Author Topic: DIY Solar  (Read 4411 times)

coopdog

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DIY Solar
« on: February 09, 2018, 05:26:46 AM »
I got a quote in late 2016 for 13KW DC (16.8KW AC) for $23,600 after tax credit. That's about $1.81/installed watt with an estimated solar generation is $1,500/year. That's a 6.3% return not including depreciation of the panels. I don't really need to pencil further to figure that's just not a good investment for me, yet. 

So I was happy to see the post on DIY solar. I was astonished at his cost per watt, but a quick search on the internet reveals 300W panels are close to 3 times the cost of what MMM was able to purchase them. I'm guessing I can't come close to that. I've still got a lot of questions.

Is this 3x price difference a reflection of the the Trump tariffs or is MMM just getting better than wholesale pricing?

I'm curious what the installed watt price for other DIY'ers is?

What are good online providers of solar array equipment?


Lan Mandragoran

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Re: DIY Solar
« Reply #1 on: February 09, 2018, 07:14:58 AM »
I know the tariff was "only" 30% so thats certainly not the entire 300% increase your seeing.

b4u2

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Re: DIY Solar
« Reply #2 on: February 09, 2018, 09:21:16 AM »
Yeah I got excited about solar again after reading his blog but my costs are coming out way higher than his as well. The kit that he links seems decent and might be enough to generate what I need. Last month my power company said we used 841 kw and my average for the last year is 1,055 kw. Trying to size a system for 100% but that may not be necessary since I can't produce at night??? So would a 7kw system do the job?

My budget billing is $130 a month and I am at a surplus currently.
« Last Edit: February 09, 2018, 10:01:51 AM by b4u2 »

MustachianAccountant

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Re: DIY Solar
« Reply #3 on: February 20, 2018, 03:52:03 AM »
I know the tariff was "only" 30% so thats certainly not the entire 300% increase your seeing.

The tariff is also only for imported panels, so panels sourced from an American manufacturer wouldn't have that extra 30%.

I'd have to re-read the article, but MMM might have been including tax incentives and other "payback" type incentives into his calculation of cost per watt.

sherr

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Re: DIY Solar
« Reply #4 on: February 20, 2018, 07:40:23 AM »
I know the tariff was "only" 30% so thats certainly not the entire 300% increase your seeing.

The tariff is also only for imported panels, so panels sourced from an American manufacturer wouldn't have that extra 30%.

I'd have to re-read the article, but MMM might have been including tax incentives and other "payback" type incentives into his calculation of cost per watt.

Right, but panels from American manufacturers are also uncompetitively expensive, which was the justification for the 30% tariff in the first place. So if the problem is that they're too expensive then that doesn't help.

Cadman

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Re: DIY Solar
« Reply #5 on: February 20, 2018, 08:29:10 AM »

Right, but panels from American manufacturers are also uncompetitively expensive, which was the justification for the 30% tariff in the first place. So if the problem is that they're too expensive then that doesn't help.

I'm not sure that's a universally true statement. Both Suniva and Solarworld are US made and just as competitively priced as LG and other off-shore manufacturers. I've been very satisfied with my OPT-285's at roughly $1/watt.

Some members here are 'lucky' to live in states where there are heavy incentives on buying US, or in-state made panels. Not sure about the OP's situation.

Livethedream

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Re: DIY Solar
« Reply #6 on: February 22, 2018, 08:20:14 PM »
We did a DIY system in California. Shopped around for panels and found there is a couple great resellers that go the extra mile for the DIY crowd and have great prices.

320w panels with optimizers 7.2kw system $14,000 before federal rebate.

MasterStache

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Re: DIY Solar
« Reply #7 on: February 23, 2018, 12:00:08 PM »
I got a quote in late 2016 for 13KW DC (16.8KW AC) for $23,600 after tax credit. That's about $1.81/installed watt with an estimated solar generation is $1,500/year. That's a 6.3% return not including depreciation of the panels. I don't really need to pencil further to figure that's just not a good investment for me, yet. 

So I was happy to see the post on DIY solar. I was astonished at his cost per watt, but a quick search on the internet reveals 300W panels are close to 3 times the cost of what MMM was able to purchase them. I'm guessing I can't come close to that. I've still got a lot of questions.

Is this 3x price difference a reflection of the the Trump tariffs or is MMM just getting better than wholesale pricing?

I'm curious what the installed watt price for other DIY'ers is?

What are good online providers of solar array equipment?

