Solar panels

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Valuethinker
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Re: Solar panels

Post by Valuethinker » Thu Jul 13, 2017 2:42 pm

bighatnohorse wrote:I was having some roof repair done on my Arizona house and asked the roofer if he thought the roof would support solar panels.
He did.
But he also mentioned that when the roof needs to be replaced, the solar panels needed to be removed first.
- A hidden cost.

A kind of obvious one if we stopped to think about it! ;-)

I wonder if panels, by reducing solar expansion, might increase life of roof?

But for sure panels have to come off when roof is redone. Good news is that you can put the panels back on at the end as part of same job. Although in reality the technology is improving fast enough that you probably install new panels at that point.

tech_arch
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Re: Solar panels

Post by tech_arch » Fri Jul 14, 2017 1:48 pm

bighatnohorse wrote:I was having some roof repair done on my Arizona house and asked the roofer if he thought the roof would support solar panels.
He did.
But he also mentioned that when the roof needs to be replaced, the solar panels needed to be removed first.
- A hidden cost.
Yep. When we signed our contract to have our PV system installed we also had them specify the cost ($50/panel) to remove & reinstall the panels if/when we re-roof. The panels *should* increase the lifespan of that section of roof, so that's a minor boon.

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czeckers
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Re: Solar panels

Post by czeckers » Fri Jul 14, 2017 2:40 pm

The math is fairly simple: cost of system vs annual cost of electric use will give you a basic idea of payback time.

However, there are a few considerations:
-It's certainly more compelling the more expensive your electricity is making the payback period shorter.
-You have to consider the cost of financing.
-State/federal incentives are often quite good, but time-limited.
-As with other electronics, the cost of solar panels is going down while the output per panel is going up.
-Be wary that installers will often play with the price to make it so the monthly payment on the financing comes out to be the same as your monthly electric bill making it seem like a no-brainer. However, if you shop around, you will often times find someone who will do it for less.
-Know what the utility does with surplus electricity. If you have "net metering", they will simply run the meter backwards. Know what rate you will get from them for surplus electricity. In my area, I was paying 8.5 cents per kwh, but was only given wholesale pricing for the surplus of 1.5 cents so for me, it made sense to "right size" the system and not try to go for the refund checks.
-If you are going to put the system on your roof, an engineer will have to approve the added roof load in some areas. A ground mounted system is often cheaper if you have the land. It also avoids dealing with the panels should a roof repair be needed.
-If you are going to mount them on a roof, consider getting metal roofing installed first: It lasts much longer and the panels can clip to the ribs without putting holes through your roof.
-In hot climates, the panels will provide shade to your south-facing roof reducing cooling load.
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zack907
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Re: Solar panels

Post by zack907 » Fri Jul 14, 2017 3:31 pm

DiscoBunny1979 wrote:I live in Southern CA and have Edison :-(


Got an estimate from Edison in terms of going on their "level pay" plan whereas each month would be the same amount. The result in asking was that they wanted $350.00 a month. My highest bill in summer had been $720.00 in August.

So, with an average utility usage cost of 350 x 12 x 10 years = $42,000.
I would also factor in that it is likely that energy costs will rise in the future with inflation and your loan repayment costs will stay the same initially and then drop to 0 after it is paid off.

I just signed up to have solar panels installed on my house in Phoenix, so I am looking forward to that. Have there been any issues with downtime on your panels where you ended up paying both bills?

Incendiary
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Re: Solar panels

Post by Incendiary » Sat Jul 15, 2017 5:47 pm

What is a reasonable rate of inflation to assume for electricity costs?

Also, a roofer told me not to get solar panels. Said roof gets badly damaged and he never recommends them because they cause many problems. He was very adamant, but I've never heard anyone with solar complain about this...

How long do panels and inverters and whatever else tend to last? 25 years?

Finally, what should it cost to remove and reinstall solar panels when roofing work needs to be done?

Thanks!

arsenalfan
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Re: Solar panels

Post by arsenalfan » Sat Jul 15, 2017 5:58 pm

Pepco MidAtlantic numbers:

$8.12 interconnect fee.
For the 9 months I've had the system on, Pepco has paid me +$134 and I've received $40 in SRECs.
Solar installer charges $250 to remove panels/put back up if roofing issues. They've been around for 40 years.
Our roofer said it protects the roof.
They have survived dime size hail and 50-60 mph winds this year.

Valuethinker
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Re: Solar panels

Post by Valuethinker » Sun Jul 16, 2017 2:32 am

Incendiary wrote:What is a reasonable rate of inflation to assume for electricity costs?

Also, a roofer told me not to get solar panels. Said roof gets badly damaged and he never recommends them because they cause many problems. He was very adamant, but I've never heard anyone with solar complain about this...

How long do panels and inverters and whatever else tend to last? 25 years?

Finally, what should it cost to remove and reinstall solar panels when roofing work needs to be done?

Thanks!
Electricity price I would use 2 to 3 per cent pa ie about inflation. If using real cash flows then 0 to 1 per cent ie a bit above inflation.

I would get another roofer's opinion. It's too important just to ignore, but I had never heard that 're damage to roof.

Panels last longer than 25 years but probably by then far more Efficient ones will be available. So 25 years. Inverters 10 to 15 years so say 12 years?

Reinstall you need to ask around.

Note make sure you have maximized electricity savings before calculating. Fridge less than 15 years old. Led light bulbs and kill o watt test to find vampires, ac seer 15 (or estimate of consumption using same) etc.

mervinj7
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Re: Solar panels

Post by mervinj7 » Thu May 17, 2018 4:09 pm

Sorry to resurrect an old thread but did anybody find a good spreadsheet to calculate ROI for rooftop solar panels? I'm probably overthinking this but here's an example for a solar quote in Campbell, CA assuming the electricity provider is Silicon Valley Clean Energy and the rate plan is EV-A.

