Here's a statement of the obvious: The opinions expressed here are those of the participants, not those of the Mutual Fund Observer. We cannot vouch for the accuracy or appropriateness of any of it, though we do encourage civility and good humor.
@davidmoran: I have no idea or could care less what I pay for electricity, I have one of my people handle that. In case I loose power, I have a back-up natural gas generator that provides power for the entire house. Regards, Ted
If you are in an area that is subject to frequent or long power outages, I think that a back-up natural gas generator is probably the best way to go.
I have a friend who is so far to the right that he makes Ted look like a commie. But some months ago he installed a rooftop solar array, cutting his PG&E bill dramatically, and is one happy camper. Interestingly, even though he rants about government subsidies, he had no problem taking his. Typical.
I would do the same, but our area in SF is frequently overcast, and it would also involve a complete rewiring of our 70 year old electric service.
All that rooftop installations do (typically) is generate power and sell it to the local utility. Net metering. Nothing to do with home usage or supply into the house wiring or anything like that. In fact when there is a power outage they stop their output, so as not to endanger utility workers.
I know people with rooftop panels in the Bay area. Have you called Solar City and had them do an assessment?
No one touched my current (old) service, although if yours is dangerously decrepit, it should be redone anyway, and then would be the time.
You may be possibly unclear about some aspects of what this new thing is.
@davidrmoran- I inadvertently conflated the two subjects in that post. Didn't mean to imply that rooftop was a backup system.
The Bay Area is anything but uniform in it's sun exposure. Here, west of Twin Peaks in SF, it is notoriously cool and overcast while on the east of the Twin Peaks hill range the rest of SF is basking in sunlight. Right now the temperature here is 68°, yet an hour north at the weekend house it's due to hit 101° today.
Our service is old, but not unsafe: I've paid much attention to balancing the household electrical load here, and there are no overload issues. Replacing incandescent lighting with LED fixtures where possible has helped a lot with that. If someone were to want to install an electric stove though, that would mean a new service for sure.
@Ted>> How much does it cost you to maintain the panels, and how often do they need to be cleaned ?
Zero and never are the answers.
Well, I've had a completely different experience, David. I spent $18.95 or some such on a long-handled broom/squeegee to clear off the snow -- a truly staggering maintenance bill. (My neighbors and I, according to one of the local installers, constitute the first three-in-a-row rooftop-solar houses in the county.)
I agree with the notion of calling out an installer for a site evaluation - it's very detailed and interesting, even if you think you're not up for a system.
As far as wiring goes, the system's wired into your main, which can't tell the difference between elec coming in from the grid vs. from your roof. (There's also an inverter between the panels and the main.)
Each state has different net metering laws - in MT we don't get paid for anything, just get bill credit. Once a year the utility settles up your account, and any generation credit you have left (beyond consumption) disappears into the utility's account. Therefore you do NOT want to overbuild.
Don't mean to obfuscate this discussion of solar, but we are geothermal'ed and find it works very well. Built 4000sf house 15 years ago. Water from 4 wells comes in at 56 degrees and is finished off by electric. Our first monthly electric bill back then was $145 and our latest this year was $263. This bill covers everything, appliances, heat, a/c etc. We have the ability to add solar (length of house faces South up high), and wind (if we didn't have railings we'd blow right off the decks) and I find the possibility intriguing. BTW, we are in eastern PA. I have often wondered by FL and CA have not run horizontal piping out into their off shore waters, but then WTFDIK? best, hawk
No MN? How dem puppies going like FL? I hate those whirley-gigs. There's a residential model like a double helix...better. Solar panels aren't so bad either. But geothermal you can't see. And free cool water works. Good luck with your move. best, hawk
>> Well, I've had a completely different experience, David. I spent $18.95 or some such on a long-handled broom/squeegee to clear off the snow -- a truly staggering maintenance bill.
Thanks. I completely forgot about that cost, plus worry about my wife slipping when she is up there with her shovel in foot-deep snow, trying not to step on the panels either...
>> I agree with the notion of calling out an installer for a site evaluation - it's very detailed and interesting, even if you think you're not up for a system.
Many do it (that is, first cut, on the phone) just via google maps, taking a satellite look at your roof and knowing the data for surrounding installs to give you an estimate or yes/no right there.
I must add that I have heard more than once that sunrun or sungen or one of those other big places have screwed this up utterly and come to quite the wrong conclusion, whereas SolarCity does not do that and is accurate. They were impressive like nothing I have dealt with prior --- flawless w my install, zero probs, on schedule, no cost, all the permitting, blah blah. I may have put in $500 to get to the cheapest tier, actually.
