CPUC NEM 3.0 discussion

[Redhill_qik]

I found a direct link in case that helps others. Have not listened yet…

Keep in mind that this is produced (or maybe just sponsored) by a company that does solar and battery installation. Some of the assertions on the page I link to below do not ring true to me. I have not found charging at public chargers to be more expensive than filling a car with gasoline (at least in California).

Repeating that I have not yet listened to the podcast.

Gas Stations Are Cheaper Than Public EV Charging - Cinnamon Energy Systems %

Wondering what the cost of EV charging is? Tune into The Energy Show to get the facts about locations and costs of EV charging.

cinnamon.energy

From the podcast/transcript:

Here is a summary of monthly charging costs based on 1,000 miles of driving per month in California:

• Charging at work costs a host company $221/month
• Charging at a public high speed EV charger costs $153/month
• Buying gas at $3.50/gallon costs $140/month (pre-covid price)
• Charging on the EV rate at home costs $80/month
• Charging from home solar at night costs $18/month

This has been posted a couple of times here and dug into it a bit to see how the numbers were constructed and came up with the following:

Place	Monthly Cost	Cost per Unit	Units
Work	$211​	$0.65123​	324 kWh
Public high speed EV (DC charging)	$153​	$0.47222​	324 kWh
Gas @ $3.50	$140​	$3.50​	40 Gallons
Home - EV Rate	$80​	$0.24699​	324 kWh
Home Solar	$18​	$0.05556​	324 kWh
Gas @ $5.374 (AAA CA avg one month ago)	$215​	$5.374​	40 Gallons
Gas @ $6.330 (AAA CA avg current)	$253​	$6.330​	40 Gallons

To get this table I took the easiest one first which was the gas as the price was given as $3.50 which gives 40.0 gallons which means the car gets 25 MPG. I think that is a fair MPG number. There wasn't any information on the EV efficiency, so I took the Home EV Rate as a starting point and using the PG&E EV-2A Off-Peak rate of $0.24699 it comes to 323.9 kWh which I round up to 324 kWh which is 0.324 kWh/mile. Again I think that this is a fair number for the EV, Tesla's are more efficient in the 0,.250-0.300kWh range, but there are many more models that are north of 0.350 kWh.

Using the 324 kWh for the other places results in work at $0.65123, Public DC at $0.47222, and Home Solar at night (?) at $0.05556. The Tesla Superchargers near me at charging $0.47/kWh so that seems like a good match. The Home Solar at night is confusing, maybe it means not selling it back at NSC rates, but that is high or maybe it is using old NSC rates of 2-3 cents plus the NBC rate of 2.6 cents to get 5.6 cents. The Work charge of$0.65123 must be an all-in number that is combing the cost of electricity plus the host company's amortized cost per kWh to build the infrastructure. My work charges $0.19/kWh which would be lower than the Home EV Rate.

The gas at $3.50 is something that California drivers won't be seeing any time soon, if ever, so I updated the table using AAA numbers for California prices from a month ago and current. Both of these exceed "Work" cost.

 

[morph3ous]

From the podcast/transcript:

Here is a summary of monthly charging costs based on 1,000 miles of driving per month in California:

• Charging at work costs a host company $221/month
• Charging at a public high speed EV charger costs $153/month
• Buying gas at $3.50/gallon costs $140/month (pre-covid price)
• Charging on the EV rate at home costs $80/month
• Charging from home solar at night costs $18/month

This has been posted a couple of times here and dug into it a bit to see how the numbers were constructed and came up with the following:

Place	Monthly Cost	Cost per Unit	Units
Work	$211​	$0.65123​	324 kWh
Public high speed EV (DC charging)	$153​	$0.47222​	324 kWh
Gas @ $3.50	$140​	$3.50​	40 Gallons
Home - EV Rate	$80​	$0.24699​	324 kWh
Home Solar	$18​	$0.05556​	324 kWh
Gas @ $5.374 (AAA CA avg one month ago)	$215​	$5.374​	40 Gallons
Gas @ $6.330 (AAA CA avg current)	$253​	$6.330​	40 Gallons

To get this table I took the easiest one first which was the gas as the price was given as $3.50 which gives 40.0 gallons which means the car gets 25 MPG. I think that is a fair MPG number. There wasn't any information on the EV efficiency, so I took the Home EV Rate as a starting point and using the PG&E EV-2A Off-Peak rate of $0.24699 it comes to 323.9 kWh which I round up to 324 kWh which is 0.324 kWh/mile. Again I think that this is a fair number for the EV, Tesla's are more efficient in the 0,.250-0.300kWh range, but there are many more models that are north of 0.350 kWh.

