Hoover dam as giant battery

[redpoint5]

Originally Posted by Piotrsko

I believe the study with vehicle packs was done, but the source was biased IIRC and the conclusions suspect. Kinda big losses going back & forth between wall and pack.

There are many homes with whole house lead acid batteries in the 20+ kwh range in use right now.

Li-ion is very efficient, which cannot be said of lead acid. Lead acid is not tolerant of being discharged without accumulating wear, which means they need to be full most of the time. The problem is, they are something like 50% efficient at accepting a charge when near full, and require constant trickle charging to keep them healthy.

I'd be curious to read that study, because I can't imagine it to be accurate. You should be able to achieve somewhere around 80% efficiency from the round trip journey charging/discharging battery back to the grid.

Originally Posted by oil pan 4

The vehicle to grid thing is dead as far as I can tell.

How so? It was never alive, so it's hard to say it's dead in my view. Improbable perhaps, but not dead. Curious what makes it improbable?

[oil pan 4]

About 8 to 12 years ago I remember seeing pipe dream news articles about vehicle to grid fairly often.
Saying that it was never alive is probably more accurate.

Why no vehicle to grid:
Cost.
Range.
Wear.
Power.
Negotiations.

Cost. Most electric vehicle owners are cheap. For it to be effective vehicle owners will need at last a 240v 20 amp circuit to charge their vehicle. It appears around half of electric vehicle owners charge with 120v power.

Range. If the power company controls when your vehicle charges and puts power on the grid is your car going to be charged when you need it?

Wear, convince people this isn't going to wear out their traction battery.

Power. How much power are the vehicles going to put on the grid, too little there's no point.

Negotiations. Who pays for it, how's it going to work, when is it going to work? This would require auto makers and power companies to sit down and talk to each other.
They don't appear to have any interest in each other.

Equipment. Then once you do all that you have to figure out what equipment is going to be used, how its going to work, who is going to use it, where they are going to use it. Are the cars going to have this built in or will it be external.
Is it something that can only be added to new vehicles or will it be a seperate piece of equipment.

I think the best way it would work is to base it on the CHAdeMO protocol. Because you are tapped straight into the vehicles battery and there are up to 50kw of power available.
Unless there is a blocking diode in the vehicle that prevents back flow of battery power to the CHAdeMO.

[redpoint5]

I think most of those problems are addressable.

There will be wear on the traction battery, but the incentive would be such that it more than compensates for wear, and there would be a strategy to limit the depth of discharge to keep the battery in the not-too-much-wear zone. The incentive to the customer is that they get to charge with cheap off-peak rate electricity, and sell it back at on-peak prices. Say the owner supplies 30 kWh of on peak energy per day, and the difference in power cost is 10 cents per kWh, that's $3/day, or $1,100/year.

EV owners would have an app on their phone that they can use to easily manage participation. They could specify scheduled days and times that they will not participate, or schedule 1-time events where they opt out. No penalty except they miss out on the profit to be had selling back energy at peak rates.

EVSE would have to be designed in such a way to allow 2-way power flow. Should be a very minor technical design consideration. The app on the phone would set the schedule of the wifi connected EVSE, which is controlled by the utility, with a manual override.

Most of the equipment necessary is already included with EVs. The onboard charger already handles converting 240v AC to high voltage DC, and vice versa. It would simply need to be made more intelligent to sync with utility waveform and detect things like power outages to disconnect from the grid.

Probably a pipe dream, but I can't see it being a failure due to cost or inconvenience, but rather organizing the various groups to work together.

[ksa8907]

Originally Posted by oil pan 4

About 8 to 12 years ago I remember seeing pipe dream news articles about vehicle to grid fairly often.
Saying that it was never alive is probably more accurate.

Why no vehicle to grid:
Cost.
Range.
Wear.
Power.
Negotiations.

Cost. Most electric vehicle owners are cheap. For it to be effective vehicle owners will need at last a 240v 20 amp circuit to charge their vehicle. It appears around half of electric vehicle owners charge with 120v power.

Range. If the power company controls when your vehicle charges and puts power on the grid is your car going to be charged when you need it?

