Part of Grid Network »

The Grid Professionals Group covers electric current from its transmission step down to each customer's home. 


Substation as Power Island

Ron Davison's picture
Chief Efficiency Officer Select...
  • Member since 2018
  • 10 items added with 5,375 views
  • Jun 26, 2020

This item is part of the Grid Modernization - Pushing Boundaries - Summer 2020 SPECIAL ISSUE, click here for more

We have these things called Substations.

Lets not actually worry what the heck a substation is right now, we will get back to that later. What is unique about any substation, we all have one near our homes. That is to say physically & mathematically, they are all spatially located and provide power to a dedicated number of loads typically.

Your access to Member Features is limited.

But that is not always true. (Think solar panels source power rather than a load when the house makes extra power, changing the  average load seen by substation.) 

If the appropriate amount of storage is added to substations so as to provide 1 to 2 hours of power to the average loads


1) Load leveling on normal evenings. (Slaying the duck curve)

2) Ability to island a load center relative to any power feed in path during an emergency or abnormal condition for a short amount of time.

20 minutes of full load capacity and 2 to 4  hours more of 1/2 capacity. (Good if can partition-allocate as needed, but general goal above god starting point.)

Smart-shed houses that switch to there own storage on request from utility or local substation command. This allows substation storage to last longer. Fire avoidance and emergency power down for clearing can now be done without interrupting downstream power users. Portable storage that integrates with switch gear at substations can be added on demand.


A large clearing job will take all day that feeds a substation. A gen set and/or storage add could be deployed to the substation prior to work. After major deficiency in clearance of safe distances has been completed, then the basic storage can be used for periodic clearing of electrical right of ways from new growth into unwanted areas. 

Use storage for power quality control to substations and 1st 1.5% to 3% will pay for storage.

Duck curve adds another doubling, but only need half that because your power quality and daily cycling do not coincide, or can co-exist to a large degree even when they are acting at the same instance in time. 

Transmission line enhancement even when the local loads are not drawing large amounts of power. If the substation is on a transmission path, each substation can enhance the transmission line for large distance runs. 

Think a rural location with the typical undersized power feeds. If the peak feed in can be supplanted along the path, with other substations storage, or at the rural substation itself with storage. Then the T&D becomes more efficient, has higher utilization, and can defer power draw when hot and high loads both cause T&D problems.

Dr. Amal Khashab's picture
Dr. Amal Khashab on Jun 26, 2020

Substation islanding means you will have your own generation.

For all example you mentioned, it is better to justify the financial viability. As a rule of thumb, all technical options are available, but the most important question is to what cost?

Ron Davison's picture
Ron Davison on Jun 29, 2020

When the payback rate starts at near infinity as does the 1st small amount of storage added to the grid, assuming excellent RTE, the cost of the storage is covered by the efficiency gained by the system at large. As the % of storage goes up there is less and less free energy to grab.

What is free energy to grab?

What everybody has shrugged there shoulders about and said thats the cost of doing business, there are some losses, always. 

But there are avoidable losses and unavoidable losses.

storage allows for capturing a very large % of avoidable losses in the grid.

That buys huge amounts of batteries. If they cost 3x to much for bulk storage ROI narrow mind sets, but gets paid for 3x as fast, then it does not matter, ROI goal is met.

Add more storage later after the 1st TW of storage is added and the cost will have 1/2 haved.

The expensive 1st phase is half paid for so no need to writedown that early investment.

Next phase storage is 2x to expensive for wholesale bulk storage.

But the next 1% to get to 2% of storage will cost 1/2 as much as the 1st phase, cause a TW of batteries will drop prices like a bricked batteries output capacity.

The switch gear is in place, so only the storage capacity add needs capitalization. The 2nd % will not pay as much as the 1st 1% because the 1st 1% took all the platinuim, leving only gold behind.

The 3rd% add, similarly, only allows for grabbing silver left behind, because the gold was taken by the 2nd % add.

On down the line, until no power quality efficiencies are left to mine.

Then the bulk storage for duck slaying is the next mining operation for grabbing the loast revenue stream.

With power quality, now improved with 1 to 2 TW hours of storage, the price of batteries will have dropped to the point that bulk storage economics are in reach, even at the wholesale level.

Add the  safety and maintanance benifits and lost revenue from shutting down the local economy for fire hazards and this is totally within reach.

