Request for addition of more flexible charging schedules to align with solar power output

[defcon888]

PPA stands for Power Purchase Agreement and it's basically a lease. You let the installer put the panels on your roof and you agree to pay a fixed rate for electricity over the life of the lease. These have a poor reputation and lots of people have gotten burned by them, so if you're not already locked into it, I would do some more homework before committing.

Thanks......we will look into it. From my research, they are becoming the defacto standard in California.

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[HaveBlue]

You'll be endlessly chasing your curve around because the car would never know the current yield of your panels. This really needs to be managed on the panel side of your system with something like this.

 

[JoMo]

An addition of a battery or two really solves the issue.

 

[Nuclianba]

Thanks......we will look into it. From my research, they are becoming the defacto standard in California.

I'm in Cali and worked in the industry. PPAs are usually a bad deal, not always. What concerns me about your quick anecdote is noting battery is optional. That isn't how it works tho since last year (Google NEM3), without a battery you're still paying the utility for power in the evening and overnight. Generally electricity is cheapest during the day because we have so much solar already in the state. Without a battery it's unlikely the system will chop off more than maybe half your bill. May be telling you stuff you already know, just want to make sure your installer isn't selling you a load of BS about savings without a battery.

 

[BabsTroy23728]

What's the rate in Tucson these days?

In Phoenix it's so cheap that I can't make sense of solar at all. 5.1 cents summer off peak and 3.1 winter.

Hi @SwampNut,

Our solar install was completed in 2022 and we were grandfathered in at a favorable rate and the force a time of use plan; right now it is winter rates: Winter On Peak @ $0.039694 and Winter Off Peak @ $0.031266.

Summer On Peak @ $0.059449 and Summer Off Peak @ $0.023516.

Before solar I was paying an average of like $140 a month for electric. We researched and got quotes from 5 or 6 different companies. They all did some kind of ROI analysis. Some were better than others, and believe me I checked the math. One thing that made a big difference for us is that we paid cash for it , but it still would have made sense with the financing. There is a reasonable financial advantage to it.

 

[BabsTroy23728]

An addition of a battery or two really solves the issue.

Thanks @JoMo, that's a slick setup. My system IS Enphase and we considered batteries, but I'm more than a little incensed that my solar contractor didn't offer me the Enphase charger! I already bought the Rivian one :|

 

[JoMo]

Yes, the Enphase charger and the app are great, but your Rivian charger should be very effective, too.

 

[djsider2]

I'm in Cali and worked in the industry. PPAs are usually a bad deal, not always. What concerns me about your quick anecdote is noting battery is optional. That isn't how it works tho since last year (Google NEM3), without a battery you're still paying the utility for power in the evening and overnight. Generally electricity is cheapest during the day because we have so much solar already in the state. Without a battery it's unlikely the system will chop off more than maybe half your bill. May be telling you stuff you already know, just want to make sure your installer isn't selling you a load of BS about savings without a battery.

What would you option out if someone is to build a system out primarily to get around peak rates and to charge the car (it's usually not home 9-5) in CA? What rates would make it worth it?

 

[defcon888]

Hi @SwampNut,

Our solar install was completed in 2022 and we were grandfathered in at a favorable rate and the force a time of use plan; right now it is winter rates: Winter On Peak @ $0.039694 and Winter Off Peak @ $0.031266.

Summer On Peak @ $0.059449 and Summer Off Peak @ $0.023516.

Before solar I was paying an average of like $140 a month for electric. We researched and got quotes from 5 or 6 different companies. They all did some kind of ROI analysis. Some were better than others, and believe me I checked the math. One thing that made a big difference for us is that we paid cash for it , but it still would have made sense with the financing. There is a reasonable financial advantage to it.

We are moving to Arizona in a few years......more north....close to Sedona.

So with your solar you are paying $0.059449 and $0.023516 after Solar or before?. What solar compan

An addition of a battery or two really solves the issue.

When we build in Arizona, we will probably get the batteries to store for sure. I am going to have to do the research on the Electric companies out there as well as the PPA's here in California.

The good thing with use getting it here, once we move, it will grandfather into the new owners and we won't be responsible for it.....if I understand correctly on how PPA's work.

 

[racekarl]

We are moving to Arizona in a few years......more north....close to Sedona.

So with your solar you are paying $0.059449 and $0.023516 after Solar or before?. What solar compan

When we build in Arizona, we will probably get the batteries to store for sure. I am going to have to do the research on the Electric companies out there as well as the PPA's here in California.

The good thing with use getting it here, once we move, it will grandfather into the new owners and we won't be responsible for it.....if I understand correctly on how PPA's work.