>> As far as wiring goes, the system's wired into your main, which can't tell the difference between elec coming in from the grid vs. from your roof. (There's also an inverter between the panels and the main.)
No elec coming from roof to main, effectively, right?
>> Each state has different net metering laws - in MT we don't get paid for anything, just get bill credit. Once a year the utility settles up your account, and any generation credit you have left (beyond consumption) disappears into the utility's account.
We get credited, and sometimes in the summer a negative bill, but there is no settling-up yearly. I do pay $58/mo for leasing the installation, which ends in 14 more years, and then they come uninstall it, wink wink.
>> Therefore you do NOT want to overbuild.
Well, not unless you're some green treehugger type and alarmed by rising temps where jets can't take off etc. etc.
@ Old_Joe: Maybe it's time for update if electrical system is 70 years young. Are you running nail & tube ? I believe that's what it was called. I couldn't help myself concerning my post. I'm still chuckling !! Derf
@hawkmountain- Hello there Hawk, and great to see that you're still with us and hopefully well. I'm very curious re your geothermal setup. Your comments seem to suggest that electricity is somehow generated due to water temperature differentials? Can you give us a brief description?
Old_Joe: Not hawkmountain, but think he was talking heat pump. It takes or gives back to the water depending on the season for heating or cooling. Derf
@davidmoran: No elec coming from roof to main, effectively, right?
In the system here, at least, the way the master elec who tied the line from the roof into the main explained it, yes, elec from the roof goes into the main and then goes either into the house or onto the grid, depending on demand from the house. Here's how the utility's net metering consumer guide says it:
In a net metered PV system, the electrical production from the array will either be utilized to service the home or transferred to the utility grid through a process called net metering. .... when (the customer is) not utilizing the power from the PV system, it is “fed” to the grid, and the consumer is credited for it. Conversely, when the consumer requires utility power, it is provided, and the consumer is charged for it. This is accomplished by the installation of a certified net meter by the utility, which in effect has controls that change direction as the result of either production or consumption.
Maybe under a different kind of net metering system it's wired and works somewhat differently? Dunno.
@Derf- The house is about 100 years old, and there are a only a few ceiling light fixtures that still use the original wiring with the knob and tube porcelain insulators. It would require demolishing the original lath and plaster walls and ceilings to get at those. All of the remaining circuits have been replaced with either conduit or other current wiring types.
Additionally, a number of fuse and circuit breaker subpanels have been added so that there is very little load on any one circuit. The trick, with only a 40amp/240 volt service, is careful design to insure that the larger loads (refrigeration, furnace motor, washer, clothesdryer etc.) are distributed so as to insure that the load on either of the 40 amp main fuses is never exceeded, even with all of that stuff running at the same time.
@AndyJ- There is only the one feed (service drop) from your electric company to your house. In a normal setup the current flows inward through that service drop, through the meter and main switch, and then to whatever load is present in the house. That load of course will vary depending upon what lights and appliances are being used at any given moment.
With the addition of solar panels, the DC current generated by those panels is first converted to AC, and then parallel-fed to the original system, usually joining it behind (on the "house" side) of the main switch. If the solar installation is generating more current than the house is needing at any given moment, the surplus current then flows "backwards" through the main switch, meter, and outward to the electric company. The meter will "run backwards", registering your current feed to the electric company.
If the house needs more current than the panels can provide, then enough current will be supplied by the electric company to make up the difference, and the meter will register that in the normal manner.
As David has pointed out, in the event of a service failure from your supplier, safety switching logic prevents current generated by your system from flowing outward to the electric company. This is not only to provide safety for service workers, but also to prevent damage to your system: if the power from your supplier is interrupted, it's a good bet that it's also interrupted to your neighbors. If your system was not isolated in this situation, your system would then attempt to feed the neighboring load as well as your own, which of course would seriously overload it, with a high probability of damage to your system.
I guess I did not fully understand that the panels were not wholly 'adjunctive' to the grid, so to speak, but were made use of first by the house. I will doublecheck that that is how my SolarCity installation works, but the commingling certainly makes sense electrically.
Ah, here is a truly weak piece of tech writing (my field):
I don't know that OJ's secondary explanation about neighborhood load is the case, as there's no "system attempt to feed with likelihood of damage" so far as I know (like a low-impedance load?). What could the damage be? Your circuits would trip, right?, as they do if you put five toaster oven on one circuit, no? Nice to see 'overload' used correctly, though. Maybe I am missing something here too, though.