Wear, convince people this isn't going to wear out their traction battery.

Power. How much power are the vehicles going to put on the grid, too little there's no point.

Negotiations. Who pays for it, how's it going to work, when is it going to work? This would require auto makers and power companies to sit down and talk to each other.
They don't appear to have any interest in each other.

Equipment. Then once you do all that you have to figure out what equipment is going to be used, how its going to work, who is going to use it, where they are going to use it. Are the cars going to have this built in or will it be external.
Is it something that can only be added to new vehicles or will it be a seperate piece of equipment.

I think the best way it would work is to base it on the CHAdeMO protocol. Because you are tapped straight into the vehicles battery and there are up to 50kw of power available.
Unless there is a blocking diode in the vehicle that prevents back flow of battery power to the CHAdeMO.

I don't necessarily disagree with any of this. I would say Tesla is in the best position to address these issues because of their powerwall product... and their cult following.

Their powerwall is already grid-tie, if I'm not mistaken. Seems like a relatively small step to incorporate the grid-tie ability to the charger and viola.

[freebeard]

Originally Posted by oil pan 4

If the power wall uses these cheap sodium tin wood batteries why is it just about the most expensive way to get 13kwh of storage anyone has yet devised?

I didn't intend to imply that wood/tin was past the R&D phase.

Vehicle-to-grid would require forecasted negotiations. 'Powerwall' to [grid else vehicle][vehicle else grid] seems a good compromise.

[oil pan 4]

Evse now and on older vehicles was never intended for 2 way power flow.
CHaadeMO, maybe if there is no vehicle side blocking diode.

[jamesqf]

Originally Posted by Piotrsko

Problem with powerwalls is they use lipo technology, so we are back to the use of rare metals with no recycling.

Lithium is not a rare metal, and it's perfectly possible to recycle it. It's just that there aren't yet enough end-of-life lithium batteries out there to make it practical.

[Piotrsko]

Lithium isn't the issue. Cobalt is. My volt pack just goes to the landfill when it's done to sit inert for millennia growing dendrites. Nobody wants them back, even if I paid.

I swag that there are many thousand tons of lithium sitting in dumps awaiting. There is no demand because raw lithium from China is cheaper. Elon WAS supposed recycle at the gigafactory when he gets to making more cars per week.

[California98Civic]

Originally Posted by Piotrsko

Lithium isn't the issue. Cobalt is. My volt pack just goes to the landfill when it's done to sit inert for millennia growing dendrites. Nobody wants them back, even if I paid.

I swag that there are many thousand tons of lithium sitting in dumps awaiting. There is no demand because raw lithium from China is cheaper. Elon WAS supposed recycle at the gigafactory when he gets to making more cars per week.

Wow. I was unaware of the scale of this problem. Here is a Euro take on it. But there are a few good pieces of journalism out there from the last year or two.

An EV should only be considered as clean as its power supply, mining, and battery recycling. A bit like cars oil/gas production and emissions. If we're not willing to consider all of it, we are greenwashing.

https://www.theguardian.com/sustaina...hium-recycling

[oil pan 4]

Originally Posted by California98Civic

Wow. I was unaware of the scale of this problem. Here is a Euro take on it. But there are a few good pieces of journalism out there from the last year or two.

An EV should only be considered as clean as its power supply, mining, and battery recycling. A bit like cars oil/gas production and emissions. If we're not willing to consider all of it, we are greenwashing.

https://www.theguardian.com/sustaina...hium-recycling

I have been saying this for years but no one believes me.

When and if lithium batteries get recycled it will be to harvest the large amounts of cobalt used. At $40+ per pound for cobalt last time I checked itcould be feasible.
Unless the recycling process also juat happens to yield useable lithium too, expect the lithium to be garbage.
Because early to current Li-ion tech used lots of cobalt. New battery tech uses a lot less. So the next generation of batteries will be even less desirable for recycling.

I think stuff should be recycled. It keeps the earth from becoming a giant strip mine and land fill at the same time. One thing that allows for recycling is cheap energy.
Support cheap energy and you will have more recycling.