1. Upfront System Cost
$3.00/Watt * 8.04kW = $24,210
After ITC (30% Federal Tax Credit) -> $16,884.00

2. AC Energy Generated
Using PVWatts and based on our panel type, system efficiency, and roof orientation, we expect 12,060 kWh produced per year
https://pvwatts.nrel.gov/

3. Average Retail Rate with Net Metering and an Electric Vehicle rate plan
Due to the Net Metering Plan available to us as part of our Community Owned Electricity Provider and being on an EV-Rate, the average retail rates during electricity generation is $0.29/kWh. During the night, when we charge our EV, we pay $0.13/kWh.
https://www.svcleanenergy.org/solar/
https://www.pge.com/tariffs/assets/pdf/ ... 0(Sch).pdf

4. Annual Electricity Value
$0.29/kWh *12,060 kWh/year = $3,535.75/year

5. Simple Breakeven
$16,884/$3535/year= 4.8 years

6. ROI?

SmallSaver
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Re: Solar panels

Post by SmallSaver » Thu May 17, 2018 5:14 pm

I've spent a whole lot of time looking into it. A good report on the financial aspects of residential solar and calculator to go with it, are available here (look for "Financial Analysis of Residential Solar" and "Residential Solar Model Spreadsheet").

The question is what you mean, mathematically, by ROI. That spreadsheet will give you IRR which, while it has its problems, is pretty close to what most people think of as rate of return. Alternatively you can come up with your personal discount rate and check the NPV. Your situation may be complicated if you have demand charges, tiered pricing, or time of use pricing. At that point if you really want to get into it you should check out the National Renewable Energy Lab's SAM model, but it takes some learning to use.

That's a good payback. Might tell you all you need to know.

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just frank
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Re: Solar panels

Post by just frank » Thu May 17, 2018 5:24 pm

If I had a sunny lot I would get solar for a decent price.

The investment is not without its risks however. As solar gets cheaper and continues to grow eventually there will be an oversupply of electricity during daylight hours, which will lead to time of use rates, and cut into your savings.

This will likely become a factor when solar on your local grid reaches 10-20% of total electrical energy.

On a national basis, in the last 12 months solar produced 2% of all electrical energy, or about 5-6% of midday electrical demand, and is growing at a rate which doubles roughly every 2-2.5 years. Three doublings, which should take about 6-8 years from now, will get us to 15% of US electrical power. Higher solar utilization states will likely switch to TOU at or before that time. Lower ones will take a couple more years. Storage will come on line around then to store the excess, but the daytime rate discount will likely remain.

So, if your simple payback looks like it will take less than 6-8 years, you should be fine. If it looks to take longer than that, you might lose a bit.

I wouldn't lose sleep over it in any event. But the 'free power for 20 years' thing is unlikely to materialize.

As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?

SmallSaver
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Re: Solar panels

Post by SmallSaver » Thu May 17, 2018 5:42 pm

just frank wrote:
Thu May 17, 2018 5:24 pm
As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?
Interesting. I have always taken the opposite view: at the least prices will stay flat (real), but they're almost certain to go up over the next 25 years. Honestly the opposite had never even crossed my mind.

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yatesd
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Re: Solar panels

Post by yatesd » Thu May 17, 2018 6:13 pm

My electric bill is going down $11 a month
https://www.bge.com/News/Pages/Press%20 ... Month.aspx

mervinj7
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Re: Solar panels

Post by mervinj7 » Thu May 17, 2018 6:36 pm

just frank wrote:
Thu May 17, 2018 5:24 pm
The investment is not without its risks however. As solar gets cheaper and continues to grow eventually there will be an oversupply of electricity during daylight hours, which will lead to time of use rates, and cut into your savings.

This will likely become a factor when solar on your local grid reaches 10-20% of total electrical energy.
....
As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?
Frank,
My current energy provider already uses solar for 50% of its generation. The TOU rates have already been implemented and the peak rates are no longer at midday. I've already accounted for that with my lower average rate compared to the peak rate.

For example, during the summer, the peak is defined as 2PM-9PM (majority of household consumption). Part Peak is from 7AM-2PM (majority of solar generation). Off-peak is the rest (majority of EV charging).

Total Energy Rates ($ per kWh) PEAK PART-PEAK OFF-PEAK
Summer Usage $0.47334 (I) $0.25994 (I) $0.12753 (I)
Winter Usage $0.32987 (I) $0.20417 (I) $0.13046 (I)

Since I live in CA, I have no doubt my energy costs will continue to go up.

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dgm
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Re: Solar panels

Post by dgm » Thu May 17, 2018 6:36 pm

mervinj7 wrote:
Thu May 17, 2018 4:09 pm
Sorry to resurrect an old thread but did anybody find a good spreadsheet to calculate ROI for rooftop solar panels? I'm probably overthinking this but here's an example for a solar quote in Campbell, CA assuming the electricity provider is Silicon Valley Clean Energy and the rate plan is EV-A.

1. Upfront System Cost
$3.00/Watt * 8.04kW = $24,210
After ITC (30% Federal Tax Credit) -> $16,884.00

2. AC Energy Generated
Using PVWatts and based on our panel type, system efficiency, and roof orientation, we expect 12,060 kWh produced per year
https://pvwatts.nrel.gov/

3. Average Retail Rate with Net Metering and an Electric Vehicle rate plan
Due to the Net Metering Plan available to us as part of our Community Owned Electricity Provider and being on an EV-Rate, the average retail rates during electricity generation is $0.29/kWh. During the night, when we charge our EV, we pay $0.13/kWh.
https://www.svcleanenergy.org/solar/
https://www.pge.com/tariffs/assets/pdf/ ... 0(Sch).pdf

4. Annual Electricity Value
$0.29/kWh *12,060 kWh/year = $3,535.75/year

5. Simple Breakeven
$16,884/$3535/year= 4.8 years

6. ROI?
A friend recently (late last year) got solar and I helped extensively so I am up to date on prices and suggestions. This is in silicon valley w/ PG&E. A few comments.

1. The price is good. You can probably get them down a bit more as that is close to what my friend got in a very large city w/ presumably higher labor costs. Your city may also have some solar incentives so it is worth spending a few mins checking.
2. for ROI calculators you will need to include various things that the utility company will still charge you like distribution fees, so your estimate is probably a bit short for breakeven time. in addition, if you are selling electricity back to the grid, that can be a different price than what you purchase it at (wholesale vs retail) so you should keep that in mind and keep your generation as close to consumption as possible.
3.can't help w/ a good ROI calculator. usually the solar companies have an ROI calculator they use, which may be a good starting point to begin asking questions-- being in a large market meant there were multiple online tools that would pull in data directly from their utility bill to calculate ROI so this was not an issue

emoore
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Re: Solar panels

Post by emoore » Thu May 17, 2018 7:34 pm

SmallSaver wrote:
Thu May 17, 2018 5:42 pm
just frank wrote:
Thu May 17, 2018 5:24 pm
As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?
Interesting. I have always taken the opposite view: at the least prices will stay flat (real), but they're almost certain to go up over the next 25 years. Honestly the opposite had never even crossed my mind.
+1 to energy production costs going down. As more and more renewable energy gets added to the mix the cost to generate a unit of energy will decrease to near 0. The biggest costs will be maintaining he grid and transmission costs. And of course taxes.