Using the 324 kWh for the other places results in work at $0.65123, Public DC at $0.47222, and Home Solar at night (?) at $0.05556. The Tesla Superchargers near me at charging $0.47/kWh so that seems like a good match. The Home Solar at night is confusing, maybe it means not selling it back at NSC rates, but that is high or maybe it is using old NSC rates of 2-3 cents plus the NBC rate of 2.6 cents to get 5.6 cents. The Work charge of$0.65123 must be an all-in number that is combing the cost of electricity plus the host company's amortized cost per kWh to build the infrastructure. My work charges $0.19/kWh which would be lower than the Home EV Rate.

The gas at $3.50 is something that California drivers won't be seeing any time soon, if ever, so I updated the table using AAA numbers for California prices from a month ago and current. Both of these exceed "Work" cost.

Thanks for the analysis.

 

[holeydonut]

Who is paying $0.056 per kWh to "charge from home solar at night"? Like what does this even mean? Like charging from the moon?

For a NEM 2 customer, they do see a bit of savings by charging from solar in the daytime. But isn't night-time charging for a solar customer the same as the "home EV rate"?

 

[Redhill_qik]

Who is paying $0.056 per kWh to "charge from home solar at night"? Like what does this even mean? Like charging from the moon?

For a NEM 2 customer, they do see a bit of savings by charging from solar in the daytime. But isn't night-time charging for a solar customer the same as the "home EV rate"?

I am speculating that this is a sum of the NBC charge of $0.026 and the loss of a surplus export credit at NBC of $0.03. The other possibility is that it is charging from ESS at night and it represents a 10% efficiency loss plus the NBC charge.

 

[STS-134]

The Work charge of$0.65123 must be an all-in number that is combing the cost of electricity plus the host company's amortized cost per kWh to build the infrastructure.

That's just stupid. When I calculate my home charging costs, I do not include the cost of the service upgrade, new subpanel, and wiring for the EVSE.

 

[Redhill_qik]

That's just stupid. When I calculate my home charging costs, I do not include the cost of the service upgrade, new subpanel, and wiring for the EVSE.

Ok, I did the unthinkable and listened to the podcast. Hear the numbers

• Gas car was calculated with 25 MPG which matches my earlier post
• The EV car is 3 miles/kWh or 0.333kWh/mile which is a little higher than my earlier post of 0.324kWh/mile
• Public charging is near Sacramento (ChargePoint) $15.03/32.66kWh = $0.4602/kWh which is pretty a little lower than my earlier post of $0.4722/kWh
• Night time EV charging rate is $0.24/kWh which is a little lower than my earlier post of $0.24699
• Night time solar is coming from a battery that was charged by solar during the day and $0.05/kWh is stated with no explanation as to how it is derived
• Companies pay per kWh ($0.23/kWh) plus a demand charge on kW ($19/kW). Assuming that the company has a peak demand of 100kW ($1900), employee plugs into a L2 charger that is pulling 7.6 kW * $19 = $144.40. The monthly charging for 333 kWh * $0.23 = $76.59 and the total is $220.99

So the argument for the higher cost for workplace charging is that it increases the maximum demand charge for the month. I think that this is a faulty rationale that might be true for some small businesses, but for larger business is likely not true. This could also be avoided with some smart control functionality that is looking at the meters for the business and throttles the L2 chargers when the it gets close to the maximum to avoid the additional upcharge. With "smart" L2 chargers that manage the charging vs business demand the cost could just be the $0.23/kWh which is lower than the EV2 Off-Peak rates.

Additionally, assigning the demand charge to a single vehicle is faulty as not every car is going to be charging on every day at the same time. Assuming that 3 cars each used the same charger during a day then that drop the $144.40 down to $48.13 with a monthly total of $124.72 which is lower than gas at $130. If 6 cars each used the same charger over two days than it drops to $24.07 for a monthly total of $100.66.

 

[Southpasfan]

The "demand charge" must be wrong when converted to cost per kwh.

I don't run a business that has a "demand charge," but it looks to me as if, OK, I am pulling alot of KW. So, if a have a business that needs whatever amp service gets you to 100KW ( I mean, my 150amp service gets us to like 15 to 20 KW, so its like what, a 600 amp service?), then as you said, that's $1900 per month,

But for the calculation you have to DIVIDE that number ($1900) by the number of KWH per month for starters. We don't have the numbers to really do that, so to assume if my house had a $19 per KW demand charge it would be the high (15KW) times $19, or $285. But in those months, I usually use, let's say 2,850 kwh. So its like ten cents extra per kwh. I could sort of see that.