Your post doesn't make much sense.
1. DC -> AC conversion typically experiences some power loss, not power gain.
2. A 13kW solar array is gigantic. Even at 300W/panel you need 44 panels.
3. Solar generation is typically measured in power produced (kWh), not monetary return. $1,500/year is considerably low. Where do you live? I live in the midwest with average solar insolation and our self installed 5.74kW system still saved us roughly $1K every year. 


coopdog

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Re: DIY Solar
« Reply #8 on: March 09, 2018, 05:52:12 AM »


1. You are correct. I meant 13k watts DC to 16.8 watt-hours. Two different measurements. The latter used since that's how we pay for electricity.
2. Yes. 13kw is gigantic. The company wanted to maximize my roof space so they could sell me more panels. My DIY install will be around 8.7kw.
3. Yes. I live in Southeast. We have low electricity rates. However,  TVA provides a 20-year guaranteed rate contract of $0.09/kwh, thus I convert that to monetary return. Based on my calcs, I can DIY it for about $7,100 after tax credits. Factoring NREL pvwatts data and taking into account degradation, it pencils out to just shy of a 13% IRR.


I'm a red panda

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Re: DIY Solar
« Reply #9 on: March 09, 2018, 10:04:34 AM »
I am super excited about solar, but our electricity is so cheap, and very few incentives for them here, it makes no sense here.  Last I did all the math I was looking at $5-7 per watt!

If we could do it like MMM maybe we would
Step 1: Find friend who can sell you system for wholesale price
Step 2: Find friend who can help you install system.

I mean, I'm lucky my husband is really handy, so we can DIY a lot- but step 1 seems to be what kept his costs so low; plus it looks like his area has some major incentives.


b4u2

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Re: DIY Solar
« Reply #10 on: March 10, 2018, 06:47:14 AM »
I don't have access to a great deal on panels but if you live in Iowa, By your name I make that assumption, I would certainly help install. I would like to install but I think cost is still to high in Iowa. Why does Colorado have such great incentives and yet Iowa doesn't?

I'm a red panda

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Re: DIY Solar
« Reply #11 on: March 10, 2018, 06:59:57 AM »
I don't have access to a great deal on panels but if you live in Iowa, By your name I make that assumption, I would certainly help install. I would like to install but I think cost is still to high in Iowa. Why does Colorado have such great incentives and yet Iowa doesn't?
I'm about 15 miles south of the airport you live by.

We are now facing a bit of job uncertainty, so while we were iffy before, I think it's a big no to such a major cost to the house (just in case we have to move). If you decide to putting in a system, I'd love to know your details, as I hope we do stay here!

I assume incentives are low because of wind energy here. Solar would take away from that. It's all lobbying.

I think our payback time is also low just because our energy is cheap.

coopdog

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Re: DIY Solar
« Reply #12 on: March 10, 2018, 08:44:16 AM »
I am super excited about solar, but our electricity is so cheap, and very few incentives for them here, it makes no sense here.  Last I did all the math I was looking at $5-7 per watt!

If we could do it like MMM maybe we would
Step 1: Find friend who can sell you system for wholesale price
Step 2: Find friend who can help you install system.

I mean, I'm lucky my husband is really handy, so we can DIY a lot- but step 1 seems to be what kept his costs so low; plus it looks like his area has some major incentives.

Yikes. $5/watt is nuts. I assume that is professional install. As mentioned in my earlier post, I was quoted around $1.80 after fed tax credit. I have zero incentives in my state other than fed tax credit.

I'm learning DIY is much much more cost effective. Granted my particular install should be very easy as for as solar goes. There are no roof or wall penetrations to do. It goes from my garage roof down an exterior wall to the meter bases.

I can buy a complete system, rack and everything, online for $8,744 from a reputable selller. That's nothing fancy, single inverter, no optimizers. Add in $1,500 for fees, design, electrician and I'm in for just over $10k. Fed tax credit makes that $7k or about $0.82/watt.


b4u2

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Re: DIY Solar
« Reply #13 on: March 10, 2018, 09:44:52 AM »
I'm trying to figure out the size and how many panels I would need based off my numbers in post third from top. I have a shed and patio with a roof that would be perfect if they would all fit. I would then need to dig a ditch to get wiring to house. I had plans for a ditch anyway to run power and maybe water out to shed and patio anyway.

SwordGuy

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Re: DIY Solar
« Reply #14 on: March 11, 2018, 02:49:29 PM »
I'm trying to figure out what size system we would need.

I can tell from my utility bill how many KWH we use in a month.  From that I can figure out an average and peak load I need to support. 

Just to make the math easy, let's say my average monthly usage is 1000kwh and thus I use 12,000kwh per year.  Let's pretend my peak monthly usage is 2000kwh.

Here's the part I can't figure out.   I see a kit advertised as a 4000kwh kit.   What does that mean?
Does that mean that it produces 4kwh per month?   Or per year?

It clearly makes a difference because with one I've got twice what I need for peak capacity and with the other, I'm only producing 1/3 what I need per month on average.

It's such a simple thing but rather important...

