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LTLFTcomposite
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Re: Tesla Powerwall

Wed May 13, 2015 2:57 pm

edatoakrun wrote:Why would you not want your BEV to have this capability?
...
So, even if you have only ~20 kWh available from your pack, and need nearly 20 kWh for your daily commute, you could still drive to work on a full charge, discharge during the morning peak, recharge midday, and discharge again during the evening peak after you get home, before recharging to full again during the off peak hours at night.
...
And you could pocket a nice piece of change every day, as long as TOU rates have significant price variations.

Pretty much everything you just described is from some future world where cars go from one grid connection to the next. That's not the reality here where a plugin car is likely to be one of a kind at the workplace parking lot of a clueless employer (or at a leased building where you're even further distanced from any decision maker) then come home at night empty needing to charge.
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mjblazin
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Re: Tesla Powerwall

Wed May 13, 2015 3:34 pm

evnow wrote:
mjblazin wrote:An expert is also someone that is acquainted with the current state of work in a an area and what problems/solutions exist in active development. He or she does not have be a flange head beating on metal.

How do you know he is - because he was on TV and wrote a book ?

A wall is a point that you do not yet know how you will get over it. Until someone invents a ladder, it is a wall. The truth is a lot of smart people in this area have an idea they need a ladder, but are not close to understanding what goes into a ladder. The prescription now is to work out, build your legs, get better shoes and be able to jump a little bit higher. Doing leg lifts will only get you so far.

You are making a lot of assertions here based on ... what ?

Battery is big business. Commercial state of the art battery R&D is not disclosed easily to anyone ...


He spent several years going to the various labs. The reviews by scientists in the field said he did a good job. He has a good rep with other books. It was good enough for me.
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evnow
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Re: Tesla Powerwall

Wed May 13, 2015 3:54 pm

mjblazin wrote:He spent several years going to the various labs. The reviews by scientists in the field said he did a good job. He has a good rep with other books. It was good enough for me.

Never said he wasn't a good journalist - just that he was no battery expert.

His books and reporting are only as good as what people are willing to tell him and who are willing to talk to him. People at new companies like Shakti or old ones like LG are not going to tell him their most important stuff.

But if you are saying, things like Li Air aren't ready - that's quite obvious.
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RegGuheert
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Re: Tesla Powerwall

Wed May 13, 2015 4:06 pm

evnow wrote:But if you are saying, things like Li Air aren't ready - that's quite obvious.
As an aside, here is an excellent presentation by Jeff Dahn of Dalhousie University with some pretty compelling arguments why Li-air may *never* replace Li-ion batteries.
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edatoakrun
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Re: Tesla Powerwall

Thu May 14, 2015 9:45 am

LTLFTcomposite wrote:
edatoakrun wrote:Why would you not want your BEV to have this capability?
...
So, even if you have only ~20 kWh available from your pack, and need nearly 20 kWh for your daily commute, you could still drive to work on a full charge, discharge during the morning peak, recharge midday, and discharge again during the evening peak after you get home, before recharging to full again during the off peak hours at night.
...
And you could pocket a nice piece of change every day, as long as TOU rates have significant price variations.

Pretty much everything you just described is from some future world where cars go from one grid connection to the next. That's not the reality...

No it's not the present reality, unfortunately.

Most consumers have no access to TOU rates, which allow them to reduce the cost and environmental impact of their kWh consumption, at all.

And every BEV/PHEV manufactured with an onboard charger, every AC EVSE installed at a fixed site, and every BEV battery incapable of discharging as well as charging through its DC port, is a stranded asset, an investment in obsolescent technology.

And (back on-topic) the Powerwall will likely be just another wasted investment in the inefficient past, not the future of energy use.

By spending $5,000 to $50,000 (?) to install one to ten of these things, and placing them in your garage, right next to your BEV, which has a battery incapable of V-to-G, you are making a statement all right...
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AndyH
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Re: Tesla Powerwall

Fri May 15, 2015 4:08 am

edatoakrun wrote:Most consumers have no access to TOU rates, which allow them to reduce the cost and environmental impact of their kWh consumption, at all.

TOU rates don't 'allow' anyone to do anything. The only factor is the consumption and that is and always has been in the hands of ALL consumers.

edatoakrun wrote:And (back on-topic) the Powerwall will likely be just another wasted investment in the inefficient past, not the future of energy use.

I can't believe how backward this is! The condition of "no storage" is 19th century. Distributed renewable generation and storage on a smart grid is exactly the course we need.
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Slow1
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Re: Tesla Powerwall

Fri May 15, 2015 6:53 am

AndyH wrote:
edatoakrun wrote:Most consumers have no access to TOU rates, which allow them to reduce the cost and environmental impact of their kWh consumption, at all.

TOU rates don't 'allow' anyone to do anything. The only factor is the consumption and that is and always has been in the hands of ALL consumers.


TOU rates DO allow people to benefit from choosing when to consume the power which can have indirect environmental benefits. By time shifting loads more generation can be done at a steady state which benefits all the way around. Granted, one can time-shift even without TOU rate, but the access to TOU lets consumers see direct benefit and thus "allow' them to better manage their energy costs. Total consumption is not the only factor but certainly is a major one.