But, for a business, if they are using far, far more Kwh than a house does, that demand charge number might be divided by a really, really large number of kwh. In my case I only hit 15kw for like minutes during the day, which of course effects total kwh for the month. I would not be surprised if a $19 pe KW demand charge penciled out to less than 5 cents extra per kwh for a business open for 12 hours a day during the summer with the AC blasting non-stop for all 12 hours.

The are also assuming, probably correctly, that installing business chargers automatically results in an upshift in total demand, I mean fair enough but that might not be the case considering A/C vs. winter use. Especially if the demand charge is month by month.

Ugh. Article after article dissing EVs in which (a) you need to make some assumptions to convert kwh to gasoline and (b) the assumptions are made to make EVs appear to be less of a savings.

 

[holeydonut]

Ok, I did the unthinkable and listened to the podcast. Hear the numbers

• Gas car was calculated with 25 MPG which matches my earlier post
• The EV car is 3 miles/kWh or 0.333kWh/mile which is a little higher than my earlier post of 0.324kWh/mile
• Public charging is near Sacramento (ChargePoint) $15.03/32.66kWh = $0.4602/kWh which is pretty a little lower than my earlier post of $0.4722/kWh
• Night time EV charging rate is $0.24/kWh which is a little lower than my earlier post of $0.24699
• Night time solar is coming from a battery that was charged by solar during the day and $0.05/kWh is stated with no explanation as to how it is derived
• Companies pay per kWh ($0.23/kWh) plus a demand charge on kW ($19/kW). Assuming that the company has a peak demand of 100kW ($1900), employee plugs into a L2 charger that is pulling 7.6 kW * $19 = $144.40. The monthly charging for 333 kWh * $0.23 = $76.59 and the total is $220.99

So the argument for the higher cost for workplace charging is that it increases the maximum demand charge for the month. I think that this is a faulty rationale that might be true for some small businesses, but for larger business is likely not true. This could also be avoided with some smart control functionality that is looking at the meters for the business and throttles the L2 chargers when the it gets close to the maximum to avoid the additional upcharge. With "smart" L2 chargers that manage the charging vs business demand the cost could just be the $0.23/kWh which is lower than the EV2 Off-Peak rates.

Additionally, assigning the demand charge to a single vehicle is faulty as not every car is going to be charging on every day at the same time. Assuming that 3 cars each used the same charger during a day then that drop the $144.40 down to $48.13 with a monthly total of $124.72 which is lower than gas at $130. If 6 cars each used the same charger over two days than it drops to $24.07 for a monthly total of $100.66.

Lol MF'ers charge a battery in the day-time that is then used to charge an EV at night for $0.056 per kWh... but they won't allow that same solar to just directly charge the EV battery while the car is parked at work for $0.056 per kWh? Mooooon Power is the future.

FWIW, the office park I'm at added solar panels over the South parking lots... which are then used to charge two Tesla MegaPacks. This provides permanent battery backup to the building to attract more IT tenants. They're also supposed to add some dedicated "on-prem-only-excess-whatever-doesn't-go-into-the-Megapacks" EV chargers to give a few spots free EV charging as a executive-tenant perk. My thinking is the only people that will get this free charging are the baller execs with their Taycans, Hummer EVs, Ludicrous Model X's, and ETronRS's.

Anyway. If you assume $3 per kW solar cost ... and assume 10kW solar generates 12,000 kWh per year... it would stand to reason that every $30,000 spent on excess solar panels could provide 36,000 EV miles per year (ignoring conversion losses). I guess if this worked for 20 years it'd be about $0.06 per kWh. So maybe that's how they derived their "moon powered at night time battery transfer to a EV battery whatever BS $0.056 per kWh".

 

[Dave EV]

Night time solar is coming from a battery that was charged by solar during the day and $0.05/kWh is stated with no explanation as to how it is derived

Yeah - I think this is unrealistic for a number of reasons.

How much home battery storage are we talking about here? Enough to cover the daily average? Enough to cover the 90th percentile of night-time use? Looking at recent charging stats, it looks each charge session is typically 10-30 kWh... so is that 2-4 Powerwalls?

