Does solar power save money?

[GuitarStv]

Sorry, haven't read all the comments yet, but this post is so timely I had to chime in...

Our neighbors got solar this year. We're in the middle of a heat wave. We've noticed that their A/C has been running constantly, while we haven't even turned our fans on yet. Why? Um, we just open our windows at night?? My larger house is 72 degrees right now. No chance the A/C's going on, as the heat wave is due to break today.
So, we were discussing this at dinner last night. (We put the G. Foreman grill out on the back porch so as not to heat up the kitchen. Forgot it out there, which made some random raccoons very happy, ugh.) Anyway, the concensus is that SOLAR MAKES YOU SOFT. Can this be true or are we just jealous because we have too many redwood trees to have an effective solar array?

We found that the roof top solar panels very slightly help reduce A/C usage because they are slightly raised from the shingles and act to shade your roof, while adding an insulative air gap.  YMMV.

[nereo]

Our neighbors got solar this year... Anyway, the concensus is that SOLAR MAKES YOU SOFT. Can this be true or are we just jealous because we have too many redwood trees to have an effective solar array?

I've thought about something similar.  Suppose I put in my intended 6.4kw system; in all likelihood it's way more than we'll use, and credits will be useful only to a point.  So do we run the air conditioner more frequently or generally be less vigilant about wasting energy?  I'm not sure...

One argument against this comes from a blog post Erica/NWEdibles made about their solar system.  tl/dr the continuous and almost instantaneous feedback from their solar energy monitor provided postive reinforcement for being energy efficient. 

[thd7t]

Sorry, haven't read all the comments yet, but this post is so timely I had to chime in...

Our neighbors got solar this year. We're in the middle of a heat wave. We've noticed that their A/C has been running constantly, while we haven't even turned our fans on yet. Why? Um, we just open our windows at night?? My larger house is 72 degrees right now. No chance the A/C's going on, as the heat wave is due to break today.
So, we were discussing this at dinner last night. (We put the G. Foreman grill out on the back porch so as not to heat up the kitchen. Forgot it out there, which made some random raccoons very happy, ugh.) Anyway, the concensus is that SOLAR MAKES YOU SOFT. Can this be true or are we just jealous because we have too many redwood trees to have an effective solar array?

Most people are soft. Solar is a tool that doesn't add convenience, so I doubt it makes people softer.

[Erica]

Our Energy bills were averaging $101 per month with all 12 months added up and divided by 12
One time $4000 investment meant no energy bills from that month on


There is no water company here. So we all have springs, water from a mine, or usually, a well.

Got rid of that $65 mo. bill too ($59 set fee, $6 for the actual water usage)

[nobodyspecial]

Anyway, the concensus is that SOLAR MAKES YOU SOFT.

What's even worse is that for a MMM having solar massively INCREASES the cost of your electricity.
Most people would think of the solar electricity as free. But if you are paid a feed-in tarrif at 150% to 200% of the price you pay then any electricity usage means less to give back, which means you are losing money at the higher rate.

It's like any money I spend at starbucks (rather than investing it) is like borrowing that money at 7% forever .

[nereo]

Anyway, the concensus is that SOLAR MAKES YOU SOFT.

What's even worse is that for a MMM having solar massively INCREASES the cost of your electricity.
Most people would think of the solar electricity as free. But if you are paid a feed-in tarrif at 150% to 200% of the price you pay then any electricity usage means less to give back, which means you are losing money at the higher rate.

It's like any money I spend at starbucks (rather than investing it) is like borrowing that money at 7% forever .

I do not follow your logic here. Could you elaborate?

What matters is total cost per kw consumed per unit time.  As others have demonstrated in some circumstances you can pay less over several years having solar than purchasing that power from the electric company. One can calculate the opportunity cost of installing a solar array too.

[Another Reader]

My neighbor was an early adopter with a 10 kw system.  Runs the A/C all the time.  Converted the hot water heater from gas to electricity.  Only gas left is the furnace, and he is looking at ways to replace that.  Sells enough back to PG&E to cover all the electricity he uses so he doesn't care.

Apparently the danger to fire fighters is high.  There was a recent discussion over at early-retirement.org about this.  Apparently the panels keep generating and cannot be shut off.  Even if you kill the connection, those moving electrons are still there waiting.  You can easily be electrocuted.  Haven't checked the insurance consequences, but it might be a good idea to do so.