WhyNotUs
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Re: Solar panels

Post by WhyNotUs » Thu May 17, 2018 10:41 pm

just frank wrote:
Thu May 17, 2018 5:24 pm

As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?
While my crystal ball does not tell me electric rates 10-20 years from now, the effects described above do not seem to have hit yet unless Frank knows more that the US Energy Information Administration

"EIA’s Short-Term Energy Outlook forecasts the typical U.S. household will spend an average of $426 for electricity this summer (June–August), an increase of about 3% from the average summer expenditures in 2017. The expected increase in electricity bills is a result of forecast higher retail electricity prices and slightly higher projected electricity use to meet increased cooling demand.

EIA expects U.S. residential retail electricity prices to average 13.5 cents per kWh between June and August 2018, about 2% higher than last summer. Electricity prices are rising primarily in response to higher generation fuel costs, especially for natural gas. Retail electricity rates are also rising as utilities increase their investments in transmission infrastructure. Electricity prices are expected to be higher this summer in all regions of the country."
I own the next hot stock- VTSAX

wootwoot
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Re: Solar panels

Post by wootwoot » Fri May 18, 2018 1:02 am

emoore wrote:
Thu May 17, 2018 7:34 pm
SmallSaver wrote:
Thu May 17, 2018 5:42 pm
just frank wrote:
Thu May 17, 2018 5:24 pm
As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?
Interesting. I have always taken the opposite view: at the least prices will stay flat (real), but they're almost certain to go up over the next 25 years. Honestly the opposite had never even crossed my mind.
+1 to energy production costs going down. As more and more renewable energy gets added to the mix the cost to generate a unit of energy will decrease to near 0. The biggest costs will be maintaining he grid and transmission costs. And of course taxes.
Energy production costs can go down but don't expect to see that reflected in your utility bills. Utilities are legal monopolies in many localities, much like cable companies. There is no competition and prices will not drop until competition exists. Many local utilities are also in the pocket of politicians so good luck waiting for any price reductions.

Valuethinker
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Re: Solar panels

Post by Valuethinker » Fri May 18, 2018 6:54 am

SmallSaver wrote:
Thu May 17, 2018 5:42 pm
just frank wrote:
Thu May 17, 2018 5:24 pm
As for energy inflation....I would not be surprised if it was negative over the next 10-20 years. Numerous new ways of making energy cheaply have been fielded recently, and are being rapidly built out. What do you expect to happen in that case?
Interesting. I have always taken the opposite view: at the least prices will stay flat (real), but they're almost certain to go up over the next 25 years. Honestly the opposite had never even crossed my mind.
I encourage you to read Professor Dieter Helm "The Carbon Crunch" and (especially) "Burnout: the end game for fossil fuels". The path to the end point is never exactly as the experts predict, but the latter book in particular is persuasive about where this is all going.

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jharkin
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Re: Solar panels

Post by jharkin » Fri May 18, 2018 9:44 am

I dont have solar myself, but a good fiend does. He achieved break even in about 6 years by overbuilding the system so that he net sells electricity even in winter, and heavily leveraging the install tax credit and SREC incentives for selling power. He also bought a plug in hybrid to use some of that extra generation.


Without all those incentives I dont think it works out financially in less than decade timespans?

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teacher
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Re: Solar panels

Post by teacher » Fri May 18, 2018 10:15 am

We would have solar panels installed in a heartbeat if it weren't for several Canary Island Pines we planted 35 years ago shading a large portion of our roof. Even though they are lush, and they cool the house naturally on summer days, our decision to plant them precludes taking advantage of much lower rates solar panels would provide during guaranteed sunny days. Our landscape decision would have been different under today's energy opportunities and requirements.

Solar panels could be required on all new California homes. Here's what it would cost
http://www.sacbee.com/news/business/rea ... 30194.html
Last edited by teacher on Fri May 18, 2018 10:49 am, edited 1 time in total.

mervinj7
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Re: Solar panels

Post by mervinj7 » Fri May 18, 2018 10:44 am

emoore wrote:
Thu May 17, 2018 7:34 pm
+1 to energy production costs going down. As more and more renewable energy gets added to the mix the cost to generate a unit of energy will decrease to near 0. The biggest costs will be maintaining he grid and transmission costs. And of course taxes.
Although energy production costs have been going down, it doesn't necessarily mean that utility rates are going down. For example, on my last bill, I was charged $0.28 per kWh at the retail rate. Of this, the generation cost was $0.065 (less than 25% of the total cost) and its only that high because all of my power comes from renewable sources. Even if generation costs gets cut in half, that only only decreases my retail cost by $0.03.

mervinj7
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Re: Solar panels

Post by mervinj7 » Fri May 18, 2018 11:05 am

dgm wrote:
Thu May 17, 2018 6:36 pm
A friend recently (late last year) got solar and I helped extensively so I am up to date on prices and suggestions. This is in silicon valley w/ PG&E. A few comments.

1. The price is good. You can probably get them down a bit more as that is close to what my friend got in a very large city w/ presumably higher labor costs. Your city may also have some solar incentives so it is worth spending a few mins checking.
2. for ROI calculators you will need to include various things that the utility company will still charge you like distribution fees, so your estimate is probably a bit short for breakeven time. in addition, if you are selling electricity back to the grid, that can be a different price than what you purchase it at (wholesale vs retail) so you should keep that in mind and keep your generation as close to consumption as possible.
3.can't help w/ a good ROI calculator. usually the solar companies have an ROI calculator they use, which may be a good starting point to begin asking questions-- being in a large market meant there were multiple online tools that would pull in data directly from their utility bill to calculate ROI so this was not an issue
Campbell is in Silicon Valley (https://goo.gl/maps/ijBEsmziXUn). Even though its a "small town", we are surrounded by San Jose, Los Gatos, and Saratoga. When we moved down from Menlo Park, I had to point out my town to our other friends who have lived in the Bay Area for years. :annoyed Labor rates are no lower here than anywhere else in Silicon Valley. As far as I know, there are no specific local solar incentives except that we do get to use a Community Owned utility service that works with PG&E.