15 million dollars was the estimated cost of a few days of power shuoffs last Fall in the bay area in California.

Storage could have saved this loss of GDP.

So if you use the efficiency gains to capture the paladuim, Platinuim, gold, silver , and down into the bulk commodity metals analogy then this pays for itself all the way to copper mining the duck slaying.

Even if storage never makes it to wholesale energy pricing pencil out, it will definetly become economically at the industrail and residential retail ricing structures. Its there now, for all but the smallest of systems.

My opaque crystal ball can see a significant fraction of the duck slaying being done at substations, just with the storage that is needed to break even with power quality efficiency adds.

With enough behind the meter storage adds this gets better, because those loads do not need duck service.

Why do we not have this now if all this is true?

Because we can't get there with lead-acid with a RTE of 50-75% or we would have in 1920. If you have to run two coal plants instead of one just to use the storage, then you lost before you started.

Curtailed wind and solar change this, because the powerwould have been thrown away anyway, makes little GHG emmissions so the RTE hit from lad acid is not so bad. If the batteries can be trickled chared for 20 hours and used for 2 to 4 hours then the RTE can be improved upward of 25% of the RTE hit. 1/10th to 1/20th RTE improvement then ~ 5 to 10% upward gain.

Beyond the 1st few hours of bulk storage, the same thing happens with the low lying fruit of power quality losses, the utilization starts to drop off after 2 hours with a long tapered tail of extra evening use out to 5 or 6 hours.

The copper has now been mined after about two hours of bulk evening loads. Now we have to mine the iron, we are down into the bottom of the commodities in terms of profits to be made.

We have batteries that are RTE above 90% now.

It will own what ever it can own upto a certain % of storage relative to grid power. The high cost of the storage is offset by the lower cost of operation via better RTE and higher utilization.

7200x60x24=207,648 cycles a day (at a small fraction of C)


And we don't have to choose between grandma dieing and economic shutdown during fire emergencies,

Can you put a price on that?

If we only just add the storage that pays for itself in efficiency gains, this alone kills a significant fraction of the evening duck curve.

The T&D utilization of the grid goes up, yet peak losses go down, and thus average losses go down.

T&D deferment and/or hidden capacity add via substation storage adds is a significant cost benifit.

Add theat in as well.

Why is this not happening now?

FERC-ing good question.


The rate structure and how utilitise get monitized.

Losses are paid about 2x the profits of real power delivery.


Rate base real power delivery for residential customers.

And rate base, real power, PF, and peak power charges for industrial customers.

Perform an equivilent base structure that only pays for power delivery at the loads, with only the cost of the delivered energy being allowed to map to the energy sourced, watt for watt (#watt4watt) In such a way that the standard markup for 100% of the power generated allowed now under current rate structures is converted to a higher % profit, but on a smaller % of the power generated.

So that no ones bill changes at the turn on of the rate structure change.

This instanly maps losses into one lump.

Suddenly, everyone will scramble to define avoidable and unavoidable losses, and the costs become justifiable with the data being catagorized properly.

To lower them becomes more of a sort on cost of losses, both $ cost and GHG release cost.

Add the cost to fix column, and cost of $ till payoff (ROI), based on actual efficiency gains recorded, in time, not just modelled.

What I am saying above and in original post will all be beared out, when this is put in a spreadsheet.

Then just start knocking out improvement punch list.

Dr. Amal Khashab's picture
Dr. Amal Khashab on Jul 23, 2020

Thanks for reply. I promiss to study it carefully and come back to you with my questions to learn more . Thanks again.

Ron Davison's picture
Ron Davison on Jul 24, 2020

It would be nice to converse about these topics with others who want to improve the existing system.

I look forward to any comments or critiques, assuming they are explained why.

If alternate solution invisioned, even better.

Ron Davison's picture
Thank Ron for the Post!
Energy Central contributors share their experience and insights for the benefit of other Members (like you). Please show them your appreciation by leaving a comment, 'liking' this post, or following this Member.
More posts from this member

Get Published - Build a Following

The Energy Central Power Industry Network is based on one core idea - power industry professionals helping each other and advancing the industry by sharing and learning from each other.

If you have an experience or insight to share or have learned something from a conference or seminar, your peers and colleagues on Energy Central want to hear about it. It's also easy to share a link to an article you've liked or an industry resource that you think would be helpful.

                 Learn more about posting on Energy Central »