[nereo]

My neighbor was an early adopter with a 10 kw system.  Runs the A/C all the time.  Converted the hot water heater from gas to electricity.  Only gas left is the furnace, and he is looking at ways to replace that.  Sells enough back to PG&E to cover all the electricity he uses so he doesn't care.

Wow!  How early of an adopter can he be with a 10kw system?  How many panels is that... 50? 60?? more???

[nobodyspecial]

Anyway, the concensus is that SOLAR MAKES YOU SOFT.

What's even worse is that for a MMM having solar massively INCREASES the cost of your electricity.
Most people would think of the solar electricity as free. But if you are paid a feed-in tarrif at 150% to 200% of the price you pay then any electricity usage means less to give back, which means you are losing money at the higher rate.

I do not follow your logic here. Could you elaborate?

What matters is total cost per kw consumed per unit time.  As others have demonstrated in some circumstances you can pay less over several years having solar than purchasing that power from the electric company. One can calculate the opportunity cost of installing a solar array too.

In most areas where domestic solar is popular it is because the local utility is forced to buy excess power that you generate back from you at more than the retail price of the electricity they supply to you.
(This is a subsidy to encourage environmental energy production / a bribe to well off home owners.)

So although at first glance any solar energy you use is free. A mustacian would think of it as "any solar that I generate  but don't sell back to the utility at the higher rate is costing me the same as buying electricity at the higher rate".
It is the opportunity cost of using your excess capacity vs selling it back to the utility.

[ender]

In most areas where domestic solar is popular it is because the local utility is forced to buy excess power that you generate back from you at more than the retail price of the electricity they supply to you.
(This is a subsidy to encourage environmental energy production / a bribe to well off home owners.)

So although at first glance any solar energy you use is free. A mustacian would think of it as "any solar that I generate  but don't sell back to the utility at the higher rate is costing me the same as buying electricity at the higher rate".
It is the opportunity cost of using your excess capacity vs selling it back to the utility.

When I asked where I live, our utilities company (through the city) will purchase it back -- at their cost of production (so ~4 cents a kWH)... which is not much incentive.

[Tyson]

Which is why inexpensive batteries are so important.  With batteries you store the energy you generate and use it yourself.  When batteries start to drop massively in price, then the utility companies will be very scared and will wish they hadn't acted like such jerks about the whole solar thing.

Cheap batteries are also going to allow electric vehicles to be much more disruptive as well. 

Although I predict that the big companies will in fact adapt and shift more and more to solar as the backbone for their own energy production.  And here's why - a lot of people make the shift to solar because they want to get away from oil, coal, gas, nuclear, etc... If the power companies make solar the backbone of their business, then they remove that incentive for people to move off the grid.  Will they be able to get it done?  I don't know but I think they will.

[nereo]

When I asked where I live, our utilities company (through the city) will purchase it back -- at their cost of production (so ~4 cents a kWH)... which is not much incentive.

For where I live they will credit your account at their lower-tier rate which you can use to offset future bills.  However, they will not cut you a cheque.

In most areas where domestic solar is popular it is because the local utility is forced to buy excess power that you generate back from you at more than the retail price of the electricity they supply to you.
(This is a subsidy to encourage environmental energy production / a bribe to well off home owners.)

So although at first glance any solar energy you use is free. A mustacian would think of it as "any solar that I generate  but don't sell back to the utility at the higher rate is costing me the same as buying electricity at the higher rate".
It is the opportunity cost of using your excess capacity vs selling it back to the utility.

That still doesn't mean solar always "massively INCREASES the cost of your electricity" as you claimed earlier.
Sure, some people might consume extra electricity instead of selling it back to the utility (if possible) for a better return, but the cost per kw can still be much less depending on your area.  Hawai'i is the poster-child here.
For many installations the goal isn't 100% replacement - many shoot for about 80%, which is often around the optimal amount for the fastest ROI. In those cases it doesn't even make sense to waste electricity since they're still buying electricity (particularly in the winter) and counting on summer overages to offset their winter consumption.

[nereo]

Although I predict that the big companies will in fact adapt and shift more and more to solar as the backbone for their own energy production.  And here's why - a lot of people make the shift to solar because they want to get away from oil, coal, gas, nuclear, etc... If the power companies make solar the backbone of their business, then they remove that incentive for people to move off the grid.  Will they be able to get it done?  I don't know but I think they will.