Thanks in advance!
« Last Edit: March 11, 2018, 03:24:18 PM by SwordGuy »

Livethedream

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Re: DIY Solar
« Reply #15 on: March 11, 2018, 08:41:13 PM »
Forgetting the AC/DC conversion and loss here how it works.

System from wholesale solar: https://www.wholesalesolar.com/1894824/wholesale-solar/complete-systems/solar-sky-7.56-kw-grid-tied-solar-system-with-sma-and-24x-ja-solar-315-panels

(24) 315w panels for 7.56kw (that’s your peak hourly production) They estimate this system will average 1,050kwh a month.

Everything will depend on your location, panel angle, shade, temperature, and weather.

This website is helpful in figuring out calculations oases on these factors. http://pvwatts.nrel.gov/index.php

All utility companies manage the excess solar you produce differently, you will need to find out how yours works. Mine is based on a 12 month cycle. If I produce 1,000 in a month and only use 500, it stays with me for the 12 month period Incase there are months I use more power then I produce. If I have produced more power then I have used, I get paid wholesale rate of like 5 cents a kWh and they write me a check.

So to answer your question, a 4000kw kit would be having a system of say (16) 250w panels and your peak hourly production would be 4000kw (4kwh). So maybe it would produce 600kwh a month.


I ended up around $1watt in California with only the federal incentive.

SwordGuy

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Re: DIY Solar
« Reply #16 on: March 11, 2018, 10:26:56 PM »
Thanks!   I'm going to work thru what I now understand based on the example in my question.

If I understand this, that kit would cost ~$9000 * 0.70 (us fed tax credit) or $6300.
On average it would produce (depending on shade, etc. etc.) ~1050kwh per month.

On an average month, that would cover all my electrical usage, which at our prices would be about $100.  I would still have to pay all the fees just to have basic service. 

On peak usage months with 2000kwh usage, I would produce about $100 worth of electricity and pay for another $100, plus the fees for basic service.

On below average usage months (for example, 750kwh), I would run a surplus of 250kwh, which I could sell later to the utility company.  Those sale terms and conditions can vary dramatically.

I recall from reading about this before that some utilities charge you on this formula :Usage - production = surplus or deficit.   They would buy the surplus at the wholesale price and sell the deficit at the retail price.  That's the best deal available.

Others charge you full usage * retail price and subtract production * wholesale price.   That sucks for consumers and is great for utilities.

Did I get that right?

Livethedream

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Re: DIY Solar
« Reply #17 on: March 11, 2018, 11:32:43 PM »
That pretty much sums it up.

For ours, PGE we pay $10 connection fee each month.

I’ll use small numbers to make this easy

Jan prod 10 use 25
Feb prod 15 use 10
Mar prod 25 use 10

“End of 1 year cycle” would be -15 +5 +15: 5kwh surplus I would be paid.

Jan prod 10 use 30
Feb prod 10 use 25
Mar prod 10 use 40.

“End of 1 year cycle” would have used more would owe them.

I get credit for my extra production at retail value, it only drops to wholesale if I produce more at end of year. So if I have 100 extra kWh one month @ 22 cents I would cary a $22 credit forward. If i ended the year that $22 credit turns into (100kwh x 5 cents) $5 this incentivizs people to size their system correctly and makes over production not worth it.

I am grandfatherd in for 20 years as PGE has switched the program I’m on to one less beneficial to all new solar customers. I got in at the right time, paying $10 a month to be tied into their system is crazy cheap and the reason they have now changed new solar. They realized they were leaving too much $$ on the table

b4u2

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Re: DIY Solar
« Reply #18 on: March 12, 2018, 05:51:09 AM »
So even in Iowa the above system would work for me. Our average bill is $130 a month and average use is 1,055KW.
I don't know what the connection fee is here for Alliant Energy but say it's $30 a month we would "save $100 a month. Payback would be roughly 5.25 years.

Is this still a viable option? I see us being in this house for at least that long. I'll need to dig a little deeper into the numbers and also see if all the panels would fit on my shed roof.

Cadman

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Re: DIY Solar
« Reply #19 on: March 12, 2018, 01:35:47 PM »
To the IA peeps, we went online mid-year 2016 with a DIY 10kw system, cost was just a little over $1/watt after the tax credits. From my research, MidAmerican and Reliant  may actually have some incentives/energy rebates which our local PoCo did not.

If you live within an area that has code compliance oversight, you'll either have to pay an electrician for part/all of the install, or work out some sort of inspection agreement with them. The exception is if you're considered a farm.

Also, if you're considering a roof-top install, think about the pitch. The cold temps and sunny winter days are ideal for power generation, but not if you've got a foot of snow on those panels.

Some pics and a write up here: http://www.linearlook.com/solar/solar.html


trollwithamustache

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Re: DIY Solar
« Reply #20 on: March 22, 2018, 09:10:58 AM »
so... buying panels for *value* is really really hard.

