Home Solar

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#1
Has anyone else been looking into this? My house consumes a fairly large amount of electricity, and I've been considering it for years. Finally decided to call Solar City and get a quote (they start with a preliminary over the phone, my at-home estimate is on the 27th).

Based on past usage, I'm looking for a system that can generate ~1mWh/month. Using this neat calculator, I started pricing the hardware for a system using 20x 300-watt panels @ ~$11k. I'm aware that installation and permitting will be significant additional costs, but the preliminary quote from Solar City was for a system 60% this size and $26k. Unless they can get that under control it looks like I'll be bringing in my own roofer, electrician, and construction crews in.
 

Howell

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#2
10 years ago I had priced out a system at about that cost for parts. But the electric rates here are so cheap that the ROI for just the installation with no usage subtracted was so far into the future that it made more sense to wait for better technology.
 

Stereodude

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#3
... but the preliminary quote from Solar City was for a system 60% this size and $26k. Unless they can get that under control it looks like I'll be bringing in my own roofer, electrician, and construction crews in.
That's because a large part of the whole "green" energy thing is a quasi scam setup to fleece the well off who want to show off to everyone else that they're being "green".
 
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#4
Signaling theory and the Prius

Moved up the Solar City in-home to 30 minutes from now. The more research I do, the more likely I am to do the install with my usual local contractors and me running the project.

Main reason for the timing is that I'm under the impression that the market will be under-performing for the next couple years and I can probably get a better return doing this.
 

DrunkenBastard

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#5
How will you get around the problem where a grid connected array has to disconnect from the grid if the grid goes down? Have a relay to disconnect from the grid feed and just feed the house load or battery bank? Or just shutdown the inverter and run off batteries for the duration of the outage?
 
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#6
I'll just leave the whole system off. No batteries connected at all. I already have a UPS for all the important stuff. Code only requires that a manual shutoff switch be located adjacent to the main electrical panel and labeled clearly.
 
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#8
If grid connected, you also need to coordinate with and meet the connection requirements of the utility. They can be rather exacting and onerous.
PG&E has made it really easy provided you are supplying less than 40kW and that the amount you are supplying is <15% of the total capacity of your service (up to 7.2kW in my case, which I will be right at).

Two basic rules:
1. Use an Inverter that is approved by them (most of the ones for sale around here are on their list)
2. Have an AC disconnect switch <10ft from the meter and within line of sight

Here is the root of their Distributed Interconnect Handbook if anyone wants some light reading.
 
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#9
After starting the permitting process a bit on my own, I ended up having Solar City do it after all. I did get them to up the capacity to what I was after and drop the price a bit, but I won't see those savings until next year. Even without the fed and state tax benefits my usage is so high that break-even will be in 6.5 years. If I manage to get all the breaks and rebates I'm expecting it will bring that down to ~5 years.

On the permitting front, the building permit wasn't the issue, it was my power company and their process that made it near-impossible.
 
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#13
It really depends on how much space you have.

With the current cost of panels (so low), it is rare for tracking mounts to be more effective than more panels. Mine are arranged on two different planes that combined offer some generation all day. Same with the high-efficiency panels, I ended up spending more just because I ran out of roof space. If I had room for more panels I could have dropped the efficiency and saved some cash.
 
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#16
Wouldn't it be cheaper to reduce your consumption a bit instead? Efficiency is by far the cheapest sort of generation.
Absolutely.

1. Move all energy consumption to electricity (appliances, HVAC, etc)
2. Maximize efficiency of all those systems (LED lighting, heatpump-based water heater, heatpump HVAC, induction cooktop, smart thermostat, etc)
3. Measure energy consumption to size system (optional add for future electric car)
4. Spec system
 

DrunkenBastard

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#19
Aren't you in upstate NY?
Yes, that's why I'm thinking of a ground mount tracker because the sun is low on the horizon during winter months.

Looks like SolarCity panels are at around 22% efficiency and they manufacture them close by in Buffalo.

Some of my high load demand is covered by propane (forced air heat, hot water, drier, stove). Main electrical load is dehumidifier in basement, furnace fan, A/C in summer and then the pcs/laptops/consoles/tvs. Expecting that to increase as I increase gpu folding.
 

