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"The solution is -- and this may seem silly -- batteries. See, instead of connecting EV chargers directly to the power grid, the E.On/VW model would see a large battery installed that feeds up to two chargers at 150-kilowatts. The battery gets discharged by the vehicles, and then, once they're done, it's recharged by the grid at between 16 and 63 amps."

The solution doesn't just "seem silly" it is silly.
As all EV drivers are constantly reminded... batteries degrade over time and will eventually reach end of life. Now these VW stations will have a huge battery that will add to the growing pile of dead batteries we have to deal with down the line.
Point two: Great that the first two vehicles will get a nice fast charge... but what happens to vehicles 3,4,5,6, etc... that are waiting for a charge at busy locations from the now depleted batteries inside the charge station?
Another ridiculous "solution" from VW...
 

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I disagree. I think this solution is self-evident. It seems obvious to me that the solution to demand charges is a battery. According to E.ON And Volkswagen Aim To Make Fast Charging Possible Everywhere, the batteries are up to 360kWh. Assuming that a typical car will pull 45kWh in a charge session (adding 75% to the Bolt), that's 8 cars that can charge back-to-back. You may be able to squeeze in a 9th since some of the energy will come from the grid. For example, if charging 8 cars (2 at a time) takes 2 hours (30 minutes per car), and the system draws up to 63A at 240V (15kW), it adds 30kWh during those 2 hours, almost enough for another 45kWh session.

And having more batteries increases the savings due to scale while also providing more batteries for the recycling businesses ;)
 

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Here is another concept which seems to have merit; solar powered (using batteries) charging stations that don't require connection to the grid. Not for everywhere, but certainly a lower cost option for places which don't see all that much EV traffic.


Rich
 

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Large scale expansion of renewable energy is going to require a lot of batteries. It makes sense that they would be located at any intermittent high demand load like DCFC for EVs.

Some applications may end up reusing partially degraded EV batteries, but that will be a fraction of the needed capacity. Chemistries other than lithium ion will be needed. When the battery doesn't need to be packaged in a car, weight and bulk are much less important and control of temperature is much easier. That opens up options like sodium-sulfur, which may be the most scaleable battery technology as it requires no rare elements.
 

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Large scale expansion of renewable energy is going to require a lot of batteries. It makes sense that they would be located at any intermittent high demand load like DCFC for EVs.

Some applications may end up reusing partially degraded EV batteries, but that will be a fraction of the needed capacity. Chemistries other than lithium ion will be needed. When the battery doesn't need to be packaged in a car, weight and bulk are much less important and control of temperature is much easier. That opens up options like sodium-sulfur, which may be the most scaleable battery technology as it requires no rare elements.
Perfect use model for a flow battery instead of a lithium ion battery... no need to worry about size or weight.


Keith
 

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There are many other techs such as lithium iron phosphate that last 2 x as long or Lithium Titanate Oxide lasts 10 x as long.
 

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Flow batteries based on vanadium won't scale any better than lithium ion. The stationary battery capacity needed to support a mostly renewable grid will be in the TWh range. Any primary ingredients not readily available in multi-million ton quantities will be problematic.
 

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Another ridiculous "solution" from VW...
I also disagree. It isn't silly. There might be insufficient electrical capacity in the area and there's the issue of demand charges, as been pointed out which can be very bad for sites that aren't heavily utilized (not enough to make up for demand charges).

Wayback Machine (very long and complicated, haven't read it all myself) from Rocky Mountain Institute and Evgo fleet and tariff analysis (relates to DC FCing) - My Nissan Leaf Forum on page 3:
With today’s EV market penetration and current public DCFC utilization rates, demand charges can be responsible for over 90% of electricity costs, which are as high as $1.96/kWh at some locations during summer months.
This is part of why Tesla has solar and/or batteries and some of their Supercharger sites to help combat charges and why VW owned EA is doing this: Electrify America to add Tesla battery storage to more than 100 new charging stations.

Wayback Machine is a tutorial on demand charges (not common on US residential plans) which I found via New Supercharger Fair Use Policy.
 

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One of the problems with the math in the article you linked was the idea of needing 7 days of storage. If this is tied into a national grid, then it is not going to be low sunlight cloudy conditions, or low wind conditions nation wide, those are localized problems. With a full national grid able to share power from areas with good conditions into those experiencing localized problems you could scrape by with 12 hours of storage, and be fine with one day of storage.

