If you could provide power to your neighbors, would you?

[bthomas66]

The grid is more unstable each year due to increasing renewable penetration without sufficient energy storage. It was designed for slow, stable, turbine-based generators and we are offsetting them with massive banks of inverters that don't contribute a fraction of the stability.

The grid of the future must integrate resources to the residential level, like EVs, to address this. Imagine a tight web with millions of generators and loads where power can be supplied right next to where it’s needed.

What would it take to allow someone to sell your EV's power while you weren't using it? What control over it or flexibility would you need? What would hold you back?

 

[ItsNotAboutTheMoney]

V2G isn't going to happen at scale.

 

[bthomas66]

V2G isn't going to happen at scale.

Why’s that?

 

[jjrandorin]

The grid is more unstable each year due to increasing renewable penetration without sufficient energy storage. It was designed for slow, stable, turbine-based generators and we are offsetting them with massive banks of inverters that don't contribute a fraction of the stability.

The grid of the future must integrate resources to the residential level, like EVs, to address this. Imagine a tight web with millions of generators and loads where power can be supplied right next to where it’s needed.

What would it take to allow someone to sell your EV's power while you weren't using it? What control over it or flexibility would you need? What would hold you back?

I already have that choice, because I have Solar + Tesla powerwalls and for me, the answer is "no, I dont do that". I participated in a demand response type thing some years ago, and the utility started cycling my AC off during peak time every evening when it was like 100+ degrees outside, and I didnt have any ability to override it.

That was the worst summer I have ever spent in my house and I swore I would never, ever ever again give some other entity control over my AC in my house. This was before I had solar, and I got the solar in 2015, the powerwalls in 2020.

I am simply not going to participate in any of those programs, unless or until the utility pays 100% of the cost to install the equipment at my house (thats powerwalls). I would use my vehicle for powering my own house off grid, but im not putting battery cycles on it to sell the power somewhere else.

I have run an extension cord from my house to my neighbors during a power outage, totally willing to do that, but having some other outside company in a demand response system where they can "take" vs me having 100% control? Nope, thats not for me.

 

[ItsNotAboutTheMoney]

Why’s that?

Smart charging and V2H cover almost everything. Big utility scale batteries will operate at wholesale, retail customers need to be paid retail prices.

 

[bthomas66]

Smart charging and V2H cover almost everything. Big utility scale batteries will operate at wholesale, retail customers need to be paid retail prices.

What if retail customers could be paid wholesale prices and participate in ancillary service markets?

 

[bthomas66]

I already have that choice, because I have Solar + Tesla powerwalls and for me, the answer is "no, I dont do that". I participated in a demand response type thing some years ago, and the utility started cycling my AC off during peak time every evening when it was like 100+ degrees outside, and I didnt have any ability to override it.

That was the worst summer I have ever spent in my house and I swore I would never, ever ever again give some other entity control over my AC in my house. This was before I had solar, and I got the solar in 2015, the powerwalls in 2020.

I am simply not going to participate in any of those programs, unless or until the utility pays 100% of the cost to install the equipment at my house (thats powerwalls). I would use my vehicle for powering my own house off grid, but im not putting battery cycles on it to sell the power somewhere else.

I have run an extension cord from my house to my neighbors during a power outage, totally willing to do that, but having some other outside company in a demand response system where they can "take" vs me having 100% control? Nope, thats not for me.

It sounds like the concern is flexibility? If you were able to cap how much capacity they were allowed to control, and could remove the vehicle from enrollment at any time, would that change things for you?

 

[jjrandorin]

It sounds like the concern is flexibility? If you were able to cap how much capacity they were allowed to control, and could remove the vehicle from enrollment at any time, would that change things for you?

No.

 

[stopcrazypp]

What if retail customers could be paid wholesale prices and participate in ancillary service markets?

Retail customers would have even less interest if they are paid wholesale prices. See the whole NEM fight.