You should make sure you read the fine print of the PPA you are being offered to be certain you really do understand correctly. Leases and PPAs can be an impediment to selling your home because buyers may be scared off by the requirement to sign a contract with a company they have had no prior contact with, and taking on the risk of higher payments since there will be less useful life left in the panels. Even if your buyer is on board, the transfer process can delay your closing.

The industry has hopefully improved from when we put our panels on, but after doing my due diligence I ultimately concluded that owning our system was much more financially attractive than a lease or PPA.

 

[Nuclianba]

What would you option out if someone is to build a system out primarily to get around peak rates and to charge the car (it's usually not home 9-5) in CA? What rates would make it worth it?

What utility? Rate structures depend on the utility, but PG&E (for example) has EV specific rate plans...peak is a bit higher but off peak is lower. Then program the car to only charge off peak (and run the dryer and any other big loads you can do whenever in the morning before noon). Shifting your load (where possible) to off peak rates is way cheaper than using solar and/or battery to serve loads during the peak.

The problem nowadays is that the cheapest power is when the sun shines (and it's getting worse... Google 'duck curve'). Most expensive power is basically right around sunset when all the solar on the grid comes off (and people get home and turn on lights etc). This didn't use to be the case btw, solar has totally changed electricity markets by creating a huge glut of supply midday. Because of this, solar with no battery generates power when the grid needs it least... And as a result current net metering rules (NEM 3) make it incredibly hard to offset bills without a battery. This is purposeful by the regulator, they need to shift the supply curve and flatten the midday solar bump, a battery enables this: you make power during the day, use that to charge the battery and hold it, then use the stored power from the battery in the evening to avoid the grid (and California also has massive grid-scale batteries coming online to do this arbitrage too).

Anyways... My suggestion to reduce costs is to charge after midnight on an EV specific rate plan (since you aren't home after 9 to use the solar directly). Then size your solar system and battery to offset your *other* power needs from 6 to midnight that you can't shift (tv, lights, stove, oven, etc). Use extra solar during the day to run other big loads and turn them off in the evening (run the AC extra during that, turn it off at 5 and ride it out. Hot tub heating during the day, not in the evening, etc). Don't oversize the solar such that you send power to the grid during the day (you get paid virtually nothing for that now). Much more bang for your buck to solve 6 to midnight electric needs than off peak needs after midnight.

Hope that helps.

 

[djsider2]

What utility? Rate structures depend on the utility, but PG&E (for example) has EV specific rate plans...peak is a bit higher but off peak is lower. Then program the car to only charge off peak (and run the dryer and any other big loads you can do whenever in the morning before noon). Shifting your load (where possible) to off peak rates is way cheaper than using solar and/or battery to serve loads during the peak.

The problem nowadays is that the cheapest power is when the sun shines (and it's getting worse... Google 'duck curve'). Most expensive power is basically right around sunset when all the solar on the grid comes off (and people get home and turn on lights etc). This didn't use to be the case btw, solar has totally changed electricity markets by creating a huge glut of supply midday. Because of this, solar with no battery generates power when the grid needs it least... And as a result current net metering rules (NEM 3) make it incredibly hard to offset bills without a battery. This is purposeful by the regulator, they need to shift the supply curve and flatten the midday solar bump, a battery enables this: you make power during the day, use that to charge the battery and hold it, then use the stored power from the battery in the evening to avoid the grid (and California also has massive grid-scale batteries coming online to do this arbitrage too).

Anyways... My suggestion to reduce costs is to charge after midnight on an EV specific rate plan (since you aren't home after 9 to use the solar directly). Then size your solar system and battery to offset your *other* power needs from 6 to midnight that you can't shift (tv, lights, stove, oven, etc). Use extra solar during the day to run other big loads and turn them off in the evening (run the AC extra during that, turn it off at 5 and ride it out. Hot tub heating during the day, not in the evening, etc). Don't oversize the solar such that you send power to the grid during the day (you get paid virtually nothing for that now). Much more bang for your buck to solve 6 to midnight electric needs than off peak needs after midnight.

Hope that helps.

Very insightful. I have a pretty good utility right now. ~0.17 off-peak and ~0.52 peak weekdays. (5-9p). The issues you point out about solar being available only during the day is the hiccup I can't seem to get around to actually pull the trigger. It would require a few batteries to even have enough to cover the daily commute of the car.

 

[Nuclianba]

Very insightful. I have a pretty good utility right now. ~0.17 off-peak and ~0.52 peak weekdays. (5-9p). The issues you point out about solar being available only during the day is the hiccup I can't seem to get around to actually pull the trigger. It would require a few batteries to even have enough to cover the daily commute of the car.

Yeah. If you HAD to charge during peak evening hours, the battery would pencil with a 4 to 6 year payback (depending on assumptions about future utility rate increases and your installer costs). But if you can charge off peak overnight, the battery won't pencil basically ever (for the car.... It still pencils for whatever other peak loads you can offset).

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