Stereodude

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#20
With the current cost of panels (so low), it is rare for tracking mounts to be more effective than more panels. Mine are arranged on two different planes that combined offer some generation all day. Same with the high-efficiency panels, I ended up spending more just because I ran out of roof space. If I had room for more panels I could have dropped the efficiency and saved some cash.
Do you mind sharing what you paid for your 6kW system and what all you got for that money (panels, installation, batteries, charge controller, etc)?
 
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#24
One is actually still down, but thanks for the reminder. And I couldn't get permission to install the 6kW system, so it ended up being much smaller :(

Everything installed
20x 260w panels
1x 3.6kW inverter
1x Wireless network interface
20 year performance warranty and monitoring

$26,520
 

Stereodude

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#25
Permission from whom? Did you get any sort of battery bank?

Edit: Also, you have 5.2kW of panels, but only a 3.6kW inverter? What's the logic there?
 
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#28
Permission from whom? Did you get any sort of battery bank?

Edit: Also, you have 5.2kW of panels, but only a 3.6kW inverter? What's the logic there?
PG&E (our local power company) only allows residential solar to reach 80% of their average consumption (or something like that). Otherwise they won't let it grid-connect.

And you are correct, that is a typo. 6.3kW.

Edit: No battery bank, though that is in the plan for later.
 

Stereodude

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#29
PG&E (our local power company) only allows residential solar to reach 80% of their average consumption (or something like that). Otherwise they won't let it grid-connect.

And you are correct, that is a typo. 6.3kW.
So are the panels and the inverter gold plated or something? For what you got that seems really expensive.
 
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#30
So are the panels and the inverter gold plated or something? For what you got that seems really expensive.
It was about double what the parts alone were at the time. Considering what was involved for permitting (let alone installation), I am entirely happy with the decision. Lawyers were involved over the course of 3 months to get permission to install a system of that size.
 

Stereodude

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#31
It was about double what the parts alone were at the time. Considering what was involved for permitting (let alone installation), I am entirely happy with the decision. Lawyers were involved over the course of 3 months to get permission to install a system of that size.
:scratch: It looks to be about 4x cost of the parts based on my quick research.
 
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#32
Make sure the stuff you are looking at carries the right warranties and that the companies themselves will be around to see it through. There is some shady stuff out there.
 

Stereodude

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#33
If it costs 2x to by something with the "right warranties" you might as well get the cheap one for half the cost. If it breaks you can buy a complete 2nd one, and odds are technology will make the 2nd one cheaper and better by the time it's necessary. I mean what are the odds of having 20 solar panels fail?
 
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Handruin

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#34
It was about double what the parts alone were at the time. Considering what was involved for permitting (let alone installation), I am entirely happy with the decision. Lawyers were involved over the course of 3 months to get permission to install a system of that size.
That's a bummer. I remember that you were trying to increase your average so that you could build out the panels to meet your own power requirements. What are their reasonings for not letting the home consumer purchase more panels than 80% of their average? Is it that the power companies don't want to pay you for power generation?
 
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#35
That's a bummer. I remember that you were trying to increase your average so that you could build out the panels to meet your own power requirements. What are their reasonings for not letting the home consumer purchase more panels than 80% of their average? Is it that the power companies don't want to pay you for power generation?
Unless there is some very technical reason that I haven't found relating to backfeeding the grid significant amounts of power, it is not only obstructionist, but counterproductive. They do have to pay me for excess power I produce, but at a rate so low it must be below their production cost. They should be encouraging it.
 
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#36
If it costs 2x to by something with the "right warranties" you might as well get the cheap one for half the cost. If it breaks you can buy a complete 2nd one, and odds are technology will make the 2nd one cheaper and better by the time it's necessary. I mean what are the odds of having 20 solar panels fail?
Fail doesn't seem to be the issue. Efficiency falling to a fraction of initial in a few years seems to be the common one, and even 2x savings wouldn't be enough in that case.
 

mubs

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#37
Fail doesn't seem to be the issue. Efficiency falling to a fraction of initial in a few years seems to be the common one, and even 2x savings wouldn't be enough in that case.
This seems to be happening everywhere, especially with Chinese made panels that they are flooding the market with.
 

Stereodude

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#38
This seems to be happening everywhere, especially with Chinese made panels that they are flooding the market with.
Just buy a Chinese panel with US made Sunpower cells. That should solve the problem, unless they've made knockoff Sunpower cells. The would be difficult as I understand it since most cell makers can't hit the efficiency Sunpower has.
 
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