Solar to be or not ?

[wanaberetiree]

I live in SF CA and thinking about going solar.

My average bill is +/-100$ with max in winter time ~150$

On one hand going green sounds like a noble goal, but we also want to address the issue to stay with power in case of outages.

Wonder if anybody has done this and wants to share feedback.

Thx

[ckelly78z]

While the idea of going solar is appealing to many folks, the actual numbers may prove not cost effective. How long will it take to pay off your system with lower bills (Your electric bill is already fairly low) ?

[wanaberetiree]

Quote:

Originally Posted by ckelly78z While the idea of going solar is appealing to many folks, the actual numbers may prove not cost effective. How long will it take to pay off your system with lower bills (Your electric bill is already fairly low) ?

Definitely a consideration.
But for this exercise we can say it's out of consideration.

[Retire52]

I just went through the exploring the idea phase. One tip is to get multiple quotes. It was a big spread and well worth the effort of obtaining 3 quotes.

For cost efficiency, I opted to wait until I need to replace my roof. I've got maybe 5 years or more left in it, then I plan to go solar.

[wanaberetiree]

Quote:

Originally Posted by Retire52 I just went through the exploring the idea phase. One tip is to get multiple quotes. It was a big spread and well worth the effort of obtaining 3 quotes. For cost efficiency, I opted to wait until I need to replace my roof. I've got maybe 5 years or more left in it, then I plan to go solar.

Good thx.

Did you get any idea on how long can you survive on a battery in case power outage ?

[Nature Lover]

Wanabe, In determining your project scope, make sure to inquire about whether you can connect/disconnect from the grid here in CA in the event of an outage. My understanding is that if you connect a solar system to the grid here, then the solar won't work when the grid is down. That would leave you with the option of a stand alone system with batteries (and no "sell" back to the grid if you produce more than you use).

I'm not knowledgable about how to configure a stand alone system to provide power for a specific need (and suspect that specific need would need to be regularly powered off-grid once the system is set up). Anyway, just a potential issue to explore while developing/reviewing options.

Maybe there's a "switch" that could connect/disconnect to the grid? I asked and got a muddled answer that was either "you can't do that" (meaning a violation of code), or "we won't do that" (because we just don't do those) - and I never really clarified since clearly the contractors were either experienced and it is not allowed, or not experienced with it and unwilling to consider it.

I'm in the SF Bay Area, and the cost/benefit of traditional solar just wasn't worth it without the ability to keep me powered during outages, and going off grid entirely wasn't a viable option. Once I found out traditional grid connected solar wouldn't provide significant backup power in the event of an outage/public safety power shutoff here, I was done.

NL

[travelover]

Quote:

Originally Posted by wanaberetiree Good thx. Did you get any idea on how long can you survive on a battery in case power outage ?

That is a complex question, which of course depends on what electrical loads you expect to run, how big of a battery you want to pay for and if the solar application allows it to provide power when the grid if off (some do).

[NW-Bound]

Quote:

Originally Posted by wanaberetiree Good thx. Did you get any idea on how long can you survive on a battery in case power outage ?

It depends on the size of the battery in the system, relative to what you are using. Same with how large a solar array you will need, and this also depends on your location (latitude, and cloud cover), and the orientation of the roof.

Start out with knowing how many kWh you typically use a day, and go from there.

[HI Bill]

With such a low power bill, a payback/cost-benefit analyis would likely show that at the end of the PV system's lifespan (currently around 15-20 years), you'd likely be at/near the break even point. I'm not sure about electrical codes and disconnects in CA, and whether a back-up battery can be online during a power outage. I'd think that to do so, you'd have to isolate the circuit.

I'd personally consider a back-up generator, with a transfer switch in your case. Unless you decide to get an electric car, in which case, the payback would be faster.