Tesla estimates a 7.2 kW solar system with 3 Powerwalls at $30,198 after rebates. 7.2 kW will generate around 1500 kWh / year here if you have a good roof, so that's about 10 MWh / year. For now, assume that the system lasts 15 years with no additional maintenance costs just to make the math easy (Powerwall warranty is 10 years, typical solar panel warranty is 10-25 years, inverters are typically 10 years, don't know Tesla's specific warranty).

That's 150 MWh over 15 years, or a cost of $0.20 / kWh. Far cheaper than peak electricity costs, but similar to typical off-peak electricity costs.

Let's say the whole system runs out to 25 years w/out any failures or maintenance, that brings the cost down to $0.12 / kWh.

Taking inflation into account, a pretty good deal either way, but no where near the $0.05 / kWh the podcast claims.

To get to $0.05 / kWh on a system that lasts 25 years, the installed cost of solar + batteries must be around $1.875 / watt.

None of this should be taken to indicate that I don't think it's worth it - it's pretty clear that we need as much solar and batteries on the grid as possible and even the base Tesla Solar 4.8 kW / 13 kWh Powerwall system that costs $16,282 that is completely replaced after 10 years will generate electricity at a rate of around $0.23 / kWh which IMO is a bargain.

 

[holeydonut]

PS, this podcast sucks.

How come Tesla Energy Subforum doesn't get any time in the TMC podcasts? @Redhill_qik needs to do a section of the next TMC podcast about how to read the PG&E black and white bills.

 

[Redhill_qik]

Lol MF'ers charge a battery in the day-time that is then used to charge an EV at night for $0.056 per kWh... but they won't allow that same solar to just directly charge the EV battery while the car is parked at work for $0.056 per kWh? Mooooon Power is the future.

The second half of the podcast was about this concept arguing that the right choice is for businesses to install solar, batteries and DC chargers to charge the employee's cars without the thousands of miles of transmission lines between remote solar farms and the end point to get the cost down to $0.10/kWh and then maybe charge employees $0.20/kWh for the convenience which is less than the EV off-peak rates. The $0.05/kWh was also mentioned as the amortized value for a solar system (I think including batteries) over 25 years per kWh generated.

The podcast host made a number of misstatements in an effort to attack the original Stanford study's conclusion that charging at work provides the most benefit. The biggest was how the demand charge that might be increased to a single vehicle another was claiming that charging at night does not increase carbon emissions. Sure, some of that will be coming from nuclear, wind and hydro, but most will be coming from gas plants for now.

 

[holeydonut]

The second half of the podcast was about this concept arguing that the right choice is for businesses to install solar, batteries and DC chargers to charge the employee's cars without the thousands of miles of transmission lines between remote solar farms and the end point to get the cost down to $0.10/kWh and then maybe charge employees $0.20/kWh for the convenience which is less than the EV off-peak rates. The $0.05/kWh was also mentioned as the amortized value for a solar system (I think including batteries) over 25 years per kWh generated.

The podcast host made a number of misstatements in an effort to attack the original Stanford study's conclusion that charging at work provides the most benefit. The biggest was how the demand charge that might be increased to a single vehicle another was claiming that charging at night does not increase carbon emissions. Sure, some of that will be coming from nuclear, wind and hydro, but most will be coming from gas plants for now.

I feel like it's a no brainer to have office buildings, factories, and wherever else there are parking lots full of cars waiting for their owners to drive home from work to charge those cars a bit while parked. The key is to get the site solar generation to be the source rather than the grid.

They don't need 48A each; maybe just 8A over 5 hours of solar-powered charging gives the auto-owners 30 miles of range. That ought to get them mostly round trip without taxing the grid at all.

I like what my office building is doing... giving a $5,000,000 annual TC exec driving a Taycan free "no-grid-impacted-EV-charging" is a start. One day everybody will be able to charge while parked at work with zero impact to the grid at large. Then those people being paid by the energy lobbies to hate on EVs will STFU.

 

[wwu123]

I feel like it's a no brainer to have office buildings, factories, and wherever else there are parking lots full of cars waiting for their owners to drive home from work to charge those cars a bit while parked. The key is to get the site solar generation to be the source rather than the grid.

They don't need 48A each; maybe just 8A over 5 hours of solar-powered charging gives the auto-owners 30 miles of range. That ought to get them mostly round trip without taxing the grid at all.

That's what they have with the solar at our local school parking lots, in addition to providing power to the school buildings, there are numerous L2 charger networked to an app, teachers/staff can charge for free, but it allocates the available amps to the vehicles based on how much charge and range you input you need. After school hours, local residents can charge there, but it's about $0.40 from 4-9 pm when the panels aren't producing much, and the utility's marginal cost of power is expensive; otherwise free.