It's worth noting here that California has a state mandate to generate ≥50% of their electricity from renewable sources by 2030 and 33% by 2020.  So far they are actually ahead of schedule.

There are similar trends in regions where solar is favorable.  Storage is an ongoing hurdle, but there are some interesting research projects that are trying to get away from using traditional 'batteries' (ARES is one).

[Cadman]

We're in the middle of installing a 10kW ground mount system, however my background being electrical, we're doing the work ourselves so I can't comment on any contractor 'gotchas'. What I can say for those considering such a thing is that it only makes sense if your utility wants to play ball. For roof mount systems, you also have to consider all of the penetrations in your roof and the quality of the workmanship. Putting that many holes in my shingles would scare me off the idea, but the panels themselves would improve your roof life from wear/tear and UV.

Neighboring utilities here are offering rebates and incentives for installs, while the best ours will do is buy back any power produced (not a bad deal given their payback rate is higher than the consumption rate). Some utilities will only allow you to offset your usage, though you'll still pay a connection fee. Still others will credit you for all power produced in a 12 month period, but if you don't use it, you lose it at that yearly date. Word in the solar community is that these incentives are going away and established plans are being modified to discourage future solar installs. I wish I knew why.

I see the Fed tax credit was extended another 5 years, but check your state taxes to see if they extended, too. For IA the 'online' deadline is/was Dec 31 2016. I haven't checked to see if that got moved out since I should be producing power this summer.

The NEC previously had specific verbiage that would prevent an inverter from producing power if the utility power was lost. Some inverters now have an integral 120V outlet that you can plug into in such a case, but this source is only as good as a continuous supply of the sun. Also, this could be a tough sell depending on your local jurisdiction as such a source can be open to inspector interpretation.

The type of equipment needed for a grid-tie setup vs. an off-grid arrangement is apples and oranges. About all they have in common is the panels and even then, the wiring and fusing is totally different. One would never get ahead financially with the off-grid setup as battery maintenance and replacement will eat you alive. But if you had to have power and there were no other options, it's doable with several caveats. I have an 'off-grid' garage with LED lights and a modified garage door opener running off such a thing. A panel from Amazon, an ebay charge controller and a local marine battery and it's doing okay.

[Dicey]

Our neighbors got solar this year. We're in the middle of a heat wave. We've noticed that their A/C has been running constantly, while we haven't even turned our fans on yet. Why? Um, we just open our windows at night?? My larger house is 72 degrees right now. No chance the A/C's going on, as the heat wave is due to break today...Anyway, the concensus is that SOLAR MAKES YOU SOFT. Can this be true or are we just jealous because we have too many redwood trees to have an effective solar array?

Oh, I just had to come back with this update. The heat wave broke today and a lovely, brisk breeze kicked up at dinnertime. The house had gotten up to 80, so we opened all the windows. Within an hour it had dropped to 71 and I was actually chilly, so I put on a light jacket and closed most of the windows. My neighbors? Nope, their A/C is still blowing full blast. They have no idea how lovely it is outside.

[Kax]

I believe it totally depends on where such batteries are placed and how it used.

[MoneyCat]

If you really want to get your money's worth out of your solar panels, I highly recommend getting a plug-in hybrid car or electric vehicle. It's like making gasoline on your roof. Drastically drops the cost of operating your vehicle.

[Erica]

No one needs to be connected to their electrical company at all after getting solar.

We break even after the cost of $4000 after 3 years and 4 months. Actually 4 months as my husband did a bit of overkill so says he might
sell off some of it. There is no electrical company in our town. And around here, they only pay 4 cents a killowat in buying back the power.

[Erica]

If you really want to get your money's worth out of your solar panels, I highly recommend getting a plug-in hybrid car or electric vehicle. It's like making gasoline on your roof. Drastically drops the cost of operating your vehicle.

Yes, we might inherit a 2015 Tesla when my FIL passes away. He drove it 3 times.
Another thought is ebikes. We are buying one next month during our time off. Then maybe another for me if we like that one.

[SomedayStache]

Our neighbors got solar this year. We're in the middle of a heat wave. We've noticed that their A/C has been running constantly, while we haven't even turned our fans on yet. Why? Um, we just open our windows at night?? My larger house is 72 degrees right now. No chance the A/C's going on, as the heat wave is due to break today...Anyway, the concensus is that SOLAR MAKES YOU SOFT. Can this be true or are we just jealous because we have too many redwood trees to have an effective solar array?

