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received EV -> EV2 transition letter [Discussion: CA Rate plans and PV or PV+Storage]

holeydonut

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Jun 27, 2020
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East Bay NorCal
Of course, that's why I mentioned it. The Powerwalls allow me to only draw Off-Peak energy from PG&E for 6 months a year. There are probably another 2 months a year that I draw some Part-Peak but nothing during Peak. The 4 Winter months, I don't have enough solar generation to even cover my Peak usage.

Yeah, that's why the dream is to be able to grid-charge your Powerwalls a bit using off-peak energy at like 1am. Then when the next day rolls around, you get some solar production, and the Powerwalls fill up enough to bridge you through the shoulder/peak time. This is especially useful if there is a lot of cloud cover or weather further dampening solar production in that Winter month.

I really don't know why Tesla will not allow this type of programming. It helps lessen the load during peak time and presumably wouldn't significantly increase the dependence on fossil fuels or imports compared to the homeowner not grid-charging their Powerwalls.
 

holeydonut

Supporting Member
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Jun 27, 2020
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East Bay NorCal
Probably because the ITC doesn't allow it?

I guess the answer is yes/no.

Below is a chart from the NREL (back when the incentive was 30% instead of the current 26%). There's a way to get the ITC as a pro-rated percentage of the MARCS schedule. So, pretend a Powerwall was 95% charged by renewables and 5% charged by non-renewables, then the homeowner would get 95% of the 30%.

BUT, I'm in a PG&E community choice aggregator (CCA) known as MCA. I'm technically allowed to elect 100% renewable by adding a few cents per kWh so the MCA applies credits towards only renewables. This (on paper) means I am only purchasing energy from renewables, and presumably would only charge the system with renewables even if the energy comes from the grid. This would mean I'd get the full 100% of the 30%.

I mean, I know the actual electrons entering the batteries is coming from whatever energy is flowing through the Grid at that moment. Presumably, it's mostly grid exports from our neighboring states, some natural gas, a nuclear plant, and some wind blowing around. But I think the ITC doesn't differentiate the on-paper charging from the real-electrons charging. We just need Tesla to allow time of use management with grid charging when the system happens to include on-prem solar.
1624305769587.png
 

power.saver

Grid Specialist
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Mar 4, 2018
603
637
Arcadia, CA
I guess the answer is yes/no.

Below is a chart from the NREL (back when the incentive was 30% instead of the current 26%). There's a way to get the ITC as a pro-rated percentage of the MARCS schedule. So, pretend a Powerwall was 95% charged by renewables and 5% charged by non-renewables, then the homeowner would get 95% of the 30%.

BUT, I'm in a PG&E community choice aggregator (CCA) known as MCA. I'm technically allowed to elect 100% renewable by adding a few cents per kWh so the MCA applies credits towards only renewables. This (on paper) means I am only purchasing energy from renewables, and presumably would only charge the system with renewables even if the energy comes from the grid. This would mean I'd get the full 100% of the 30%.

I mean, I know the actual electrons entering the batteries is coming from whatever energy is flowing through the Grid at that moment. Presumably, it's mostly grid exports from our neighboring states, some natural gas, a nuclear plant, and some wind blowing around. But I think the ITC doesn't differentiate the on-paper charging from the real-electrons charging. We just need Tesla to allow time of use management with grid charging when the system happens to include on-prem solar.
View attachment 675968
I thought MARCS was only applicable to business/commercial installations, not residential?
 

holeydonut

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Jun 27, 2020
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Yeah - the above applies to the commercial credit only, not the residential one. There is no provision in the residential credit for a partial credit.


Oh - I thought private meant any private entity... since businesses are "people" too heh.

But still, couldn't a homeowner with a "100% renewable CCA" claim the grid-charging was with 100% renewables?