 

[aesculus]

The key is to get the site solar generation to be the source rather than the grid.

Actually as the grid get richer in solar, this is a great place to send the energy during the day. So you really don't need on site solar, to get the value of a solar charged car.

It won't be long before daytime power is the cheapest, and then it will really pay to have charging at work locations.

 

[Dave EV]

It won't be long before daytime power is the cheapest, and then it will really pay to have charging at work locations.

SDG&E's super-off-peak rates are from 12am-6am weeknights along with 12am-2pm weekends/holidays, but in the spring in Mar-Apr, 10am-2pm are also super-off-peak weekdays.

I expect the time of year that super-off-peak runs from 10am-2pm is expanded until it runs all year.

On the EV-TOU5 rate, if you pay a flat $16 meter/connection fee, super-off-peak rates are about $0.10/kWh while on-peak rates in the summer 4pm-9am are $0.64/kWh. The rest of the time rates are $0.37-0.41 / kWh.

 

[aesculus]

On the EV-TOU5 rate, if you pay a flat $16 meter/connection fee, super-off-peak rates are about $0.10/kWh while on-peak rates in the summer 4pm-9am are $0.64/kWh. The rest of the time rates are $0.37-0.41 / kWh.

With PWs you could probably live with that. I wonder how it would look if you just had PWs (no solar) and charged from super off peak? Might be an interesting exercise.

 

[Dave EV]

With PWs you could probably live with that. I wonder how it would look if you just had PWs (no solar) and charged from super off peak? Might be an interesting exercise.

Good point! I would take a wild guess that two Powerwalls charged during super off peak would cover 95% of off-peak and on-peak usage for when AC or heat-pump is needed.

Could probably get away with one Powerwall most of the time when AC or heat isn't needed.

Would be really interesting to run the numbers to see what it looks like.

If it were possible to just run grid arbitrage, you could net ~$0.50 / kWh in the summer and ~$0.30 / kWh in the winter and net close to $1500/year giving you about a 6 year breakeven for a single Powerwall (~$12,500 - ITC / $1500).

Economics wouldn't work out that well in the typical case where you can usually only self-consume energy and not export, and adding more Powerwalls than you can consistently fully discharge will likely reduce economics.

 

[RKCRLR]

It will be interesting to se how this all plays out in the future. As utilities continue to raise their rates and solar+storage prices continue to fall we could get to a crossover point where it is cheaper to be off-grid than on-grid. This would be especially true for people that need backup power anyway due to the unreliability of the grid. Some places have requirements that a house has to be connected to the grid but many places don't. As people start defecting from the grid the burden of grid maintenance would fall on fewer people which would be a problem for many urban areas.

 

[sunwarriors]

solar+storage prices continue to fall

Have solar prices fell actually? Prices I've seen have been higher than 2021 actually. Tesla prices, independent installers, all higher.

 

[holeydonut]

It will be interesting to se how this all plays out in the future. As utilities continue to raise their rates and solar+storage prices continue to fall we could get to a crossover point where it is cheaper to be off-grid than on-grid. This would be especially true for people that need backup power anyway due to the unreliability of the grid. Some places have requirements that a house has to be connected to the grid but many places don't. As people start defecting from the grid the burden of grid maintenance would fall on fewer people which would be a problem for many urban areas.

The utilities know this; which is why they've been amping up the campaign that 100% grid defection is very difficult and expensive. Those that share the IOU's perspective insist that as long as a home ever needs one microsecond of the grid, then the home needs to pay its fair share.

They use that normal playbook an abusive partner uses to keep victims around. They find a few reasons why they provide positive benefit and extend that to an all-encompassing "you're nothing without me ... blah blah blah".

Like look at h2ofun. Even with a ton of batteries and solar, he needs PG&E in the winter time to get energy. And he involves PG&E in the summertime for NEM. So PG&E says "See, you need me, you can't leave. And if you can't leave, then you need to be under my thumb because that's how things work around here."

The abusive mindset that PG&E uses then allows PG&E to ignore any avenues of self improvement to actually behave like an efficient and well intended PoCo. They have no reason to do things better because they hold the monopoly power while ratepayers are just idiots with cash. So PG&E can keep bribing for favorable policies, grifting through inflated PPAs, and telling ratepayers to pay up more $ since they're handcuffed to the PoCo.