Re: The Physics Behind the Spanish Blackout

On 6/12/25 5:55 PM, Don Y wrote:

On 6/12/2025 5:10 PM, KevinJ93 wrote:

On 6/12/25 5:04 AM, Don Y wrote:

On 6/12/2025 2:48 AM, Liz Tuddenham wrote:

Don Y <blockedofcourse@foo.invalid> wrote:
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On 6/12/2025 1:08 AM, Liz Tuddenham wrote:

Waldek Hebisch <antispam@fricas.org> wrote:
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[...]

Instantly dropping loads may be possible, but if it is the
only short term balancing mechanizm, then effect on loads may
be nasty.

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That option will become less effective as a greater proportion of the
supply is generated by renewables.  Dropping the load may also drop a
significant proportion of the supply from local solar and wind sources.

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That's specious reasoning.
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I can contract with the utility to allow some of my BIG loads to be
dropped (on THEIR command) without disconnecting me (and my cogeneration
capabilities) from the network.

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The key word here is "instantly".  To instantly drop thousands of
individual loads whilst maintaining their co-sited generation capacity,
in a completely reliable way, may be possible, but we are nowhere near

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But that is likely because the folks who developed "residential solar"
likely assumed the grid would be the "800 pound gorilla" that would
provide stability.  That may have been a valid assumption when solar was
relatively "rare" but is an increasingly unfortunate assumption.

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California residential solar requires that the inverters adhere to what's referred to as "California Rule 21". The inverters change their output as the frequency or voltage rises. This is to promote grid stability. So it is not quite as you say.

 But, is that the case everywhere and for every (legacy) installation?

Not yet but it is a standard that has been adopted in other states and countries. Since newer installations will quickly exceed the older ones in the total capacity it(or something similar)  will eventually become dominant.

that at present.  Emergency load-shedding consists of switching of big
chunks of consumers but that is increasingly liable to switch off
generating capacity in an unpredictable way.

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Using current/legacy technology.  But, there is no reason to force a
new technology to adopt old strategies and mechanisms.
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We didn't assume BEVs would have to be charged using a standard 15A
branch circuit -- maybe 20A available in an outdoor location (garage).
This was deemed inappropriate for all but special use cases and
ALTERNATIVE charging systems were created -- at a significant cost in
infrastructure.

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There are financial incentives to shift demand for EV charging to times of low grid utilization. (eg 12AM to 6AM). The grid is mainly limited by peak use, not overall consumption.

 Connecting a PV array to the grid automatically changes the client to a
ToU tariff.  So, if your array can't meet all of your needs (at the granularity
of the measuring system), you pay a BIG premium for the power you need to
import (even if you've exported enough to cover those needs as you are
reimbursed at a lower rate)

The local utility is forcing all consumers onto a ToU tariff, regardless of whether they have solar.

And, if your array is out of service (e.g., having repairs done or roof
maintenance), then any savings the array might have realized quickly evaporate.

Yes, definitely possible - that would possibly cost $5,000 or equivalent to one year's consumption without solar.

 We looked at the ToU tariff thinking we could easily shift our consumption
to leverage any rate reductions.  But, most of the cooling load (which is most
of the load!) happens during on-peak hours (3P-7P); and the rate is ~50% higher
per KWHr during those times.  Hard to imagine the cost in comfort to appreciate
any real savings!

I run off batteries/solar during the peak time in summer.

 

Ditto rail lines when the iron horse became viable.  Paved roadways
for horseless carriages.  etc.
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Someone "got cheap" with solar and decided it didn't need any special
SYSTEMIC investment beyond the individual cogenerators.