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Glass is more than half full... PV+ESS is the bomb.

holeydonut

Active Member
Supporting Member
Jun 27, 2020
3,066
2,412
East Bay NorCal
So I post a lot of PoCo hate, But to turn things on a more happy upside, I just want to post about how great PV+ESS is for a homeowner. Like, it's amazeballs, and I hope anyone on the fence about getting such a system can be motivated to try and make it happen.

While it sounds like Tesla Energy is going to be pushing the PV+ESS as "standard" on future installs... it's worth shopping around to find a complete PV+ESS installer that will do the best design for your particular house. Maybe Tesla is that installer, maybe it's Sunrun, maybe it's someone else.

My goal of getting PV+ESS was to use my own PV energy as much as possible. The batteries would be essential to power through the peak time where solar energy is not bountiful, but household demand starts to spike. For people in Northern California and an EV, the rate schedule "EV2-A" has heightened costs that span 3pm to midnight.

For almost every day since mid February, this is what I see across ALL my home loads...

1. From midnight to sunrise: I am on Grid energy with the PW as backup.
2. From sunrise to about 1pm: Solar is powering the house with excess going into the PWs
3. At about 2pm, the Powerwalls reach 100% SoC
4. From 2pm to 3pm: Solar is powering the house with excess going to the Grid
5. From 3pm to sunset: Solar is doing full export to the Grid, while the Powerwalls power the house
6. From sunset to midnight: The Powerwalls power the house

Rinse and repeat. This is the best possible outcome I could have imagined. I generate as much juicy NEM credit as I can to cover the high-AC and Winter months. And at no point in time do I give a second thought about what time it is before run a home load. The only thing I'll have to do is make sure to only charge an EV after midnight... which should be rather easy to do.

I gave this TOU shifting "timeline" to numerous installers in 2020. This included Tesla, Sunrun, SunPower, and a slew of local shops. And not one of them thought it was possible. But the folks here on TMC made it seem like this was totally normal and expected. It turns out TMC with people like @wwhitney and @Vines knows more than a huge number of East Bay solar companies :)

So yeah, the process of getting PV+ESS may not be the most fun, but the outcome is just amazing. 10/10 highly recommended even if the financial ROI is tough to rationalize.
 

h2ofun

Active Member
Aug 11, 2020
3,604
867
auburn, ca
So I post a lot of PoCo hate, But to turn things on a more happy upside, I just want to post about how great PV+ESS is for a homeowner. Like, it's amazeballs, and I hope anyone on the fence about getting such a system can be motivated to try and make it happen.

While it sounds like Tesla Energy is going to be pushing the PV+ESS as "standard" on future installs... it's worth shopping around to find a complete PV+ESS installer that will do the best design for your particular house. Maybe Tesla is that installer, maybe it's Sunrun, maybe it's someone else.

My goal of getting PV+ESS was to use my own PV energy as much as possible. The batteries would be essential to power through the peak time where solar energy is not bountiful, but household demand starts to spike. For people in Northern California and an EV, the rate schedule "EV2-A" has heightened costs that span 3pm to midnight.

For almost every day since mid February, this is what I see across ALL my home loads...

1. From midnight to sunrise: I am on Grid energy with the PW as backup.
2. From sunrise to about 1pm: Solar is powering the house with excess going into the PWs
3. At about 2pm, the Powerwalls reach 100% SoC
4. From 2pm to 3pm: Solar is powering the house with excess going to the Grid
5. From 3pm to sunset: Solar is doing full export to the Grid, while the Powerwalls power the house
6. From sunset to midnight: The Powerwalls power the house

Rinse and repeat. This is the best possible outcome I could have imagined. I generate as much juicy NEM credit as I can to cover the high-AC and Winter months. And at no point in time do I give a second thought about what time it is before run a home load. The only thing I'll have to do is make sure to only charge an EV after midnight... which should be rather easy to do.

I gave this TOU shifting "timeline" to numerous installers in 2020. This included Tesla, Sunrun, SunPower, and a slew of local shops. And not one of them thought it was possible. But the folks here on TMC made it seem like this was totally normal and expected. It turns out TMC with people like @wwhitney and @Vines knows more than a huge number of East Bay solar companies :)

So yeah, the process of getting PV+ESS may not be the most fun, but the outcome is just amazing. 10/10 highly recommended even if the financial ROI is tough to rationalize.
I am close to you. But from midnight to some times all the way to peak, battery is charging house, I never need the grid. IT is so cool.
 

getakey

Active Member
Jan 28, 2020
1,736
630
95762
So I post a lot of PoCo hate, But to turn things on a more happy upside, I just want to post about how great PV+ESS is for a homeowner. Like, it's amazeballs, and I hope anyone on the fence about getting such a system can be motivated to try and make it happen.