Right, @OldJoe, thanks for the clear explanation. Hope I didn't leave the impression that there's more than one feed between the utility and house - the beauty of AC ...
Great piece. Remember BP's international solar division? Skipping the centralized fossil fuel era was the idea, and they did some work in that direction starting in the '80s, but abandoned it ~ 2011-12, with India's Tata taking it over.
Sir John Browne had tried to take it up a notch ~ 2000 and thereafter, but his 'rebranding' of the corporate image to "Beyond Petroleum" generated a lot of buzz but didn't deliver that much. The whole idea was dumped after Browne retired. So now it's apparently rolling again, in startup mode, with Big Oil on the sidelines.
@davidrmoran- No, you're quite right with respect to the damage limitation provided by fuses and circuit breakers. I was simply emphasizing that the logic inherent in these systems avoids these potential problems by isolating an individual installation in the event of a utility supply failure.
Comments
Regards,
Ted
http://www.latimes.com/projects/la-fi-electricity-solar/
I have a friend who is so far to the right that he makes Ted look like a commie. But some months ago he installed a rooftop solar array, cutting his PG&E bill dramatically, and is one happy camper. Interestingly, even though he rants about government subsidies, he had no problem taking his. Typical.
I would do the same, but our area in SF is frequently overcast, and it would also involve a complete rewiring of our 70 year old electric service.
All that rooftop installations do (typically) is generate power and sell it to the local utility. Net metering. Nothing to do with home usage or supply into the house wiring or anything like that. In fact when there is a power outage they stop their output, so as not to endanger utility workers.
I know people with rooftop panels in the Bay area. Have you called Solar City and had them do an assessment?
No one touched my current (old) service, although if yours is dangerously decrepit, it should be redone anyway, and then would be the time.
You may be possibly unclear about some aspects of what this new thing is.
The Bay Area is anything but uniform in it's sun exposure. Here, west of Twin Peaks in SF, it is notoriously cool and overcast while on the east of the Twin Peaks hill range the rest of SF is basking in sunlight. Right now the temperature here is 68°, yet an hour north at the weekend house it's due to hit 101° today.
Our service is old, but not unsafe: I've paid much attention to balancing the household electrical load here, and there are no overload issues. Replacing incandescent lighting with LED fixtures where possible has helped a lot with that. If someone were to want to install an electric stove though, that would mean a new service for sure.
Thanks for your response.
Still would give SC a call; you don't need cloudless sun.
Solar won't affect your service, almost certainly.
I agree with the notion of calling out an installer for a site evaluation - it's very detailed and interesting, even if you think you're not up for a system.
As far as wiring goes, the system's wired into your main, which can't tell the difference between elec coming in from the grid vs. from your roof. (There's also an inverter between the panels and the main.)
Each state has different net metering laws - in MT we don't get paid for anything, just get bill credit. Once a year the utility settles up your account, and any generation credit you have left (beyond consumption) disappears into the utility's account. Therefore you do NOT want to overbuild.
We have the ability to add solar (length of house faces South up high), and wind (if we didn't have railings we'd blow right off the decks) and I find the possibility intriguing. BTW, we are in eastern PA.
I have often wondered by FL and CA have not run horizontal piping out into their off shore waters, but then WTFDIK?
best, hawk
I hate those whirley-gigs. There's a residential model like a double helix...better.
Solar panels aren't so bad either. But geothermal you can't see. And free cool water works.
Good luck with your move.
best, hawk
>> Well, I've had a completely different experience, David. I spent $18.95 or some such on a long-handled broom/squeegee to clear off the snow -- a truly staggering maintenance bill.
Thanks. I completely forgot about that cost, plus worry about my wife slipping when she is up there with her shovel in foot-deep snow, trying not to step on the panels either...
>> I agree with the notion of calling out an installer for a site evaluation - it's very detailed and interesting, even if you think you're not up for a system.
Many do it (that is, first cut, on the phone) just via google maps, taking a satellite look at your roof and knowing the data for surrounding installs to give you an estimate or yes/no right there.
I must add that I have heard more than once that sunrun or sungen or one of those other big places have screwed this up utterly and come to quite the wrong conclusion, whereas SolarCity does not do that and is accurate. They were impressive like nothing I have dealt with prior --- flawless w my install, zero probs, on schedule, no cost, all the permitting, blah blah. I may have put in $500 to get to the cheapest tier, actually.
>> As far as wiring goes, the system's wired into your main, which can't tell the difference between elec coming in from the grid vs. from your roof. (There's also an inverter between the panels and the main.)
No elec coming from roof to main, effectively, right?