Oh, I just had to come back with this update. The heat wave broke today and a lovely, brisk breeze kicked up at dinnertime. The house had gotten up to 80, so we opened all the windows. Within an hour it had dropped to 71 and I was actually chilly, so I put on a light jacket and closed most of the windows. My neighbors? Nope, their A/C is still blowing full blast. They have no idea how lovely it is outside.

I'm going to go out on a strong and sturdy limb here to say that your neighbors  behavior doesn't affect the cost efficiency of solar power to anyone but themselves.  I will not take your neighbors behavior into account when determining if solar panels will make sense for me.  (It is an interesting tangent though!).  Their A/C would probably be on full blast with or without the solar panels.

Also following this post because my pipe dream is to get solar panels before the federal tax credit expires and also someday get an electric vehicle.  My state offers zero incentives and my electric company will offset usage on a monthly basis but not pay me anything.    Without help at the state or local utility level the numbers are much less convincing.  But we are an all electric house and plan to live here until we die...so maybe it makes sense?

[nereo]

Also following this post because my pipe dream is to get solar panels before the federal tax credit expires and also someday get an electric vehicle.  My state offers zero incentives and my electric company will offset usage on a monthly basis but not pay me anything.    Without help at the state or local utility level the numbers are much less convincing.  But we are an all electric house and plan to live here until we die...so maybe it makes sense?

There are reasons beyond whether its economical or not.  For example, my parents live in a state that have any state support of solar. Their estimated payback on a system is about 10 years. But they've decided to go ahead when they replace their roof this fall.  Why? As my dad explains it, after 5 years their net cost should be somewhere between $4-5k. It gives them an added measure of safety/independence in case energy prices spike and they like knowing their power will come from a renewable.

Ultimately people pay that much for sillier stuff all time. Some people will pay $5k more for an otherwise comparable car just because they like the way it looks or because it comes in a certain color. It's up to you whether the cost is worth it.

[Tyson]

Also following this post because my pipe dream is to get solar panels before the federal tax credit expires and also someday get an electric vehicle.  My state offers zero incentives and my electric company will offset usage on a monthly basis but not pay me anything.    Without help at the state or local utility level the numbers are much less convincing.  But we are an all electric house and plan to live here until we die...so maybe it makes sense?

There are reasons beyond whether its economical or not.  For example, my parents live in a state that have any state support of solar. Their estimated payback on a system is about 10 years. But they've decided to go ahead when they replace their roof this fall.  Why? As my dad explains it, after 5 years their net cost should be somewhere between $4-5k. It gives them an added measure of safety/independence in case energy prices spike and they like knowing their power will come from a renewable.

Ultimately people pay that much for sillier stuff all time. Some people will pay $5k more for an otherwise comparable car just because they like the way it looks or because it comes in a certain color. It's up to you whether the cost is worth it.

That's a good point - solar is a really good hedge against inflation and specifically against spikes in energy costs, which can and do happen. 

[SomedayStache]

I've been recently contemplating time of use (peak hours) billing.  I know electric companies do various flavors of this - my electric company institutes higher electricity rates (3x higher) from 3pm to 7pm June-August to all customers.  Another local company has an opt-in voluntary program for the peak hours and the rates vary daily - texts are sent out the day before.

During these hours the sun would typically be shining and with solar panels I would expect to very rarely use grid electricity during the peak hours. 

[nereo]

I've been recently contemplating time of use (peak hours) billing.  I know electric companies do various flavors of this - my electric company institutes higher electricity rates (3x higher) from 3pm to 7pm June-August to all customers.  Another local company has an opt-in voluntary program for the peak hours and the rates vary daily - texts are sent out the day before.

During these hours the sun would typically be shining and with solar panels I would expect to very rarely use grid electricity during the peak hours.

I've started to wonder if "peak pricing" won't shift in the next several years as a result of increased wind and solar (both of which tend to produce the most electricity during the late afternoon, when peak demand also hits.
... just thinking out loud here...

[nobodyspecial]

For the southern US peak demand is mostly due to AC and so matches peak solar.
There is a reasonable argument for fitting panels wired directly to the AC avoiding all the inverters/batteries/controllers feed-in complications.

In Quebec - probably less well correlated ;-)

[nereo]

For the southern US peak demand is mostly due to AC and so matches peak solar.
There is a reasonable argument for fitting panels wired directly to the AC avoiding all the inverters/batteries/controllers feed-in complications.