While it sounds like Tesla Energy is going to be pushing the PV+ESS as "standard" on future installs... it's worth shopping around to find a complete PV+ESS installer that will do the best design for your particular house. Maybe Tesla is that installer, maybe it's Sunrun, maybe it's someone else.

My goal of getting PV+ESS was to use my own PV energy as much as possible. The batteries would be essential to power through the peak time where solar energy is not bountiful, but household demand starts to spike. For people in Northern California and an EV, the rate schedule "EV2-A" has heightened costs that span 3pm to midnight.

For almost every day since mid February, this is what I see across ALL my home loads...

1. From midnight to sunrise: I am on Grid energy with the PW as backup.
2. From sunrise to about 1pm: Solar is powering the house with excess going into the PWs
3. At about 2pm, the Powerwalls reach 100% SoC
4. From 2pm to 3pm: Solar is powering the house with excess going to the Grid
5. From 3pm to sunset: Solar is doing full export to the Grid, while the Powerwalls power the house
6. From sunset to midnight: The Powerwalls power the house

Rinse and repeat. This is the best possible outcome I could have imagined. I generate as much juicy NEM credit as I can to cover the high-AC and Winter months. And at no point in time do I give a second thought about what time it is before run a home load. The only thing I'll have to do is make sure to only charge an EV after midnight... which should be rather easy to do.

I gave this TOU shifting "timeline" to numerous installers in 2020. This included Tesla, Sunrun, SunPower, and a slew of local shops. And not one of them thought it was possible. But the folks here on TMC made it seem like this was totally normal and expected. It turns out TMC with people like @wwhitney and @Vines knows more than a huge number of East Bay solar companies :)

So yeah, the process of getting PV+ESS may not be the most fun, but the outcome is just amazing. 10/10 highly recommended even if the financial ROI is tough to rationalize.
I second your thoughts. I'm still on EV1-A so my off and peak times are different, but virtually the same result with respect to those periods.
I did not have the install problems that you had to go through, so my feelings are even better :)
 
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h2ofun

Active Member
Aug 11, 2020
3,604
867
auburn, ca
So I post a lot of PoCo hate, But to turn things on a more happy upside, I just want to post about how great PV+ESS is for a homeowner. Like, it's amazeballs, and I hope anyone on the fence about getting such a system can be motivated to try and make it happen.

While it sounds like Tesla Energy is going to be pushing the PV+ESS as "standard" on future installs... it's worth shopping around to find a complete PV+ESS installer that will do the best design for your particular house. Maybe Tesla is that installer, maybe it's Sunrun, maybe it's someone else.

My goal of getting PV+ESS was to use my own PV energy as much as possible. The batteries would be essential to power through the peak time where solar energy is not bountiful, but household demand starts to spike. For people in Northern California and an EV, the rate schedule "EV2-A" has heightened costs that span 3pm to midnight.

For almost every day since mid February, this is what I see across ALL my home loads...

1. From midnight to sunrise: I am on Grid energy with the PW as backup.
2. From sunrise to about 1pm: Solar is powering the house with excess going into the PWs
3. At about 2pm, the Powerwalls reach 100% SoC
4. From 2pm to 3pm: Solar is powering the house with excess going to the Grid
5. From 3pm to sunset: Solar is doing full export to the Grid, while the Powerwalls power the house
6. From sunset to midnight: The Powerwalls power the house

Rinse and repeat. This is the best possible outcome I could have imagined. I generate as much juicy NEM credit as I can to cover the high-AC and Winter months. And at no point in time do I give a second thought about what time it is before run a home load. The only thing I'll have to do is make sure to only charge an EV after midnight... which should be rather easy to do.

