So what is your average daily kw consumption from PSE? Or total monthly kw consumption?My monthly power bill averages $300 so the contractor based the 32 kw off that with bout 104% offset. As far as what I want to accomplish. I don't want to be dependant on puget sound energySo perhaps I could go with a smaller system and battery backup.
ground mount installation questions
- Thread starter DocDCS
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Sometimes you also have to take into account other factors. I'm on a dead end road and only one who lives on the road full time. They recently came through and used tracked skid steer with one of those stump type eaters on front to shred large number of trees anywhere near the power lines. Made huge mess and drastically altered look. I was standing at property line making sure he didn't come through my property since I'll be making full effort this year to completely disconnect the grid before they insist on cutting large number of tree on my place.
Hedges
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$300/month x 12 months/year = $3600/year
$122,400 / $3600 = 34 years to break-even (as Texas-Mark said) (ignoring interest or time/value of money, rate increases, broken equipment.)
Any questions?
Tell us your annual kWh usage and we might be able to right-size it for you.
$4/W is not unreasonable for grid tie + battery backup PV system including installation.
But size and type of battery is key to cost. And for operating with grid down, battery inverter surge and continuous rating is important.
DocDCS
New Member
annual this last year was 34,774 KWh
Hedges
I See Electromagnetic Fields!
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I forget if you gave us location; check an insolation calculator. Using my San Jose figures:
34,774 / 365 days / 5 hours = 19kW grid-tie system with net metering should supply annual usage.
About 25kW (STC) rated panels.
(If someone was off grid, would need to consider peak winter and summer consumption.)
The quotes you got for 80kW of panels seem 3x oversize. At those prices, if you actually get paid 0.20, you make money. But if only credits no cash, the excessive size returns nothing.
Given cheap kWh from PV vs. moderately expensive from grid, good to oversize a bit. Like 30kW or so panels. More if you anticipate increased consumption.
If the quote scales downwards, and I haven't screwed up the math (ask for vendor's calculations), this could reduce it to pocket change. The price of a used car.
34,774 / 365 days / 5 hours = 19kW grid-tie system with net metering should supply annual usage.
About 25kW (STC) rated panels.
(If someone was off grid, would need to consider peak winter and summer consumption.)
The quotes you got for 80kW of panels seem 3x oversize. At those prices, if you actually get paid 0.20, you make money. But if only credits no cash, the excessive size returns nothing.
Given cheap kWh from PV vs. moderately expensive from grid, good to oversize a bit. Like 30kW or so panels. More if you anticipate increased consumption.
If the quote scales downwards, and I haven't screwed up the math (ask for vendor's calculations), this could reduce it to pocket change. The price of a used car.
Zwy
Emperor Of Solar
If your total bill averages $300/month and you are using 35Kwh per year, I'd stay on the grid. That is less than $0.10Kwh. That would be extremely hard to beat with any solar system.
You can build a UPS system for grid down type situations where you have backup power. You can use this UPS system daily for load reduction to get the money back it cost you. Just a few panels, a LFP battery, SCC/inverter and a critical loads panel.
Zwy
Emperor Of Solar
It appears he is around the Puget Sound. Nice dreary, rainy weather pattern. I can see why the installers quote that large of a system now.
shadowmaker
Solar Addict
Today it snowed/rained the whole day and it was impossible to see where the sun is. Visibility was ~500m. My friend has a 50kWp conventional south oriented system on his barn roof with no shadows. He is located some 10km away from me, but the weather was kind of the same there. He collected 10,3kWh today (no previous snow accumulation on those panels and today snow was really heavy/wet). My vertical system (44kWp) made 43kWh. I expected something like this, but never even dreamed this big of a difference... But then four times per nothing is still nothing.
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DocDCS
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cs1234
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Zwy
Emperor Of Solar
It's best to determine what you want to run in a grid down situation and perform an energy audit to determine how much power will be needed to run those items for the length of time you think the grid may be down. One advantage of a UPS system is you can recharge the batteries with a generator (if you have poor sun) fairly quickly using LFP which allows only running a generator for short periods without an absorption period like lead acid chemistry. You wouldn't need an extremely large bank, just one that will run what you need for a specified time such as 2 days and could possibly be recharged each day you have good sun off panels.
First step determine what you want to run in grid down, obtain a Killowatt meter or similar device so you can measure what each one of those items will require for power during the time frame you want backup power. Add up the power needed for all your devices for that length of time, then design the system around that. Number of panels/array size will come after you know what your power needs are and how much yield can be achieved for your area.
OH shit, now you did it. @timselectric will be busy now!
Zwy
Emperor Of Solar
timselectric
If I can do it, you can do it.
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Oh, I've been eyeballing the hillside for quite a while. lol
scoharri
New Member
Not at all. If possible, go off grid all the way.
So, Pohjanmaa, Keski-Suomi, Savo or Pohjois-Karjala? Just trying to figure out how far you are from me and if we should meet up for coffee some time
timselectric
If I can do it, you can do it.
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Getting
Personal......
Up north
Personal......
Up north
I think part of what’s happening is that vendors and lenders are hijacking the tax credit, basically marking up pricing by 30%, and in addition are capitalizing on the en vogue greenwashing trend towards electrifying everything and getting “off-grid”. Everybody wants to plug in their Tesla and reverse charges on their utility.
So, consumers are paying a double premium, both of which can be avoided to some extent by DIY. The competitive nature of the online equipment vendor marketplace tends to depress pricing somewhat, but both premium drivers apply there as well to a lesser extent.
So, consumers are paying a double premium, both of which can be avoided to some extent by DIY. The competitive nature of the online equipment vendor marketplace tends to depress pricing somewhat, but both premium drivers apply there as well to a lesser extent.
shadowmaker
Solar Addict
You have mail.So, Pohjanmaa, Keski-Suomi, Savo or Pohjois-Karjala? Just trying to figure out how far you are from me and if we should meet up for coffee some time
Hedges
I See Electromagnetic Fields!
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To the contrary, if net metering is available, that could make tying into grid worthwhile.
The reason not to tie into grid would be if cost to do so (plus electric charges) exceeds cost to go off grid.
If 1:1 net metering is available, the grid provides "battery" storage at lower cost than a battery, greater (100%) efficiency, unlimited capacity, zero self-discharge (except maybe for an annual true-up when balance is erased.)
Even if not "net", rather only giving a credit 1/3 of retail so you have to put in 3 kWh to get 1 kWh back, that is still a better deal than buying batteries. For the price of battery storage giving say 10 MWh lifetime cycling capability, you can buy additional PV panels and grid-tie inverters producing 20 MWh over 20 years. And they should last twice that long (the panels; might replace GT PV inverter at that point.)
Once you've put in a PV system with power output 3x your usage, even on cloudy days they'll often produce all you use. A small storage battery can be kept full all day long as loads are powered PV direct. I have 10kW+ (overpaneled) PV system and a battery with 14kWh usable capacity which can run A/C during the day if grid is down. When I built it, PV panels cost $5/W, but today $0.50/W or even less used, so you can way over-panel.