As another pointed out, running an extension cord to a neighbor in a rare outage, I'm pretty sure most people are ok with, but they don't really want the power company taking the power directly (especially when not paid retail rates).

 

[bthomas66]

Retail customers would have even less interest if they are paid wholesale prices. See the whole NEM fight.

As another pointed out, running an extension cord to a neighbor in a rare outage, I'm pretty sure most people are ok with, but they don't really want the power company taking the power directly (especially when not paid retail rates).

I'm not familiar with the NEM debate, but I would agree that wholesale prices would be awful for rooftop solar which peaks in production during the lowest priced hours of the day. Batteries would benefit from having wholesale prices because they could capture realtime high priced hours. I'm not sure where my disconnect is with your point above.

I guess I would question your logic of there being no conditions under which you'd allow an organization to dispatch your asset.


Let's say it's overnight, and you are guaranteed 100% charge in the morning. Surely there is a price you'd accept for those conditions?

 

[stopcrazypp]

I'm not familiar with the NEM debate, but I would agree that wholesale prices would be awful for rooftop solar which peaks in production during the lowest priced hours of the day. Batteries would benefit from having wholesale prices because they could capture realtime high priced hours. I'm not sure where my disconnect is with your point above.

Wholesale prices even in high priced California peaks at less than 14 cents.
California electricity prices by hour? - Thunder Said Energy
Retail residential prices even at tier one is 43 cents. Lowest rate possible is 34 cents (off-peak winter season on EV plan)
https://www.pge.com/assets/pge/docs/account/rate-plans/residential-electric-rate-plan-pricing.pdf
No residential customer would every want wholesale prices at those kind of rates. That's why solar owners all want NEM (net metering) so that they get residential rate equivalent. The wholesale prices typically offered are single digit cents.

I guess I would question your logic of there being no conditions under which you'd allow an organization to dispatch your asset.


Let's say it's overnight, and you are guaranteed 100% charge in the morning. Surely there is a price you'd accept for those conditions?

Sure, a price that accounts for the amortized cost on the wear of the battery, the cost to install the equipment to support the EV exporting power to the grid, plus the electricity cost, plus a small profit, people might find acceptable, but it'll be much higher than wholesale prices. Wholesale prices suck. And when they account for that cost, I think the power utilities found that it is more cost effective to have their own batteries.

Just for degradation alone, a Model 3 LR refurb pack lowest Tesla price I found was $13k, 75kWh usable, warranty is for 30% degradation over 120k miles, which at EPA 358 miles works out to 335 full cycles or about 25MWh DC. High quality inverters are about 90-95% efficient, let's say 95%, that goes down to 24MWh AC.

If pack dies shortly after 70%, that's $0.54/kWh. If you assume it is linear and pack lasts to 360k miles equivalent (and you don't mind the much lower range as it degrades), that's still $0.18/kWh.

Even the pack degradation alone costs more than the peak hour wholesale electricity cost!

 

[bthomas66]

I see. As I said, net metering rules are a weak point of mine so thanks for sending through that information. I understand the argument now.

The spread between the wholesale prices and the residential prices represents the gross profit PG&E takes when selling electricity. Residential customers are in a unique position when compared to utility stationary energy storage facilities to take back some of PG&E's gross profit because they have access to that very inflated price of power when selling. It is fixed, so they can not play arbitrage markets with their storage, but price is inflated to 6-8x the wholesale prices.

Based on your values of $13k for a 75kWh battery that degrades to 52.5kWh (70%) after 120k miles:

1. If I understand your assessment above correctly, you consider that $13k representing the difference between these two capacities (~25MWh DC or 335 full cycles). I'd disagree. Let's use 20k miles a year just to simplify the degradation profile to yearly. You have 75kWh to market in year 1, 71.25kWh in year 2, 67.5kWh in year 3, etc. Rather than the 25MWh_dc value you use, this would sum to 393.75MWh_dc over the life of the battery. Factoring in 95% efficiency and the $13,000, the cost per marketable kWh is ~$0.034 rather.

