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Question

Utilization of storage facilities installed in solar fields?

EITAN PELED's picture
CEO PELOP

Education: Industrial Engineering and Management, MBA, LLB. Initiation and development of energy management systems in complexes and high-rise buildings. Establishment of a system for energy-zero...

  • Member since 2021
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In order to shift solar energy production to hours when there is no sun, large-scale storage facilities are installed and the solar field's output is doubled. What is the common use of these storage facilities during the winter when there is not enough sun to load the storage facilities? On the other hand, the efficiency of the main turbines goes up and down and is maintained precisely for the winter period. Is it not correct to use the idle storage facilities for the purpose of extending the operation of the turbines at night and reducing their operation at the peak of consumption? Is it right to use the storage facilities also as a reserve for stabilizing production?

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Thank you for the information. I realized that it is possible and perhaps even desirable to use the storage facilities of the PV fields for other roles as well. Do you know of a project that has already implemented this option?

EITAN PELED's picture
EITAN PELED on May 7, 2021

We in Israel are only now beginning to retire significant solar fields in Israel. As a government policy, all new fields will include storage facilities that will double the amount of energy supplied from that field. This means installing storage facilities of more than 12GWH, with the average consumption in Israel being about 6GWH. We are examining, under these conditions, the possibility of using the storage facilities for other purposes beyond diverting energy to the evening. In my opinion the most efficient use that can be added to storage facilities is to replace part of the production reserve with these batteries. In proper planning in my opinion, the fossil production array can be reduced to a significant extent.

Yes of course , since a power system operation is the art of demand-supply balancing , which has been conducted on hourly basis as unit commitment. An hourly supply can include conventional and renewable as well as storage power.  

Eitan, contrary to popular belief, grid batteries are useless as a source of sustained power (all batteries in California combined would be capable of powering our state's grid for a period measured in seconds). Though many believe grid batteries next to wind and solar farms are being charged by exclusively renewable energy, they're there for appearance only. Charged primarily at night with electricity from gas plants, they're used the next day for brief periods to help stabilize irregular solar and wind generation. Consumers should know the truth about battery installations on the grid - they're not being used as many think they are.

Joe Deely's picture
Joe Deely on May 6, 2021

Chart below is from recent day on CA grid.

About 2,500 MWh of battery charging between 8am and 3pm when electricity is cheap - plenty of solar.

 Discharged in early evening - replacing NG generation during that time period - and also when storage owners can get more money.

The total generation on Apr 28th was 550,000 MWh so the 2,500 MWh of battery charging represented 0.45% of full day generation or about 6.5 minutes. 

Really early days for Storage in CA - in fact these numbers will at least double by end of year. 

 "I skate to where the puck is going to be, not where it has been" - Wayne Gretzky

Note: as Bob said there was also a little bit of charging between 10-11pm and there was a little bit of discharging between 6-7 am.  There is normally a rise in prices for short period in early morning as demand rises with people waking and solar generation not yet ramped.

Bob Meinetz's picture
Bob Meinetz on May 7, 2021

Anyone can cherry-pick data to support an ideological preference, and I see you were able to find a day last week that was particularly sunny. But maybe we should put the glorious contribution of CA grid batteries in context, and look at data from a random day - like today, for example.

The contribution of batteries is on the graph below, but the light orange line snaking around 0 on the y-axis is hard to make out. What's plain to see is the pathetically-insignificant contribution batteries make every day - compared to nuclear, to solar and wind combined, and to natural gas. Most importantly, at their peak they were briefly contributing less than one one-hundredth of demand, the turquoise line at the top.

Grid batteries are a feelgood, useless marketing toy to perpetuate the naive dream of a 100% renewable grid.

"...in fact these numbers will at least double by end of year."

Big deal! Multiply storage capacity tenfold or one hundredfold, and you still don't solve intermittency - what CNN's Fareed Zakariah calls the Achilles' Heel of solar and wind.

Joe Deely's picture
Joe Deely on May 7, 2021

Anyone can cherry-pick data to support an ideological preference, and I see you were able to find a day last week that was particularly sunny

I didn't cherry-pick to find a day that was particularly sunny.  I cherry-picked to find a day where battery usage was high. In fact, the day you picked-  05/06 had 131K MWh of solar versus 130K MWh of solar on the day I picked. Solar is pretty consistent in CA.

The contribution of batteries is on the graph below, but the light orange line snaking around 0 on the y-axis is hard to make out. What's plain to see is the pathetically-insignificant contribution batteries make every day - compared to nuclear, to solar and wind combined, and to natural gas. Most importantly, at their peak they were briefly contributing less than one one-hundredth of demand, the turquoise line at the top.

What we care about for batteries is not displacing overall supply - just NG. On both April 28th and May 6th the overall NG supply in CA was just over 150K MWh. That is what we want to replace. No need to replace other zero carbon sources of supply. 

Also no need to "make-out" the contribution of batteries from the chart you show. It's easily seen in the batteries trend graph I show from CAISO supply page. Or if you want you can download the .csv file to see battery usage at 5 minute intervals.

We are still in really early days of solar/storage. However, the current results are show the solar/storage is able to displace early evening NG usage. Pretty simple - it works.  

Because it works and will continue to get cheaper solar/storage is going to grow dramatically over this decade. Of course, these batteries are still only useful for 0-4 hours worth of charge.  They don't "solve" the problem of intermittency. Next up will be batteries that expand storage from 4 to 12 hours.

This "marketing toy" will be displacing 100K MWh of NG generation from CAISO grid on a daily basis by 2030.  

By the way Bob - in a comment you made a few weeks ago - you said solar curtailment would grow at 69% per year till 2029.  How's that going so far this year?  

Its down Y-Y? Whats going on?  Hmmm.. maybe some of that curtailed solar is charging batteries.

 

Bob Meinetz's picture
Bob Meinetz on May 9, 2021

"Solar is pretty consistent in CA."

Solar is very consistent. Like clockwork, it's useless for at least half of every day.

"What we care about for batteries is not displacing overall supply - just NG."

But batteries aren't displacing "just NG". Charged by either the direct ouput of gas plants or a grid mix, they're displacing overall supply (including solar) with electricity that's dirtier than what was used to charge them.

"It's easily seen in the batteries trend graph I show from CAISO supply page."

It's only seen on exaggerated-scale charts calculated to set the hearts of renewables advocates aquiver and make California's RPS appear effective at lowering carbon emissions.

"However, the current results are show the solar/storage is able to displace early evening NG usage. Pretty simple - it works. "

Almost as well as filling a bucket from an eyedropper.

As usual, you finish with more of the same glorious predictions for renewables we've been hearing for a half-century. Isn't it time to give it up, Joe?

Eitan, Yes I believe that we should use storage not only as an answer to the solar issue but also as a means of managing peak demand using power generated by other generating equipment.

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