In Quebec - probably less well correlated ;-)

I was actually describing peak pricing in NA in general, but your response highlights what I was pondering.  both solar and wind (on average) produce the most power in the late afternoon, which is when peak demand also hits.  As the amount of solar and wind power tied to the grid increases, the available power generated will go up at the same time that demand goes up.  So - less need to ramp up more costly auxillary plants.  At least that's my reasoning...

[katsiki]

There are reasons beyond whether its economical or not.  For example, my parents live in a state that have any state support of solar. Their estimated payback on a system is about 10 years. But they've decided to go ahead when they replace their roof this fall.  Why? As my dad explains it, after 5 years their net cost should be somewhere between $4-5k. It gives them an added measure of safety/independence in case energy prices spike and they like knowing their power will come from a renewable.

Ultimately people pay that much for sillier stuff all time. Some people will pay $5k more for an otherwise comparable car just because they like the way it looks or because it comes in a certain color. It's up to you whether the cost is worth it.

Excellent point.  I think some people follow a similar path determining a generator or solar.  I realize it is not a 1 to 1 solution.  I considered solar before my state phased out the credits.

[TomTX]

I've been recently contemplating time of use (peak hours) billing.  I know electric companies do various flavors of this - my electric company institutes higher electricity rates (3x higher) from 3pm to 7pm June-August to all customers.  Another local company has an opt-in voluntary program for the peak hours and the rates vary daily - texts are sent out the day before.

During these hours the sun would typically be shining and with solar panels I would expect to very rarely use grid electricity during the peak hours.

I've started to wonder if "peak pricing" won't shift in the next several years as a result of increased wind and solar (both of which tend to produce the most electricity during the late afternoon, when peak demand also hits.
... just thinking out loud here...

And peak pricing actually makes it more important to shift your panel orientation more West than South, to get the optimum afternoon/evening power.

[ender]

I've been recently contemplating time of use (peak hours) billing.  I know electric companies do various flavors of this - my electric company institutes higher electricity rates (3x higher) from 3pm to 7pm June-August to all customers.  Another local company has an opt-in voluntary program for the peak hours and the rates vary daily - texts are sent out the day before.

During these hours the sun would typically be shining and with solar panels I would expect to very rarely use grid electricity during the peak hours.

I've started to wonder if "peak pricing" won't shift in the next several years as a result of increased wind and solar (both of which tend to produce the most electricity during the late afternoon, when peak demand also hits.
... just thinking out loud here...

And peak pricing actually makes it more important to shift your panel orientation more West than South, to get the optimum afternoon/evening power.

Hmmm, west for us is facing the street. Not sure that would be aesthetically that nice :)

[GuitarStv]

I've been recently contemplating time of use (peak hours) billing.  I know electric companies do various flavors of this - my electric company institutes higher electricity rates (3x higher) from 3pm to 7pm June-August to all customers.  Another local company has an opt-in voluntary program for the peak hours and the rates vary daily - texts are sent out the day before.

During these hours the sun would typically be shining and with solar panels I would expect to very rarely use grid electricity during the peak hours.

I've started to wonder if "peak pricing" won't shift in the next several years as a result of increased wind and solar (both of which tend to produce the most electricity during the late afternoon, when peak demand also hits.
... just thinking out loud here...

And peak pricing actually makes it more important to shift your panel orientation more West than South, to get the optimum afternoon/evening power.

Hmmm, west for us is facing the street. Not sure that would be aesthetically that nice :)

Shingles aren't aesthetically very nice . . . they're black sheets of tar and pebbly dirt.  If people can learn to love that, they can learn to love that with a couple black panels on top.  Aesthetics are determined simply by what you're used to in a lot of cases.

[clarkfan1979]

Solar makes a lot of sense in Hawaii because of the amount of sun and the high cost of electricity.

[HipGnosis]

Sorry, haven't read all the comments yet, but this post is so timely I had to chime in...

Our neighbors got solar this year. We're in the middle of a heat wave. We've noticed that their A/C has been running constantly, while we haven't even turned our fans on yet. Why? Um, we just open our windows at night?? My larger house is 72 degrees right now. No chance the A/C's going on, as the heat wave is due to break today.
So, we were discussing this at dinner last night. (We put the G. Foreman grill out on the back porch so as not to heat up the kitchen. Forgot it out there, which made some random raccoons very happy, ugh.) Anyway, the concensus is that SOLAR MAKES YOU SOFT. Can this be true or are we just jealous because we have too many redwood trees to have an effective solar array?