2. We can't use the fixed rate schedules above because you have no price spread to make profit from, so let's use the winter season EV plan you mentioned. The spread between on-peak and off-peak is $0.19c/kWh. In the first year alone, managed charging would return $14k, albeit assuming you don't use the vehicle as a vehicle, charge and discharge perfectly, etc.

3. The above is an analysis of purely energy throughput. Batteries are capable of contributing much higher value to the grid than simply sinking and sourcing energy at the right times (capacity, ultra-fast frequency response, operating reserves). At a fundamental level, as we look at the impact of low short circuit contributions from inverter-based resources like wind and solar, we would instability would increase and the market to provide support services would become more lucrative.

Thanks for provoking the thoughts.

 

[stopcrazypp]

I see. As I said, net metering rules are a weak point of mine so thanks for sending through that information. I understand the argument now.

The spread between the wholesale prices and the residential prices represents the gross profit PG&E takes when selling electricity. Residential customers are in a unique position when compared to utility stationary energy storage facilities to take back some of PG&E's gross profit because they have access to that very inflated price of power when selling. It is fixed, so they can not play arbitrage markets with their storage, but price is inflated to 6-8x the wholesale prices.

Based on your values of $13k for a 75kWh battery that degrades to 52.5kWh (70%) after 120k miles:

1. If I understand your assessment above correctly, you consider that $13k representing the difference between these two capacities (~25MWh DC or 335 full cycles). I'd disagree. Let's use 20k miles a year just to simplify the degradation profile to yearly. You have 75kWh to market in year 1, 71.25kWh in year 2, 67.5kWh in year 3, etc. Rather than the 25MWh_dc value you use, this would sum to 393.75MWh_dc over the life of the battery. Factoring in 95% efficiency and the $13,000, the cost per marketable kWh is ~$0.034 rather.

I don't see how you get 393.75MWh. I think you likely mixed up your units.

25MWh represents 120k equivalent miles of usage before it degrades to 70% (which is "end-of-life" for laptop batteries).

The math is 358 miles EPA for a full cycle. 120k miles / 358 miles = 335 equivalent full cycles have been put on the battery for that usage. So 75kWh * 335 full cycles = 25MWh have been put on the battery at 120k miles of driving.

Note the battery doesn't care if you put that 25MWh via driving or via using it for the grid.

I put it to 3x (75MWh) or 360k equivalent miles of usage assuming you wear the battery well beyond 70%. That is what gives $0.18/kWh assuming a $13k pack price.

2. We can't use the fixed rate schedules above because you have no price spread to make profit from, so let's use the winter season EV plan you mentioned. The spread between on-peak and off-peak is $0.19c/kWh. In the first year alone, managed charging would return $14k, albeit assuming you don't use the vehicle as a vehicle, charge and discharge perfectly, etc.

How many MWh are you assuming to get that $14k? Your battery might be EOL already by the time that is used up (plus as you mention you don't get to use your car for its primary purpose: transportation). What you mention might make sense for a stationary battery, but if you go to forums for them, power companies pretty much don't let you try to profit like that because they don't offer you the peak rate. It's more cost effective for them to have their own large scale battery than to try to push V2G.

3. The above is an analysis of purely energy throughput. Batteries are capable of contributing much higher value to the grid than simply sinking and sourcing energy at the right times (capacity, ultra-fast frequency response, operating reserves). At a fundamental level, as we look at the impact of low short circuit contributions from inverter-based resources like wind and solar, we would instability would increase and the market to provide support services would become more lucrative.

Thanks for provoking the thoughts.

 

[David_Cary]

I would say that this isn't that simple and guesses are guesses.

Certainly the battery "cares" what the use is for - low temperature, low current draws are less damaging to the battery. Keeping battery between central portions of capacity is less damaging. There is some debate over the magnitude of these differences but there is no debate that there is a difference.