We use PG&E as our delivery service but one advantage of using Silicon Valley Clean Energy as our energy source is that when we sell electricity back to the grid, we get it at retail rates with a maximum annual cap of $5000. With "pure" PG&E service, you only get the wholesale rate of $0.02-$0.03 per kWh. That said, with NEM 2.0 (net metering 2.0), that retail rate is reduced by the non-by-passable charges (NBC) at 2-3 cents per kWh. However, in our case, we won't be overproducing electricity based on our expected electricity usage.

https://www.svcleanenergy.org/solar/

emoore
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Re: Solar panels

Post by emoore » Fri May 18, 2018 11:17 pm

mervinj7 wrote:
Fri May 18, 2018 10:44 am
emoore wrote:
Thu May 17, 2018 7:34 pm
+1 to energy production costs going down. As more and more renewable energy gets added to the mix the cost to generate a unit of energy will decrease to near 0. The biggest costs will be maintaining he grid and transmission costs. And of course taxes.
Although energy production costs have been going down, it doesn't necessarily mean that utility rates are going down. For example, on my last bill, I was charged $0.28 per kWh at the retail rate. Of this, the generation cost was $0.065 (less than 25% of the total cost) and its only that high because all of my power comes from renewable sources. Even if generation costs gets cut in half, that only only decreases my retail cost by $0.03.
I agree. I was trying to say something like that but I was doing it poorly. Unfortunately utilities won’t reduce overall rates even though electricity will be much cheaper to generate. They will jack up the transportation or maintainence costs to at least maintain the same overall rate.

Lyonsguy
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Re: Solar panels

Post by Lyonsguy » Sat May 19, 2018 12:36 am

Mine (in Colorado) have a 10-12 year roi. But it is fairly low risk - so that is about 8% per year. You can’t beat that risk/return in the market.

Looking back. I would be comfortable buying and installing the panels myself, but then paying a n electrician to install and connect the inverter. Roi would have been 3-4 years instead of 10-12.

Also I like talking about the cool technology on my roof - it’s a little bit of a social status here in Colorado.

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unclescrooge
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Re: Solar panels

Post by unclescrooge » Sat May 19, 2018 2:20 am

Incendiary wrote:
Sat Jul 15, 2017 5:47 pm
What is a reasonable rate of inflation to assume for electricity costs?

Also, a roofer told me not to get solar panels. Said roof gets badly damaged and he never recommends them because they cause many problems. He was very adamant, but I've never heard anyone with solar complain about this...

How long do panels and inverters and whatever else tend to last? 25 years?

Finally, what should it cost to remove and reinstall solar panels when roofing work needs to be done?

Thanks!
I've had a roofer argue with me about putting vents near the bottom of the roof. He said he's been doing this for 30 years and he never does that. Only ridge venting, or vents near the top of the roof.

Of course, this means he's been doing it wrong for 30 years.

samtex
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Re: Solar panels

Post by samtex » Sat May 19, 2018 4:02 am

SCV_Lawyer wrote:
Mon Jul 10, 2017 11:04 pm
We are in the process of interviewing several installers for solar. We are in SoCal and have Edison. Our average price for electricity for our usage is $0.24/kWh. A 9kW system will run us $27,300 pre tax credit ($3.03/W) and $19,100 after the tax credit. This system will be sufficient to provide all of our annual use (13,600 kWh), albeit we will be buying power in some months while selling power in other months. Our annual bill is about $3,250, so the break-even is less than 6 years. Over 10 years (our expected hold time for this house), our savings should be over $13k, or even more if electricity rates continue to rise.

And this does not include the increase in house value. Some recent studies claim that owned (not leased) solar power systems add $4/W to house value, or in our case, $36k, which is $17k more than we are paying for the system. Even if it adds half that value, the system is 100% covered by house value increase alone. Since the panels are guaranteed to produce no less than 80% of their initial power 25 years out, this increase in home value should be sustained for the long term.
$0.24/kwh - ouch.

With deregulation in Texas, ours plan is currently at $0.084/kwh. (Includes energy costs and distribution - in other words total bill divided by kilowatts) Back about 20 years ago, we were around $0.12/kwh. Not all of the state is deregulated, some have municipal power plants, which I believe tend to be higher (higher overhead and no competition).

With increase in natural gas production it's price has gone down and replaced many of the coal fired plants, reducing costs and pollution. If I understand it correctly, a sizable cost in Ca. is for decommissioning nuclear power plants. We also have some large wind farms but they do kill a substantial number of birds. Bit of a quandary for alternate fuel supporters.

I have a family member that was licensed for solar installation some years back as a side line. He is very techie, analytical but says currently it's hard to justify going solar from a financial perspective (in our part of the country), without substantial government tax credits and higher electric prices. In his area the city dropped their solar subsidy after a few years, one of the few Texas cities that tried it. He says most of the installers tend to be overly optimistic on their payback numbers. Also the solar panels do have a life expectancy to take in account (some brands worse than others), as well as a slight efficiency loss every year, you may have to start replacing panels before getting your full payback. Most of his business was for people doing it for "environmental" reasons and oddly enough some corporations that will never see any major payback but the solar panels were more for show and PR. But YMMV in your area.

Samtex

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just frank
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Re: Solar panels

Post by just frank » Sat May 19, 2018 5:57 am

Lyonsguy wrote:
Sat May 19, 2018 12:36 am
Mine (in Colorado) have a 10-12 year roi. But it is fairly low risk - so that is about 8% per year. You can’t beat that risk/return in the market.

Looking back. I would be comfortable buying and installing the panels myself, but then paying a n electrician to install and connect the inverter. Roi would have been 3-4 years instead of 10-12.

Also I like talking about the cool technology on my roof - it’s a little bit of a social status here in Colorado.
Did you include depreciation? A 10 year 'simple payback' is not the same as an investment returning 10% CAGR while returning principal. It takes 10 years to return the initial investment and break even...$0 NPV with no earnings.