We found that the roof top solar panels very slightly help reduce A/C usage because they are slightly raised from the shingles and act to shade your roof, while adding an insulative air gap.  YMMV.

I'd think solar panels will similarly extend the life of your shingles. SWEET!

[tonysemail]

I was actually describing peak pricing in NA in general, but your response highlights what I was pondering.  both solar and wind (on average) produce the most power in the late afternoon, which is when peak demand also hits.  As the amount of solar and wind power tied to the grid increases, the available power generated will go up at the same time that demand goes up.  So - less need to ramp up more costly auxillary plants.  At least that's my reasoning...

There's proof on this webpage; a nice visualization of conventional power sources ramping down when solar/wind are generating.
FREE energy, woo!

https://www.energy-charts.de/power.htm

[Dicey]

We found that the roof top solar panels very slightly help reduce A/C usage because they are slightly raised from the shingles and act to shade your roof, while adding an insulative air gap.  YMMV.

I'd think solar panels will similarly extend the life of your shingles. SWEET!

Uhm, there's the issue of all the mountings that get screwed into your roof, which then compromise the roof in those areas. Once the panels are in place, the holes can't be easily accessed to reseal them. Also, the portions of your roof not covered by panels continue to age at the normal rate, so there's no real advantage.  Not being anti-solar, but please don't discount the effects over time of putting all those holes in your roof.

[bacchi]

We found that the roof top solar panels very slightly help reduce A/C usage because they are slightly raised from the shingles and act to shade your roof, while adding an insulative air gap.  YMMV.

I'd think solar panels will similarly extend the life of your shingles. SWEET!

Uhm, there's the issue of all the mountings that get screwed into your roof, which then compromise the roof in those areas. Once the panels are in place, the holes can't be easily accessed to reseal them. Also, the portions of your roof not covered by panels continue to age at the normal rate, so there's no real advantage.  Not being anti-solar, but please don't discount the effects over time of putting all those holes in your roof.

Solution: Standing seam metal roof with S5 (or similar) clamps.

[Rhoon]

I'm in an Anti-Solar powered state of Sunny Florida, where the power companies have bought the elected officials and pay next to nothing for extra power generation (2-3cents per kWh). That being said, I still put solar on my roof. Although my excessive power consumption was due to someone hot-wiring the heater in my AC unit; I've gone from $350/mo to near $0, before I pay for the Solar panels ($24K - $8K in tax credits). Net $16K to me and I'm using my previously outrageous Electrical bill budget to pay down the loan. In 5-6 years I will have no more payments to either a loan or electric company.

Since I plan to stay in the house a minimum of 10 years, that's at least 4-5 years of free power. That's worth it to me. It also has the entire neighborhood exploring the option and if a few more convert to solar, that's less money for the power company and better for the environment.

Power bill was $22 this month. Definitely better than the $350 I usually see in the summer months. Add in the loan payment of $150 for the panels for the month and I'm still way ahead.

[GuitarStv]

We found that the roof top solar panels very slightly help reduce A/C usage because they are slightly raised from the shingles and act to shade your roof, while adding an insulative air gap.  YMMV.

I'd think solar panels will similarly extend the life of your shingles. SWEET!

Uhm, there's the issue of all the mountings that get screwed into your roof, which then compromise the roof in those areas. Once the panels are in place, the holes can't be easily accessed to reseal them. Also, the portions of your roof not covered by panels continue to age at the normal rate, so there's no real advantage.  Not being anti-solar, but please don't discount the effects over time of putting all those holes in your roof.

Solution: Standing seam metal roof with S5 (or similar) clamps.

Have you guys ever roofed a house with shingles?  You pound hundreds of nails into the roof while roofing.  What protects them from leaking is that the shingles are arranged to that water flows over the nail holes rather than to them.  For our solar installation, the installers used a similar technique.  There are overlapping raised barriers that mechanically prevent the flow of water to the screw holes, and each screw hole is coated with sealant.

Properly installed, solar panels shouldn't be any more leak prone than the shingles themselves.