I gave this TOU shifting "timeline" to numerous installers in 2020. This included Tesla, Sunrun, SunPower, and a slew of local shops. And not one of them thought it was possible. But the folks here on TMC made it seem like this was totally normal and expected. It turns out TMC with people like @wwhitney and @Vines knows more than a huge number of East Bay solar companies :)

So yeah, the process of getting PV+ESS may not be the most fun, but the outcome is just amazing. 10/10 highly recommended even if the financial ROI is tough to rationalize.
One thing I notice, even though I have south and west panels, if how quickly the output drops off. So even though we can send back solar at peak, the amount that gets sent really is pretty low. If I had a choice, would rather just stay on tou-c, but will see what happens
 

jboy210

Well-Known Member
Supporting Member
Dec 2, 2016
6,505
4,452
Northern California
So I post a lot of PoCo hate, But to turn things on a more happy upside, I just want to post about how great PV+ESS is for a homeowner. Like, it's amazeballs, and I hope anyone on the fence about getting such a system can be motivated to try and make it happen.

While it sounds like Tesla Energy is going to be pushing the PV+ESS as "standard" on future installs... it's worth shopping around to find a complete PV+ESS installer that will do the best design for your particular house. Maybe Tesla is that installer, maybe it's Sunrun, maybe it's someone else.

My goal of getting PV+ESS was to use my own PV energy as much as possible. The batteries would be essential to power through the peak time where solar energy is not bountiful, but household demand starts to spike. For people in Northern California and an EV, the rate schedule "EV2-A" has heightened costs that span 3pm to midnight.

For almost every day since mid February, this is what I see across ALL my home loads...

1. From midnight to sunrise: I am on Grid energy with the PW as backup.
2. From sunrise to about 1pm: Solar is powering the house with excess going into the PWs
3. At about 2pm, the Powerwalls reach 100% SoC
4. From 2pm to 3pm: Solar is powering the house with excess going to the Grid
5. From 3pm to sunset: Solar is doing full export to the Grid, while the Powerwalls power the house
6. From sunset to midnight: The Powerwalls power the house

Rinse and repeat. This is the best possible outcome I could have imagined. I generate as much juicy NEM credit as I can to cover the high-AC and Winter months. And at no point in time do I give a second thought about what time it is before run a home load. The only thing I'll have to do is make sure to only charge an EV after midnight... which should be rather easy to do.

I gave this TOU shifting "timeline" to numerous installers in 2020. This included Tesla, Sunrun, SunPower, and a slew of local shops. And not one of them thought it was possible. But the folks here on TMC made it seem like this was totally normal and expected. It turns out TMC with people like @wwhitney and @Vines knows more than a huge number of East Bay solar companies :)

So yeah, the process of getting PV+ESS may not be the most fun, but the outcome is just amazing. 10/10 highly recommended even if the financial ROI is tough to rationalize.
Our timeline for or solar is similar to yours except we are TOU-B so the peak is 4PM-9PM. Works out well with excess power going out to the grid from 2PM until sunset. We have EVs but don't have a commute so charge sporadically and only use somewhere near 20 kW/week.
 
I run self-powered with “just” 2 powerwalls and my 8kw system .. looks like I may get down to my reserve of 30% about 3am or so and start using some of my credits as summer heat really hits
thing I love most is not caring what time of day it is ... no more of that nagging feeling when we do dishes or laundry between 4pm-9pm :)I
I decided that during the summer I'm going to run my reserve at 15% because if the grid does go down we can limp along until the sun comes up.
YMMV
 
I decided that during the summer I'm going to run my reserve at 15% because if the grid does go down we can limp along until the sun comes up.
YMMV
this was exactly my thinking .. of limping along i guessed 30% but yea prob could go lower .. also did not want to run powerwalls below 30% unless true outage .. but thats a whole diff thread ;)
 

holeydonut

Active Member
Supporting Member
Jun 27, 2020
3,066
2,412
East Bay NorCal
I guess one silver lining with PG&E having stopped by 2x Battery installation and required me to get a third battery. So I can set the backup to 50% and that leaves me an ample amount to power through the 3pm to midnight EV2A sad-face TOU period.

Although once I have to start running those AC's, I'm wondering how much energy I'll be using during peak times. Maybe 39 kWh isn't going to be enough 🤔 .
 

holeydonut

Active Member
Supporting Member
Jun 27, 2020
3,066
2,412
East Bay NorCal
oh since we are on the PV / ESS love train ..
when i'm leaving for work in morning and its quiet I love the gentle buzzing bee sound of the powerwalls charging .. i've been caught pressing my ear to them on more than one occasion 🤓


I'm partial to the gentle wum wum wum sound... it's like I'm on the USS Enterprise D
 
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h2ofun

Active Member
Aug 11, 2020
3,604
867
auburn, ca
I guess one silver lining with PG&E having stopped by 2x Battery installation and required me to get a third battery. So I can set the backup to 50% and that leaves me an ample amount to power through the 3pm to midnight EV2A sad-face TOU period.