That said...I hope you continue to enjoy your panels! :beer

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Re: Solar panels

Post by Valuethinker » Sat May 19, 2018 7:59 am

samtex wrote:
Sat May 19, 2018 4:02 am

With increase in natural gas production it's price has gone down and replaced many of the coal fired plants, reducing costs and pollution. If I understand it correctly, a sizable cost in Ca. is for decommissioning nuclear power plants. We also have some large wind farms but they do kill a substantial number of birds. Bit of a quandary for alternate fuel supporters.
Roughly speaking, plate glass windows kill about 1 billion birds a year, and domestic cats about 3 billion, in the USA. Wind farms kill perhaps a million. The newer wind farms, with larger, slower moving blades, kill fewer. The first US wind farms, in the Altamont Pass area of California, which were built in the 70s/ 80s turned out to be uniquely badly placed vis-a-vis raptor deaths, and with small high speed turbines. Nobody is arguing for abolishing plate glass windows nor domestic cats?

https://www.sciencenews.org/article/win ... ted-states

https://www.carbonbrief.org/bird-death- ... e-evidence

BTW coal fired power stations kill more birds every year than wind farms. (there is an issue with a couple of types of bat, and I am not sure where the science has gotten to on that).

On decommissioning nuclear plants, if you mean Diablo Canyon, it has yet to decommission. But yes, that cost will fall on consumers. So will the cost of decommissioning *all* nuclear power plants-- that's the nature of the technology. That cost to the system is baked into the initial adoption of the technology when you build the plant. Keeping Diablo Canyon open would only have delayed that by say 10 years. Once the plants are over 40 years old, their operation becomes increasingly uneconomic. Right now a lot of nuclear power plants are losing money, because of cheap natural gas and static/ declining overall electricity demand.
I have a family member that was licensed for solar installation some years back as a side line. He is very techie, analytical but says currently it's hard to justify going solar from a financial perspective (in our part of the country), without substantial government tax credits and higher electric prices. In his area the city dropped their solar subsidy after a few years, one of the few Texas cities that tried it. He says most of the installers tend to be overly optimistic on their payback numbers. Also the solar panels do have a life expectancy to take in account (some brands worse than others), as well as a slight efficiency loss every year, you may have to start replacing panels before getting your full payback. Most of his business was for people doing it for "environmental" reasons and oddly enough some corporations that will never see any major payback but the solar panels were more for show and PR. But YMMV in your area.

Samtex
It looks like the life of panels is c. 25 years (inverters c. 12 years) however that is with declining efficiency. But there are panels that old still running so we know it.

What will actually probably happen is that as solar technology improves conversion efficiency and the price per kw drops, it will be economic to replace panels sooner.

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Re: Solar panels

Post by Lyonsguy » Sat May 19, 2018 1:07 pm

just frank wrote:
Sat May 19, 2018 5:57 am
Lyonsguy wrote:
Sat May 19, 2018 12:36 am
Mine (in Colorado) have a 10-12 year roi. But it is fairly low risk - so that is about 8% per year. You can’t beat that risk/return in the market.

Looking back. I would be comfortable buying and installing the panels myself, but then paying a n electrician to install and connect the inverter. Roi would have been 3-4 years instead of 10-12.

Also I like talking about the cool technology on my roof - it’s a little bit of a social status here in Colorado.
Did you include depreciation? A 10 year 'simple payback' is not the same as an investment returning 10% CAGR while returning principal. It takes 10 years to return the initial investment and break even...$0 NPV with no earnings.

That said...I hope you continue to enjoy your panels! :beer
How would I include depreciation on this calculation? So I paid $9000 out of pocket and save $100 / month. I have no idea the cost of the panels after 10 years. I could assume they still generate about 70% of new efficiencies.

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Re: Solar panels

Post by just frank » Sat May 19, 2018 1:34 pm

Lyonsguy wrote:
Sat May 19, 2018 1:07 pm
just frank wrote:
Sat May 19, 2018 5:57 am
Lyonsguy wrote:
Sat May 19, 2018 12:36 am
Mine (in Colorado) have a 10-12 year roi. But it is fairly low risk - so that is about 8% per year. You can’t beat that risk/return in the market.

Looking back. I would be comfortable buying and installing the panels myself, but then paying a n electrician to install and connect the inverter. Roi would have been 3-4 years instead of 10-12.

Also I like talking about the cool technology on my roof - it’s a little bit of a social status here in Colorado.
Did you include depreciation? A 10 year 'simple payback' is not the same as an investment returning 10% CAGR while returning principal. It takes 10 years to return the initial investment and break even...$0 NPV with no earnings.

That said...I hope you continue to enjoy your panels! :beer
How would I include depreciation on this calculation? So I paid $9000 out of pocket and save $100 / month. I have no idea the cost of the panels after 10 years. I could assume they still generate about 70% of new efficiencies.
A real NPV calculation would require an assumed discount rate.

All I am saying is that your simple payback is 9000/1200 = 7.5 years. This is not a 1/7.5 = 13% rate of return, because you have 'lost' the principal.

After 7.5 years, you haven't earned anything, you have just made your $9000 back (ignoring inflation). Then you start 'making money'. At year 15 you've made another $9k, so you've made $9k net over 15 years on a $9k investment, or a rate of return of equivalent to 72/15 = 4.8% CAGR (rule of 72).

If electricity prices are flat in nominal dollars, you are looking at ~2% real return.

By year 15 you might need a new inverter, you might have moved (and not recouped the value in sale price) or the market might have made solar less valuable. So banking on a 30-year no-cost service life to do the economics is a bit iffy IMO.

If you DO assume a 30 year return, you make 3x your investment in 30 y then that is 3*72/30 = 7.2% CAGR, or maybe 5% real CAGR over that span.

There is a big LBNL presentation here
http://eta-publications.lbl.gov/sites/d ... on_pdf.pdf
that suggests that more wind+solar on the grid will lead to a reduction in future electricity prices. On the order of 10-20% with high penetration factor (currently wind and solar are at 12% of US electricity)...this could wipe out a decade or two of electricity price inflation.