[NW-Bound]

Quote:

Originally Posted by Nature Lover Wanabe, In determining your project scope, make sure to inquire about whether you can connect/disconnect from the grid here in CA in the event of an outage. My understanding is that if you connect a solar system to the grid here, then the solar won't work when the grid is down. That would leave you with the option of a stand alone system with batteries (and no "sell" back to the grid if you produce more than you use). I'm not knowledgable about how to configure a stand alone system to provide power for a specific need (and suspect that specific need would need to be regularly powered off-grid once the system is set up). Anyway, just a potential issue to explore while developing/reviewing options. Maybe there's a "switch" that could connect/disconnect to the grid? I asked and got a muddled answer that was either "you can't do that" (meaning a violation of code), or "we won't do that" (because we just don't do those) - and I never really clarified since clearly the contractors were either experienced and it is not allowed, or not experienced with it and unwilling to consider it. I'm in the SF Bay Area, and the cost/benefit of traditional solar just wasn't worth it without the ability to keep me powered during outages, and going off grid entirely wasn't a viable option. Once I found out traditional grid connected solar wouldn't provide significant backup power in the event of an outage/public safety power shutoff here, I was done. NL

In the past, solar systems with battery storage were mainly off-grid systems and built by DIY'ers or hobbyists. And they tended to be in remote areas not serviced by a utility company.

Nowadays, there are commercial systems that can do both functions of a grid-tie system as well as a stand-alone storage in case the grid goes down. Tesla Powerwall is the most well-known example, but others exist.

You can check these out, but be forewarned that they are not cheap.

[Midpack]

I have to assume net metering may change, to be less advantageous to homeowners, not soon but eventually. It may be that solar homes are grandfathered (for 20 years?) with the net metering terms in place at the time of installation.

I'm asking, not telling. But it's a factor in breakeven analysis.

[NW-Bound]

Quote:

Originally Posted by Midpack I have to assume net metering may change, to be less advantageous to homeowners, not soon but eventually. It may be that solar homes are grandfathered (for 20 years?) with the net metering terms in place at the time of installation. I'm asking, not telling. But it's a factor in breakeven analysis.

Yes.

In some places in the US, the UK, and Australia, they are dropping the old way of allowing the homeowner to pump electricity into the grid and then to be able to pull out the same kWh later. The reason for that is sound, that is peak solar production does not coincide with peak demand periods. One hour you have more electricity than anyone can use, and the next hour you do not have enough. One cannot bank the surplus power this way.

When there were few home solar systems, the above was acceptable, but they now have the situation where California had to pay Arizona to use some of the surplus electricity. I posted about this several times in the past.

Existing home systems are grandfathered, but with newly installed systems the homeowners may be paid only the wholesale price of their surplus power, at the time that is pumped into the grid.

With a home battery storage, instead of getting peanuts for their surplus power produced in the early hours of the day, the homeowner can store it himself for use later in the day, when electricity cost is higher. Thus, he gets more dollar value out of the same kWh that his panels produce, by saving it when he cannot use it, and using it later when it is worth more.

Some places including California have a rate schedule where the homeowner pays an additional penalty if his usage exceeds a certain threshold. The battery can be used for "peak shaving" by absorbing the power at low usage periods like at night, and releasing it in the mid-afternoon to offset the AC usage.

The only problem with using batteries for storage and peak-shaving is that the lithium battery wears out with each charge/discharge cycle. Tesla guarantees its Powerwalls for so many kWh of throughput, and the hardware has a built-in metering system to keep track of that, and to report back to Tesla.

Figuring out the cost effectiveness will take a bit of work. However, if one is using such a system for emergency power during periods of PSPS ("Public Safety Power Shutoff") because of high winds, the availability of the backup power is worth a lot more than the cost of the kWh. It is even harder to put a price on that.

[travelover]

If the OP's main concern is having power when the grid is down, there are lots of more cost effective ways to do that than adding solar panels.

A small $500 inverter generator will power lights and computers, for example.

[wolf]

Also, live in S.F. Bay area. Agree with many of the above posters.
Not cost effective.
Also, solar panel, do not last forever. And eventually need to be replaced.