Although once I have to start running those AC's, I'm wondering how much energy I'll be using during peak times. Maybe 39 kWh isn't going to be enough 🤔 .
Yep, same concern. I turned on my AC for the first time last night. Sure took a lot more of my battery storage
 

holeydonut

Active Member
Supporting Member
Jun 27, 2020
3,066
2,412
East Bay NorCal
Wow... I totally underestimated how much energy it takes to get a home through the 3pm to midnight TOU naughty-time period without behavior modification. Under EV2-A PG&E doesn't want you to charge your car during this timeframe. But this TOU also acts as a penalty for actually running home loads during that time.

Yesterday was the first day both of my AC's kicked on at the same time we were making a big hot meal (no cold cuts!) for dinner. We also want to get our chores done before the day ends, so we ran the dishwasher after eating and did a couple loads of laundry before turning in at 10pm. Plus we had the TV on with the brightness set to something clear and visible.

We used 38 kWh for the full day, but 70% (27 kWh) was used from 3pm to midnight. I originally had scoped out 2x Powerwalls, but this wouldn't have been enough to get me through the TOU peak even if I set the backup reserve to 0%.

And I'm thinking in the really hot Autumn months, my daily usage will go up to about 47 kWh; with around 75% (35 kWh) coming during peak time due to the ACs.

Assuming this large-scale SGIP incentive actually pays out, then all the pain PG&E forced me through to get the 3rd Powerwall will actually be worth it :)


1620757939880.png
 

jboy210

Well-Known Member
Supporting Member
Dec 2, 2016
6,505
4,452
Northern California
Wow... I totally underestimated how much energy it takes to get a home through the 3pm to midnight TOU naughty-time period without behavior modification. Under EV2-A PG&E doesn't want you to charge your car during this timeframe. But this TOU also acts as a penalty for actually running home loads during that time.

Yesterday was the first day both of my AC's kicked on at the same time we were making a big hot meal (no cold cuts!) for dinner. We also want to get our chores done before the day ends, so we ran the dishwasher after eating and did a couple loads of laundry before turning in at 10pm. Plus we had the TV on with the brightness set to something clear and visible.

We used 38 kWh for the full day, but 70% (27 kWh) was used from 3pm to midnight. I originally had scoped out 2x Powerwalls, but this wouldn't have been enough to get me through the TOU peak even if I set the backup reserve to 0%.

And I'm thinking in the really hot Autumn months, my daily usage will go up to about 47 kWh; with around 75% (35 kWh) coming during peak time due to the ACs.

Assuming this large-scale SGIP incentive actually pays out, then all the pain PG&E forced me through to get the 3rd Powerwall will actually be worth it :)


View attachment 661335
Wow!

We try to move most of the heavy electrical usage items like laundry to the mornings and weekends. We are also still on TOU-B so have off-peak all weekend and from 9PM - 4PM weekdays.
 

holeydonut

Active Member
Supporting Member
Jun 27, 2020
3,066
2,412
East Bay NorCal
Wow!

We try to move most of the heavy electrical usage items like laundry to the mornings and weekends. We are also still on TOU-B so have off-peak all weekend and from 9PM - 4PM weekdays.


Yeah TOU-B and TOU-C wouldn't be so bad... assuming you were able to size your solar to cover your EV charging as well. Because then you could just use the NEM with TOU-B/C and you wouldn't need the "discounted" off-peak charging period under EV2-A.

But this EV2-A rate is just insane for all your other normal home consumption. I can't imagine how people live with this EV2-A thing. Solar generation is a fraction of what you'd see under TOU-C, but the costs during peak time are like 2x higher.
 
Wow... I totally underestimated how much energy it takes to get a home through the 3pm to midnight TOU naughty-time period without behavior modification. Under EV2-A PG&E doesn't want you to charge your car during this timeframe. But this TOU also acts as a penalty for actually running home loads during that time.