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Re: Solar panels

Post by swettymon » Sun May 20, 2018 8:47 am

I am in NH where the electric rates are high and the solar days are mid-range so a strict ROI could be 7-10 years. However, solar panels do not conform to a traditional investment in a couple of different ways. Using my situation, a 5.1K array, targeting 110% replacement of used electricity cost me $10,518 out of pocket after a 30% federal tax credit and a $2,500 grant from the State of NH. My town does not tax the value added to the property for solar panels, so I immediately realized a $20-25,000 uptick in equity for my home with no corresponding increase in property tax. NH does not have any broad based taxes, so a great deal of services/education is funded via property taxes, so this benefit is saving me around $600 per year on my property taxes. My electric bill has gone to virtually $0 per month, just the $13.00 service charge from Eversource, and I have received approximately $100 from the sale of clean energy credits. Our bill used to average $100 per month so my $10,518 is returning a raw 11.4% tax free return. In 8-9 years, using the price of electricity at the time of the installation (.17971/kWh), the system will have literally paid for itself. If the price of electricity goes up the payoff is even faster. We made this investment as part of our retirement strategy for the reasons stated above. If we keep the home for several more years we have virtually eliminated one monthly utility bill. When we sell the home we will realize the equity of the panels in whatever value it adds to the sale price without having paid property taxes on that portion since 07/2016 (installation date).

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Re: Solar panels

Post by Ricola » Sun May 20, 2018 10:48 am

The whole solar panels on houses, makes me think of the old aluminium siding business depicted in the movie Tin Men.

https://www.youtube.com/watch?v=CnvXjCv089s
Last edited by Ricola on Sun May 20, 2018 1:19 pm, edited 1 time in total.

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Re: Solar panels

Post by Sandtrap » Sun May 20, 2018 10:58 am

Total cost of solar system.
Annual savings compared to no solar.
Years to recoup cost of solar system in those savings.
Plus repair and replacement of items that wear out or degrade.

compared to:
My estimated retirement years at this residence and time left on the planet.
DW estimated retirement years at this residence and time left on the planet.

Decided not to install solar.
Money better spent on a whole house emergency electric system.

j

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Re: Solar panels

Post by Nate79 » Sun May 20, 2018 11:00 am

swettymon wrote:
Sun May 20, 2018 8:47 am
I am in NH where the electric rates are high and the solar days are mid-range so a strict ROI could be 7-10 years. However, solar panels do not conform to a traditional investment in a couple of different ways. Using my situation, a 5.1K array, targeting 110% replacement of used electricity cost me $10,518 out of pocket after a 30% federal tax credit and a $2,500 grant from the State of NH. My town does not tax the value added to the property for solar panels, so I immediately realized a $20-25,000 uptick in equity for my home with no corresponding increase in property tax. NH does not have any broad based taxes, so a great deal of services/education is funded via property taxes, so this benefit is saving me around $600 per year on my property taxes. My electric bill has gone to virtually $0 per month, just the $13.00 service charge from Eversource, and I have received approximately $100 from the sale of clean energy credits. Our bill used to average $100 per month so my $10,518 is returning a raw 11.4% tax free return. In 8-9 years, using the price of electricity at the time of the installation (.17971/kWh), the system will have literally paid for itself. If the price of electricity goes up the payoff is even faster. We made this investment as part of our retirement strategy for the reasons stated above. If we keep the home for several more years we have virtually eliminated one monthly utility bill. When we sell the home we will realize the equity of the panels in whatever value it adds to the sale price without having paid property taxes on that portion since 07/2016 (installation date).
Why would the value of the home be more than the installed price of a depreciating asset whose installation cost is declining every year?

Perhaps home buyers can't do math but that is insanity if true.

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Re: Solar panels

Post by Valuethinker » Sun May 20, 2018 12:18 pm

Nate79 wrote:
Sun May 20, 2018 11:00 am
swettymon wrote:
Sun May 20, 2018 8:47 am
I am in NH where the electric rates are high and the solar days are mid-range so a strict ROI could be 7-10 years. However, solar panels do not conform to a traditional investment in a couple of different ways. Using my situation, a 5.1K array, targeting 110% replacement of used electricity cost me $10,518 out of pocket after a 30% federal tax credit and a $2,500 grant from the State of NH. My town does not tax the value added to the property for solar panels, so I immediately realized a $20-25,000 uptick in equity for my home with no corresponding increase in property tax. NH does not have any broad based taxes, so a great deal of services/education is funded via property taxes, so this benefit is saving me around $600 per year on my property taxes. My electric bill has gone to virtually $0 per month, just the $13.00 service charge from Eversource, and I have received approximately $100 from the sale of clean energy credits. Our bill used to average $100 per month so my $10,518 is returning a raw 11.4% tax free return. In 8-9 years, using the price of electricity at the time of the installation (.17971/kWh), the system will have literally paid for itself. If the price of electricity goes up the payoff is even faster. We made this investment as part of our retirement strategy for the reasons stated above. If we keep the home for several more years we have virtually eliminated one monthly utility bill. When we sell the home we will realize the equity of the panels in whatever value it adds to the sale price without having paid property taxes on that portion since 07/2016 (installation date).
Why would the value of the home be more than the installed price of a depreciating asset whose installation cost is declining every year?

Perhaps home buyers can't do math but that is insanity if true.
In an efficient market, the system cost is irrelevant to the uplift of the value of the home>

Present Value = sum of [ value of saved electricity bill ith year x 1/(1+ cost of capital)^i]

So we could assume a 25 year period, make assumptions about electricity rates and degradation of system performance over time, and calculate what our saved bills would be. One would want a terminal value as well, unless we believe the system to be useless after 25 years. We would have to factor in a replacement of inverters 10-15 years in.

Discount rate is tricky but I would argue 4% nominal (i.e. risk free rate + 1%) is reasonable.

If we use real cash flows rather than nominal, we could assume real change in electricity rates of zero, and discount by say 1.5-2.0% p.a. (ie somewhat above the TIPS rate).

However the savings are going to be income tax free, which is a nice little bonus we might not be able to assume for a financial investment.

The key thing to understand here is the Present Value = sum of the future cash flows (the savings from the system).

That's a good approximation of the uplift that installing the system will give to the value of the house. You then have to take a value whether that's true, by seeking out local comparable examples. My gut is in high adoption areas, this value is recognized by the market (for example areas with high retail electricity prices) and in low adoption areas, maybe less so.

The Net Present Value is then = (costs of system) + disctd value of inflows . Only if NPV > 0 should the homeowner consider making the investment (on strictly economic grounds, at least).