For national grid size systems, how about this?


Keith
 

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One of the problems with the math in the article you linked was the idea of needing 7 days of storage. If this is tied into a national grid, then it is not going to be low sunlight cloudy conditions, or low wind conditions nation wide, those are localized problems. With a full national grid able to share power from areas with good conditions into those experiencing localized problems you could scrape by with 12 hours of storage, and be fine with one day of storage.

For national grid size systems, how about this?


Keith
We can't get the rich to pay to fix our bridges. What makes you think they will pay for a massive powerline upgrade?
 

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We can't get the rich to pay to fix our bridges. What makes you think they will pay for a massive powerline upgrade?
Perhaps no need for anyone to "pay" for it. At the end, it will come down to cost. Renewables+storage is killing even coal plants. We could be close to the point where perhaps regional grid is sufficient. Plus, there's lots of push for hydrogen including converting natural gas plans to burn hydrogen, so maybe just use excess renewable and make hydrogen for long term storage.
 

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Unless you are trying to send rockets into space, making hydrogen just to burn it is a ridiculous idea. Fuel cells are more efficient than any heat engine. Using surplus renewable energy to produce hydrogen as an energy storage medium makes some sense, but with round trip efficiencies of 50% or less there are better alternatives.
 

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Energy is getting to be literally dirt cheap (1 cent a kWh and dropping). 50% round trip efficiency may not matter. I am a fan of EV vs hydrogen cars because it is just so much more convenient. For long term grid storage, hydrogen may be a contender as it has the benefit of emission = water vapor.

Who knows, the industry is still trying to figure it out. It may make sense if we combine hydrogen plants with desalinization in one plant as fresh water is just as, or even more important, than energy.

... another advancement, offshore solar... adjusts daylight hours for solar production... and also keeps the ocean cool, albeit very little.
 

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We can't get the rich to pay to fix our bridges. What makes you think they will pay for a massive powerline upgrade?

What upgrade are you speaking of? We already have power lines that go everywhere but Texas (smart bastards have an isolated grid)... we were speaking of energy storage.

Keith

PS: Preachy Hollywood stars fly in their private jets... why should they pay for the plebes in their cars to have bridges?
 

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What upgrade are you speaking of? We already have power lines that go everywhere but Texas (smart bastards have an isolated grid)... we were speaking of energy storage.

Keith

PS: Preachy Hollywood stars fly in their private jets... why should they pay for the plebes in their cars to have bridges?
There is research about the high power national DC lines that will be necessary to get of fossil fuels. Our current electric infrastructure is not up to the task. Even in EV paradise California.

California's huge, humiliating power outages expose the vulnerabilities of PG&E's power grid
 

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There is research about the high power national DC lines that will be necessary to get of fossil fuels. Our current electric infrastructure is not up to the task. Even in EV paradise California.

California's huge, humiliating power outages expose the vulnerabilities of PG&E's power grid
Looks like PG&E didn't do preventive maintenance (tree / shrubbery trimming and removal) on the power line corridors throughout the state (keep flammables away from sparks M'kay?) I heard rumor that they were prevented by environmentalists from doing necessary clearance work, but this may have been BS and they just didn't do it to save money in the short run... and it came back to bite them in the butt.

On to Electricity!

You may already know all of this, not sure of your electrical systems knowledge and background... not trying to be a know it all :D

The problem with high power DC is getting line voltage up to a high enough value to avoid power loss from high current. Line losses in an electrical conductor are based on the resistance of the line multiplied by the current squared, so you want to maintain the current as low as possible... so for the same power rating you have less power loss with a high voltage line than you do at low voltage, since as voltage goes down current has to go up for the same power transfer.

I know of only one DC long distance power line, can't remember where I saw it. It is so easy to change voltages in an AC system using step up, and step down transformers that it is hard to get away from that system and move into a DC setup. Also, a DC line in high winds and dry conditions with poor maintenance on the power line corridor is just as much of a fire hazard as and AC power line. Not a solution to California's fire problems.

Later,

Keith
 

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Looks like PG&E didn't do preventive maintenance (tree / shrubbery trimming and removal) on the power line corridors throughout the state (keep flammables away from sparks M'kay?)

You may already know all of this, not sure of your electrical systems knowledge and background..
Thanks. I can never have too much information. Here is an interesting piece that Jack Rickard found on PG&E..

 
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