[Fishindude]

If you don't think that a bunch of solar panels mounted atop a shingle roof will be a problem, you don't know much about building or roofing.   I predict those solar panel install guys do things just about like the guys that install your TV or internet satellite, as cheaply and as easy as possible so they can get down the road to the next job.   They just screw some brackets atop your shingles, and caulk the fasteners.    News flash ..... anytime you put a hole in your roof membrane, you increase your chance of leaks significantly.   It might not be leaking yet, but give it five years.

Even if the solar guys do things perfectly and you never experience leaks from any of those solar panel brackets, you will have upped the price of your next re-roof significantly, because they will have to remove the solar panels, brackets and wiring, tear off and re-shingle the roof, then re-install the complete solar panel system.    The standing seam roof idea with clamps would be the best option, but a good standing seam roof costs double or more than the price of a shingle roof.

Solar systems should be installed on a "rack" in the yard somewhere to prevent the roof issues, plus allowing access for cleaning or service if necessary.

[GuitarStv]

If you don't think that a bunch of solar panels mounted atop a shingle roof will be a problem, you don't know much about building or roofing.  I predict those solar panel install guys do things just about the guys that install your TV or internet satellite, as cheaply and as easy as possible so they can get down the road to the next job.  They just screw some brackets atop your shingles, and caulk the fasteners.    News flash ..... anytime you put a hole in your roof membrane, you increase your chance of leaks significantly.   It might not be leaking yet, but give it five years.

What actual experience with solar installers have you had?

Solar systems should be installed on a "rack" in the yard somewhere to prevent the roof issues, plus allowing access for cleaning or service if necessary.

You appear to be unaware that most solar panels sold these days are self cleaning, there's no need to regularly wipe them down.  What service are you expecting to be necessary for solar panels?  One of the benefits of a solar installation is that they're virtually maintenance free (replacing inverters every 10 - 15 years should be about it).

Having solar panels down low opens a whole host of new problems:
- You hurt the value of your land . . . since a huge chunk of it is now rendered unusable and covered with panels
- It becomes much more difficult to guarantee that your panels will get full sunlight through most of the day due to the large number of obstructions (large fences, trees, neighbours playhouses or other structures, etc.)
- Then there's the issue of safety with a ground mounted system if you have children, the increased risk of animal damage, etc.

[Cadman]

I'd argue that both setups have their place. If a person is considering a ground-mount, then I doubt loss of usable space is that big of a deal for them. We went with an Ironridge setup on 3" galv pipe because we have the space, but more importantly we live in snow country and we have to keep 36 panels clear. The cleaning is also a factor- even with self cleaning coatings, dusting is still a consideration and it's part of the loss calculation when figuring your system. This becomes much more challenging on a rooftop, plus you sacrifice some efficiency being at the mercy of the house orientation and roof pitch.

There's also one big advantage that ground mount has over all others- adjustability and tracking to maximize output.

[Travis]

In most areas where domestic solar is popular it is because the local utility is forced to buy excess power that you generate back from you at more than the retail price of the electricity they supply to you.
(This is a subsidy to encourage environmental energy production / a bribe to well off home owners.)

So although at first glance any solar energy you use is free. A mustacian would think of it as "any solar that I generate  but don't sell back to the utility at the higher rate is costing me the same as buying electricity at the higher rate".
It is the opportunity cost of using your excess capacity vs selling it back to the utility.

When I asked where I live, our utilities company (through the city) will purchase it back -- at their cost of production (so ~4 cents a kWH)... which is not much incentive.

Some utilities have argued for altering how net metering works because they have the same concerns that go with electric vehicle folks not paying gasoline taxes - they're not paying their "fair share" of the system's maintenance.  Net metering reimbursement/credits seem to be on the decline in several states.

I can't recall the state, but there's at least one place out there where the utility is required to buy back your excess at the rate they charge the homeowner which the utility is fighting since at best case they break even using that homeowner's electricity.

https://www.nvenergy.com/renewablesenvironment/renewablegenerations/NetMetering.cfm

http://blog.sfgate.com/energy/2014/03/27/california-regulators-to-extend-solar-net-metering/

http://energy.agwired.com/2015/01/26/solar-net-metering-ends-in-cali/

[tonysemail]

They just screw some brackets atop your shingles, and caulk the fasteners.    News flash ..... anytime you put a hole in your roof membrane, you increase your chance of leaks significantly.   It might not be leaking yet, but give it five years.

really?  I don't think any solar company would use caulk.
they should use flashing, same as other roof penetrations for exhaust or clean out pipes.
The risk of leak is not zero, but it's small enough that it should not factor into roof vs ground mount system.
http://www.quickmountpv.com/pdfs/Tile_SolarPro_10_10.pdf

[dragoncar]

I don't personally like the look of solar, and would prefer not to have it on my house.  In the beginning, solar was a sign of affluence -- but this is already changing as I see more and more leased systems get installed on run-down houses. 