Edit: what if your home was a day care or rental property? Could you claim a business MARCS/ITC instead of the purely residential one?
 

astrorob

stealth performance M3
Aug 27, 2014
483
111
oakland, ca
Seems if you do not have AC, which most of use run full time during peak, it could big time change you comparison numbers?

well, if you have historical consumption and generation data as i do, AC or not, the analysis should yield a proper comparison, assuming you had and used the AC the same way in the past as you will in the future.

I am on NEM1 too. According to PG&E that for solar customers moving to non-TOU is still possible depending on location. It seems that there is some kind of cap on number of solar customers on non-TOU plans in each area and it happens to be available to me

i think i vaguely remember hearing about this when i installed solar, but almost certainly here in the larger bay area the # of E1 people with solar has got to be maxed out...

anyway the analysis is a lot harder with a tiered plan and i'm not sure i ever got it right in my software. i should take another look.
 

holeydonut

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Supporting Member
Jun 27, 2020
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East Bay NorCal
But in reality it's not. Just because the CCA buys enough "green" energy to cover your usage doesn't mean all the electrons going through your meter are green.


Yeah, I talked about this a few posts above. So you and I are 100% on the same page with regard to the electrons.

But if a CCA can advertise to tens of thousands of homeowners that it is "100% renewable" then I feel the same logic/argument could be applied toward the residential ITC. The CCA even gives people these stickers to put on their windows bragging about how the energy being used to power their home is 100% renewable. Seems like somebody out there has already done the research/legowork to establish it's not about the electrons, it's about the credits.

Like I can't fax this sticker to the IRS? Come on, why would anything affiliated with California's energy scene lie to meeeeeee /s

1624310726346.png
 

power.saver

Grid Specialist
Supporting Member
Mar 4, 2018
603
637
Arcadia, CA
Yeah, I talked about this a few posts above. So you and I are 100% on the same page with regard to the electrons.

But if a CCA can advertise to tens of thousands of homeowners that it is "100% renewable" then I feel the same logic/argument could be applied toward the residential ITC. The CCA even gives people these stickers to put on their windows bragging about how the energy being used to power their home is 100% renewable. Seems like somebody out there has already done the research/legowork to establish it's not about the electrons, it's about the credits.

Like I can't fax this sticker to the IRS? Come on, why would anything affiliated with California's energy scene lie to meeeeeee /s

View attachment 675987
I think the requirement is for on-site renewable energy.
 
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holeydonut

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Jun 27, 2020
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East Bay NorCal
I think the requirement is for on-site renewable energy.

Bah, you're right... it actually needs to be 100% on-prem solar for the residential credit. Someone with windmills on their own property wouldn't qualify.

Residential Solar Storage is Eligible for Tax Credit, Subject to a 100% Cliff

But that also means using Stormwatch on a Powerwall effectively makes the Powerwall ineligible for the ITC since any grid charging for any reason drops it from the 100% cliff.
 

wjgjr

Active Member
May 11, 2020
1,300
1,034
Silver Spring, MD
Bah, you're right... it actually needs to be 100% on-prem solar for the residential credit. Someone with windmills on their own property wouldn't qualify.

Residential Solar Storage is Eligible for Tax Credit, Subject to a 100% Cliff

But that also means using Stormwatch on a Powerwall effectively makes the Powerwall ineligible for the ITC since any grid charging for any reason drops it from the 100% cliff.
A lot of this gets to the fact that battery storage is not explicitly covered in the current law, so everything is relying on a private letter ruling from the IRS. With that said, I would guess that a PW tied to wind power would also qualify since the same code that authorizes the solar ITC also has a section for wind (you can get the 26% for installing turbines.) And, I would think a PW that exclusively charges both from qualifying (on-site) solar and wind would probably qualify.

And the issue with stormwatch has been previously discussed, and it is a potential issue, but it is likely a small enough source of energy that it won't cause an issue, particularly where Tesla controls whether or not it is available.

There is proposed legislation which will hopefully more explicitly make PWs eligible and provide some more flexibility than the current private letter ruling.
 

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