AndyH wrote:
edatoakrun wrote:And (back on-topic) the Powerwall will likely be just another wasted investment in the inefficient past, not the future of energy use.

I can't believe how backward this is! The condition of "no storage" is 19th century. Distributed renewable generation and storage on a smart grid is exactly the course we need.


While you may be correct about distributed generation with storage being desirable, I tend to agree with edatoakrun that the PowerWall isn't likely to be a part of that future. Too little, too expensive, and not offering economic value - more a symbolic gesture. My opinion is that the best thing about the Powerwall is it is getting folks thinking about the value storage can offer to the future and helping facilitate the conversation. I wonder how the economics of their commercial version of it work out - my guess is that it scales well there in volume and thus could well be a real practical solution.
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edatoakrun
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Re: Tesla Powerwall

Fri May 15, 2015 7:40 am

AndyH wrote:...Distributed renewable generation and storage on a smart grid is exactly the course we need.

Slow1 wrote:...the PowerWall isn't likely to be a part of that future. Too little, too expensive, and not offering economic value - more a symbolic gesture...

Correct.

But (with enough public subsidies) the PowerWall could be a sales success, to those wanting to make "a symbolic gesture", as the Tesla S has been.

IMO, high battery costs mean the economic use of batteries for the foreseeable future is in integrating BEV batteries with the grid, both while they are in the vehicle and afterward, as I posted previously:

edatoakrun (page 7)...BEV batteries have will be an important component of the future grid, but Tesla has pursued policies that will probably make it's products batteries useless for these goals.

There are two major future applications for BEV batteries in grid stabilization/load balancing.

The first is using the BEV batteries while they are in the vehicle.

This requires widespread installation of DC charger/Vehicle to grid devices at useful locations, mostly homes and workplaces.

Tesla instead "Free" supercharger policy, means VtoG is economically impossible.

Sad to say, that huge battery in every S will probably never be available to meet grid demand, not while parked at work, nor while parked in every S owners garage.

Which is part of why Tesla is now trying to sell S owners even more batteries for their garage.

The second application of BEV batteries is in repurposing them is stationary applications, after they lose enough of their initial capacity/energy density to make replacement desirable.

The complexity and cost of using Tesla batteries, which require thermal management for safety reasons, probably makes them a poor choice in most new installations.

IMO, trying to repurpose used S packs for this application involves so many additional challenges, it will probably never happen on any scale.

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Re: Tesla Powerwall

Fri May 15, 2015 8:07 am

edatoakrun wrote:IMO, high battery costs mean the economic use of batteries for the foreseeable future is in integrating BEV batteries with the grid, both while they are in the vehicle and afterward, as I posted previously:

There are two major future applications for BEV batteries in grid stabilization/load balancing.

The first is using the BEV batteries while they are in the vehicle.

This requires widespread installation of DC charger/Vehicle to grid devices at useful locations, mostly homes and workplaces.


I disagree here - we do NOT need V2G devices in order to use BEV batteries while in the vehicle. To advocate for putting V2G everywhere is to add unnecessary complexity to the solution. Use batteries in the cars to propel the vehicle - if the battery pack is too large for this, buy a smaller battery pack.


edatoakrun wrote:The second application of BEV batteries is in repurposing them is stationary applications, after they lose enough of their initial capacity/energy density to make replacement desirable.


Reuse after useful life in the vehicle likely is a good idea. A car needs high energy/weight density, stationary applications do not. So, if you lose 50% of your capaicty (and weigh the same) then taking it out and using that capacity in a stationary application just makes sense - sure you have twice the weight/size per kWh, but that isn't nearly as important outside the vehicle. Considering the re-use value in reduced manufacturing etc this is would make a very good policy. Also consider that cooling can be achieved in different ways than the space/weight constrained vehicle. Take the cells, and mount them on a rack and control the environment in other ways as required. Spread them out and they won't generate 'hot spots' as quickly etc.

So the Powerwall doesn't appear to be made of re-used Tesla batteries; rather they look like 'new' ones. Perhaps if/when they do apply re-used batteries the size may grow but costs could plummet making the solution economically viable.

V2G is nice for backup in the home (more V2H?), but I submit that the cost of vehicle batteries/systems is too high to justify planning this capacity into the vehicle (excess size just do do V2G?). Further, the complexity of billing, management, hardware etc makes the marginal value of using the 'needed' vehicle battery for grid load balancing an exercise in futility IMO.
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WetEV
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Re: Tesla Powerwall

Fri May 15, 2015 8:24 am

Slow1 wrote:V2G is nice for backup in the home (more V2H?), but I submit that the cost of vehicle batteries/systems is too high to justify planning this capacity into the vehicle (excess size just do do V2G?). Further, the complexity of billing, management, hardware etc makes the marginal value of using the 'needed' vehicle battery for grid load balancing an exercise in futility IMO.


Grid load balancing by controlling charge rates might have enough value to be useful. The car owner gets a slightly lower rate for charging his car. The Utility gets the right to turn off charging for short time intervals as needed.
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