve (the generation capacity that is available to quickly ramp up or down to match load and generation), which forced them to drop load to get back within safe operating margins. It's better to do this than let the system get into an insecure state where a forced outage may cause cascading failures.

---------------------------------------------------------------- NOTICE: 202002424 POSTED: 2020-08-14 18:38:00 ---------------------------------------------------------------- CAISO Grid STAGE 3 System Emergency Notice [202002424]

The California ISO hereby issues a CAISO Grid Stage 3 System Emergency Notice effective 08/14/2020 at 18:36 through 08/14/2020 at 23:59.

Reason: California ISO is Reserve Deficient.

Refer to the ISO System Emergency Fact Sheet (http://www.caiso.com/Documents/SystemAlertsWarningsandEmerge...) for additional detail.

The ISO requires load curtailments, use of Interruptible Loads* and requests Out-of-Market (OOM) and Emergency Energy from all available sources. Maximum conservation efforts are requested.

Spinning Reserves have depleted or are forecast to deplete to levels below minimum requirements. Load curtailments are required and will continue until such time as sufficient Spinning Reserves are available.

Monitor system conditions on Today's Outlook (http://www.caiso.com/TodaysOutlook/Pages/default.aspx) and check with local electric utilities for additional information.

[dredmorbius]

Thanks for that.

To be clear,I was pointing out a general property, not intending to attribute the recent/current blackouts to this cause.

[Steltek]

Residential solar once posed the opposite problem: generating power during the day in suburbs where it wasn't being consumed nor could it be transported to areas of high demand.

If our current problem is higher daytime residential demand, maybe power companies can stop fighting residential solar initiatives now?

[makomk]

As I understand it, the problem was evening demand, not daytime and that's probably also the real reason why all the empty office buildings aren't helping - most people would probably be out of the office and back home by them. If anything, residential solar makes this problem worse both by making non-solar generation less financially viable and causing a sharp increase in demand for it during the evening as the sun goes down.

[dredmorbius]

The "duck curve".

https://en.wikipedia.org/wiki/Duck_curve