[Souschef]

DW asked about it, and did some research. Our bill came out to about $1000/ year, so there would be a 15 year payback on the system. We really only have to protect against the grid being down.
SCE has a system where they shut down power if the winds are too high. How well does this work? Well they energized a 16 KV line on the mountain behind us and caused the Maria fire. We had to evacuate for one night!
Our solution to outages was to buy a 3600 watt generator. It was enough to power our refrigerator and a 6 cu ft freezer as well as our tv. We also had a power strip to charge our devices as well as our neighbors'.

[rk911]

Quote:

Originally Posted by wanaberetiree Good thx. Did you get any idea on how long can you survive on a battery in case power outage ?

you could always add a standby generator. is your area served by natural gas?

[DSC800]

Quote:

Originally Posted by wanaberetiree I live in SF CA and thinking about going solar. My average bill is +/-100$ with max in winter time ~150$ On one hand going green sounds like a noble goal, but we also want to address the issue to stay with power in case of outages. Wonder if anybody has done this and wants to share feedback. Thx

Here in San Diego with SDG&E (the worst) we've had 4.5kw solar for 4 years and very happy with it. It produces 100% of our needs and so far the climate credits have covered the minimum monthly bill. Initial outlay was $15k, after rebate the net was $10.5k. Our electric bill for our home + EV driving 10k miles a year would be around $2k/annual so the payback is just under 6 years. Without the EV we'd have installed a smaller system, but payback would be longer, closer to 8 years. Combining solar with an EV and not buying much gas is a real plus for saving money. They complement each other, but of course, the EV cost more. Another plus is that we use AC more without worrying about 50c kwh rates (our AC costs $2/hr in the summer).

For the battery backup, we didn't consider it. Not many outages around our area and I have a small generator to run critical stuff if needed. With the 50c/kwh peak shifting later to 4-9pm there could be a benefit for battery storage even without solar.

Oh, and there is a "feel good" factor. We cut our gasoline usage by 75% or over 200 gallons a year.

[Alan]

Quote:

Originally Posted by Midpack I have to assume net metering may change, to be less advantageous to homeowners, not soon but eventually. It may be that solar homes are grandfathered (for 20 years?) with the net metering terms in place at the time of installation. I'm asking, not telling. But it's a factor in breakeven analysis.

As NW points out the UK does not have net metering. The company we signed up with has “agile” pricing where the tariff changes every half hour and is published every day in advance. Using the app IFTTT (if this then that) you can connect various devices to your account to do things like turn on the hot water boiler when the price drops below a certain value, or turn one or more of your Hue lights to red when the price goes above a certain value. Even our internet connected washing machine can be loaded and set to only come when the price is right. (Being retired we don’t really need that feature, although it is amusing to get an alert on the phone when a wash load finishes)

The excess electricity we generate we get paid the price on that half hourly tariff, and if the credit builds in the account. You can let the credit build to use against your winter gas bill, or have it deposited to your bank account (I did this end of August just to see how easy it was and it worked great). Our inverter has a forced export timer as well as a forced charge timer. This means we can charge during a cheap period and then discharge during an expensive time, useful during the winter.

A fully installed 4kW solar system here costs around £6k ($8k), adding battery storage (4kwh) adds another £2.5k.

[COcheesehead]

We bought our house with solar already installed and we really didn’t pay more based on comps. We do have a tech time bomb down the road if we stay here long enough if/when they need to be replaced, but the excess energy we generate pays for our gas usage, so overall at the end of the year we actually had about a $200 credit in our account. So our utilities are actually a money maker for us.

[folivier]

If you only want to power lights, fridge/freezer, fans, tv, etc. a battery storage system shouldn't be too expensive. However any large wattage items such as electric stove/oven, air conditioner, electric heater would need a huge battery system and larger solar system to recharge. In my motorhome I have 300 amp hours of LiPO batteries with 400 watts of solar and it is adequate in cooler climates. But certainly won't run an a/c or anything larger. But I do have some friends who have filled their roof with 1600 watts or more of solar and 1000+ amp hours of batteries and can run their a/c for a few hours.