PV Panels degrade over time. All of them. A lot of your cheapo panels can go at 5% a year, while a good one might only be 2%... so 4 to 5 years out there can be a huge gap in performance. This is my many of your American and European panels are worth the dollar premium to the cheapest of the cheap Chinese panels.

Between cleaning and weather, the average home user won't see any measurable degradation in the first year or two and by year 3 has really lost interest in tracking the data close enough to see it. But its there and all the legit Utility size PV plant developers track various manufactures degradation rates.



Livethedream

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Re: DIY Solar
« Reply #21 on: March 23, 2018, 07:35:59 PM »
so... buying panels for *value* is really really hard.

PV Panels degrade over time. All of them. A lot of your cheapo panels can go at 5% a year, while a good one might only be 2%... so 4 to 5 years out there can be a huge gap in performance. This is my many of your American and European panels are worth the dollar premium to the cheapest of the cheap Chinese panels.

Between cleaning and weather, the average home user won't see any measurable degradation in the first year or two and by year 3 has really lost interest in tracking the data close enough to see it. But its there and all the legit Utility size PV plant developers track various manufactures degradation rates.


Don’t know where you are getting that info from. I have Low/mid grade panels and I am less then 1% a year. 83.89% at 25 years is a great deal.


The linear warranty guarantees power generated will not decrease more than 0.7% per year from its nameplate. This guarantees that each module will produce at least 83.89% of its nameplate power after 25 years. On top of this SolarWorld offers a 20-year product warranty.

trollwithamustache

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Re: DIY Solar
« Reply #22 on: March 25, 2018, 06:07:33 PM »
so... buying panels for *value* is really really hard.

PV Panels degrade over time. All of them. A lot of your cheapo panels can go at 5% a year, while a good one might only be 2%... so 4 to 5 years out there can be a huge gap in performance. This is my many of your American and European panels are worth the dollar premium to the cheapest of the cheap Chinese panels.

Between cleaning and weather, the average home user won't see any measurable degradation in the first year or two and by year 3 has really lost interest in tracking the data close enough to see it. But its there and all the legit Utility size PV plant developers track various manufactures degradation rates.


Don’t know where you are getting that info from. I have Low/mid grade panels and I am less then 1% a year. 83.89% at 25 years is a great deal.


The linear warranty guarantees power generated will not decrease more than 0.7% per year from its nameplate. This guarantees that each module will produce at least 83.89% of its nameplate power after 25 years. On top of this SolarWorld offers a 20-year product warranty.

Solar World is an American made panel, so you do not have a low end panel, and I don't see any other warranty offers as good from my limited perusing of the residential side of solar.   Its worth noting without a reasonably high accuracy measurement of solar irradiation, you don't really know how your panels are performing.  That solar world offer appears to be a much better product than one might get from all the roofers turned PV installers that are out there now days.

Livethedream

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Re: DIY Solar
« Reply #23 on: March 25, 2018, 10:46:04 PM »
so... buying panels for *value* is really really hard.

PV Panels degrade over time. All of them. A lot of your cheapo panels can go at 5% a year, while a good one might only be 2%... so 4 to 5 years out there can be a huge gap in performance. This is my many of your American and European panels are worth the dollar premium to the cheapest of the cheap Chinese panels.

Between cleaning and weather, the average home user won't see any measurable degradation in the first year or two and by year 3 has really lost interest in tracking the data close enough to see it. But its there and all the legit Utility size PV plant developers track various manufactures degradation rates.


Don’t know where you are getting that info from. I have Low/mid grade panels and I am less then 1% a year. 83.89% at 25 years is a great deal.


The linear warranty guarantees power generated will not decrease more than 0.7% per year from its nameplate. This guarantees that each module will produce at least 83.89% of its nameplate power after 25 years. On top of this SolarWorld offers a 20-year product warranty.

Solar World is an American made panel, so you do not have a low end panel, and I don't see any other warranty offers as good from my limited perusing of the residential side of solar.   Its worth noting without a reasonably high accuracy measurement of solar irradiation, you don't really know how your panels are performing.  That solar world offer appears to be a much better product than one might get from all the roofers turned PV installers that are out there now days.

Agree, that is true. The version of panels I have are actually China. 320w panels for $218 before 30%, so $153. Get in before all these tariffs are going to raise prices if your still looking.

b4u2

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Re: DIY Solar
« Reply #24 on: March 28, 2018, 05:18:40 AM »
I did some rough measurements on my shed in the backyard. On the side facing the sun I could install most of the panels. Then I could install the rest on the roof of my house? Not sure how a split set up like that would work. I was hoping I could keep it simple and avoid the roof of the house but they just won't all fit.