Hydrogen vs. Battery

[nwdiver]

The stress matter if the electrical connections between WalMart and your solar areo bottlenecks. That has happened around here on and off(and this is the heart of SV), e.g. on heat waves in the last few days, when local loads trip up transformers and fuses.

That's rarely if ever the bottleneck that forms peak hours.

 

[buyer123456]

Let's say we use demand response and EV charging to improve grid stability

Those who pay attention to the verbose descriptions in the article probably may question how a complicated pricing structure(as often championed by utilities?) as described can lead to increased or reduced prices for consumers.

E.g. for those who do not charge EVs, how do all these complexities affect their net out-of-pocket costs?

 

[nwdiver]

From other power sources. Let me break it down differently. Suppose you have

Day demand: 100-120 GW
PV: 40 GW
Nuclear: 60 GW
Fossil: 0–20 GW

Night demand: 60–70 GW
Nuclear: 60 GW
Fossil: 0-10 GW

Now store some of the solar and replace it with nuclear power.

Day demand: 100-120 GW
PV: 30–40 GW
Nuclear: 70–70 GW
Fossil: 0–10 GW
Storage: 10–0 GW

Night demand: 60–80 GW
Nuclear: 70–70 GW
Fossil: 0–0 GW
Storage: -10–10 GW

Notice that the fossil fuel load dropped in half during the day and to zero at night, the nuclear base load increased, and the only difference is the availability of storage.

Now I suppose one can argue over how much of this is actually storing nuclear power versus PV power, but that's kind of splitting hairs.

Let's try reality. (Because no where in the US is nuclear >50% of demand...)

At no point this week will there be an opportunity to store energy that will not result in increased generation from fossil fuels...

 

[nwdiver]

Those who pay attention to the verbose descriptions in the article probably may question how a complicated pricing structure(as often championed by utilities?) as described can lead to increased or reduced prices for consumers.

E.g. for those who do not charge EVs, how do all these complexities affect their net out-of-pocket costs?

It lowers it by allowing fuller utilization of utility infrastructure. If SDG&E can sell 20% more kWh without spending 20% more on equipment they can charge less per kWh.

 

[buyer123456]

That's rarely if ever the bottleneck that forms peak hours.

Again, peak hours are those hours with peak usage, and/or with peak PV outputs.

Having excess PV outputs means usage(demand) is not as high, but the excess PV outputs still need to go somewhere, unless the excess is stored locally. Without local storage, the excess PV outputs at peak hours (of production) stress out the grid.

 

[nwdiver]

Again, peak hours are those hours with peak usage, and/or with peak PV outputs.

Having excess PV outputs means usage(demand) is not as high, but the excess PV outputs still need to go somewhere, unless the excess is stored locally. Without local storage, the excess PV outputs at peak hours (of production) stress out the grid.

How exactly would an EV 'waiting for surplus solar' be any different than local storage????

 

[buyer123456]

How exactly would an EV 'waiting for surplus solar' be any different than local storage????

Tesla's claim at one point was to take all superchargers off grid and be powered by solar and battery storage, but that has not proceeded that far, meaning most superchargers are still grid tied.

Obviously if your EV happens to be close by local solar, the EVs do work as local storage. But that also means either one is retired/work-from-home, waiting for the sun to charge their EVs, or employers need to have acres of solar to charge those 1 million EVs sitting at work.

Or excess PV outputs from all over the place needs to go through the main grid, stressing the grid, to get to those 1 million EVs.

 

[buyer123456]

It lowers it by allowing fuller utilization of utility infrastructure. If SDG&E can sell 20% more kWh without spending 20% more on equipment they can charge less per kWh.

That is a noble goal, but given how PG&E operates, that is unlikely cost savings will materialize.

 

[nwdiver]

Obviously if your EV happens to be close by local solar(or solar that is close by), that works as local storage. But that also means either one is retired/work-from-home, waiting for the sun to charge their EVs, or employers need to have acres of solar to charge those 1 million EVs sitting at work.

Or excess PV outputs from all over the place needs to go through the main grid, stressing the grid, to get to those 1 million EVs.

Yeah.... the combined solar of the employers of 1M people would probably add up to acres....

Expand that out to where there are say 1 million vehicles sitting at work, plugged in, just waiting to soak up any/all available excess power.

Wouldn't that solve the need to curtail excess generation?


RT

That is a noble goal, but given how PG&E operates, that is unlikely cost savings will materialize.

That's what the utility commission is for....

 

[buyer123456]

Yeah.... the combined solar of the employers of 1M people would probably add up to acres....

One can do the calculation to figure out how many square meters locally are needed to charge those 1M cars.

But then, that beats the purpose of reducing curtailments at those big solar farms that are recorded by CA ISO, plus the local (non-tallied) curtailments implemented as export limits by utilities.

 

[nwdiver]

But then, that beats the purpose of reducing curtailments at those big solar farms that are recorded by CA ISO, plus the local (non-tallied) curtailments implemented as export limits by utilities.

LOL.... electricity is fungible. Those farms are curtailed because the google campus is exporting 30MW. If the google campus is instead importing 10kW because everyone is charging their cars the solar farm can decrease curtailment by ~30MW. Math.