Yesterday was the first day both of my AC's kicked on at the same time we were making a big hot meal (no cold cuts!) for dinner. We also want to get our chores done before the day ends, so we ran the dishwasher after eating and did a couple loads of laundry before turning in at 10pm. Plus we had the TV on with the brightness set to something clear and visible.

We used 38 kWh for the full day, but 70% (27 kWh) was used from 3pm to midnight. I originally had scoped out 2x Powerwalls, but this wouldn't have been enough to get me through the TOU peak even if I set the backup reserve to 0%.

And I'm thinking in the really hot Autumn months, my daily usage will go up to about 47 kWh; with around 75% (35 kWh) coming during peak time due to the ACs.

Assuming this large-scale SGIP incentive actually pays out, then all the pain PG&E forced me through to get the 3rd Powerwall will actually be worth it :)


View attachment 661335
Priorities got in the way of conducting this analysis but with 3 PW and a PV production curve shifted later in the day due to my mostly west facing panels, I wondered if it would be BETTER for me to be on EV2-A rather than TOU-B. I have high confidence in making it from 3 pm to midnight without touching grid power. (In the summer we will reach 100 kWh usage days.) If I could run my home off 18 cent power from 12a - 3 pm while the power walls fill up and then export 100% of PV production from 3:00 pm to sundown, I think i'd be in even better price arbitrage situation than I am currently. Am I crazy?

Maybe stupid questions, but does your Dishwasher and other appliances have a delay start features? I often load up my dishwasher after dinner, put in the soap and then hit 2 or 3 hr delay so it starts after 9:00 pm. It would not be any different to say 5 or 6 hour delay so it kicked off after midnight.
 

holeydonut

Active Member
Supporting Member
Jun 27, 2020
3,066
2,412
East Bay NorCal
Priorities got in the way of conducting this analysis but with 3 PW and a PV production curve shifted later in the day due to my mostly west facing panels, I wondered if it would be BETTER for me to be on EV2-A rather than TOU-B. I have high confidence in making it from 3 pm to midnight without touching grid power. (In the summer we will reach 100 kWh usage days.) If I could run my home off 18 cent power from 12a - 3 pm while the power walls fill up and then export 100% of PV production from 3:00 pm to sundown, I think i'd be in even better price arbitrage situation than I am currently. Am I crazy?

Maybe stupid questions, but does your Dishwasher and other appliances have a delay start features? I often load up my dishwasher after dinner, put in the soap and then hit 2 or 3 hr delay so it starts after 9:00 pm. It would not be any different to say 5 or 6 hour delay so it kicked off after midnight.


If you assumed the ESS solved your "TOU Peak vs Off Peak" problem, then the next question to ask if if your PV production and consumption are broadly neutral from a NEM standpoint. If you're expecting your TOU-B to break-even (ignoring TOU crap) then your opportunity cost is the same on both plans.

My situation is a bit stupid because my solar system is only sized to my normal home annual usage. A future EV cannot be covered by the generation of my solar panels. So I need the EV2-A since my house is a NEM net-deficit with the EV being the culprit. I can fit maybe 1 or 2 more solar panels that actually face South. I guess down the road if PG&E increases off-peak EV charging rates to $0.40 per kWh ... then North facing panels would still make economic sense for the NEM credit.
 
If you assumed the ESS solved your "TOU Peak vs Off Peak" problem, then the next question to ask if if your PV production and consumption are broadly neutral from a NEM standpoint. If you're expecting your TOU-B to break-even (ignoring TOU crap) then your opportunity cost is the same on both plans.

My situation is a bit stupid because my solar system is only sized to my normal home annual usage. A future EV cannot be covered by the generation of my solar panels. So I need the EV2-A since my house is a NEM net-deficit with the EV being the culprit. I can fit maybe 1 or 2 more solar panels that actually face South. I guess down the road if PG&E increases off-peak EV charging rates to $0.40 per kWh ... then North facing panels would still make economic sense for the NEM credit.
My thought was that price polarization increased the value of the ESS. Currently on TOU-B the price differential even for summer doesn't seem to create enough value to do anything but minimize imports from the grid.

Last year my system underperformed production estimates by 3-4k kWh. This year we are trending very good, perhaps even above estimates due to drought conditions. I don't have an EV and my PV production vs home usage doesn't support getting one if break even was a requirement.

With 90% round trip efficiency, would it be wrong to assume parity with taking ~ 2 kWh from the grid at EV2-A off peak prices for every 1 kWh exported to the grid during peak rates?
 

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