Warranty tells us something about EOL for perhaps the worst 1% - how that compares to the 50% mark is probably a 2X lifespan if not more. My Model S at 8 years and 110k miles had maybe 10% degradation before it got totaled. Using warranty as some exact statement about lifespan is a technique that a lot of anti-EV studies like to use. So think of that company you would like to keep.

It isn't just charging cycles. In fact, calendar time is much worse that cycles from what I have seen. Time doesn't change. I would guess that in a situation with shallow, well-regulated discharges and charges, time could be 90% of degradation.

None of this means we have no concerns that V2G would effect lifespan but they might not be as bad as you are making them out to be. It may (or may not) be a good use of resources even taking increased degradation into account.

But let's face it - it would be way easier and more beneficial to at least control the charging to some extent - ie allow the utilities to control when the car is charged. And we haven't gotten there yet and the majority would resist even that basic idea - except when they are paid for it I guess.

My car has a 330 mile capacity. Most of the time I am under 30 miles a day. I can restrict charging mostly to sunny weekend days with moderate temps. Early in the day in the summer and later in the winter. But no one asks me to do that or pays me for it. Low hanging fruit....

 

[stopcrazypp]

I would say that this isn't that simple and guesses are guesses.

Certainly the battery "cares" what the use is for - low temperature, low current draws are less damaging to the battery. Keeping battery between central portions of capacity is less damaging. There is some debate over the magnitude of these differences but there is no debate that there is a difference.

My statement is more intended to say assuming similar conditions, the battery doesn't care if it is driving or stationary, it's still going to wear (the cycles are not suddenly "free" just because the car isn't moving). And as per other threads doing deep analysis of battery wear, surprisingly the conditions seem to matter a lot less than originally expected (at least as it relates to Model 3/Y, may not necessarily be the case for other EVs for example the Leaf with no cooling).

Warranty tells us something about EOL for perhaps the worst 1% - how that compares to the 50% mark is probably a 2X lifespan if not more. My Model S at 8 years and 110k miles had maybe 10% degradation before it got totaled. Using warranty as some exact statement about lifespan is a technique that a lot of anti-EV studies like to use. So think of that company you would like to keep.

Putting aside the Model S performs a lot better than the Model 3/Y (likely because of capacity differences, may also have to do with 2170), that's why I put the 3x modifier. That's the equivalent of 360k miles on a smaller battery. The economics still work out extremely poorly.

And for a owner, why shouldn't they assume the worst case to figure out the costs to themselves? The power company isn't going to pay you back your battery if it wears faster than expected, so it's up to you to factor in the risk (in which case it benefits to be conservative).

It isn't just charging cycles. In fact, calendar time is much worse that cycles from what I have seen. Time doesn't change. I would guess that in a situation with shallow, well-regulated discharges and charges, time could be 90% of degradation.

The calendar and cycle life does have interactions that are not well specified (it is not additive), but the general algorithm from when I looked it up, is it is the worse of the two. Meaning if you let car sit it will degrade x amount per year. If you cycle a lot it will also degrade. In general for cars, people don't cycle fast enough to hit EOL quickly via cycling, so calendar dominates.

None of this means we have no concerns that V2G would effect lifespan but they might not be as bad as you are making them out to be. It may (or may not) be a good use of resources even taking increased degradation into account.

But let's face it - it would be way easier and more beneficial to at least control the charging to some extent - ie allow the utilities to control when the car is charged. And we haven't gotten there yet and the majority would resist even that basic idea - except when they are paid for it I guess.

My car has a 330 mile capacity. Most of the time I am under 30 miles a day. I can restrict charging mostly to sunny weekend days with moderate temps. Early in the day in the summer and later in the winter. But no one asks me to do that or pays me for it. Low hanging fruit....

Yes, I agree that controlled charging is low hanging fruit and it's kind of telling power companies haven't really been enthusiastic about even that. I think the problem is people always want the ability to opt out of certain events and that reduces the reliability factor of it.

 

[David_Cary]

My model S was a 70 so same as a 3. The 3 and Y we have now are faster than my S was.
Agree that cars aren't driven enough so calendar becomes important.