>> Each state has different net metering laws - in MT we don't get paid for anything, just get bill credit. Once a year the utility settles up your account, and any generation credit you have left (beyond consumption) disappears into the utility's account.
We get credited, and sometimes in the summer a negative bill, but there is no settling-up yearly. I do pay $58/mo for leasing the installation, which ends in 14 more years, and then they come uninstall it, wink wink.
>> Therefore you do NOT want to overbuild.
Well, not unless you're some green treehugger type and alarmed by rising temps where jets can't take off etc. etc.
Derf
Thanks- OJ
Derf
In the system here, at least, the way the master elec who tied the line from the roof into the main explained it, yes, elec from the roof goes into the main and then goes either into the house or onto the grid, depending on demand from the house. Here's how the utility's net metering consumer guide says it:
In a net metered PV system, the electrical production from the array will either be utilized to service the home or transferred to the utility grid through a process called net metering. .... when (the customer is) not utilizing the power from the PV system, it is “fed” to the grid, and the consumer is credited for it. Conversely, when the consumer requires utility power, it is provided, and the consumer is charged for it. This is accomplished by the installation of a certified net meter by the utility, which in effect has controls that change direction as the result of either production or consumption.
Maybe under a different kind of net metering system it's wired and works somewhat differently? Dunno.
Additionally, a number of fuse and circuit breaker subpanels have been added so that there is very little load on any one circuit. The trick, with only a 40amp/240 volt service, is careful design to insure that the larger loads (refrigeration, furnace motor, washer, clothesdryer etc.) are distributed so as to insure that the load on either of the 40 amp main fuses is never exceeded, even with all of that stuff running at the same time.
OJ
With the addition of solar panels, the DC current generated by those panels is first converted to AC, and then parallel-fed to the original system, usually joining it behind (on the "house" side) of the main switch. If the solar installation is generating more current than the house is needing at any given moment, the surplus current then flows "backwards" through the main switch, meter, and outward to the electric company. The meter will "run backwards", registering your current feed to the electric company.
If the house needs more current than the panels can provide, then enough current will be supplied by the electric company to make up the difference, and the meter will register that in the normal manner.
As David has pointed out, in the event of a service failure from your supplier, safety switching logic prevents current generated by your system from flowing outward to the electric company. This is not only to provide safety for service workers, but also to prevent damage to your system: if the power from your supplier is interrupted, it's a good bet that it's also interrupted to your neighbors. If your system was not isolated in this situation, your system would then attempt to feed the neighboring load as well as your own, which of course would seriously overload it, with a high probability of damage to your system.
Ah, here is a truly weak piece of tech writing (my field):
http://www.solarcity.com/residential/how-does-solar-power-work
Note lacuna b/w 2 and 3.
This is better, lede para:
http://www.gosolarcalifornia.ca.gov/solar_basics/how.php
All righty, then.
I don't know that OJ's secondary explanation about neighborhood load is the case, as there's no "system attempt to feed with likelihood of damage" so far as I know (like a low-impedance load?). What could the damage be? Your circuits would trip, right?, as they do if you put five toaster oven on one circuit, no? Nice to see 'overload' used correctly, though. Maybe I am missing something here too, though.
http://www.newyorker.com/magazine/2017/06/26/the-race-to-solar-power-africa
and from a year before
https://www.pv-tech.org/news/bill-gates-solar-is-not-the-energy-solution-africa-needs
https://washingtonpost.com/news/morning-mix/wp/2017/06/22/john-oliver-a-giant-squirrel-and-a-defamation-lawsuit-by-a-coal-industry-titan/?utm_term=.2db46a1f634f
https://usatoday.com/story/life/tv/2017/06/22/murray-energy-sues-hbo-oliver-over-coal-story-from-last-week-tonight/103105860/
money.cnn.com/2017/06/22/media/john-oliver-coal-king-murray-lawsuit/index.html
Regards,
Ted
Coal: John Oliver:
https://www.youtube.com/user/LastWeekTonight
Sir John Browne had tried to take it up a notch ~ 2000 and thereafter, but his 'rebranding' of the corporate image to "Beyond Petroleum" generated a lot of buzz but didn't deliver that much. The whole idea was dumped after Browne retired. So now it's apparently rolling again, in startup mode, with Big Oil on the sidelines.
https://en.wikipedia.org/wiki/BP_Solar
@davidrmoran- No, you're quite right with respect to the damage limitation provided by fuses and circuit breakers. I was simply emphasizing that the logic inherent in these systems avoids these potential problems by isolating an individual installation in the event of a utility supply failure.