 

[mblakele]

Again, peak hours are those hours with peak usage, and/or with peak PV outputs.

Wrong. There's nothing inherently "peak" about high solar output: CA ISO today showed high solar output from about 09:00, but PG&E peak on my rate plan didn't start until 14:00. Solar begins to drop around 16:00, but peak rates continue until 21:00.

Having excess PV outputs means usage(demand) is not as high, but the excess PV outputs still need to go somewhere, unless the excess is stored locally. Without local storage, the excess PV outputs at peak hours (of production) stress out the grid.

Wrong. Curtailed solar power doesn't go anywhere: it's an open circuit. Hence there's no extra stress on the grid. CA ISO knows what they're doing.

To illustrate what happens during curtailment: what do you think happens to PV panels after they've been set up, but before PG&E give the homeowner permission to operate?

Spoiler

Correct answer: nothing. It's an open circuit.

 

[buyer123456]

Wrong. There's nothing inherently "peak" about high solar output: CA ISO today showed high solar output from about 09:00, but PG&E peak on my rate plan didn't start until 14:00. Solar begins to drop around 16:00, but peak rates continue until 21:00.

Wrong. There are peak PV outputs(that can stress the grid), there are peak electricity rate hours.

Wrong. Curtailed solar power doesn't go anywhere: it's an open circuit. Hence there's no extra stress on the grid. CA ISO knows what they're doing.

To illustrate what happens during curtailment: what do you think happens to PV panels after they've been set up, but before PG&E give the homeowner permission to operate?

Wrong, Curtailed solar power is not excess PV output, because there are curtailed.

But the discussion is how to possibly avoid those curtailments, by sucking up the un-curtailed excess solar to charge 1M EVs.

 

[buyer123456]

LOL.... electricity is fungible. Those farms are curtailed because the google campus is exporting 30MW. If the google campus is instead importing 10kW because everyone is charging their cars the solar farm can decrease curtailment by ~30MW. Math.

Assuming that extra 30MW from those remote farms do not trip a circuit breaker in the grid and cause brownouts/blackouts.

 

[nwdiver]

Assuming that extra 30MW from those remote farms do not trip a circuit breaker in the grid and cause brownouts/blackouts.

Why would that happen? They're generally curtailed of insufficient demand not transmission constraints.

 

[mblakele]

Wrong. There are peak PV outputs(that can stress the grid), there are peak electricity rate hours.

I don't think CA ISO agrees. This is what worries CA ISO: ramping ~10-GW over 3-hr.

Wrong, Curtailed solar power is not excess PV output, because there are curtailed.

CA ISO knows what they're doing. They curtail power to avoid stress on the grid.

California ISO - Managing Oversupply

But the discussion is how to possibly avoid those curtailments, by sucking up the un-curtailed excess solar to charge 1M EVs.

Well, no. The thread topic is "hydrogen vs battery". You've been off-topic for a long time, trying to build a case for storage. Yeah, and we all know that if you can do that you'll try to argue that hydrogen is the answer.

No sale.

As for curtailment in general: who says it's a problem?

https://www.latimes.com/business/la-fi-solar-batteries-renewable-energy-california-20190605-story.html

In a study published in March, New York-based researchers Richard Perez and Karl Rábago argue that solar power has gotten so inexpensive that overbuilding it will probably be the cheapest way to keep the lights on during cloudy or overcast days — cheaper than relying entirely on batteries. Solar power can meet high levels of daytime electricity demand without energy storage, the researchers say, as long as there are enough solar panels on the grid during times when none of them are producing at full capacity.

“It’s not like solar is going to be available all the time,” said Perez, a solar energy expert at the State University of New York at Albany. “At night you will need storage, and on cloudy days you will need storage. But you will need much less of it.”​

Based on this paper:

Solar Energy Journal study

 

[nwdiver]

Wrong, Curtailed solar power is not excess PV output, because there are curtailed.

...... explain why it's curtailed.....

 

[buyer123456]

CA ISO knows what they're doing. They curtail power to avoid stress on the grid.

Why would that happen? They're generally curtailed of insufficient demand not transmission constraints.

That is exactly right, but nwdiver argues that curtailment is not to avoid stress on the grid, hence the last few pages of discussion.

 

[buyer123456]

Well, no. The thread topic is "hydrogen vs battery". You've been off-topic for a long time, trying to build a case for storage. Yeah, and we all know that if you can do that you'll try to argue that hydrogen is the answer.

Well how come it is just me off-topic while the other posters also build their cases for/against storage?

The discussion of hydrogen as storage is mainly on remote solar farms, not local distributed generators like rooftop solar. From the above quote, It is you what build a case for local hydrogen storage, so it is on you not me.

 

[nwdiver]

That is exactly right, but nwdiver argues that curtailment is not to avoid stress on the grid, hence the last few pages of discussion.

'Stress' has more than one contributor. There's transmission, generation, reactive power, frequency... Sometimes they have to curtail solar because a larger thermal generator is idled as much as possible, sometimes it's transmission...