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Re: Solar panels

Post by pshonore » Sun May 20, 2018 12:39 pm

Valuethinker wrote:
Thu Jul 13, 2017 10:08 am
squirm wrote:How do you project out 35 years? I do data projections and even 20 years is difficult to forecast with any type of realistic accuracy.

If your solar system doesn't pay off within ten years it's probably better to take other measures.
It's not too bad in this respect. The capital costs are known, and you can make reasonable assumptions 're cost and timing of inverter replacement. The panel life can be estimated and there are known metrics for performance degradation. You can run your model until panels are very likely to need replacement (30 years?).

Over to the revenues. Harder. You can assume electricity rates grow at Inflation. Or you can assume they stay constant in nominal terms. Neither is particularly aggressive in terms of overstating present value.

A niggle. Daytime electricity prices (wholesale) could well be zero in 30 years as renewable electricity floods the grid. Wind and nuclear penetration have meant that nighttime prices can be negative ( excess generation).

Its already happened in New England; not zero rates but less demand:
On Saturday, April 21, 2018, the right combination of sunshine and mild weather led to light consumer demand on the high-voltage electric power system, coupled with record-high output from the more than 130,000 solar power installations in the region. The result was that midday grid demand dipped below overnight demand for the first time ever in New England.
http://isonewswire.com/updates/2018/5/3 ... ity-m.html

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Re: Solar panels

Post by Ricola » Sun May 20, 2018 1:13 pm

For about $50 extra per month or so, based on your average usage, my utility is offering to provide all solar-derived energy. So if you feel environmentally conscious and want to get all of your energy from solar, you can do it without actually adding any real hardware on your part. Where they are getting the solar, I don't know, maybe they are selling me the solar energy they are getting off my neighbours' roofs :oops: I don't know where this is going, but it could be along the lines of excess energy production.

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Re: Solar panels

Post by Valuethinker » Sun May 20, 2018 1:16 pm

Ricola wrote:
Sun May 20, 2018 10:48 am
Valuethinker wrote:
Thu Jul 13, 2017 10:18 am
StealthWealth wrote:I am a huge advocate for solar but do encourage people to do their own math. Unfortunately some installers show a much more attractive payback by including an overly aggressive "inflation" rate for traditional power costs. I do not think this is good for the industry as a whole but the public is by-and-large pretty oblivious to their utility bill and the various components. There can be quite a lot of subtlety as some places have time-of-use pricing or pricing based on peak demand over the course of the year. Things like this increase the value of solar but aren't always included on back-of-the-envelope calculations.
This is it. Caveat emptor.

I don't like solar panel leading for similar reasons. And who does the liability fall on If the system underperformed?

There's too much room for hucksterism in the current arrangements.

The whole solar panels on houses, makes me think of the old aluminium siding business depicted in the movie Tin Men.

https://www.youtube.com/watch?v=CnvXjCv089s
Ricola

You have misquoted me. I did not write the original quote that you have attributed to me.

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Re: Solar panels

Post by Ricola » Sun May 20, 2018 1:24 pm

Valuethinker wrote:
Sun May 20, 2018 1:16 pm
Ricola wrote:
Sun May 20, 2018 10:48 am
Valuethinker wrote:
Thu Jul 13, 2017 10:18 am
StealthWealth wrote:I am a huge advocate for solar but do encourage people to do their own math. Unfortunately some installers show a much more attractive payback by including an overly aggressive "inflation" rate for traditional power costs. I do not think this is good for the industry as a whole but the public is by-and-large pretty oblivious to their utility bill and the various components. There can be quite a lot of subtlety as some places have time-of-use pricing or pricing based on peak demand over the course of the year. Things like this increase the value of solar but aren't always included on back-of-the-envelope calculations.
This is it. Caveat emptor.

I don't like solar panel leading for similar reasons. And who does the liability fall on If the system underperformed?

There's too much room for hucksterism in the current arrangements.

The whole solar panels on houses, makes me think of the old aluminium siding business depicted in the movie Tin Men.

https://www.youtube.com/watch?v=CnvXjCv089s
Ricola

You have misquoted me. I did not write the original quote that you have attributed to me.
Valuethinker,
System glitch I guess...but I have edited to remove any quotes.
Thanks for notifying and for your contributions to this subject.

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Re: Solar panels

Post by RCL » Sun May 20, 2018 7:16 pm

Another solar user here

I got my 8959 rated Kwhs system (8959 is the 80% output number) in August 2012. It still generates over a megawatt/year.
My monthly electric bill averaged about $210 a month (some months were over $400) prior to solar. For the first few years, up until 2016, my monthly fee to SCE (Southern California Edison) was a basic charge of between $1-$2. In 2016, SCE decided to change to a minimum charge scam scheme, which raised my monthly fee to about $10 a month.

I generate more electricity than I use, so I am called a gross provider.
Each year SCE pays me, via a check, for any extra electricity I produced during my 12 month period (as another poster earlier stated, this is at the wholesale rate and not the retail rate).
The yearly amount SCE pays me covers about 9-10 months of the minimum fee they charge me, so essentially, my electricity costs me about $18-$21 a year.

My property taxes were not increased due to the solar being installed. My roof (the paper product under the tile), at time of installation, was reaching it's end of life, so I had it replaced prior to installing the solar panels.

At the time, I was still in the work force, and thought I'd get this done while I still had an income, thus reducing my cost of living going forward into retirement.

It has worked out real well for me, and I'm glad I did it when I did (even though I realize I could have invested that money in my retirement account).
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mervinj7
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Re: Solar panels

Post by mervinj7 » Mon May 21, 2018 4:17 pm

just frank wrote:
Sat May 19, 2018 1:34 pm
There is a big LBNL presentation here
http://eta-publications.lbl.gov/sites/d ... on_pdf.pdf
that suggests that more wind+solar on the grid will lead to a reduction in future electricity prices. On the order of 10-20% with high penetration factor (currently wind and solar are at 12% of US electricity)...this could wipe out a decade or two of electricity price inflation.
Your own citation talks about decreasing wholesale prices for electricity. That, however, is not the retail rate that we as normal homeowners pay. For example, for me during the day out of my $0.28/kWh rate I pay to PG&E in NorCal, only $0.06 is for electricity generation (of which 50% comes from solar). Cut generation costs in half, and my retail rate drops to $0.25.