I also personally have shading problems, so don't expect to go solar anytime soon.  And I would expect a utility company to produce more efficient solar by placing bulk panels out in nearby farmland with no shading issues (to the degree that solar is cheaper for a homeowner that is more thanks to subsidies than efficiency, although there are certainly grid losses).

So I'm hoping that plentiful solar power drives down the market price enough that I never have to install it myself.

I've been recently contemplating time of use (peak hours) billing.  I know electric companies do various flavors of this - my electric company institutes higher electricity rates (3x higher) from 3pm to 7pm June-August to all customers.  Another local company has an opt-in voluntary program for the peak hours and the rates vary daily - texts are sent out the day before.

During these hours the sun would typically be shining and with solar panels I would expect to very rarely use grid electricity during the peak hours.

I've started to wonder if "peak pricing" won't shift in the next several years as a result of increased wind and solar (both of which tend to produce the most electricity during the late afternoon, when peak demand also hits.
... just thinking out loud here...

Yes, it's called the "duck curve" and in California the utilities have a decade-long plan to shift time-of-use rates/hours.

[nereo]

Yes, it's called the "duck curve" and in California the utilities have a decade-long plan to shift time-of-use rates/hours.

Facinating!  Yup, that's basically what I was thinking about.
What exactly is "over-generation risk"?  Does it actually hurt the grid to produce more electricity than needed, or is it simply wasted?
amazing that we might see an almost 50% reduction in net-load during the early afternoon in 2020 compared with 2012.

[dragoncar]

I'm not a power engineer, but I believe you have to actively manage excess power.  Otherwise it could cause over-voltages or overheated components.  For example, an off-grid solar panel could overheat if excess energy is not dissipated (as heat? not sure how that is handled)

[Travis]

What exactly is "over-generation risk"?  Does it actually hurt the grid to produce more electricity than needed, or is it simply wasted?

Power generated has to go somewhere.  On the diesel generators I use at work, we have a phenomenon called "wet stacking" where if there isn't enough demand on the generator, then fuel and oil leak into parts of the engine damaging it since the power generated doesn't change.  With larger power grids too much juice in the transmission lines is bad if there's nothing on the other end to consume it.  On coal, oil, wind, and hydro plants the engineers can turn off and on different generators at various times of the day to regulate how much electricity is generated.  I'm guessing you can't simply turn off a solar panel. It's always on soaking it in.

[nereo]

What exactly is "over-generation risk"?  Does it actually hurt the grid to produce more electricity than needed, or is it simply wasted?

Power generated has to go somewhere.  On the diesel generators I use at work, we have a phenomenon called "wet stacking" where if there isn't enough demand on the generator, then fuel and oil leak into parts of the engine damaging it since the power generated doesn't change.  With larger power grids too much juice in the transmission lines is bad if there's nothing on the other end to consume it.  On coal, oil, wind, and hydro plants the engineers can turn off and on different generators at various times of the day to regulate how much electricity is generated.  I'm guessing you can't simply turn off a solar panel. It's always on soaking it in.

So what happens in an off-grid system once the batteries are full?  Where does that excess go? 
so many questions, so much for me to learn ...

[dragoncar]

So what happens in an off-grid system once the batteries are full?  Where does that excess go? 
so many questions, so much for me to learn ...

I believe it has to burn off as heat -- through a resistive network (i.e., an electric heater).  Again, if there is too much excess heat it will break.

[NaturallyHappier]

Regarding ground mount vs. roof mount; I have both and I feel the ground mount is far superior to roof mount if you use the pole mounts.  The pole mounts i have are basically a rack/frame mounted at the top of an 8 inch heavy wall pipe. 

With pole mounts I can tilt the panels more south in the winter and make them nearly flat in the summer.  Besides getting more energy production, I also don't have to remove snow in the winter.

[wienerdog]

With pole mounts I can tilt the panels more south in the winter and make them nearly flat in the summer.  Besides getting more energy production, I also don't have to remove snow in the winter.

What?  No east / west auto tracking?  lol