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Re: Solar panels

Post by psteinx » Tue May 22, 2018 11:05 am

Per the US Energy Information Administration, wind + solar were at 7.6% in the US in 2017 (6.3% wind, 1.3% solar).

https://www.eia.gov/tools/faqs/faq.php?id=427&t=3

EDIT: This is for utility scale generation. As another poster points out below, there is some additional solar generation done on a smaller scale. Specifically, that smaller scale stuff is estimated at 24 billion KwH, vs. the 53 billion KwH in the utility scale figure. Only the 53 billion KwH is used in the 1.3% figure.
Last edited by psteinx on Tue May 22, 2018 3:27 pm, edited 2 times in total.

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Re: Solar panels

Post by psteinx » Tue May 22, 2018 11:14 am

More generally, and speculatively (and per my layman's understanding):

Retail electricity cost is a combination of the wholesale cost, plus a bunch of other stuff - delivery costs (that vast network of electricity lines, substations and the like that gets electricity to your home and/or local industry and businesses), various other overhead, profits, etc. Since the industry is generally structured as a public utility, prices are generally set by regulators, commissions, etc., and are probably not super responsive in the short term, but probably ARE fairly responsive to underlying cost shifts in the medium to longer term.

Should cheaper supply lower wholesale costs (at least in real, if not nominal terms), then that should trickle down to consumers, over time, in part. Of course, other parts of the retail cost (i.e. the delivery network) are driven by largely separate factors, so a 10% decrease (or increase) in wholesale prices should not be expected to translate into a 10% shift in retail prices.

My (pretty seriously underinformed) guess? Retail electricity costs across the country will rise at somewhat less than the cost of inflation over the next couple decades - perhaps 0.5 to 1.0% below inflation. Why? Improvements to wind, solar and storage, and probably a long term supply of cheap natural gas. Offset to some extent by new regulatory driven costs related to CO2 and the like...

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Re: Solar panels

Post by emoore » Tue May 22, 2018 11:39 am

psteinx wrote:
Tue May 22, 2018 11:05 am
Per the US Energy Information Administration, wind + solar were at 7.6% in the US in 2017 (6.3% wind, 1.3% solar).

https://www.eia.gov/tools/faqs/faq.php?id=427&t=3
Nice to see those renewable percentages rise. Hopefully in 2018 renewables pass nuclear and maybe even coal. That would be a surprise to a lot of people.

VaR
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Re: Solar panels

Post by VaR » Tue May 22, 2018 2:12 pm

Incendiary wrote:
Mon Jul 10, 2017 8:28 pm
For those of you who have looked into solar panels, how did you decide if it was worth doing or not? I'm talking from a purely economic perspective, not factoring in environmental concerns. The installer told us a break even period of nine years, but looking at the electric bills it seems more like 15 years. And that doesn't take into account TVM. I'm wondering what I'm missing.
Our solar installer payback analysis wasn't incorrect but is less comprehensive than the analysis here on this forum.

For the ones presented by my installers, here are the areas where they could improve:
1. Since I'm paying cash for my installation, incorporate my cost of capital. In my case, I instead used as my target for comparison a hypothetical amortizing municipal bond. This is because your saved electricity costs are equivalent to a combination of tax-free interest on your investment plus some return of capital. The solving for the rate on this bond gives me my after-tax IRR.
2. Account for a terminal value on the installation after 20 years. (this usually has a negligible effect on the outcome of the analysis)
3. Account for the the 1% per annum degradation in electricity generation. (this usually has a negligible effect on the outcome of the analysis)
4. Either price in one replacement of a central inverter if you're using power optimizers (which you should be if you're optimizing for ROI/IRR)

One thing I've noticed is that there's a lot of variation in both pricing of installation and in expense of the panels themselves. It definitely pays to shop around. And it's critical to think carefully about whether you want the best ROI or whether you want other ineffable qualities. For instance, you'll get the best ROI from the cheapest panels. OTOH, I wouldn't blame anyone for wanting to "buy American" and support domestic industry, even though you sacrifice the best ROI for this.

Finally, it also pays to remember that saving energy almost always has the best ROI. Switching to LED lighting, adding insulation and weatherstripping, and getting newer windows almost always has great payback periods. If you have a pool getting a dual-speed or variable speed pool pump will pay for itself in a year or two. We recently replaced a TV and achieved 2.5 year payback period.
psteinx wrote:
Tue May 22, 2018 11:05 am
Per the US Energy Information Administration, wind + solar were at 7.6% in the US in 2017 (6.3% wind, 1.3% solar).

https://www.eia.gov/tools/faqs/faq.php?id=427&t=3
It's also footnoted that small-scale residential and commercial solar photovoltaic are estimated to have generated an additional 0.6% of electricity in 2017.
emoore wrote:
Tue May 22, 2018 11:39 am
Nice to see those renewable percentages rise. Hopefully in 2018 renewables pass nuclear and maybe even coal. That would be a surprise to a lot of people.
Not new but you should take a look at the EIA projection for 2018 and 2019, https://www.eia.gov/todayinenergy/detail.php?id=34612

Long-term forecasts from the EIA project renewables overtaking coal in 2040, and non-hydro renewables alone overtaking coal by 2050. That's a long way away.

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Re: Solar panels

Post by Hug401k » Tue May 22, 2018 2:43 pm

RCL wrote:
Sun May 20, 2018 7:16 pm
Another solar user here

My property taxes were not increased due to the solar being installed. My roof (the paper product under the tile), at time of installation, was reaching it's end of life, so I had it replaced prior to installing the solar panels.
I'm in the same boat. Did you claim your new roof as "site preparation" on your taxes? The solar company would not install on my existing roof (and I agreed with that).

Thanks
Last edited by Hug401k on Tue May 22, 2018 4:23 pm, edited 1 time in total.

RCL
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Re: Solar panels

Post by RCL » Tue May 22, 2018 3:00 pm

Hug401k wrote:
Tue May 22, 2018 2:43 pm
RCL wrote:
Sun May 20, 2018 7:16 pm
Another solar user here

My property taxes were not increased due to the solar being installed. My roof (the paper product under the tile), at time of installation, was reaching it's end of life, so I had it replaced prior to installing the solar panels.
I'm in the same boat. Did you claim your new roof as "site preparation" on your taxes? The solar company would not install on my existing roof (not that I thought that was a good idea).

Thanks
Hmm, no I did not. I guess that was a lost opportunity :annoyed
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